Suppose you are running a 5k race on an out-and-back course, and there’s a strong headwind on the way out—should you aim to run at the same effort the whole way, allowing the wind to slow you down on the way out and speed you up on the way back? Or should you maintain the same speed, working harder on the way out and relaxing more on the way back?
For most runners, it feels intuitive that constant-effort running should be better—in the sense of leading to better performance—than constant-speed running: constant-effort pacing is better than speeding up and slowing down, after all. But here’s a potential counterargument: if you run faster when going into the wind, you spend less time exposed to the wind, so you’ll save energy on balance.
So, which argument is correct?