Searching for answers on loss of leg coordination while running: a comprehensive review

Because medical and scientific literature on this problem is scant, much of what follows is based on reports from runners with loss of leg coordination and logical inferences from what's known about how the body works it is running correctly.  Because of this, you should view everything I have to say below with skepticism, especially because I'm not an unbiased writer (having suffered from this problem for quite a while before recovering). 

I told myself I would write this article when I was able to run 50 miles per week again with some faster running.  That point came and went a long time ago—it was far easier to get distracted by my own running again, but it's long past time I write this article.

The working definition of loss of leg coordination is something that I've come up with by analyzing as many descriptions of the problem as I can find.  Much, though not all, comes from posts on the LetsRun.com thread. 

Put in its most universal terms, "loss of leg coordination while running" is characterized by a gradually increasing sensation of tightness, weakness, and poor coordination in the muscles of one leg, but only while running—stopping to walk or stand still lessens the symptoms.  There isn't pain, per se, just tightness, vague aching, and an overwhelming sense of something being off.  And the sensation of losing coordination isn't localized to any precise area; rather, it is associated with a more general feeling of your leg not doing what you want it to do.  It feels like your stride is just "off," like your leg just won't go.  Instead, it flops along uselessly. 

Further, these symptoms seem highly specific to running.  Other activities, even cyclical and highly aerobically demanding ones like using an elliptical or riding a bike, do not reliably recreate the symptoms.   The loss of coordination sensation is typically localized to the muscles which are the prime movers of the legs: the calves, the hamstrings, the quads, the calves, and the glutes.  Some people find that the tightness and poor coordination progress from one muscle group to another as the problem worsens, but there isn't any distinct pattern to this.  Some posters find that their problems start in their feet or ankles and progress upwards, while others have issues in the thigh and calf only.  Though these muscles feel weak and uncoordinated when you run, you can head into the weight room and do just as much weight on hamstring curls, leg extensions, and single-leg squats on your "bad" leg as you can on your good one, so there is no frank loss of muscular strength.  Though this initial wave of symptoms might sound similar to a nerve problem like sciatica, there is not usually any numbness, shooting pains, or "pins and needles" feelings like you would expect with a nerve problem. 

Certain running conditions also exacerbate the problem.  Running faster magnifies the degree to which coordination in the leg is lost, with high speeds resulting in the leg seeming to flop around uselessly, while the opposite leg (the healthy one) picking up the slack.  Puzzlingly, flat, even surfaces like tracks, roads, and treadmills bring on symptoms to a much greater degree than uneven terrain like trails or grassy cross country courses.  Some runners describe being able to complete very long and challenging runs or workouts without any problem on rough terrain, but being completely unable to run any faster than a slow, easy pace on flat surfaces.  Other runners are able to run at an easy pace, but cannot complete any workouts involving faster running.  Some experienced problems at virtually any pace, though faster running on flat surfaces certainly magnified the issue.  Stopping makes the loss of coordination sensation go away almost immediately, but some lower leg muscular tightness or "off-ness" can persist for days after a particularly bad episode, even if you aren't running on the following days.

Further complicating the diagnostic puzzle is the fact that continuing to train with loss of leg coordination often causes a slew of secondary injuries because of the abrupt change in stress on the body.  Several runners reported foot, knee, and hip injuries that occurred concurrently.  In my case, I suffered a sacral stress fracture.  The people with this problem also have the usual smattering of Achilles, plantar fascia, knee, and shin issues that are common in regular runners. 

Add on top of that all numerous health-related idiosyncrasies ("I get tingling sensations in my left elbow," "If I flex my hamstring on my bad leg for a while, it cramps up," "I tore my hamstring playing hockey when I was 12 and have a lot of scar tissue"), plus the rarity of the problem, and you've got an incredibly difficult to diagnose issue.  It's not even clear that all or even most of the people posting about this issue online even have the same problem. 

Doctors, physical therapists, chiropractors, and any number of other medical professionals seem unable to pin down the problem.  Some of the posters report seeing dozens of different doctors and spent thousands of dollars yet coming back empty-handed.  MRIs, nerve conduction studies, and other diagnostic tests either come back clean or identify fairly common issues that are often asymptomatic, like a herniated lumbar spine disc.  Runners report that physical therapists and chiropractors inevitably find muscular weakness or tightness, often in the hip muscles and hamstrings, but they report that their rehab exercises have, at best, very limited and short-term success.

I conducted a survey via email with several runners from the LetsRun thread, along with others who had self-reported loss of leg coordination, to get a better understanding of the problem.  The respondents filled out a two-page survey asking about their history with this issue.  The survey itself is presented in Appendix C.  The data from the sixteen respondents (one being me) who had clearly-identifiable loss of leg coordination, as defined in this article, gives a clearer picture of who gets loss of leg coordination—or at least, who winds up reading a thread on LetsRun about it. 

The working definition is as follows:

Loss of leg coordination while running is a sensation of aching, tightness, soreness, or  weakness in the leg, always accompanied by a feeling of loss of coordination in the muscles of the leg that occurs only or mainly during running and without burning, numbness, tingling, localized pain, or obvious muscular weakness in daily life, all of which cannot be easily and completely ascribed to any conventional injury diagnosis.

The age of onset of loss of leg coordination ranged from 16 to 49 years of age (mean 26.6 years, median 22).  In most cases, the runners have had the problem from one to ten years, though one respondent indicated she had been dealing with it for eighteen years.  Mean duration was 5.4 years; median was four.

Of the sixteen respondents,  five were female.  Loss of leg coordination appears to show no bias towards a particular leg; eight right legs and six left legs were affected (two reported both legs affected to differing extents).    The runners who suffer from this problem range from high school & college runners to middle-aged runners, but all appear to log relatively high mileage and aim to compete at a high level.

It is not clear to what extent this is a reflection of potential causal factors—these criteria describe a substantial proportion of the demographic that visits LetsRun.com and running websites in general (relatively young, high mileage, interested in competitive racing). 

Unfortunately, the LetsRun thread (or any of the other internet discussions of this problem) offers relatively little in the way of useful information.  Rather, it is a case study of the problems with seeking out medical information on an anonymous message board. 

First, there is no guarantee that the individual posters even have the same problem—since a great many things could lead to a "loss of coordination" sensation while running, this topic attracts comments from runners who claim to have had everything from herniated discs to multiple sclerosis.  Readers project their own specific symptoms onto what they read online, which makes sorting out the comments a mess. 

Second, because of the anonymous nature of the message boards, there are all sorts of self-appointed experts who claim that they have the answer to the runners with loss of leg coordination.  This isn't unique to this injury, but because there's a complete lack of medical authority on this problem, the understandably frustrated runners with loss of leg coordination (including myself) are vulnerable to the type of proselytizing that is all too common in these sorts of situations.  Everyone wants to believe that there is an easy solution to this problem, and the power of belief is deceptively strong—at least in the short term.  Some people seem to get addicted to the kind of temporary power that comes from claiming to know all the answers.

The alleged "solutions" to the problem range from logical (poor hip abductor strength limiting your leg control) to odd (your hips are off because you ran too many intervals counter-clockwise on the track, so to fix it you must go to the track and run laps clockwise) to the truly absurd (the radiation from your cell phone in your pocket damaged your sciatic nerve).  Reading back through the thread is a painful exercise.  Every few weeks, someone comes along, either a newcomer with a grand solution, or a recurrent poster who's sure he or she has really got it figured out this time, and drums up the promise of the new treatment or cause, whether it's an accessory navicular or a new strengthening exercise or a shoe modification.  A few weeks later, the poster or those who tried out the new fix sheepishly return and admit it wasn't the solution to the problem after all.  The emotional vulnerability of dedicated runners who have lost their ability to do what they love only magnifies this issue.

On top of this, there is very little incentive to keep posting for people who have been "fixed" and are able to run again—of which there are at least a few.  Even after I'd been running healthy for months, I found myself avoiding the thread when I saw it crop up from time to time.  It's not easy to relive those memories.  Meanwhile, the people who continue to have problems commiserate on how hopeless the situation seems.

So, to redress these issues, what follows is a thorough, methodical analysis of the possible causes and treatments for loss of leg coordination.

In this article, the terms "loss of leg coordination" and "loss of coordination in leg while running" refer strictly to the following cluster of symptoms: a unilateral sensation of aching, tightness, soreness, or weakness, always accompanied by a feeling of loss of coordination in the muscles of the leg that is exclusive to running and cannot be easily and completely ascribed to any conventional diagnosis.  This sensation is present without sharp and specific musculoskeletal pain (concurrent musculoskeletal injuries notwithstanding, e.g. a muscle strain or stress fracture caused by compensation); numbness or pins and needles; or notable muscular weakness in the affected leg during general activities (e.g. lifting weights).

As noted above, the medical literature is severely lacking when it comes to this type of loss of leg coordination in runners.  As such, we'll have to approach the problem by inference, determining which of the body's systems could be at fault.

The best place to start is with a model of what goes right when your body is running normally. 

Running starts not in the legs, but in the brain.  Stored somewhere in your brain is a set of instructions on how to run.  You can picture it saying something like "move left leg forward, move right leg forward," but of course it is a lot more complicated than that.  There are hundreds of muscles in your body, and a high percentage of them are involved in some manner in running.  Your brain stores these instructions somewhere, probably in the same place that it stores other muscular skills like how to throw a ball or ride a bike—even though running is a much more natural and instinctive motion than riding a bike, you still can't do it right away when you're born; you need to learn how to do it. 

When you command your body to run, your brain circuitry accesses this stored information and sends the appropriate muscular commands to your legs.  It's important to note that the mental image of running in your brain isn't permanent and unchanging. The way you run is refined over time, as you get more efficient, stronger, or more explosive.  It also changes dynamically based on the situation you're in.  You run substantially differently on a muddy field than you do on a flat sidewalk.  Though some of this adjustment comes from feedback from your legs (we'll get to this in a bit), a portion of it comes from stored information as well. 

If you're running along a sidewalk that dead-ends at a grass football field and you continue to run, your brain will adjust your leg stiffness after your final step on the concrete and before your first step onto the grass using information stored in your brain about the perceived and anticipated stiffness and surface characteristics of what you're about to land on.¹ 

Some portion of the running stride may also come from an automatic response in the spinal cord.  This phenomenon is not fully understood, but when you put people with a severed spinal cord on a treadmill with their body weight supported, their legs will automatically complete parts of the gait cycle when motion is initiated by a therapist.  They are still, of course, unable to walk on their own, but this provides evidence that at least some basic movement patterns are stored in the spinal column, not in the brain.  Whether this extends to running is not clear.² 

To actually initiate leg movement, your brain fires electrical signals along the nerves that run down your spinal cord and ultimately to each of your muscles.  Many of the relevant nerves that connect to the major muscles involved in running exit the spinal cord at the last few vertebrae of the lower back and the sacrum, then fan out into the different muscles of the leg. 

Once an electrical impulse from the nervous system reaches a muscle, a chain of chemical reactions is set in motion, causing the muscle's fibers to "fire" and contract, which creates motion.  

While all of the above steps are happening, there is another neural system dedicated to evaluating motion and sending feedback to your brain on your body's position in space. The five-dollar word for this is "proprioception," and it involves nerve endings in your skin, muscles, joints, and probably a lot of other places too. 

