To prevent hamstring injuries, the leg curl (knee curl) is often recommended. There is no questioning the fact that this is a good exercise for development of the hamstring muscles and to strengthen the tendons that cross the knee joint. It provides a more stable knee while running and performing other activities.
However, doing the exercise with only an ankle weight around the ankle is far from sufficient to truly tax this muscle. You must be extremely weak before only a two or three pound ankle weight will develop any appreciable strength regardless of how many sets of ten you do.
Also, when this exercise is done in a lying position, the hamstring is not placed on stretch which does not create the strongest contraction possible. More effective is to do the exercise in a standing position with Active Cords™.
When you raise the thigh so that it is level to the ground or even at a 45-degree angle to the ground, the hamstring at the hip end is taut and when you bend the knee, you will illicit a much stronger contraction. There will be no slack in the muscle as there is in the lying position.
Even more important for runners is to strengthen the hamstrings at the hip joint where they are involved in hip extension. Most injuries to the hamstrings occur at the upper hip end, not at the knee end. For this you can do the good morning, deadlift and best of all, the glute-ham- gastroc raise. This latter exercise strengthens the hamstring muscle at both the hip end and the knee end in sequence.
Most important for runners is to strengthen the hamstring muscle in a manner that close more closely duplicates what occurs in running. Doing this will not only enhance your running but also help prevent injury.
For example, by strengthening the hamstring at the hip end you can enhance the pawback action which is the key to proper touchdown, a longer stride length and increased stride frequency. Doing the Paw Back exercise with the Active Cords™ duplicates this action which makes it a specialized exercise that shows direct positive improvement. (See video below)
For more information on other specialized exercises for running, see Explosive Running. To show how these exercises duplicate what occurs in the running stride many sequence pictures taken from live digital film are displayed.