Browse evidence-based analysis of health-related claims and assertions
Your body burns more calories after leg presses than after chest flys—even if you rest the same amount—because your legs use way more muscles and need more oxygen to recover.
Causal
Right after leg presses with only 1-minute breaks, your body gasps for air more intensely in the first minute than if you took 3-minute breaks—but this doesn’t happen with chest flys.
Whether you rest 1 minute or 3 minutes between sets, you burn about the same total calories—rest time doesn’t change your overall energy burn in these workouts.
After lifting heavy with your legs, your body keeps burning extra calories for about 40 minutes—but after doing chest flys with long breaks, it only lasts 20 minutes.
Doing leg presses burns way more calories than doing chest flys—even if you do the same number of reps—because your legs use more muscles and keep burning energy longer after you finish.
When doing leg presses, taking only 1 minute of rest between sets makes you breathe harder overall than taking 3 minutes, but this doesn’t happen when doing chest flys—your body handles short breaks better when using smaller muscles.
When you’re just starting out, how much total work you do matters more than how long you rest between sets—your muscles grow and get stronger either way.
Correlational
This study only looked at beginners doing one leg at a time, so we can’t say for sure if the same results would happen to experienced lifters or people training both legs together.
Descriptive
You don’t need long breaks between sets to get strong—just do the same total amount of work, even with short rests, and you’ll get just as strong.
The study used high-tech scans (MRI) to measure muscle growth in specific parts of the thigh, making the results more accurate than just guessing from body measurements.
If you take only 20 seconds between sets, you have to do way more sets to match the same total weight lifted as someone taking 2-minute breaks, making your workout longer and more intense.
The study didn’t find a difference between short and long rests, and even if there was a tiny difference, it’s too small to matter in real life.
Quantitative
By training only one leg at a time, the study made sure that things like overall tiredness or hormones didn’t mess up the comparison between short and long rest periods.
The strength gains from this study are about what you’d expect from regular weight training—whether you rest a little or a lot—so rest time doesn’t seem to change how much stronger you get.
Lifting weights that you can only do 10 times, pushing to failure, for 10 weeks makes your thigh muscles bigger and stronger—even if you rest only 20 seconds between sets.
By training both legs of the same person—one with short breaks, one with long breaks—the study made sure differences weren’t due to people being naturally different, making the results more reliable.
If you push yourself to the limit every set, whether you rest 20 seconds or 2 minutes, you’ll end up doing about the same total amount of work.
When people train just one leg with heavy weights, their thigh muscles get bigger and stronger—and this method works well for studying how different rest times affect muscle growth.
If you take only 20 seconds between sets, you can still lift the same total weight as someone taking 2 minutes—you just have to do more sets to make up for the shorter breaks.
If you lift heavy weights with either short or long breaks between sets—while doing the same total work—you’ll get about the same stronger in your leg muscles after 10 weeks.
Whether you take short or long breaks between leg exercises, as long as you do the same total number of reps, your inner and outer thigh muscles grow about the same.
When people who’ve never lifted weights before do leg exercises with either 20-second or 2-minute breaks between sets—while doing the same total amount of work—their thigh muscles grow about the same amount.
If you’ve never lifted weights before, you can get stronger by doing either light or heavy weights — as long as you push each set until you can’t do another rep.
Lifting light or heavy weights to exhaustion for 12 weeks didn’t change body fat or muscle mass in women who had never lifted before.