There was a time- perhaps we’re still living it- when hamstring stretching was a panacea in physio. Then research elucidated the motor control function of the hamstring at the pelvis and knee and hamstring stretching became “bad”; the implication being that stretching “weakened” the hamstrings. Then physios came to the defense of hamstring stretching with histological data demonstrating that the duration and force required to “lengthen” and “weaken” the hamstrings is so substantial that hamstring stretching in isolation is unlikely to alter hip and knee mechanics. Alas, the popular narrative in physio now seems to be “stretch anything as much as you want if you enjoy it”. This advice is misguided.
Just because hamstring stretching isn’t “bad” (a fair statement) doesn’t mean it’s “good”. It’s doubtful that uninformed people enjoy stretching their hamstrings for its own sake. They probably stretch their hamstrings because they’ve been conditioned to believe that it’s beneficial. It’s also very easy to contort one’s body in a way that elicits a stretch sensation in the hamstrings; you straighten your knee and pull your leg towards your face. Advising people to stretch their hamstrings to their heart’s content could very well be a complete waste of time despite the fact that hamstring stretching is unlikely to weaken the muscle or create tissue change. Again, people generally do not stretch their hamstrings for the pleasure it produces. Somebody, perhaps a physio, told them it was a good idea.
Physios are supposed to be movement experts, not cheerleaders for anything that isn’t harmful. Physios should be educating the public about when it is appropriate or inappropriate to stretch hamstrings instead of advising that it be done arbitrarily because hamstring stretching as traditionally prescribed effectively does nothing beyond transiently altering one’s tolerance for stretch. That many physio diagnoses are contingent upon flawed biomechanical constructs need not swing the pendulum so far in the other direction that any mechanical pursuit is deemed worthy of one’s time and effort. Perhaps some old mechanical boundaries were drawn up incorrectly. Physios should collectively seek to establish better mechanical boundaries within a more global framework instead of effectively saying that any type of movement is beneficial. “Just stretch your hamstrings” isn’t responsible advice merely because the practice isn’t damaging. Physios can give concrete movement advice without being judgmental and paternalistic. Otherwise physio will become so obsequious that it stands for nothing.