I just finished an excellent book that I highly recommend, Running – Biomechanics and Exercise Physiology Applied in Practice by Frans Bosch and Ronald Klomp for further information go to www.elsevierhealth.com. I will talk more about the book in another post.
The following quote from their book substantiates the negative effect of the use of the hamstring curl. Bosch and Klomp state: “In particular the, the popular leg-curl exercise should not be used for hamstrings during strength training. Because of its drastic concentric shortening effect, this exercise runs completely counter to the structure and function of these muscles and will more likely result in injury than in improved performance. The exercise is non-functional and will disrupt the state of equilibrium between active and passive muscle segments. The reason why this exercise is nevertheless still included so frequently in training programs is probably that injury generally does not occur while actually performing the exercise, but rather develops later, so that its cause cannot be pinpointed exactly.” (P 348) Once again think movements not muscles. Strength the movement that involves the hamstring group in a pattern similar to their use in function.