Final answer:
The hamstrings (option B) control excessive forward hip flexion during the swing phase of gait, working to decelerate the thigh and balance the action of the hip flexors.
Step-by-step explanation:
The muscles that control excessive forward hip flexion during the swing phase of gait are the hamstrings. During the swing phase, the hamstrings work eccentrically to decelerate the forward movement of the thigh, ensuring that the leg moves forward in a controlled manner. The primary muscles in the hamstring group include the biceps femoris, semitendinosus, and semimembranosus. These muscles are located at the back of the thigh and are responsible for hip extension and knee flexion.
It is also important to note that while the gluteus maximus plays a significant role in the stabilization and extension of the hip, it is the hamstring muscles that specifically control the forward motion of the hip during the swing phase. The hip flexors, including the iliopsoas group, are actively flexing the hip but must be balanced by the hamstrings to avoid excessive movement.