David sustained a complete avulsion of his hamstring tendons from their origin on the ischial tuberosity . what classes of lever are the hamstring muscles? (2) the origin of the hamstring muscles is on the ischial tuberosity. where are their insertions. (3)

The hamstring muscles is one of the third class lever.  In a third-class lever, the most common in the human body, force is applied between the resistance (weight) and the axis (fulcrum).  This originate from the ischial tuberosity as a common tendon. Though the biceps femoris is known to be injured more than the semitendinosus.  The insertion works with contraction because the origin is fixed attachment. The Hamstrings consist of three muscles the Biceps Femoris muscle, the Semitendinosus muscle, and the Semimembranosus muscle.

heat a spark and oxygen

that is wrong, its not thymus.