If a muscle works best when it's stretched out, it grows more when you do full movements. But if it doesn't rely on that stretched position, how far you move doesn't really change how much it grows.

What we've found so far is limited, but the evidence we've reviewed suggests that how much a muscle grows in response to range of motion during resistance training may depend on where that muscle performs best along its length-tension curve [1]. Our analysis of the available research shows that if a muscle generates more force when it’s in a stretched position, it may respond better to full range of motion exercises [1]. In these cases, using a longer range of motion could lead to greater muscle growth [1]. However, for muscles that don’t rely as much on the stretched position for force production, the range of motion might not make a big difference in growth [1]. Right now, we’re working with a very small amount of evidence—just one assertion supporting this idea and none contradicting it [1]. That means our current analysis is based on a narrow foundation. We can’t say for sure how strong this pattern is across different muscles or individuals. There may be other factors at play that this evidence doesn’t address. Because the data is so limited, we can’t draw broad conclusions about all muscles or all types of training. What we can say is that the idea makes some biomechanical sense—muscles tend to grow more when challenged in positions where they’re mechanically stressed, especially when stretched [1]. But whether this applies equally to every muscle group isn’t clear from what we’ve reviewed so far. The practical takeaway: If you're training a muscle that feels strong or stretched at the bottom of a movement—like the chest in a deep push-up or the glutes at the bottom of a squat—using a full range of motion might help maximize growth. For other movements where the muscle doesn’t feel loaded in a stretched position, the exact range might matter less. But we’ll need more evidence to strengthen this analysis.