Which group of muscles is responsible for flexing the knee and extending the hip?

The hamstrings are the group of muscles responsible for flexing the knee and extending the hip. This group includes three main muscles: the biceps femoris, semitendinosus, and semimembranosus. When these muscles contract, they pull the lower leg towards the body, effectively flexing the knee. Simultaneously, they also assist in extending the hip joint by drawing the thigh backward.

In contrast, the gluteus maximus primarily functions to extend the hip but does not play a role in knee flexion. The vastus group, which is part of the quadriceps, is responsible for extending the knee but does not facilitate hip extension or knee flexion. The soleus, located in the calf, primarily aids in plantar flexion of the foot and has no significant role in knee flexion or hip extension. Thus, the hamstrings are uniquely positioned to perform both of these movements.