Proprioceptive feedback explains a lot of interesting phenomena in sports medicine studies, like why it's sometimes easier to balance barefoot on a rough surface than on a smooth one and why "placebo" knee taping appears to be just as helpful a tightly-applied patellar strapping.^{3, 4}   More relevant to our interests, it is the brain's primary mechanism to determine whether or not the body is doing what it's supposed to do.  If you try to trick people by telling them they are walking in super-cushioned shoes when they're actually wearing a very hard-soled shoe, their brain initially calculates walking (or running) gait based on the "soft shoes" assumption, i.e. using stored information about how to run on a soft surface.  But after only a few steps, proprioceptive feedback from the body makes it obvious that the brain needs to change its conception of how to walk under these particular conditions.⁵  As a result, the brain adjusts muscular tension and leg tightness, and gait normalizes. 

When you run, all of this is happening in a split second.  Each step you take involves a set of commands being drawn up by the brain, fired down the nerves and executed nearly perfectly by the muscles, and proprioceptive feedback being gathered and sent back to the brain, where it is evaluated and any necessary adjustments (like allowing your knee to buckle to avoid an ankle sprain) are made.  Given the complexity and precision necessary for such a task, it's incredible that things go right as often as they do!

Now that we have a rudimentary understanding of how things work when the body is running properly, we'll use this as a framework to evaluate what types of things could be going wrong in the case of loss of leg coordination while running.  We'll start at the end of that chain of events and work our way back.  Understanding what might be going wrong will give us a system to categorize the numerous proposed causes of loss of leg coordination, which will be evaluated subsequently.

At the final step, evaluation of motion, there could be some impediment to the body's ability to sense what is going on in the leg.  Without appropriate and correct feedback coming from the muscles and joints, the brain won't be able to get an accurate picture of how the leg is responding to commands; this could plausibly cause a mismatch between intended leg motion and actual leg motion and hence a loss of coordination.  This sort of situation is familiar to most people, at least fleetingly, in the "phantom stair" problem: when you're walking up a staircase but are unable to see the stairs, you often anticipate another step, but instead clomp your leg down awkwardly onto the floor, realizing too late that the step is not there.

This is fairly theoretical, but given the rarity and oddity of loss of leg coordination—which has reportedly baffled some of the best orthopedists and physical therapists in the country—it is prudent to leave no stone unturned.

What type of condition could cause damage or interference with the body's proprioceptive feedback mechanisms? The most obvious would be damage to the mechanoreceptors on the skin—think the deadened sensation on an area of skin you've recently iced— but this should be easily detectable with a monofilament test, and would probably be accompanied by tingling or burning, none of which occurs in loss of leg coordination. 

Another option would be damage or instability inside a joint.  People with labral tears, for example, also display worse single-leg balance on their injured side when compared to their healthy side.⁶  This too would impair the brain's ability to sense the position of the leg as it swings through the stride.  The central role of the hip in the running stride, coupled with the apparent centrality of the hip joint in many leg coordination problems (excessive external rotation of the leg, inability to properly flex or extend the hip joint, or abnormal adduction of the leg during the swing phase of the stride) make this a potentially promising candidate.  We'll revisit the topic of labral tears later.

The vast majority of the alleged causes of loss of leg coordination while running have to do with the penultimate stage of running: how your muscles actually respond to the signals being sent from your brain.  In a vacuum, it seems fairly simple: any muscular weakness, tightness, joint misalignment, or structural flaw in the body could create a situation where the muscles and joints are incapable of properly executing the commands sent to them by the central nervous system. 

The broad nature of loss of leg coordination provides physical therapists, chiropractors, osteopaths, and orthopedists with a veritable field day for testing out their biomechanics knowledge.  This has led to many runners with loss of leg coordination being told they have a leg length discrepancy, pelvic tilt, hyperpronation, weak hips, tight hips, poor flexibility, and so on. 

These theories can be divided into two categories: muscular issues and structural issues. 

A muscular issue might be something like an imbalance between the strength of the hamstrings and the quadriceps, or poor gluteus medius strength on both sides.  It could also be excessive tightness or scar tissue built up in a muscle which is impeding that muscle's proper functioning.

A structural problem is something that is intrinsically connected to your anatomy—a true leg-length discrepancy or a misshapen femoral head are two examples of structural abnormalities that could theoretically contribute to an inability to properly execute muscular commands.

To be clear, this distinction isn't black and white.  Poor ankle joint range-of-motion, for instance, could be the result of muscular tightness in the calves, the structure of the ligaments surrounding the joint, or the basic anatomy of the tibia and the talus.

With regards to muscular strength and flexibility, several of the runners in the loss of coordination thread on LetsRun report that doctors or PTs find their hip strength lacking, a finding which should not be surprising given that poor hip strength is connected with several distinct injuries as well as injury incidence overall in runners.^{7, 8, 9}  The two other findings that appear to be fairly common are tight hip flexor muscles and  tight or weak hamstrings. 

It is notable that (with one exception) the few individuals in the thread who claimed to have made a full recovery did so in part by following rehab programs that involved some combination of hip abductor and external rotator strength, hamstring flexibility, and hamstring strength.  At the same time, many runners claimed to have followed a huge range of strength routines without making any measurable progress.

I spend a good bit of my time reading biomechanics research, and as far as I know, there is no cohesive, scientifically validated model of what constitutes "proper" biomechanics in a runner.  That's not to say such a model doesn't exist; merely, it means that the biomechanical theories given to you by a doctor, physical therapist, or random loony on an internet thread are just personal opinions, rooted (to some degree, hopefully) in that individual's view of biomechanics and injury.  When held up to scientific scrutiny, many of these theories fall flat—take, for example, the paradigms of "pelvic tilt" and its effects on posture, or static limb alignment and its effects on injury rates.^{10, 11} This is not to say that they will always fail to produce a good outcome, just that they are incomplete model.

That being said, muscular strength, flexibility, and postural alignment are undoubtedly the first place to start when looking for a treatment for loss of leg coordination, since these are issues that are addressed with relative ease.

A less-often noted aspect of the muscular portion of motion is that muscles need an adequate blood supply to properly execute commands sent by the central nervous system.  A lack of blood supply to a muscle could plausibly lead to poor coordination or similar symptoms mimicking a neurological problem—think of the pins-and-needles sensation and the awkward challenge of moving an arm or a leg that has "fallen asleep" from a temporary lack of blood supply.  Muscular blood supply could be curtailed in two ways: swelling of the muscle compartment (chronic exertional compartment syndrome), which cuts off or drastically slows bloodflow, or constriction of one of the arteries that supplies the muscles of the leg.  Both of these can be detected by diagnostic tests and will be elaborated on later.

The integrity of the nerves that transmit the signals from your brain to your muscles is the first place that many orthopedists and neurologists think to look when they hear the phrase "loss of coordination."  This is probably because poor coordination is a feature of a number of neurological problems, from pinched nerves in the lower back to systematic diseases like multiple sclerosis. 

Notably, however, the phenomenon of loss of coordination in leg while running is not accompanied by other classic neurological symptoms like burning, tingling, electric shock sensations, or numbness.  Additionally, there are some problems with pinning down the problem to a single nerve.  Even the sciatic nerve, an enormous, lengthy nerve that runs from your low back all the way to the bottom of your feet, doesn't innervate all of the muscles in the leg that are associated with loss of leg coordination.   Though the glutes, calves, and hamstrings are indeed innervated by the sciatic nerve, quadriceps fatigue or soreness is a fairly common complaint among runners with loss of leg coordination too, but the quads are innervated by a completely different nerve—the femoral nerve.  Worse, the femoral nerve doesn't even originate at the same level of the lower back as the sciatic nerve! The same is true for the hip flexors.  Arterial supply is inadequate as an explanation in this respect, too.  We'll look more closely at these issues later.

Another potential impediment to proper function of the nerves is a neurological disease like multiple sclerosis.  Some people have suggested that loss of leg coordination represents the early stages of neurological disease.  While plausible (and worrisome), the absence of other symptoms of neurological disease, like pins and needles, numbness, balance problems in daily life, and abnormal nerve conduction responses, casts some doubt on this.  Further, many runners report having loss of leg coordination for many years with no apparent worsening (or improvement) of their symptoms.  The possibility of neurological disease being the cause of loss of leg coordination while running will be discussed in the subsequent section.

Lastly, we're left with problems with the brain's mental image of how to run.  This is the least-considered and also appears, at least initially, as the most dubious of any general consideration about what's going on in loss of leg coordination—how could you forget how to run? The brain is extremely good at "muscle memory," or remembering how to do technical feats involving strong muscular coordination, like riding a bike, hitting a golf ball, or balancing on a skateboard.  These just aren't skills that you "forget" how to do.

But the brain is a very complex organ, and there's some precedent for its circuitry going haywire.  Hand-writers, musicians, and other practitioners of highly complex, fine movements have been known to suffer from focal dystonia, an apparently inexplicable, task-specific loss of fine motor control and a gradual tightening of the muscles related to the task.¹²  Loss of leg coordination while running being the result of a "runner's dystonia" is a very intriguing possibility, one which we'll return to in the following section.

Finally, we've come to a point where we can actually begin to examine and evaluate some of the specific causes of loss of leg coordination that have been proposed.  Because we find ourselves in uncharted waters, it is only due diligence to systematically consider every plausible explanation, reviewing its strengths and weaknesses as a potential cause for loss of leg coordination while running before drawing any conclusions.  I have included all but the most outrageous and preposterous proposed causes.  We will begin with the most commonly-suggested causes and work our way towards the less-discussed ones.  Each cause implies potential solutions, which will be discussed as well, but their efficacy is of course contingent on the proposed cause being the correct one.  Because of this, each proposed cause is accompanied by a verdict offering my opinion on the usefulness of that cause as an explanation for loss of leg coordination.

A muscular problem is usually what physical therapists "see" when examining a runner with loss of leg coordination.  It is what they are trained to do, and runners with the condition doubtless have any number of different muscular problems.  Muscle weakness is known to affect running mechanics—take, for example, the case of IT band syndrome or patellofemoral pain syndrome ("runner's knee"), where poor hip strength and coordination are directly linked to injurious changes in running form.¹³  This theory would also explain why symptoms seem to get worse with faster speeds or longer runs—at high speeds, greater muscular strength is required to maintain proper mechanics, and during a long run, muscles get more fatigued and hence are even less successful at controlling the leg.  Further, muscular weakness or tightness might explain why flat surfaces are particularly apt to cause loss of leg coordination: the flat surface would put the exact same demands on the muscles every step, leading to more rapid fatigue.

As I said above, this is a very good place to start, since if muscular weakness or tightness is indeed the problem, it's reasonably easy to fix, at least in theory.  The major problem with this proposed cause is that many runners with loss of leg coordination have found little or no improvement with lengthy stretching and strengthening programs.  Even with very strong hip muscles and supple hamstrings, loss of coordination remains a problem.  Clearly, strength is not the solution for everyone.

That being said, it is extremely important to note that all but one of the people who did report making a full recovery did so in part by doing glute, hip flexor, and hamstring strength exercises religiously.  Hamstring and hip flexor stretches were also highly recommended by at least a few posters on the LetsRun thread.

Verdict: Stretches and strengthening exercises are a worthy place to start.  The best places to start are the major muscles of the hip and thigh: the hamstrings, the hip abductors, flexors, and external rotators.  To make a meaningful difference, any stretching and strengthening program would need to be done daily for several weeks and would consist of a high number of repeats of several different exercises.  This is something a good physical therapist should be able to devise—though individual therapists may not agree on what's tight, what's weak, or what needs strengthening. 

