This variant of the leg curl is the most effective
If your gym has different types of leg curl machines, invest a minute and a half of your precious time reading this post. Not all variants of the leg curl are equally effective when it comes to hypertrophy.
Sumiaki Maeo, a Japanese exercise scientist affiliated with Ritsumeikan University, got 20 young men to train their legs twice a week with a leg curl machine for 12 weeks. The men consistently trained one leg on a seated leg curl machine, and the other leg on a prone leg curl machine. Before and after the 12 weeks, Maeo took scans of the men's hamstrings and determined by what percentage the volume of these muscles had increased.
The seated leg curl produced a greater increase in hamstring muscle mass than the prone leg curl. The first variant resulted in an increase in total hamstring muscle mass of 14.1 percent, the second variant resulted in an increase of 9.3 percent.
Most hamstrings have two functions. They bend the lower leg towards the thigh, and they bend the thigh towards the trunk. So when you sit, your hamstrings are already a bit lengthened and under tension. This apparently means that you can train them better, the researchers think.
Med Sci Sports Exerc. 2021 Apr 1;53(4):825-37.
Hitting the hamstrings with leg curls yields more results than hitting them with deadlifts 06.03.2015