When people lift weights through a full motion vs. just part of the motion, the muscles might look like they grow more in one case—but that could just be because the weight feels heavier at different points, not because the muscle is stretched more. So we can’t be sure if stretching the muscle is what’s causing the growth.

The study found that lifting weights through a partial range (stretched position) and full range gave the same muscle growth, even though the resistance felt different at the top or bottom. This supports the idea that it’s hard to tell if muscle length alone causes differences — because other factors like where the weight feels heaviest might be messing with the results.

This study looked at whether doing partial lifts with muscles stretched (long length) vs. shortened (short length) makes muscles grow differently — and it found that muscle length itself matters, not just where the weight feels heaviest. So yes, it supports the idea that peak resistance isn't the only thing causing growth differences.

The study found that where you stop or start your exercise matters more than just how far you stretch the muscle — meaning it’s not just muscle length causing growth, but where the hardest part of the lift happens.

The study says that when you train with a full range of motion, you might see more muscle growth—but that’s probably because the weights feel heavier at the stretched position, not just because the muscle is longer. So it’s hard to tell if length or resistance is the real reason.