Training on Fatigued Legs Builds Durability—as Long as You Do It Right. Experts Explain How.

Most runners know the feeling: dragging yourself out for a jog when your legs feel like lead. Your calendar says it’s supposed to be an easy day, but your quads seem to have missed the memo. You settle into a shuffle, wondering how a pace that felt effortless last week could demand so much today.

That effort might come from a hard run or strength session, but emotional and work stress can also contribute, he says. A run in that state isn’t necessarily a bad idea. Practicing on tired legs can help prepare you for the later miles of a race, when you no longer feel fresh.

The trick is knowing when pushing through fatigue is useful to performance—and when a rest day will do you more good. Simply put, running through some fatigue makes you stronger, both physically and psychologically. A more resilient muscular system means your muscles can not only recover faster, but also carry you longer and at a quicker clip.

Whatever you do, if you’re running on tired legs, keep the effort easy. Here are a few strategies for how to practice running on tired legs. The easiest strategy to try running on tired legs is simply to schedule an easy run right after a long training run or speed workout.

You are certainly at an increased risk of injury on that day, which is why it’s imperative to keep that easy day easy.” If you’re increasing mileage or prepping for a long-distance race, consider running twice in one day. There’s a fine line between training smart and overtraining. If you’re not fueling properly or skimping on rest, pushing through fatigue is going to backfire, says Sekely.

So before you head out with heavy legs, check in on a few variables: Check in with your emotional state before you head out for your run. Don’t be afraid to take a day or two off, so you feel ready to get back out there. This is a good guideline to gauge whether you’d benefit more from a run or rest on any given day, says Whitley: If you start your run with moderately fatigued legs and find that you’re not feeling better after moving for 10 minutes, modify the run by making it lower effort (slowing the pace or eliminating hills), or cut it short if you’re seriously struggling.