Hard, explosive workouts use muscle fibers that are naturally better at refilling energy stores, which helps you recover faster.

After a short, super-hard workout, your muscles refill their energy stores way faster than after a long, slow one—even if you eat the same amount of carbs.

If healthy young people don’t eat for a week, their muscles lose half their stored energy from carbs, but they can still work just as hard during intense exercise.

Lifting weights refills muscle energy slower than sprinting or HIIT, maybe because you don’t build up as much lactic acid and your muscles get more sore from stretching under load.

When you work out really hard and your muscles burn, the buildup of lactic acid might help your muscles refill energy faster—but after lifting weights, less lactic acid means slower recovery.

The more you deplete your muscle energy stores during a hard bike ride, the more your muscles can overfill with energy afterward when you eat carbs.