This theory seems to be popular among PTs, chiropractors, and massage therapists—maybe a manifestation of the "when you have a hammer..." problem.  Adhesions or scar tissue allegedly inhibit proper muscular function, or cause functional weakness/tightness/loss of range of motion.  It almost goes without saying at this point, but the role of adhesions and scar tissue in any running injury is almost wholly in the realm of opinion, not scientific fact.  This does not mean it's wrong, just that there is a lack of evidence. 

If indeed loss of leg coordination were simply a matter of muscular adhesions or scar tissue, it should only take a handful sessions of soft tissue manipulation to see significant improvement.  Problematically, the various soft tissue manipulation techniques have probably the worst reported track record among people with loss of leg coordination while running: several posters on the LetsRun thread report trying sports massage, Active Release Technique, Graston Technique, Rolfing, and all sorts of other soft tissue therapies but with little or no improvement. 

Verdict: It's a near certainty that people with loss of leg coordination have palpably tight or "adhered" muscles, but it is more likely that this is a result of continuing to run with poor coordination, not the actual cause.  Training on a wildly asymmetric stride is sure to cause knots and tightness in any number of muscles, so this can't be the sole cause.

Fixing running form is perhaps the most simple solution to the problem.  You're not running correctly? Well, teach yourself to run correctly and the problem will go away! Or, that's the idea.  As simple as it sounds, it is a noble principle.  In theory, if loss of leg coordination were simply a matter of improper neural programming—an incorrect picture of how running is supposed to work in your brain—it should be fixable by making changes to running form or by doing coordination drills.  Notably, some of the runners with loss of leg coordination report they are midfoot or forefoot strikers, while others were heelstrikers, indicating that loss of coordination is not tied to one specific running style.

Undoubtedly, nearly every runner with loss of leg coordination has tried to alter his or her stride—switching to forefoot striking, running with a quicker cadence, or maybe trying to keep your feet landing on either side of a straight line painted on a soccer field.  One poster reported that his daughter was experiencing loss of leg coordination while running, only to have it disappear permanently when she increased her stride frequency.  While promising, others were not able to replicate this success.  Several people reported seeing gait specialists, and a few even went to university labs with full 3D kinematic labs.  The gait analysts inevitably found abnormalities and attempted to fix them with stretches, strengthening exercises, or form cues, but surprisingly, no one reported significant success with these treatments.  It is at least plausible that real-time feedback could result in real gait retraining and avoidance of loss of leg coordination, but the setup required for this type of therapy (a full 3D kinematics lab with simplified real-time displays) is nonexistent outside of a few research labs.¹⁴

To reiterate, the core sensation associated with loss of leg coordination is that the leg is not doing what it's supposed to do, and the runner is aware of this.  It would be one thing if running felt totally normal, but your form was jarring or erratic to other observers, but we shouldn't ignore the fact that all runners with this problem consciously realize and can sense that they are running in an unusual way.

Verdict: Though promising, alterations to form and muscle coordination drills also suffer the same problems as strength and stretching exercise: no one can agree on what to change, and they appear to be ineffective.  Two things worth trying are increasing stride frequency and running along a painted line (soccer field, football field, road, etc.), trying to keep your feet landing just on either side of the line, not crossing over each other.  Running with a high stride frequency is a good idea in general,¹⁵ and since leg crossover and rotation is a very common feature in loss of leg coordination, directly correcting it (or at least trying) may improve the situation.  For me, this served more as a checkpoint than an actual treatment—seeing that I was indeed landing with my feet in a straight line was one objective marker of progress, which was very helpful given that so many of the other sensations associated with loss of leg coordination are subjective.

This cause seems to be the darling of chiropractors and osteopaths, as they see musculoskeletal problems through the lens of alignment and posture.  Improper alignment of the pelvis or back allegedly inhibits the muscles and/or the nerves from properly executing the commands sent by the nervous system.  As mentioned earlier, there are a variety of models which attempt to associate back, pelvis, leg, or foot alignment with injury risk.  None of these have been validated by scientific evidence—on the contrary, as mentioned earlier, most fall flat.  This doesn't necessarily mean that every alignment-based theory is wrong; it just means that there's no guarantee two specialists will see your problem the same way.

Nearly every runner with long-lasting loss of leg coordination while running has gone to a physical therapist, chiropractor, or osteopath to get a pelvic, back, or joint adjustment, often with little or no improvement.  Some runners with loss of leg coordination reported moderate improvements with posture exercises focused on strengthening the abs, back, or hips.  Understandably, there is quite a bit of crossover between physical therapy-style stretches and strengthening exercises and "posture exercises"; the distinction is mostly semantic. 

Notably, one early poster on the LetsRun thread who made a full recovery reported that his rehab program consisted of manipulations by an osteopath and a proprietary routine of postural alignment exercises designed primarily for people with low back pain (the Egoscue method, which has apparently changed significantly since 2007 when the poster had his success).  However, the vast majority of people (including me) found adjustments, manipulations, and posture exercises wholly unhelpful.

Verdict: Like soft tissue manipulation, adjustments and manipulations are a tempting solution because they promise a quick fix.  But the unreliability of any alignment-based diagnosis, coupled with their ineffectiveness in most runners with loss of leg coordination, makes them a questionable proposition.  More than one person should have found success by working with a medical professional who specializes in manipulations and adjustments if alignment or postural issues are truly the root cause.

Further, impediments to nerve function caused by alignment issues should be detectable by a nerve conduction study.  Though only a few runners reported having this test done, it returned normal values in all cases.

If you mention "loss of coordination" to an orthopedist (or really any medical doctor), the first thing that will pop up in his or her head is "neurological problem."  And rightfully so—the vast majority of patients they see who complain about coordination-related problems are probably suffering from some sort of nerve issue.  The most common among these is sciatica, a compression or irritation of the sciatic nerve, which runs from your lower back through all of the muscles on the back side of your leg, including your glutes, hamstring, and calf.  The fact that all of these muscles are commonly involved in loss of leg coordination makes it an appealing culprit.  But sciatica is accompanied by other neurological symptoms, like sharp or shooting pains, pins and needles, low back pain, burning, and frank muscular weakness, which are not present in loss of leg coordination (as strictly defined in this article).

Additionally, loss of leg coordination sometimes involves muscles not innervated by the sciatic nerve, most notably the quadriceps and the hip flexors.  In these cases, the sciatic nerve couldn't be the only major nerve involved, unless the quadriceps-related symptoms are merely a reaction to or compensation for other problems related to the sciatic nerve.

Other major nerves, or branches of nerves, could plausibly be involved instead.  But the highly running specific nature of loss of leg coordination, plus the absence of any neurological symptoms other than loss of coordination, makes this unlikely. 

Sciatica should be revealed either by simple clinical tests which attempt to provoke pain (straight leg raise, etc.) or by an MRI.  Other nerve impingements or injuries should show up on a nerve conduction study, though if there is no presence of other neurological symptoms (burning, tingling, electric sensations, pins and needles, shooting pain), it is unlikely that a nerve conduction study is worth your time unless your doctor believes it is necessary.  Though a few posters in the LetsRun thread had nerve conduction studies done, the testing did not uncover any problems. 

Verdict: Sciatic nerve injury or irritation is the first thing to rule out in a suspected case of loss of leg coordination while running.  But because of several issues with pinning loss of leg coordination on sciatica or another nerve problem, nerve injuries do not hold much promise for explaining the cause of loss of leg coordination.

Disc injuries to the low back tie in somewhat with nerve injuries as a proposed cause.  Herniated discs are familiar to most people: disc herniation or a "slipped disc" occurs when the soft material that cushions the space between the vertebrae in your spine bulges out, pushes up against a nerve, and causes pain. Loss of leg coordination has been blamed on a herniated disc putting pressure on a nerve root, impairing coordination.

Herniated discs in the low back can cause neurological symptoms like weakness, tightness, and loss of coordination, but these tend to be accompanied by pain, both in the low back and along the sciatic nerve, as well as burning, electrical, or shooting pain symptoms.  Pinning the problem to a herniated disc also runs into the same problem as nerve injuries—if muscles not innervated by the sciatic nerve are involved in loss of leg coordination, as they appear to be in most cases, a single herniated disc is unlikely to cause problems in two different major nerves. 

Herniated discs are easily seen on an MRI of the lower back, and indeed, several of the posters in the LetsRun thread on loss of coordination in leg report that their doctors discovered a herniated disc upon examining their MRI results.  However, herniated discs are reasonably common in completely healthy people too.  One study found 35% of healthy people aged 20-39 have a herniated disc in their lower back, and this rate appears to increase with age.¹⁶  So, just because you have a herniated disc does not mean it's causing any problems. 

Most cases of herniated discs are treated conservatively with physical therapy and possibly other adjunctive treatments like spinal manipulation.  Some proportion are treated with surgery with fairly good success, but it's certainly no guarantee of recovery.¹⁷

Verdict: Given the absence of low back pain or radiating sciatic nerve pain, lumbar spine disc herniation is not likely to be the cause of loss of leg coordination while running.  The presence of a herniated disc on the MRIs of a number of several of the posters in the LetsRun thread is probably nothing more than the incidental appearance of asymptomatic disc herniation, which is quite common among the general population.

One explanation that has been occasionally suggested is a slow-progressing variant of multiple sclerosis or some other systematic disease of the nervous system.  This would be a very unusual variant of multiple sclerosis, but MS has a broad range of symptoms and can present in a number of ways, so it seems plausible.  Now, I'm not a doctor, and my knowledge of the body starts and ends with the musculoskeletal system, so I'm not comfortable going too much further than this.  One poster in the LetsRun thread mentioned having loss of coordination-like symptoms, along with foot drop and tingling, which disrupted his running off and on for several years until it was finally diagnosed as multiple sclerosis.

If loss of leg coordination really is the result of multiple sclerosis or some other neurological disease, the only course of action is a proper diagnosis and management by a doctor.  Though these types of diseases do not have a good long-term prognosis, it does not necessarily preclude improvements—people with multiple sclerosis sometimes experience "flare ups" that go away after a few days, weeks, or months.  This would explain why some people have recovered—but presumably it would come back, and should also get worse over time.  Neither of these seem to happen, at least based on the posts in the LetsRun thread, which spans a period of almost eight years. 

Verdict: Though the possibility that loss of leg coordination while running being the result of multiple sclerosis or another neurological disease seems remote, it is something that is at least worth asking a doctor about for reassurance—it's certainly not anything you'll find encouraging information on by searching the internet.  Notably, one case series in the scientific literature describes two cases of young-onset Parkinson's disease that initially manifested as leg-coordination problems while running.  However, this spread to all exercise and soon affected walking, too.¹⁸

A disruption in the blood supply to the muscles of the leg would also impair the ability of the muscles to properly function during running.  A vascular problem shows some promise as a potential cause, because it would explain several of the puzzling aspects of loss of leg coordination.  First, because faster speeds require more bloodflow, the problem should worsen when running faster (which it does).  Second, loss of coordination disappears more or less immediately when you stop running, which also lines up with a vascular cause: when you stop running, the bloodflow required by your muscles drops too.   It may even explain why the problem seems to be exclusive to running—cyclists, for example, can experience compression of the iliac artery, near the hip flexor muscle, when they're riding bent over on their bikes.¹⁹  This causes vague lower leg pain, cramping, numbness, abnormal fatigue, and pain in their thigh, a cluster of sensations known as "claudication."  Maybe a similar problem arises, though perhaps with a different artery, in runners. 

