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.

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 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.

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.

By having each person train one leg with short rests and the other with long rests, researchers can be more sure that any differences (or lack of differences) are really due to rest time, not individual differences.

Even if you rest only 20 seconds between sets instead of 2 minutes, as long as you do the same total number of reps and weight, your muscles still grow and get just as strong.