If women who don't usually work out do certain leg exercises only through part of the movement—when the muscle is stretched—they might build more muscle in specific spots compared to doing the full movement or nothing at all.

What we've found so far suggests that doing partial leg extensions at long muscle lengths may increase targeted muscle growth in untrained women more than full range or other partial ranges. Our analysis of the available research shows the evidence currently leans in this direction. We reviewed one key assertion from the data, and it indicates that when untrained women perform leg exercises through a limited range of motion—specifically when the muscle is stretched—there could be greater muscle growth in targeted areas compared to doing full-range movements or not training at all [1]. This finding is supported by what we’ve seen across 37.0 studies or data points, with no studies or data points contradicting it. However, we only have one distinct assertion to base this on, so our understanding is still limited. We don’t yet know how strong this effect is, or whether it applies consistently across different people or training conditions. Also, we can’t say whether the benefit comes only from the stretched position, or if other factors like time under tension or exercise intensity play a role. Since all the supporting evidence points in the same direction but comes from a single interpreted claim, we need to be cautious in how far we extend these conclusions. Our current analysis shows a pattern worth noting, but not a final answer. The body of evidence we’ve reviewed is narrow, even if it points one way. As we gather more data, our understanding could change. Practical takeaway: For untrained women starting leg training, doing partial reps with the muscle in a stretched position might help build muscle in specific areas—but it’s not the only way, and full-range movements still have value. We don’t have enough evidence to say one method is clearly better than another for everyone.