However, a few facets of loss of leg coordination are not explained by a vascular problem.  It doesn't explain why varied terrain like trails or grass is any more manageable than the roads or a treadmill, and loss of coordination in leg while running isn't accompanied by numbness or swelling, which do occur in iliac crest artery compression in cyclists. 

A vascular problem can be detected by testing your ankle-brachial index, or ABI.  An ABI test measures the ratio of your blood pressure at your ankles to your blood pressure in your arm.  If there's a problem with arterial supply to your legs, this should show up on the ABI test.  There is a catch, however—if the problem is running-specific, the test needs to be done immediately following the kind of exercise that produces symptoms: in our case, a hard run on flat terrain or a treadmill.  ABI results are normal in cyclists with iliac artery compression unless they first ride hard enough to produce symptoms on a stationary bike.

A few other tests can also identify vascular problems; these involve directly imaging the arteries in question with ultrasound, x-ray fluoroscopy, or MRI using an intravenous dye. 

Treatment for vascular problems again lies outside my realm of knowledge, but will undoubtedly involve working with a doctor who is a vascular specialist.

Verdict: A vascular problem would explain many of the seemingly strange phenomena associated with loss of leg coordination, but it lacks the ability to explain every aspect of the problem.  Why do different runners experience symptoms in different muscle groups? If there were one specific artery involved, symptoms should be more or less the same.  And why is rough terrain much less likely to provoke loss of leg coordination versus flat roads or treadmills? Finally, why do mechanically similar activities like the elliptical machine or aqua-jogging fail to reproduce the problem?

Only one or two people in the LetsRun thread reported seeing a doctor about a vascular issue, but none discovered any problems.

Chronic exertional compartment syndrome is more widely known for causing calf or shin muscle problems in runners.  Compartment syndrome in the hamstrings or quadriceps, however, has been proposed as a cause for loss of leg coordination.  Chronic compartment syndrome in the thigh is extremely rare, having only been described in case studies,²⁰ but we're in uncharted territory as it is—we might as well entertain all possible causes.

Chronic exertional compartment syndrome occurs when the compartment that encases a muscle is too small.  During exercise, bloodflow to the muscle increases, and the muscle swells up, increasing the pressure of the compartment.  This causes a tight, cramping ache, along with pain, weakness, pins and needles, and numbness as the bloodflow to the muscle is cut off.  The pain and irritation usually disappear quickly after exercise is stopped and pressure in the intramuscular compartment drops.

For long-standing cases of chronic exertional compartment syndrome, the treatment of choice is usually surgery to relieve the pressure inside the muscle compartment.  Fortunately, though, there is little guesswork involved when it comes to diagnosing compartment syndrome.  The pressure inside the muscle compartment can be measured directly using a needle and a pressure gauge.  This test involves running on a treadmill until symptoms are provoked, then measuring the intramuscular pressure of the compartments suspected to be involved.

Verdict: Given the specific, localized nature of chronic exertional compartment syndrome, it is not likely to be the cause of loss of leg coordination, which tends to cause problems in more than one muscle group.  Compartment syndrome also features numbness, palpable "fullness" in the muscle, and significant pain, none of which are present in loss of coordination in leg while running.  One poster in the LetsRun thread reported having intramuscular pressure measurements taken, but results were normal. 

Labral tears are a relative latecomer to the discussion on potential causes of loss of leg coordination.  The labrum is a small ring of cartilage that circles the hip joint and keeps the head of the femur sealed into the hip joint, more properly referred to as the acetabulum.  Labral tears themselves have only been identified as a sports injury in the past few decades, so they are not well-known, and only a few orthopedists specialize in their treatment.  Labral tears often occur in athletes that do a lot of hip-intensive movements, like hockey or football players, but they are also reasonably common in runners. Labral tears do not occur on their own—they are almost always found in conjunction with femoroacetabular impingement or FAI, an abnormality in the bone structure of the hip joint.  Though it sounds like a complex idea, it's really quite simple: the head of the femur or the socket of the hip (or both) are misshapen, and the friction between the two causes damage to the labrum and degeneration in the hip joint.  Untreated FAI in athletes can lead to hip osteoarthritis at an early age as well.

However, labral tears are usually characterized by groin and anterior hip pain.²¹  Under our strict definition of loss of coordination in leg while running, these aren't present.  But some runners (though notably, not all) with loss of leg coordination developed hip pain and ended up seeing doctors who suspected a labral tear.  Labral tears don't always show up on a regular MRI; they require an MR-Arthrogram, an MRI with a special dye injected into the hip.  Some runners with loss of leg coordination (though again, not all) had an MR-Arthrogram and found that they had a labral tear on the affected side.

However, the presence of a labral tear is not the sole indicator that the labrum is the cause of your problems.  Some healthy people have labral tears that appear to be totally asymptomatic, and there is a very high prevalence of a torn labrum in cadaver studies of 70-80 year olds, indicating that it may be part of the normal aging process.^{22, 23} 

As discussed earlier, some preliminary evidence has suggested that a labral tear can impair proprioceptive control of the hip joint, as evidenced by worse results on single-leg balance tests on the affected leg of people with labral tears, both when compared to their healthy leg and when compared to healthy control subjects.⁶ 

The impaired proprioception and hip instability associated with a labral tear could perhaps impair coordination while running, leading to loss of leg coordination, either because your body can't sense what's happening in the hip joint (due to impaired proprioception) or because the proper leg muscle contractions aren't resulting in the usual movements of the hip joint (due to the instability of the hip joint).  The loss of coordination would then be worse at high speeds, because higher speeds put more force through the hip joint and demand more muscular precision, and maybe even worse on flat surfaces, because the hip joint is being stressed in the same way over and over.

Notably, however, this has not been described in any case reports of runners with labral tears—and there are a lot of them.  Tears of the labrum and concomitant FAI are identified primarily by the hip and groin pain that they cause.

As mentioned above, the only reliable way to image the labrum is with an MR-Arthrogram, which involves injecting a dye into the hip joint to provide better contrast.  Fortunately, this injection also provides the opportunity for another test, a diagnostic injection of a local anesthetic.  In normal patients with a labral tear, this temporarily alleviates the groin or hip pain associated with the labral tear.  If a labral tear is causing or contributing to loss of leg coordination while running, a similar diagnostic injection should alleviate, or at least improve, the coordination problem.  Local anesthetics are short-acting—they wear off in a matter of hours, so to get a good idea of whether the diagnostic hip injection helps, you'd need to do a run that would usually provoke the problem more or less immediately after getting the injection.  The only problem with this is that the outcome of this test is wholly based on your own subjective perceptions of your leg mechanics while you run.

If the diagnostic injection proves beneficial, or if you develop hip or groin pain and your MR-Arthrogram results indicate that you've got a labral tear, the next step would be a corticosteroid injection.  This is a longer-lasting injection into the hip joint which also may improve symptoms.

Confirmed cases of labral tears caused by FAI are eventually treated by surgically repairing the damaged portion of the labrum and shaving down the part of the femur or hip joint that is causing the impingement.  As you might guess, this surgery is no joke—rehab takes at least four months, and it can be up to a year before you're back to your old self, so it's nothing to rush into.

Verdict: Labral tears are a particularly tricky potential cause.  On one hand, there is no medical literature that describes a loss of coordination associated with a labral tear, and a few posters in the LetsRun thread have indicated that they do not have a torn labrum, as measured by an MR-Arthrogram.  On the other hand, at least two people (one of them being me) had a confirmed labral tear on an MR-Arthrogram, later developed hip pain, underwent surgery, and are now able to run again at a high level with no restrictions. 

A few things could be going on here: First, a torn labrum might exacerbate or provoke loss of leg coordination while running because of the proprioceptive or hip stability issues as discussed above.  Second, the labral tear might have been caused, at least partially, by the abnormal hip mechanics during running that are characteristic of loss of leg coordination.  Third, labral tears and FAI could be a completely incidental finding, unrelated to the original problem. 

The only thing that is clear is that labral tears and FAI do not cause 100% of cases of loss of leg coordination while running.

Chalking up a condition as "somatic"—meaning, essentially, that you're imagining it—is technically calling it mental disorder, but it's probably something that most people with loss of leg coordination while running have been accused of at some point.  To an outsider, the problem seems incomprehensibly bizarre: some runners can do interval workouts, but not a race; they can run for two hours on trails, but not for fifteen minutes on a track.  They can hop, skip, walk, and bound just fine, but ask them to run and they'll say their leg "doesn't work"—but can't point to any specific spot that hurts.  They can do strength routines, lift weights, and do most anything else without a problem, but running is a no-go.  It's certainly a frustrating situation to try to explain to a coach, trainer, doctor, or teammate, and these mystifying discrepancies eventually lead to a breakdown of the trust between the athlete and his or her coaches, teammates, therapists, and doctors.  Coaches and medical professionals don't have the answers for the runner, and the runner's problem seems inconsistent to an outsider.

Verdict: Fortunately, disproving the idea that loss of leg coordination while running is only a somatic disorder with no physical manifestations is fairly easy.  Anyone with a sharp eye can spot the progressive worsening of the impaired coordination while doing a type of run that is particularly aggravating, like maintaining a fast, continuous pace on a treadmill.  A full description of the types of running form abnormalities that occur with loss of leg coordination can be found elsewhere in this article, but the main things to watch for on the affected leg are external rotation of the hip, leg crossover at footstrike, pronation and foot angle during the stance phase, control of the foot during footstrike, and hip flexion during the swing phase.

Another fairly obvious indicator of an abnormality is grossly asymmetric wear patterns on shoes.  After running for a while with loss of leg coordination, I found that my shoes showed a drastic asymmetry when looking at the areas of wear on the soles: the lateral heel of my right shoe looked as if it'd been held to a belt sander, while the same area of the left shoe was relatively intact.  You'll need to compare this to an old pair of shoes from before you had loss of coordination, though, because some normal runners have asymmetric wear patterns as well.

I have no doubt that a 3D kinematic analysis would provide even stronger evidence of a progressive abnormality in running mechanics that was dependent on the duration and speed of running, but labs equipped with this kind of setup are few and far between. 

The final proposed cause to review is task-specific focal dystonia.  Dystonias are a class of neurological disorders that usually involve sustained and uncontrollable muscle contractions, and focal dystonia is a type of movement disorder that affects only one area of the body.  A subset of this type of dystonia is a task-specific focal dystonia: a movement disorder that only manifests when performing certain kinds of movements.  As Diego Torres-Russoto and Jeol Perlmutter describe in a 2008 review study, "Task-specific dystonias are primary focal dystonias characterized by excessive muscle contractions producing abnormal postures during selective motor activities that often involve highly skilled, repetitive movements."²⁴  The distinction of "primary focal dystonia" is important in our case; it means that the movement disorder is not a secondary effect of a disease or other identifiable cause.

The best-known types of task-specific focal dystonia affect writers and musicians in the form of "writer's cramp" and "musician's dystonia," respectively.  Both writing and playing music involve extremely precise fine motor control in a small area of the body (the hand), and a quick search on YouTube will find videos demonstrating the effects of both conditions.

Focal dystonia is a brain problem.  Abnormal muscle patterns can be detected by EMG during the activity that causes the dystonia, but muscular strength and coordination doing other activities is usually unaffected—musicians with, say, guitar-specific focal dystonia in their hand can write, type, and button up their shirt just fine.  They have no orthopedic injuries, meaning problems in the muscles, tendons, nerves, or bones.  Sometimes, focal dystonia can be temporarily relieved by "sensory tricks" like wearing a glove while playing an instrument or writing with an oversized pen: by changing the signals sent to the brain, the faulty circuitry can be at least temporarily overridden, allowing for normal movement again.

