Numbers guy Jeff Nippard is all about the details, so he makes sure that when it comes to leg day, no muscle is left behind. But when working on hamstring development, one muscle is more illusive than the rest according to the natural bodybuilder and powerlifter. Fortunately, he has shared the solution in a recent Instagram post for his 2 million plus followers.

“There are four heads on the hamstrings,” explains Nippard. For those counting, these heads are the semitendinosus, semimembranosus, biceps femoris long head, and biceps femoris short head. Nippard says that unlike the other three heads, the biceps femoris short head does not cross the hip joint. Ok, cool fact, but what does that mean? “That means it cannot contribute to hip extension while you do a Romanian deadlift,” he adds. This is because this short head of the hamstring is only used for bending the knee when it comes to your range of motion. “If you have a straight knee (like with an RDL), it simply won’t be active,” sums up the social media fitness star.

Don’t Skip Leg Curls For Your Hamstring Development Goals

“… if you skip your leg curls, you’ll never grow this head,” explains Nippard. “So, does this mean you should only do leg curls? Probably not. You see, even though the leg curl does hit all four heads, it targets the lower hamstrings a bit more than the upper hamstrings. So, I think for the best overall hamstrings growth, you need both a leg curl exercise, like a Nordic ham curl, glute ham raise, or machine leg curl, and a hip hinge exercise like a good morning or a Romanian deadlift.”

Building the femoris short head will add to the overall shape at the back of your upper leg, and from a functional point of view, strengthening this muscle will also improve your knee flexion and leg rotation, providing better stability and staving off injury.

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