In performing a deep squat the prime movers at the knee are: 1) rectus femoris
2) biceps femoris
3) vastus lateralis
4) vastus medialis
5) semimembranosus

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Quizplus · Accepted Answer

The rectus femoris, vastus lateralis, and vastus medialis are all knee extensors, meaning they work to straighten the knee joint. During a deep squat, the knee is flexed, so these muscles must contract eccentrically to control the descent and concentrically to push the body back up. The biceps femoris and semimembranosus are both knee flexors, so they would not be considered prime movers during a deep squat.

In Performing a Deep Squat the Prime Movers at the Knee