hamstringvideos

Here you can find links to some sample videos showing how the Biceps Femoris (BF) muscle fascicles behave during fast running.

In this example (click to see video), you can see a real-time video of the BF long head during sprinting over several step cycles. 

This example shows a slow-motion video of several step cycles. In this case the subject is running at 15km/h, and the 3-dimensionality of the muscle is clear. In addition to large shifts of the muscle in the left-right direction, there is clear rotation, as confirmed by the fact that an aponeurotic border (white horizontal line) is clearly visible for parts of the step cycle but disappears at other times. Because of this rotation of the muscle, its appearance can be quite different between frames. Note also that identifying the 'correct' fascicle alignment when attaching the ultrasound probe would not resolve this problem for the same reason, i.e. 'correct' probe alignment will differ at different parts of the step cycle.