Even though these types of task-specific focal dystonia are relatively well-known, it's important to point out that they are still quite rare—most studies that discuss them are only case studies or case series.  Further, task-specific focal dystonia usually occurs in the upper limbs.  It is astoundingly rare in the lower body, though several cases have been described in the scientific literature.

This brings us to one of the central points of this article: Is loss of leg coordination a task-specific focal dystonia of the leg? Fully answering this question warrants its own separate section.

Loss of leg coordination while running fits the description of a task-specific focal dystonia on a number of important points: it presents only while running, i.e. it is task specific; it usually presents without other orthopedic problems (though recall that running with disrupted mechanics can result in secondary compensatory injuries), and there are no muscular weaknesses or nerve problems that can be identified with a diagnostic test. 

Critically, running-specific focal dystonia can also fully explain some of the most perplexing aspects of loss of coordination in leg. 

First, it explains why running on an uneven surface often alleviates the problem: an uneven surface has a more varied neurological demand from the brain, demanding slightly different muscle contractions to run on the rough surface.  In cases of upper body focal dystonia, even slightly changing the activity can alleviate the problem: pianists with musician's cramp can "play" on a flat table painted with the key layout of a piano, for example.²⁵  And this also explains why very flat surfaces are worse: each step is more or less identical to the previous one.  Running on rough trails may qualify as a "sensory trick" which allows you to bypass faulty movement patterns.  Since dystonia is a brain problem, not a musculoskeletal one, it makes sense why rest would not necessarily improve the problem either. 

It also makes sense why running-specific focal dystonia would get worse at fast speeds, too, because the muscular precision required to run 5:00 mile pace is much higher than the precision required to run 8:00 mile pace.  To use the musician analogy again, playing a very complex guitar arpeggio requires a lot more dexterity and fine motor control than strumming some simple chords, and as such is more prone to provoke musician's cramp.

Most runners with loss of leg coordination also appear to be fairly experienced, high-mileage runners.  This is in agreement with the finding that task-specific focal dystonias tend to occur in people who are highly practiced in their specialty task, whether that is writing, typing, or playing an instrument.  A great number of hours of practice calls upon the same movement patterns in the brain over and over again.

Runners with loss of leg coordination find they are able to do sprint drills, bike, run backwards, and do other types of highly coordinated lower-leg movements, again in agreement with the findings on the (relatively) more common forms of task-specific focal dystonia. 

Indeed, a number of cases of "runner's dystonia" have been described in the medical and scientific literature.  From my review of all of the scientific papers on the subject that I could find, I count a total of twenty-two cases of probable runner's dystonia described amongst nine case studies and series.

The primary complaint in most cases of runner's dystonia involves the foot or ankle.  Of the nineteen cases described that are specific about the gait anomaly, all but four involve the foot or ankle to some extent (one study [Chang and Josephs] which included three subjects with probable runner's dystonia did not describe the biomechanical features—the authors did not respond to a request for further information).²⁶  The foot and ankle complaints range from abnormal foot inversion or eversion to flexion and clawing of the 2nd through 5th toes and the forefoot.  In this sense, these cases are quite similar to the clawing, constant contractions that are the hallmark of writer's cramp and other upper-limb focal dystonias.  Some subjects described their problems as involving "severe cramping." 

More concerning is the fact that the majority of the cases of runner's dystonia described in the literature eventually spread to other activities, sometimes becoming quite debilitating.  Of the nineteen adequately-described cases of runner's dystonia extant in the literature, sixteen eventually spread to or could be triggered by other activities like walking, squatting, biking, and swimming—three of the cases never spread beyond running, and one case series of three subjects did not specify the outcome (the Chang and Josephs study—again, attempts to contact the authors to clarify this were not successful).  The timeframe when the dystonia began to spread ranged from one month to five years, when described.

The outcome, when reported, in all of the cases described in the literature was extremely poor.  Of the thirteen cases of runner's dystonia in the literature which included a detailed description of the patient's outcome, zero subjects made a full recovery (i.e. were able to return to running at their previous level).  In fact, only one was able to continue running at all, albeit only on rough terrain, not flat surfaces.  Some of the other case studies which did not fully detail outcome mentioned some improvement following treatment with various drugs—more on that in a bit—but it would seem that the authors would have made a point to emphasize that a runner made a return to sport if indeed it occurred.

The case studies described in the literature are a bit muddled with what appears to be other conditions masquerading as focal dystonia.  Four of the subjects with runner's dystonia had muscle tremors at rest; in two of these cases, the true problem turned out to be young-onset Parkinson's disease.  In these two unfortunate men (aged 27 and 45), traditional symptoms of Parkinson's appeared within 1.5 and 5 years, respectively. 

There are still a few issues with focal dystonia as the explanation for loss of leg coordination while running.  Running is traditionally described as a "gross" muscular activity, not a "fine" one—it involves quick, powerful contractions of large groups of muscles across the entire body.  Further, it's a much more "natural" motion than writing, typing, or playing an instrument, in that its motion patterns are partially hard-coded into your brain.  That's not to say that it's impossible to develop movement disorders with motions that are mostly automatic, not learned; some cases of dystonia while walking have been described in the scientific literature too.  But it is certainly at odds with the classic depiction of dystonia as a problem that is most likely to occur in highly repetitive fine-muscle-control activities, and a problem that usually affects small muscles.  Even amateur musicians spend several hours daily practicing their skill; a professional runner is not likely to run much more than 1.5-2 hours a day during peak training.

By now, it should be clear that task-specific focal dystonia is the leading candidate for the cause of loss of leg coordination while running.  That being said, there are some very important discrepancies between the experiences of runners with loss of leg coordination and the case studies of "runner's dystonia" described in the scientific literature.  It's possible that loss of leg coordination while running (as strictly defined in this article) represents a different subtype of running-specific focal dystonia than what has been described in the literature, or that loss of leg coordination is a much more mild variant of runner's dystonia that has yet to be described in a case study.

To further elucidate some of the discrepancies between the features of literature-described cases—referred to from here on out as "runner's dystonia"— and loss of leg coordination while running, we will compare and contrast the features of runner's dystonia to the symptoms experienced by the sixteen respondents to my informal survey described in the introduction.

The most obvious difference is in the distribution of complaints.  Of the nineteen adequately-described literature case studies of runner's dystonia, fifteen involve complaints that involve the foot or ankle muscles directly.  Examples are listed in the table below, with complaints involving the foot or ankle muscles highlighted in green:

Main complaint in 19 literature-described cases of lower limb dystonia in runners

Knee extension

Knee extension, hip flexion

"Clumsy, awkward" lower leg, knee flexion

Lack of hip flexion, hyperflexion of knee

Foot plantar flexion

Knee extension, foot eversion

Knee extension, foot inversion

Foot plantar flexion

Flexion of 2nd-5th toes and forefoot

Foot inversion

Inversion and plantarflexion of foot

Foot inversion

Inversion and plantarflexion of foot

Knee extension, foot eversion, foot dorsiflexion

Right hip abduction, foot eversion, and plantarflexion; left toe curling and plantarflexion (while walking)

Toe curling (while walking)

Flexion of toes

Foot inversion and toe clawing

Foot plantar flexion and inversion

In contrast, only four of sixteen cases from survey respondents involved ankle complains; zero involved toe clawing or extension (mentioned in five of nineteen literature cases).  The main complaints of the survey respondents are listed below, though it should be noted that they were asked to describe in their own words, what was "off" about their running stride.  When possible I described this using anatomic terminology but some comments were too vague to be specific.  Again, cases clearly involving the foot and ankle are highlighted in green.

Main complaint in 16 runners with self-identified loss of leg coordination

Leg adduction & external rotation, calf and hamstring tightness

"Could not put one foot in front of the other"

Problems with hip flexion during stance phase & foot placement at impact.  Aching in hamstring

Leg external rotation, loss of control in swing phase, hamstring cramping

Leg weakness and poor coordination

"Limited movement and control, particularly the backswing...foot-plant feels awkward and uncontrolled"

Uncontrollable hip internal rotation during swing phase, foot "splayed" at impact, rotated internally

Weak, unstable feeling in leg. Loss of control in swing phase

Foot lands pronated, extra effort to pull leg through swing phase

Instability in the swing phase, muscular tightness, overpronation

Uncontrollable during swing phase and where foot lands

Quad weakness and aching, "uneasy lack of control" in legs, no control over swing phase

Bilateral foot eversion in stance, poor leg control in swing phase, esp. on left side

Uncontrollable hip rotation during swing, excessive calf engagement and plantarflexion of foot, and poor glute/hamstring control

Heaviness in leg, quad.  Foot scuffing, tightness in ankle & foot, hamstring weakness

Ankle tightness, loss of hip control, inability to control leg during swing phase

It could be argued that some of the other cases involve the foot or ankle, particularly cases that complain of awkward foot plant or a splayed foot at footstrike.  But consider also that internal or external hip rotation during the swing phase will necessarily result in a "splayed" foot at footstrike. 

The experience of most of the people in the LetsRun thread and the respondents to my survey are unlike the classic description of dystonia in the literature: the sensation is not a constant, ratcheting contraction of muscles controlling the foot or ankle, but more of a rhythmic misfiring of the major muscles (glutes, quads, hamstrings) during the running stride.  The four literature cases of runner's dystonia which do not involve the foot complained of abnormal knee extension, knee extension and hip flexion, and knee flexion. 

A much greater proportion of the survey respondents with loss of leg coordination complain of problems in their running stride that seem to be rooted in the hip: by far the most common complaint is a lack of control during the swing phase of the stride.  Fundamentally, the leg is controlled during the swing phase by the hip and thigh muscles: the quads, hamstrings, hip flexors, and the internal and external rotators of the hip.²⁷

This bolsters the theory that these runners have at least a different subtype of runner's dystonia, one which involves a dull tightness and poor coordination in the "prime movers" of the leg, instead of the more vicious and easy-to-spot contractions and cramping of the smaller muscles that control the toes, foot, and ankle.

It should also be clear that loss of coordination (and runner's dystonia) does not present with the same type of mechanical symptoms in every case—some people experience foot inversion, while others experience foot inversion, for example—which makes it unlikely that you can pin loss of leg coordination on any one nerve, muscle, joint alignment, etc.

Another important difference is the relatively better prognosis in runners with self-identified loss of leg coordination as opposed to literature-described cases of runner's dystonia. In the nineteen literature cases, thirteen subjects eventually developed serious problems with walking.  Two did not, and the rest were not described adequately enough to make a judgment.  In these thirteen cases, the abnormal movements almost always involved the foot, and spread to walking after initial symptoms presented during running.  One case series by Katz et al. describes how long it took for the symptoms to spread to walking.  This timespan ranged from one month to four years.  McMlinton and Heiderscheit describe a patient who developed symptoms while running which spread to walking gradually over a period of two years.

Some of the more peculiar signs of loss of leg coordination, like the inability to do fast, continuous runs on flat surfaces even when trail running is unaffected, were mentioned in a few literature cases, but as described above, the problem very rapidly spread to running on any surface and often to walking. 

However, in survey respondents who had loss of leg coordination, the condition never worsened to this extent, even though many of them have been affected by this problem for many years.  Seven of sixteen runners with loss of leg coordination reported the sensation being triggered by walking, but only to a slight degree—nowhere near the dramatic, obviously-visible deficiencies in walking demonstrated in the literature cases of runner's dystonia and as depicted in the video below.  Those respondents who did indicate "slight" or "mild" complains while walking did not have a significantly longer injury history than those who did not.  None of the posters in the LetsRun thread mentioned any significant problems with walking either.

