There is no doubt that flexibility is an important component of fitness and stretching programs change plasticity. In the Journal of Orthopaedic & Sports Physical Therapy, “The effects of hamstring stretching on range of motion: a systematic literature review,” the overwhelming evidence indicates that range of motion of the hamstrings is increased with a variety of stretching techniques, variations of positions and durations of training. The question remains: Will flexibility reduce hamstring injuries?
In a study just published in the American Journal of Sports Medicine looking at 450 males who played amateur sport, researchers found there was no relationship between hamstring flexibility and hamstring injuries. Studies such as this only reinforce that programs must be well rounded and that conditioning, strength, warm up, and all facets of preparation are important in making ready for athletics.
In maximizing the strength of biarticular muscles, such as the hamstrings, ensuring the upper and lower portions of the appendage are equally trained will lead to greater muscular adaptation.
The glute/ham machine preferentially targets the lower part of the hamstring, the reverse glute/ham targets the upper hamstring. Strength training the entire muscle, warming up, remaining flexible and conditioning are all necessary and will lead to a reduction of injuries.