Answer
The muscles that constitute the quadriceps femoris are the rectus femoris, the vastus lateralis, the vastus medialis. and the vastus intermedius. The term hamstring muscles includes the biceps femoris, the semitendinosus and the semimembranosus. (386).
Work Step by Step
The quadriceps femoris is one muscle which originates as four different heads, but insert by a single tendon. The combined contraction of these muscles powerfully extends the leg at the knee joint-- the rectus femoris acting by itself can also flex the thigh. This quadriceps muscle(s) together with the long sartorius muscle constitute the anterior compartment thigh muscles.
The hamstring muscles of the posterior thigh compartment are flexor muscles of the leg; they also extend the thigh. They have this dual action because they cross both the knee and the hip joint.
The quadriceps muscles play very important roles in general sports activities--squatting, jumping , running etc. The hamstring muscles are very vulnerable to injury in these activities . Athletes often tear hamstring muscles.