 Patient 2 from Ramdhani and Frucht

The discrepancy between outcomes in literature-described cases of runner's dystonia and respondents to my informal survey might be rooted in the different location of the faulty movement patterns, or it might be a matter of selection bias—it's difficult to say.  Maybe the people whose loss of coordination spreads wind up going to a neurologist, and others just post on the internet about it.  In any case, it is readily apparent that there exists a subset of runners with runner's-dystonia-like symptoms that occur mainly in the prime movers of the leg and that are relatively stable over time, not spreading within a few months or years.  The relatively mild nature of these symptoms, as compared to cases where the dysfunctional movement pattern seriously impairs walking, might be why cases describing these runners do not appear in the literature.

Even within the set of runners with self-identified loss of leg coordination, there are some stark differences in the degree to which the problem limits the runner's ability to train.  Of the sixteen cases, four indicated that, on an average day, any running at all triggers loss of leg coordination.  Three more experienced loss of coordination with all running on flat surfaces.  The rest of the runners, though, could usually run at an easy pace as much as they wanted—only fast, continuous running on flat surfaces triggered loss of coordination on an average day.

However, the condition also has an ebb and flow to it.  When asked how their training was limited when loss of leg coordination was at its worst, the majority of the runners could not do any running at all, and definitely not on flat surfaces.  Two cases seemed limited to fast running on hard surfaces, no matter how bad the condition got—these runners could still do cross country races or long runs on trails.

These differences affected to what extent the runners were able to maintain their usual training and competition schedules.  Some were virtually incapable of doing any significant training and had to drastically reduce their running or eliminate it completely, some modified their training to avoid workouts that triggered the problem, and some continued to train on it despite the problems. 

Based on the evidence laid out above, loss of leg coordination while running appears to be best-explained as a form of task-specific focal dystonia.  However, loss of leg coordination while running is markedly different than the vast majority of cases of lower limb dystonia described to date in case studies in the scientific and medical literature. 

For one, the majority of runners with self-identified loss of leg coordination describe gait anomalies that can only originate from the hips and thigh—problems with external or internal rotation of the leg, or problems flexing or extending the knee.  Usually these occur during the swing phase of gait, resulting in a "floppy" leg sensation.  The foot-centric symptoms that crop up in medical case reports, like inversion or eversion of the foot, and especially clawing or extension of the toes, are not the typical features of loss of leg coordination while running.  Loss of leg coordination instead appears to be primarily a "proximal" phenomenon, mediated by the muscles of the hip—at least in the majority of cases.

The prognosis is also much different for runners with loss of leg coordination.  None of the respondents to my survey reported their coordination problems spreading to the point where it severely impaired their ability to walk, unlike the cases described in the literature.  Additionally, several runners with loss of leg coordination have been able to continue to train and race at a high level with some restrictions, and a few have even made a full recovery—no literature cases come close to an outcome this good.

Shane McLinton and Bryan Heidersheit, authors of the most detailed case study on runner's dystonia, propose eight diagnostic criteria for task-specific focal dystonia in runners ("runner's dystonia"), outlined below [formatting modified slightly from the original paper]:²⁸

Current evidence indicates the following features that can be assessed by the physical therapist in support of the diagnosis of runner’s dystonia:

(1) task specificity of the movement dysfunction

(2) long history of running with first onset of symptoms during running

(3) inconsistent orthopaedic examination

(4) negative basic neurological examination

(5) absent or minimal pain

(6) sustained or excessive muscular activation consistent with the altered gait pattern

(7) sensory or motor tricks

(8) sensorimotor impairments [e.g fine motor control and response time]

Loss of leg coordination while running appears to fulfill most of these criteria (do note that number 8 is not possible to test outside of a specialized lab).  However, as discussed above, the cases of runner's dystonia described in the literature have some very important differences.  If you accept that loss of leg coordination while running is indeed runner's dystonia, you must also accept that it is a different variant that is as-of-yet undescribed in medical literature. 

It's important not to use this as an excuse to write off being thorough with diagnostics, and going ahead with the preliminary diagnosis of task-specific focal dystonia as the underlying cause for loss of leg coordination while running does not mean that another musculoskeletal problem didn't contribute to or precipitate the problem.  For example, there's some evidence that muscular weakness or range of motion limitations can contribute to dystonic movement patterns.  Jinnah et al. describe in a 2013 review article on focal dystonias how mechanical limitations could impact dystonia:¹²

Another important factor is the interaction between the task and the mechanical ability of the limb. If the demand exceeds the ability, compensatory adaptations may result in abnormal motor behavior. This is particularly important in musicians where task demands may be extreme.

So it is indeed plausible that loss of coordination in leg could be provoked or worsened by poor muscular strength, flexibility, or joint problems, which might explain why some runners were able to improve or fully recover in part due to strength exercises.

Exploring treatment options is a very daunting task.  None of the literature-described cases of runner's dystonia were able to make what you'd call a "full recovery," though one can train with some limitations (only running on rough surfaces).  In the following section, we will look at treatments used or suggested in the medical literature on runner's dystonia, even though no case study has yet described a runner who has been able to make anything resembling a full recovery.  A subsequent section will look at the individual histories of the handful of runners who have been able to continue training and competing at a high level after suffering loss of leg coordination while running.    

In the literature, treatment of task-specific focal dystonia is mostly focused on drug treatments.  Many of the medications that have been tried are heavy-hitting anticonvulsant or anti-Parkinson's disease drugs, sometimes alongside injections of Botox, a muscle paralyzer better known for its use in plastic surgery.  Twenty-one of the twenty-two cases of runner's dystonia described in the literature were treated with drugs, with varying degrees of success.  The eight drugs used to treat twenty-one cases of runner's dystonia are detailed in the table below, along with the degree of the response to it, as reported by the authors of the case studies. Shading is provided only for ease of distinction between treatments; it does not signify success rate.

Drug treatment	Degree of response
Carbamazepine	marked
L-dopa	none
L-dopa	"yes"
L-dopa	none
L-dopa	marked
L-dopa	none
L-dopa	marked
Botox	mild
Botox	mild
Botox	mild
Botox	marked
Botox	[not reported]
Trihexyphenidyl	moderate
Trihexyphenidyl	None
Trihexyphenidyl	Some
Clonazepam, botox	minimal
Clonazepam, botox	Marked
Clonazepam, nortriptyline	some
Baclofen, botox, L-dopa	none
Diazepam	"yes"
Lorazepam, botox	[not reported]

As far as I can tell, even the "marked" responses were not a cure in the traditional sense—the case studies are almost all vague on the absolute outcome, but the narrative of a case study of runner's dystonia with a truly successful outcome (i.e. able to return fully to training/competition) would likely be very different, with the successful outcome described directly.

In studies of other focal dystonias, response to the drug levodopa has been connected with an increased risk of the dystonia being a harbinger of early-onset Parkinson's disease.  Indeed, two subjects in a case series by Bozi and Bhatia had runner's-dystonia-like symptoms that swiftly morphed into early-onset Parkinson's.¹⁸  However, in a review of a number of cases of lower limb dystonia by Florence C.F. Chang and Keith A. Josephs of the Mayo Clinic, the authors write:²⁶

In our study, three subjects were long distance runners who had leg dystonia during running. They did not develop [Parkinson's disease] after 2 years of follow-up. Although idiopathic [Parkinson's disease] cannot be excluded, our three patients probably had adult-onset primary lower limb dystonia or runner’s dystonia rather than Glut-1 gene mutation or genetic forms of [Parkinson's disease], given the older age at onset and the lack of signs to suggest secondary dystonia.

Botox has been used with reasonable success in other task-specific focal dystonias like writer's or musician's cramp, and as the table above indicates, it's had mild to moderate success in a few cases of runner's dystonia as well.  But the question remains whether high-level running is even possible with partial muscle paralysis, especially when the main complaint (and thus, the area that would need to be injected with botox) is the major muscles of the leg like the quads, glutes, and hamstrings.

I've included the above discussion largely for the benefit of any medical professionals reading this article.  The effects and the potential risks and benefits of these drugs—many of which are quite potent—are far beyond my knowledge.  Only an experienced neurologist could fully explain these. 

Physical therapy or other exercise-based rehabilitation did not feature prominently in the treatment plans for literature-described cases of runner's dystonia.  Though many of the runners surely saw a PT at some point during their often multi-year struggle with dystonia, the specifics of their regimen and its usefulness, if any, were never detailed.  This is probably because the authors of most of the case studies and series were neurologists, not orthopedists or physical therapists.  They were seeing patients who had already been seen by an orthopedist or a physical therapist with no success.  After identifying the problem as a movement disorder, not a musculoskeletal problem, these doctors likely saw little or no utility in rehab-style exercises.

An avenue of treatment that might be more promising is neuromuscular retraining—essentially, attempting to erase and overwrite the faulty movement patterns in the brain with deliberate practice.  Unfortunately, this approach is very underdeveloped; there are only a few studies which describe neuromuscular (or "motor") retraining, and none focus on running.²⁴  The most pioneering and yet most frustrating case study was a 2012 paper by physical therapists Shane McLinton and Bryan Heiderscheit at the University of Wisconsin-Madison which described their diagnosis and attempted treatment of a 56-year-old male runner with lower leg dystonia.²⁸  The patient had runner's dystonia that started while running, but over the course of three years, spread to walking, eventually impairing the man's ability to walk for more than a minute at a time.  After limited success with clonazepam and botox injections, McLinton and Heidersheit proposed an innovative "sensorimotor training" program with the intent of retraining the neuromuscular patterns associated with walking.

Since this type of program has never been done before in a case of lower limb dystonia, McLinton and Heidersheit created a lower-leg program that imitates programs used with some success in upper limb dystonia (usually for musicians).  Sadly, the authors never got a chance to fully evaluate the rehab program: the patient claimed the routine was too time-consuming, and he stopped coming in to see the therapists.  In scientific-speak, this means the patient was "lost to follow-up."  For us, it means that we don't get to find out what kind of benefits this type of motor retraining could bring about.

The specific exercises and routine are not specified, but even if they were, the usefulness of this particular routine is questionable for runners with running-specific focal dystonia that has not spread to walking.  The reason I highlighted this case study is because it represents an innovative attempt to attack the root cause of  the problem: faulty movement patterns in the brain.  There is a lot of room for innovative attempts at restoring proper movement patterns in runners with loss of leg coordination, especially in the relatively "mild" cases that allow easy running or running on rough surfaces.

As mentioned earlier, respondents to my survey of runners with loss of leg coordination had a much better prognosis than the literature-described cases of runner's dystonia.  Despite the majority of respondents (thirteen of sixteen cases) continuing to have issues with loss of leg coordination, a number of them have nevertheless been able to train and compete at a high level since their problems began.  Additionally, the other three respondents  were able to return to training and/or competition without any issues.  We'll examine some of these cases and try to learn a few things about successfully managing loss of leg coordination while running.  To preserve anonymity, I'll refer to respondents solely by a number.

