Performing seated leg curls leads to a 20–28% increase in muscle volume in the proximal regions of the semitendinosus and biceps femoris long head, which are the areas most prone to strain injuries.

We analyzed the available evidence and found that performing seated leg curls is associated with a 20–28% increase in muscle volume in the proximal regions of the semitendinosus and biceps femoris long head — areas that are commonly affected by strain injuries [1]. This finding is based on 60.0 supporting assertions, with no contradictory evidence reviewed so far. The proximal region refers to the upper part of these muscles, closer to the hip and buttocks, where the fibers begin. When people perform seated leg curls, they bend their knees against resistance, which places targeted tension on the hamstrings, especially in this upper section. The increase in muscle volume suggests these muscles grow larger in response to the exercise, which may help improve their ability to handle load and stress. What we’ve found so far points toward a consistent pattern: when seated leg curls are performed regularly, these specific parts of the hamstrings tend to get bigger. However, we did not assess whether this growth translates to reduced injury risk, improved performance, or long-term changes beyond muscle size. We also did not compare seated leg curls to other hamstring exercises, so we can’t say whether this method is more or less effective than alternatives. The evidence we’ve reviewed is limited to one type of measurement — muscle volume — and does not include data on strength, endurance, or recovery. While the numbers suggest a clear trend, we continue to gather more information as new studies become available. If you’re looking to build up the upper part of your hamstrings, seated leg curls appear to be a reliable way to do so based on what we’ve seen so far.