Pre-workouts are popular supplements that claim to boost performance, but do they work? A registered dietitian explains.

Doing so means you can more easily know ... there’s no comparing one rep to another. When to try it: Any non-race week How to do it: Do your normal pre-workout warm-up run of 1 to 3 miles.

In a nutshell, sets are a way to cluster your reps, but the optimal ... ‘You’ll do more exercises in one session than you would in a standard workout,’ says Vincent. And studies show that ...