The first thing we can learn from runners who successfully manage loss of leg coordination is that they avoid things that worsen the problem.  Subject 14, who began having leg coordination issues at age fifteen (and continues to have them to this day), was nevertheless able to be a very successful collegiate runner by shifting his focus from longer distances to the 800m and the 1500m.  Like many respondents, he was able to do easy runs and interval workouts, as long as each individual repeat was not too far.  Hard, continuous runs, like a tempo run or a track 5000m, would invariably cause his coordination issue to flare up.  Through various strength exercises, he was able to extend his ability to run fast speeds continuously from 2km up to 3.5km, but no further.  Indeed, McClinton and Heiderscheid encourage runners to "consider solutions to minimize the dysfunctional movement pattern" - i.e. avoid making the problem worse.²⁸

Subject 15, who began having issues at age twenty-six, was a successful marathon runner, but was unable to continue the tempo-heavy training that led him to success in the marathon.  He, too, shifted his focus to shorter races, though over time he has been able to improve his ability to run fast paces continuously and has since returned to marathon training.  Again, he was able to do this by avoiding the kind of training that aggravated the problem, doing strength and rehabilitation work, and sticking to workouts that did not cause loss of leg coordination.

Subject 11, who developed the issue in college and continues to train and compete on the roads, found that taking 30 second breaks to stop and briefly stretch out allowed her to get through longer training runs when her coordination issue flares up.  Running on rough or uneven surfaces is also very helpful.  She does her best to avoid the problem in training, but pushes through it when loss of coordination occurs during a race.

Subject 13, a long-distance specialist, developed coordination problems during fast, continuous running in college.  He is currently able to run at nearly the same level as before, as long as he avoids all hard or continuous efforts on flat surfaces.  Instead of tempo runs and long intervals, he does fartlek runs and repeats on the track up to one mile in length (any further triggers loss of coordination).  Instead of focusing on the 5k and 10k, he focuses on cross country races of all distances and track events up to one mile in length.

In at least half of the respondents, loss of leg coordination affected all running when it was at its worst.  But on a typical day, many runners were able to do at least some types of running—easy runs, fast intervals over cross country, etc.—without problems.  The individual aggravators for loss of coordination will vary from person to person, but from the personal histories of the above runners, it seems that there is a lot to be gained by trying not to aggravate the problem.  Various tricks employed by these runners include running barefoot, running on trails or other rough terrain, taking short breaks when loss of coordination seems imminent, and doing fartlek workouts and short intervals instead of hard, continuous efforts.

On the flip side, a number of respondents have also reported having success with consciously pushing into an "uncomfortable" zone, but stopping before severe problems.  This allows them to feel out where their limits are, and over long periods of time (weeks or months), push out the boundaries of how far or how fast they're able to run before loss of coordination sets in. 

There is conflicting evidence on whether an extended break from all running will prove helpful.  On one hand, the three respondents who are currently running without any problems have all taken long breaks from running: one voluntarily took six years off from running, and the other two (including me) underwent labral tear surgery, which involves several weeks on crutches and several months of avoiding all impact activity.  A fourth runner (subject 15 from above) underwent back surgery for a herniated disc, which also involved a long break from running and led to significant improvements, though not a full recovery.  In the cases of surgery, it can be challenging to separate the effects of the surgery itself from the effects of the time off, the rehab exercises, and the extremely gradual reintroduction to running that follows.

In the case of subject 16, however, the impact of surgery was clear.  His symptoms were somewhat abnormal compared to the rest of the respondents—he had coordination issues in both legs, and his problems tended to be aggravated more so by sprint work as opposed to hard, continuous running, but his main complaints mirrored those of other runners with loss of leg coordination: quad weakness and aching, and a lack of control over the legs, especially in the swing phase of gait.  He eventually underwent surgery for a labral tear in one hip and afterwards, noticed an immediate difference in the surgical leg, but not the other one.  He eventually had a second operation on the other hip and was able to return to full training and competition.

Notably, a few respondents have reported taking extended breaks from running without any meaningful change in symptoms, so an extended break is not a panacea.  And the subject of McLinton and Heidersheit's case study, who eventually developed dystonia while walking and was lost to follow-up, had undergone labral tear surgery without any change in symptoms.

Finally, all runners who recovered or made significant improvements incorporated strength exercises targeting the hip and thigh muscles into their rehab routine.  Exactly why these are helpful is not clear—maybe raw improvements in the strength of the affected muscles help stymie loss of leg coordination, or perhaps the strength work functions as a crude kind of neuromuscular re-education, helping to reconfigure neural patterns in the brain so that nerve impulses match up with proper muscular movements.  There's far too little evidence to make any conclusions on which types of exercises should be done; some runners did physical therapy-style exercises using only their body weight and therabands, while others used weight machines.  All targeted the prime movers and stabilizers of the hips, though: the hamstrings, the quadriceps, the glutes, and the hip flexors.

If a successful treatment program is devised for loss of leg coordination, it will almost surely include some type of neuromuscular retraining.  The goal is to reprogram the correct movement patterns into your brain; the question is how to go about doing this. 

Neuromuscular reeducation training is in its infancy even for upper limb task-specific focal dystonia, so proposing re-education methods here is nothing but hypothesizing. 

Regardless, it's worth considering options like deep water running, shallow water running, AlterG antigravity treadmill running, and doing running-related drills on land (bounding, skipping, etc.) as possible methods for neuromuscular reeducation.  The goals of neuromuscular reeducation are outlined well by Bly et al.²⁹

If focal hand dystonia results from a dedifferentiation of somatosensory structure [i.e. "crossed wires" in the brain related to muscular control], then improvement in task-specific fine motor performance must be contingent on a positive learning paradigm where precise and distinct representations of the digits are restored. [i.e. reconnecting the mental image of muscle recruitment with the actual muscle recruitment pattern] [...] Increased sensory cues can improve the ability of the nervous system to differentiate sensory information and organize a motor response.

We can perhaps envision a progression, moving from a non-impact, less-specific exercise like deep water running (aquajogging) towards progressively more running-specific exercises and drills. 

Deep water running should be done with a flotation belt to ensure that the mechanics are more similar to overground running.  The next step towards real running might be shallow water running—running in chest-deep water, still wearing a flotation belt but actually using foot contact against the bottom of the pool for forward propulsion.  After this, progressing to an antigravity treadmill (AlterG) would be the next logical step, as the AlterG allows you to precisely control your relative body weight.  An alternative would be progressing to overground running on rough terrain, then progress gradually towards more running on flat surfaces.  At some point, running-related drills on land like bounding and skipping might be included as well.

From a neuromuscular perspective, it would seem that making all efforts to avoid ingraining improper neuromuscular patterns (the loss of coordination feeling) would be ideal.  Experience from runners who have been able to manage their loss of leg coordination and still run at a high level indicates that it appears to be okay to push into mild discomfort on occasion, but that you should not continue to run when you are in full-blown loss of coordination mode.

Again, all of this is derived only from making hypotheses and inferences from what we know about loss of leg coordination.  Since successful treatment of loss of coordination in leg is wholly undescribed in medical literature, we have to approach treatment from a theoretical and anecdotal perspective, and with all the caution and caveats implied by this strategy. 

After reviewing so much information, it would be unjust of me to turn you away without any concrete advice.  At this point, I do need to reiterate that I am not a doctor, nor am I even an unbiased observer.  What follows in this section is conjecture and opinion only.  Consider the following in light of these shortcomings.

If you suspect you have loss of leg coordination while running, getting a reasonably complete diagnostic workup from an orthopedist and perhaps a neurologist is a good idea.  Your problem will almost surely perplex them, but it is important to ensure that you don't have another musculoskeletal or neurological problem that you have managed to convince yourself is loss of leg coordination.  Remember, your brain is a very powerful thing: it's quite easy for you to dismiss symptoms that don't align with a diagnosis, like numbness, tingling, or back pain, and having an impartial medical professional evaluate these things is the best way to avoid this pitfall. 

It is particularly important to see a neurologist if your symptoms are centered in your foot instead of your hip and thigh.  Foot- and ankle-centric dysfunction is the "classic" presentation of lower limb dystonia as currently described in the literature: foot eversion or inversion and especially toe extension or clawing.  And on a more sobering note, a 2003 paper describes two cases of what initially appeared to be exercise-associated lower-leg dystonia which eventually turned out to be young-onset Parkinson's disease.¹⁸  Fortunately, many other patients with similar symptoms described in other papers did not develop Parkinson's, but it is still worth looking into.

Once you've run the gauntlet of medical diagnostics and been cleared of any serious problems (which is a prerequisite for meeting this article's definition of loss of leg coordination while running anyway), it is time to start looking at potential treatment or management strategies.  You'll need to come to terms with the fact that, for the majority of people with loss of leg coordination, it is something they manage, not cure.  It's still possible to do the sport you love, but you may have to change a lot about how you train and how you race.

Working with a good physical therapist to uncover any underlying flexibility or muscular strength deficiencies is a good place to start.  A few runners with loss of leg coordination have been able to make a full recovery by doing only strength and flexibility work, and if you've been running on a "dead leg" for any significant length of time, you're sure to have developed some imbalances that will impede your ability to run properly, even if your loss of coordination was cured tomorrow.  Make sure you stick with your rehab program for several weeks; even programs for run-of-the-mill injuries like IT band syndrome take 4-8 weeks to have a full effect.

The rehab program should definitely involve strength exercises for the abductors and external rotators of the hip, and should also strengthen whichever muscles you felt were losing coordination when you ran (quads, hamstrings, glute max, etc.).  Incorporating true strength training with weight machines or free weights is a good idea too, but wait until you've got several weeks of basic physical therapy-style exercises under your belt before you start doing heavier lifting.  It's important to have a foundation of stability before you start taking on heavy loads. 

While you go about doing this, you might consider an extended (6-8 week) break from all running.  It has proved helpful for a few people with loss of leg coordination, though others have found that it made no difference.  For the first few weeks, avoid any type of exercise.  After this, you can try to ease yourself into a cyclical cross training activity, preferably aquajogging with a flotation belt.  This will allow you to practice correct running mechanics in a slow, controlled manner.  As you return to running, treat your comeback much like you'd treat returning from a stress fracture or other major injury: build up daily volume very slowly, and be particularly attuned to your running form.  Be on the lookout for any signs of altered gait, like a crossover stride or your feet splaying out to the side when they hit the ground.  Use your initial runs as short "therapeutic" sessions to ensure your running form is perfect, precise, and symmetrical.

In many cases, a full break from running may not be possible or desirable, especially if you can still do easy runs and workouts on trails without coordination issues.  In lieu of a full break, consider trying to avoid all workouts that trigger loss of coordination for several weeks while you improve your strength and flexibility.  Return to the kinds of training sessions that trigger loss of leg coordination slowly, and do your best to avoid continuing to run when you've lost control of your leg.

You will have to experiment with your training and racing practices to find out what helps you avoid losing leg coordination.  Like some of the respondents to my survey, you may have to become a middle distance runner or a cross-country specialist, even if that's not your preferred event.  You may also have to forgo workouts like tempo runs and long runs on the roads.  Anecdotal experience from runners who have successfully managed their loss of leg coordination tells us that it's okay to push into the "uncomfortable" zone on occasion, but that you should stop if you feel you are about to lose control of your leg.

Once you have returned to running, you might find it helpful to get a gait analysis from a physical therapist who specializes in treating runners.  Do keep in mind that gait analysis is very new and largely unregulated—there's no official manual on what constitutes "good running form," so what you're getting from a physical therapist is just his or her perspective.  Nevertheless, this can help you stop flaws like a crossover gait or abnormal hip rotation before they actually cause problems, which could help with your loss of leg coordination. 

Lastly, as you go through this process, make sure you check in with a doctor periodically, especially if anything changes—if your loss of coordination gets worse, if it starts to affect walking, biking, or other activities, or if you develop any kind of pain that might indicate another injury that's coexisting with loss of leg coordination.   

