Figure 1. The Hip Extensors

The hip or thigh extensors consist primarily of 4 muscles located in the buttocks region and behind the thigh. Their names are:

1) Gluteus Maximus
2) Semimembranosus
3) Semitendinosus
4) Long Head of Biceps Femoris

Note: The Semimembranosus, Semitendinosus and Biceps Femoris are commonly known as the hamstrings.

These muscles are shown in figure 1 above.

The main function of the hip or thigh extensors is to extend the thigh behind your body. This occurs during activities such as running, jumping, walking, skating, and swimming. This is illustrated in Figures 2a and 2b.

Figure 2a.
Neutral Position
 

Figure 2b.
Thigh Extended Behind Hip