Doing certain leg exercises that only use the last part of the movement doesn’t seem to help untrained women build muscle in specific parts of their thighs — it’s about the same as not exercising at all.

What we've found so far suggests that partial range of motion knee extension training does not build muscle in the front of the thigh for untrained women. The evidence we've reviewed leans toward this type of exercise being no more effective than not exercising at all for this specific group and outcome [1]. We analyzed the available research and found 37.0 assertions supporting this conclusion, with no studies or claims refuting it [1]. This means that when untrained women perform leg exercises that only use the final portion of the knee extension movement—such as the last part of straightening the leg—they don’t appear to gain meaningful muscle in the front of the thigh. The muscle-building response in that area is minimal, similar to what might happen without training [1]. It’s important to note that this conclusion is based on the specific movement pattern and population: untrained women doing partial-range exercises focused on the end range of knee extension. We’re not saying this applies to all exercises, all ranges of motion, or all groups of people. Our current analysis only covers this particular scenario. We also can’t say whether other types of partial-range training or different exercises might work better, because the evidence we’ve reviewed doesn’t address those. For now, what we’ve found so far points to limited muscle growth in the front of the thigh when untrained women use this specific approach. Practical takeaway: If you're new to training and want to build muscle in the front of your thighs, doing only the last part of a leg extension may not give you the results you’re looking for.