Loss of leg coordination while running is a pernicious, stubborn condition that is best described as a task-specific focal dystonia, usually of the upper leg and hip muscles. 

It is characterized by a sensation of aching, tightness, soreness, or  weakness in the leg, accompanied by a feeling of loss of coordination in the muscles of the leg that occurs only or mainly during running and without burning, numbness, tingling, localized pain, or obvious muscular weakness in daily life, all of which cannot be easily and completely ascribed to any conventional injury diagnosis. 

It similar to cases of runner's dystonia described in the medical literature, but with some important distinctions.  The majority of literature-described cases of runner's dystonia involve the muscles of the lower leg and foot.  Ankle inversion, eversion, or plantarflexion, and toe clawing are the most common gait flaws associated with runner's dystonia.  Loss of leg coordination is instead characterized by complaints about hip flexion, hip rotation, and knee extension. 

Additionally, the prognosis of runner's dystonia is much worse than loss of leg coordination.  Runner's dystonia almost always spreads to non-running activities, and eventually causes severe problems while walking.  Loss of leg coordination rarely spreads to other activities, and did not cause significant interference with walking in any of the sixteen self-reported cases who responded to my inquiry. 

A case study of a runner with symptoms typical of loss of leg coordination, as opposed to runner's dystonia, has yet to be published in the medical literature.  I encourage any physical therapist or doctor who is working with a patient to do so; it may spur the publication of additional case studies or series of runners with similar problems.

Treatments for runner's dystonia described in the medical literature are not promising.  From the anecdotal experience of a number of runners who have either fully overcome or successfully managed their loss of leg coordination and continued to run at a high level, there seem to be three strategies associated with a better outcome.  First, these runners avoid any type of training that triggers loss of leg coordination.  They do this by modifying their training schedule, changing their race distance of choice, and stopping workouts once loss of coordination occurs.  Second, some runners report success after taking an extended break from running and gradually reintroducing running, similar to how one might return after a major running injury like a stress fracture.   In some cases, this was a necessary result of surgery; in others it was voluntary.  Third, every runner who has made significant improvements or made a full recovery has focused on improving strength and flexibility of the hip and thigh muscles, either through physical therapy-style strength exercises, weight lifting, or both.

Though the problem appears to be rooted in faulty movement patterns in the brain, this does not preclude other musculoskeletal injuries or weaknesses from contributing to the problem.  A number of runners with loss of leg coordination reported also having other injuries; in a few cases, treating these led to improvement or recovery.  All runners who have loss of leg coordination should be screened for other injuries as well.

Future directions for research should focus on developing neuromuscular reeducation programs to address the root cause of loss of leg coordination.  The primary goal should be to restore the proper "image" of running in the brain.  Researchers and therapists should consider looking to programs used to successfully treat task-specific focal dystonia in the hand and wrist as a starting point when attempting to create programs for runners.

For runners with loss of leg coordination, the initial goal should be management.  Through strengthening the hips and thigh, modifying training to avoid anything that triggers loss of leg coordination, and perhaps an extended break from running, some runners are able to continue to train and compete at a high level with only minimal problems from loss of leg coordination.  Two runners are known to have made a full recovery, returning to training and competition at the same level as before with no restrictions, and a third appears to be symptom-free but chooses to only run a few times per week.  Unfortunately, there is not enough data to draw any conclusions about what sets them apart from runners who have not been able to move beyond loss of leg coordination. 

One of the runners who has made a full recovery is me.  I will describe my own personal experience with loss of leg coordination in a separate article which will be published by the end of next week. [link will go here]

Hopefully, this article is just the beginning of further research and reporting on this troubling condition.

 (switch to the second sheet using the tab along the bottom of the page).

I have strictly defined "loss of leg coordination while running" as the following:

Do you feel that this aptly describes your own experiences? If not, what was different in your case?

Current Age:

Age when you first had problems with loss of leg coordination while running:

Gender (M/F):

Affected leg (L/R):

In your own words, describe what was "off" about your running stride:

What specific rehab strategies (e.g. rest, stretching, strengthening, cross-training, etc.), if any, did you find helpful?

Did your loss of leg coordination ever spread to other activities like biking or swimming?

Did your loss of leg coordination ever spread to walking?

Put an "X" next to each statement which applies to you.

At its WORST, did your loss of leg coordination limit your ability to...

On an AVERAGE DAY, did your loss of leg coordination limit your ability to...

Did loss of leg coordination interfere with any other aspects of your training?

Were you able to return to your previous level of training and competition after the onset of loss of leg coordination?

Do you consider yourself "fully recovered" from loss of coordination in leg while running?

                        If so, what do you think allowed you to make a recovery?

                        If so, how long was it from the onset of loss of leg coordination until you felt

                        fully recovered?

Anything else I should know?

* * *

Loss of leg coordination while running is the working term for a rare neurological problem that occurs in long distance runners.  It is characterized by a gradually increasing sensation of tightness, weakness, and poor coordination in the muscles of one leg that occurs only while running—stopping to walk or stand still all but eliminates the symptoms.  Runners with loss of leg coordination cannot point to a specific area of pain; rather, there is a more general feeling of tightness, vague aching, and an overwhelming sense of something being "off" with the functioning of the affected leg when they run.  Further, classic signs of neurological injury, like numbness, shooting pain, or a "pins and needles" sensation, are absent.

These symptoms are also highly specific to running.  Other activities, even cyclical and highly aerobically demanding ones like using an elliptical or riding a bike, do not reliably recreate the symptoms.   The loss of coordination sensation is typically localized to the muscles which are the prime movers of the legs: the calves, the hamstrings, the quadriceps, and the gluteal muscles.  Despite the weak, uncoordinated sensation while running, absolute muscular strength is normal. 

In most cases, running longer, faster, and on flat surfaces exacerbates the problem.  Some runners find they lose coordination with any kind of running, but most are able to run at an easy pace on rough terrain (e.g. on trails or over cross-country).  Short intervals of fast running are not usually a problem, but longer intervals at fast speeds and especially fast continuous runs and races bring on loss of leg coordination more rapidly.  Ceasing a run makes the loss of coordination sensation go away almost immediately, but some lower leg muscular tightness can persist for a few days after a particularly bad episode.

Runners with loss of leg coordination often present with secondary injuries and muscular tightness or weakness as a result of continuing to run with abnormal biomechanics.  Clinical examination and diagnostic testing (straight leg raise test, nerve conduction, MRI, etc.) are typically unremarkable or uncover common conditions that are often asymptomatic, e.g. spinal disc herniation. 

Loss of leg coordination tends to occur in very experienced, high-mileage distance runners who train and compete at a high level.  An informal survey of sixteen distance runners with self-reported loss of leg coordination found a median age of onset of 22 years and median duration of four years at the time of the survey.

Managing loss of leg coordination is challenging.  The symptoms cannot be easily ascribed to a conventional diagnosis, and working with a physical therapist to address strength and flexibility deficiencies usually results in only minor improvements.  Among sixteen distance runners with self-reported loss of leg coordination, only two are able to train and compete at their previous level with no restrictions.  A few others still train and compete at a high level, but with some restrictions.  Most, however, cannot train or compete at nearly the same level as before the onset of loss of leg coordination.

The symptoms of loss of leg coordination while running are similar to task-specific focal dystonia of the lower limb (a condition termed "runner's dystonia" in some medical literature), but there are notable differences between loss of leg coordination while running and cases of runner's dystonia described in the literature. 

The prognosis of runner's dystonia is very poor—of nineteen adequately-described cases in the literature, dystonic movements spread to activities beyond running and eventually led to significant problems with walking in all but three cases.  In contrast, none of the sixteen runners with loss of leg coordination had significant gait impairments while walking.  Many runners with loss of leg coordination have symptoms that have been essentially stable or marginally improving for several years, as opposed to the nearly-inevitable spread of dystonic movements to other activities reported in runner's dystonia.

The most common location of complaints also differs between runner's dystonia and loss of leg coordination.  Fifteen of nineteen literature cases of runner's dystonia involved the muscles of the foot and ankle—ankle inversion or eversion and toe clawing were the most common gait abnormalities.  In the case of loss of leg coordination, only four of sixteen cases involved the foot and ankle.  The most common complaints with loss of leg coordination involve the muscles of the hips and thigh: hip flexion, hip rotation, and knee extension.  Runners with loss of leg coordination sometimes report that their foot "splays" out upon impact, landing rotated and everted, but often this appears to be rooted in hip external rotation during the swing phase. 

Patients with runner's dystonia complain of sustained contractions of the smaller muscles responsible for fine motor control, as is the case with better-known cases of focal dystonia (e.g. musician's dystonia, writer's cramp).  Loss of leg coordination instead appears to involve a slight but perceptible "misfiring" of the prime movers of the leg as opposed to sustained contraction.

A case study of a runner with symptoms typical of loss of leg coordination, as opposed to runner's dystonia, has yet to be published in the medical literature.  I encourage any physical therapist or doctor who is working with a patient with these symptoms to do so; it may spur the publication of additional case studies or series of runners with similar problems, some of whom may have been able to make improvements or a full recovery.

Treatments for runner's dystonia described in the medical literature are not promising.  Strategies usually revolve around antiparkinsonian or anticonvulsant drugs and botulinum toxin, but results are very poor.  No literature-described cases of runner's dystonia have made a full return to sport.

From the anecdotal experience of a number of informal survey respondants who have either fully overcome or successfully managed their loss of leg coordination and continued to run at a high level, there seem to be three strategies associated with a better outcome.  First, these runners avoid any type of training that triggers loss of leg coordination.  They do this by modifying their training schedule, changing their race distance of choice, and stopping workouts once loss of coordination occurs.  Second, some runners reported success after taking an extended break from running and gradually reintroducing running, similar to how one might return after a major running injury like a stress fracture.   In some cases, this was a necessary result of surgery (labral tear with FAI in two cases, lumbar decompression in another); in others it was voluntary.  Third, every runner who has made significant improvements or made a full recovery has focused on improving strength and flexibility of the hip and thigh muscles over the course of several months, either through physical therapy-style strength exercises, weight lifting, or both.

For runners with loss of leg coordination, the initial goal should be management.  Through improving strength and flexibility in the hips and thigh, modifying training to avoid triggering loss of leg coordination, and sometimes an extended break from running, some runners are able to return to training and competition at a high level with only minimal problems from loss of leg coordination.  Two runners are known to have made a full recovery, returning to training and competition with no restrictions, and a third appears to be symptom-free but chooses to only run a few times per week.  It is not clear what allowed these runners to make a full recovery.

Though the problem appears to be rooted in faulty movement patterns in the brain, this does not preclude other musculoskeletal injuries or weaknesses from contributing to the problem.  A number of runners with loss of leg coordination reported also having other injuries; in a few cases, treating these led to improvement or recovery.  All runners who have loss of leg coordination should be screened for other injuries and neurological problems as well.

Future directions for research should focus on developing neuromuscular reeducation programs to address the root cause of loss of leg coordination.  The primary goal should be to restore the proper "image" of running in the brain.  Researchers and therapists should consider looking to programs used to successfully treat task-specific focal dystonia in the hand and wrist as a starting point when attempting to create programs for runners.

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This article was the culmination of five years of research, nineteen months of writing, and considerable emotional investment.  I have published it free for anyone to read and distribute because I don't believe in restricting access to this kind of information.   I am a freelance writer and part-time high school coach, not a professional scholar, so if you have made it all the way down here and found this article helpful, consider donating a few dollars to support my work.