The back of thigh or hamstrings muscle is actually three individual muscles: the semitendinosus, semimembranosus and the biceps femoris. These muscles play a major role in running performance.
Muscles such as the soleus, tibialis posterior, gastrocnemius, peroneus longus and toe flexors contribute more to running at slow paces. The hip muscles, iliopsoas, gluteus maximus and hamstring muscles contribute more at faster running velocities. The hamstrings become heavily involved in acceleration force production when sprinting horizontally.
The best hamstring strengthening movement is training on the Pendulum Leg Curl. The machine is a much different experience than any other leg curling exercise that a user has tried. The only way to describe it is that once on the machine in a prone position the athlete immediately ‘feels the difference’ and suddenly knows what it means to develop the hamstrings.
Training on the Pendulum Leg Curl