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.

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.

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.

When you compare both training styles on the same person (one leg vs. the other), you get clearer results than comparing different people, because everyone’s body responds differently.

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.