The hamstrings primarily function

The hamstrings primarily function to flex the knees and extend the hips. This is why exercises such as Leg Curls, Romanian Deadlifts (RDLs), Stiff-Legged Deadlifts (SLDLs), Good Mornings, and Nordic Hamstring Curls, which directly engage these functions, are more suited for robust hamstring development.

But what about squats?

During a squat, the hip and knee joints work in a ‘concert’, undergoing simultaneous flexion in the descent (eccentric phase) and extension as you rise (concentric phase). As explained by Dr. Brad Schoenfeld, “The hamstrings shorten at the knee and lengthen at the hip during the descent and perform the opposite actions during the ascent. This means the overall length of the hamstrings doesn’t change considerably throughout the exercise.” This muscle behavior isn’t optimal for maximally stimulating muscle growth.

So, while the hamstrings are engaged during a squat, the tension they experience is relatively minor. This is crucial, as muscle tension is a key driver for muscle growth. Instead, the hamstrings serve primarily as dynamic stabilizers during squats. This is especially noticeable when the knee bends beyond 90 degrees, as the hamstrings help stabilize the knee against the anteriorly directed forces of the Quadriceps.

In summary, while squats do activate the hamstrings, activation alone doesn’t guarantee significant muscle growth. If your primary goal is to enhance your hamstring development, incorporating exercises that directly engage the hamstrings in their primary functions will yield better results.