HAMSTRING STRAINS ARE CAUSED BY FORCES IN EXTREME POSITIONS
Askling, C. M., Tengvar, M., Saartok, T., & Thorstensson, A. (April 30, 2008). Proximal hamstring strains of stretching type in different sports: Injury situations, clinical and magnetic resonance imaging characteristics, and return to sport. American Journal of Sports Medicine. [http://ajs.sagepub.com/cgi/content/abstract/0363546508315892v1]
"Hamstring strains can be of at least two types, one occurring during high-speed running and the other during motions in which the hamstring muscles reach extreme lengths, as documented for sprinters and dancers". The hypothesis that hamstring strains in different sports with similar injury situations to dancers would display similar symptoms, injury locations, and recovery times was tested. Ss (N = 30) from 21 sports were clinically assessed and viewed with magnetic resonance imaging. Follow-up lasted until Ss returned to or retired from activity.
All injuries occurred during movements reaching a position with combined extensive hip flexion and knee extension. They were located proximally in the posterior thigh, close to the ischial tuberosity. The injuries were often complex, but 83% involved the semimembranosus and its proximal free tendon. Fourteen Ss (47%) decided to end their sports activity. For the remaining 16 Ss, the median time for return to sport was 31 weeks (range, 9-104). There were no significant correlations between specific clinical or MRI parameters and time to return to sport.
Implication. In situations where the hamstring muscles reach extensive lengths, a specific injury to the proximal posterior thigh is likely to occur (as is frequently observed in dancers). Because of the prolonged recovery time associated with this type of injury, correct diagnosis, based on history and palpation, and adequate information for the S are essential.
[Editor's Note: The picture below illustrates a very frequent stretching exercise that places the hamstring muscles in the region of concern to the above article. It could be an instance of what is now termed "abusive stretching" because the trainer forces the player into a position that could never be achieved without an outside force. It does not take much to imagine what this exercise is doing to the player's groin and hamstring muscles' origins. The athlete has even put his hand on the muscle origins to illustrate the involuntary reaction to potential or actual harm being caused by the exercise and the way it is implemented.
Dr. Larry Holt of Dalhousie University offered the following comments.
"There are a number of things wrong with the picture. The most important observation for me is that the partner by pushing on both legs is creating something analogous to the 'rack'. Simply by forcing the left hip extensor attachments apart, the trainer is creating excessive tension and will either cause or predispose this athlete to a possible tear.
Neither the athlete nor partner is in the correct position. The athlete is not lying flat; the non-exercised leg is off the ground (a protective maneuver) the head and upper trunk should be against the ground without tension. I believe that the flexed right hip and tendency toward posterior pelvic tilt is the athlete's way of trying to minimize the tension on the left hamstrings created by the trainer.
Therefore, I guess the entire protocol is unacceptable".
One has to ask; "How many injuries in baseball are caused by trainers and their stretching routines that entail the type of dangerous and nonsensical activities like that pictured here?"
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