After 12 weeks of seated leg curl exercises, healthy young adults experience a 14% increase in hamstring muscle volume, which is greater than the 9% increase seen with prone leg curl exercises,...

We analyzed one assertion comparing seated and prone leg curls, and what we’ve found so far suggests that seated leg curls may lead to a greater increase in hamstring volume than prone leg curls. In the single study referenced, healthy young adults who performed seated leg curls for 12 weeks saw a 14% increase in hamstring muscle volume, compared to a 9% increase with prone leg curls. The assertion attributes this difference to the way seated leg curls position the hamstrings under more mechanical tension when stretched, which could influence muscle growth [1]. We did not find any studies that contradict this finding, but it’s important to note that only one assertion was available for review. This means our current analysis is based on very limited data. We cannot say whether this result applies to other populations, such as older adults or trained athletes, or whether longer training periods would change the outcome. The term “mechanical tension” refers to the force placed on muscles during movement — in this case, the seated position may stretch the hamstrings more fully at the start of the movement, potentially leading to greater stimulus. Because we only have one source of evidence, we cannot determine if this pattern holds across different training styles, equipment, or recovery conditions. More research would be needed to understand how consistent this effect is. For someone looking to build hamstring size, this suggests that seated leg curls might offer a slight advantage over prone leg curls — but it’s only one observation, and individual results can vary.