Apps

New web app: Predicting LT1 pace and Zone 2 pace from 5k time

I’m excited to launch a new app for predicting training paces: my LT1 and Zone 2 pace calculator is now live, and provides a simple and accurate way to estimate your first lactate threshold, or LT1 pace, as well as an upper limit for your easy run pace, a.k.a. Zone 2 pace. 

📲 Check out my LT1 / Zone 2 app here! 

Normally, LT1 requires a standardized blood lactate test for reliable results. But with this app, all you need is your 5k time (or a reasonable estimate of your current 5k fitness).

Under the hood, this calculator relies on real scientific data from thousands of runners and state-of-the-art statistical techniques to come up with its estimates. 

Try out the calculator at the link above, or read on if you want more details on the science behind how it works.

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New app for making power law predictions for race performance

I recently published a critical speed calculator app, which makes it super easy to use the critical speed model to estimate your steady-state max. However, the critical speed model is not the most accurate way to predict race performance at new distances—that honor belongs to power law models (sometimes also called Riegel models, after Pete Riegel who popularized their use in running). 

I covered the science behind power law models in this earlier article on power law models versus critical speed models for predicting race times. Thanks to the infrastructure I built for the critical speed model, it was super easy to swap out the statistical model for a power law model: so now I have a brand-new power law calculator too!

⏱️ Try my power law calculator here ⏱️

Power law models are great for extrapolating—for example, predicting your half marathon time from a 5k and a 10k, or predicting your 400m time from an 800m and a 1500m time. They perform much better at this task than the critical speed model, and my power law calculator also includes some useful features for prediction.

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New web app for calculating critical speed

When I published my detailed write-up on the science of critical speed for runners, I promised that I would code up a free calculator to calculate your critical speed (also known as “critical velocity” or CV) from a set of race performances. That calculator is now finished! 

⏱️ Try my critical speed calculator here! ⏱️

This free web app makes it super easy to implement the statistical calculations that give you critical speed—and its uncertainty bounds—given a set of race performances.  

Like all of my web apps, it’s designed to be mobile-friendly, and it includes cookie-based “memory” so you can come back to where you left off. This critical speed calculator is also super easy to use: you don’t have to convert race performances into seconds, and you can choose from a wide range of pre-set race distance options, or enter a custom distance.

This is the only critical speed calculator I know of that gives you statistically appropriate uncertainty estimates that you can use for physiologically based workouts. 

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New calculator for track workouts on windy days

I just released a brand new web app for track workouts and races on windy days! 

A common challenge when doing track workouts or races is non-ideal wind conditions. This calculator applies the same validated scientific model from my wind-adjusted pace calculator to the specific geometry of the track. 

Scientifically speaking, this is probably the most advanced calculator I’ve ever made, and yet it’s still super easy to use. All you need to know is your pace (or calm-day effort level), the wind speed, and the wind direction. Everything else is taken care of by the web app!

🍃 Check out my new wind calculator here! 🍃

This app uses state-of-the-art biomechanics and physiology data, alongside a rigorous mathematical treatment of track geometry, to accurately account for the turns on an outdoor track.

My new app even supports “non-integer lap” distances for workouts like 200m, 600m, or 1k repeats (a favorite trick of mine for dealing with windy days at the track).

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The Marathon Excellence plans are now supported by the Defy Calendar Hack

If you’ve been looking for an easy way to sync your marathon workouts to your phone, I have some good news. The Marathon Excellence training plans are now supported by the awesome and free Defy Calendar Hack tool developed by “Nanreh,” a runner and cyclist in San Francisco! If you've wanted to sync your marathon workouts to your phone’s calendar app, this tool is the perfect way to do it.

Using this tool, you can set the date of your race, select your training plan, then customize the plan by dragging and dropping workouts to rearrange as needed. Then you can export an iCalendar file and sync it to your Google or Apple Calendar app!

💻 Check out the Calendar Hack tool here! 💻

The Defy Calendar Hack also supports marathon plans from Pete Pfitzinger, Hal Higdon, and the Hansons, among others, and you can export plans both in miles and kilometers.

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New web app: a fast and simple race pace calculator for runners

screenshot of a race pace calculator for runners from running writings

I just launched a new web app: a simple and fast race-pace calculator!

🏃‍♀️ Try out my new race pace calculator here! 🏃‍♂️

After crunching pace-to-race and race-to-pace calculations by hand for about the millionth time, I decided I needed a fast and easy way to quickly play around with different paces and target race times.

There are tons of race pace calculators out there on the internet already, but I wasn’t happy with any of them. Often I want to quickly iterate on different paces or race times, or toggle back and forth between goal time and goal pace.

For example, if a runner I’m coaching has done some workouts that suggest their marathon pace might be around 6:55–6:48/mi, I often do something like this:

How fast is 6:55/mi for the marathon? It's 3:01:21. What about 6:48/mi? That's 2:58:17. It’d be nice to get under 3:00, how fast is that? It’s 6:52/mi. Is that 6:52 exactly? No it's actually 6:51.9. Ok, let's try some workouts in the next few weeks around 6:51-6:49/mi and see how that pace range feels.

With other race pace calculators, this iteration was just too slow. So, I built this calculator to make it fast and easy to play around like this, even on your smartphone.

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New app for calculating heat-adjusted paces

screenshot of heat adjusted pace calculator app

I just finished up a new app for calculating the effects of heat and humidity on workout and race paces—a “heat-adjusted pace.” 

☀️ Check out my new heat-adjusted pace calculator here! 🌡️

This app builds on the work I wrote about in a post earlier this year on heat and humidity’s effects on marathon performance.

This web app uses a statistical model fit to nearly 4,000 marathon performances to estimate the effects of both heat and humidity on race and workout times. You can enter weather conditions as a heat index, temperature and relative humidity, or temperature and dew point.

Although the app is built on data from marathon races, it’s also useful for long tempo runs, easy runs, and other long sessions in the heat. 

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New and improved threshold, CV, and VO2max pace calculator

I’ve made some major improvements to my threshold, CV, and VO2max pace calculator!

The latest update improves accuracy in longer events like the 5k and the 10k, adds data from master’s and adult runners, and provides better uncertainty ranges across a wide range of speeds. 

🎯 Check out the improved calculator here! 🚀

Below, I’ll cover some of the new features and lay out my roadmap for upcoming features.

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New app for calculating threshold, CV, and VO2max pace

I’m excited to share my latest web app: a calculator for threshold pace, CV pace, and VO2max pace! 

📱 Check out my new threshold, CV, and VO2max calculator here! 📱

This calculator allows you to predict physiological training paces from any race distance from 800m to 10 km. 

This app was developed by analyzing over 10,000 race performances using the critical speed model, the gold standard in physiology for determining metabolically stable and metabolically unstable paces. 

The app also includes uncertainty ranges so you can get an idea of the range of different physiological profiles that you might find among runners at the same level of performance.

Below the app, you’ll find a detailed write-up of how it works and what differences you’ll notice between this app and other CV pace, threshold pace, and VO2max pace calculators and tables that you might’ve used in the past. 

As with all of my apps, it is 100% free and open-source. If you find any bugs, have any suggestions for improvements, or spot something that doesn’t look right,  drop me an email. 

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Check out my new book on marathon training!