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from USA Track & Field.......
To stretch or not to stretch? That's a question millions of runners ask themselves daily, but results from a USA Track & Field-sponsored clinical trial involving close to 3,000 runners confirm there is no difference in the risk of injury for those who stretched before running and those who did not.
The study randomly assigned people to perform a specified pre-run stretching routine or to perform no pre-run stretching for a period of 3 months. Those people who completed the study and complied with their group had the same risk of injury (16%) regardless of which group they were in. Overall, stretching did not provide protection against injury.
The study manager, Alan Roth, Ph.D., said, "For the study's specified pre-run stretching routine that millions of runners commonly use, the study puts to rest claims for and against it, but the devil is in the details. Using scientific method, we have arrived at some overall conclusions and learned some important details. If you've been doing pre-run stretching, it is best to keep doing it. A surprise finding was that many variables that we thought would strongly influence injury rates, didn't. For example, injury rates among women and men were similar while mileage, flexibility or level of competition also did not appear relevant. In general, younger runners fared no better than the older runners."
The study's Principal Investigator, Dr. Daniel Pereles, a Maryland-based orthopedist, said that participants provided information on many relevant variables when they enrolled in the study, permitting a thorough analysis of potential risk factors for injury. Participants provided information on such things as age, gender, usual stretching regimen, miles run per week, years running, warm-up activities, measurements of flexibility, concurrent diseases and medications, level of competition and so on.
Two of the variables recorded were found to strongly influence injury rates; people with a higher body-mass-index were more likely to be injured as were people with a recent or chronic injury prior to participating in the study. Participation was limited to runners who had no injuries for the six weeks prior to the study.
One additional risk factor was identified for people who informed us they normally stretch before they run. If they were assigned to stretch, they had a low risk of injury but if they were assigned not to stretch, the injury risk was double those who kept stretching. It's this result that most startlingly exhibits why people consider stretching to prevent injury. This study shows that those who are comfortable with their pre-run stretching routine should maintain it. They risk injury if they discontinue their pre-run stretching. For runners comfortable without pre-run stretching, they don't necessarily improve their injury protection by starting a pre-run stretching routine.
Darby Thompson, the study statistician, commented, "With the number of runners who contributed to this study, we have shown that the difference in injury rates between those performing pre-run stretching and those who did not is negligible. Although we identified other very important risk factors (weight, prior injury, stopping a stretching routine), because this study was specifically investigating the effect of pre-run stretching, other risk factors may influence injury rates but were not identified. More studies like this one should be conducted to confirm or refute the importance of other risk factors."
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a different view of stretching.....
The Role of Stretching [Range of Motion] -----
You'll find that muscle and tendon respond to what is done, and -not-- done. For example ------- sitting at a desk at work//school for many hours per day for many years means you're in a hip flexion position for many hours per day for many years. One should expect to see tight hip flexor muscles and tendons after a period of years, and perhaps lower back problems that may accompany them......Also, sitting at a desk at work//school for many hours per day for many years means you're in a -knee- flexion position for many hours per day for many years. One should expect to see tight -knee- flexor muscles and tendons [ie. hamstring, calf] after a period of years. That gradual loss of flexibility over time is due to exposing muscles and tendons to a given position for many hours per day for many years, without exposing them to the opposite position in a sufficient manner............that's -not- about age or aging.
The duration of stretch needed to increase muscle and tendon "pliability" prior to a workout, is somewhat different than that required to increase or maintain long term "range of motion". Its best to treat stretching in your training program, in the same manner as you would strength training............in that you should have a designated day(s) for specifically going through a designed routine. Muscle and tendon fibers respond to stretching sessions in a similar manner as strength training. Rather than gaining a wider width though, they get longer by adding more sections. If a muscle//tendon lacks the -length-- to allow for limb-joint movement through it's sport required range of motion..some sort of tissue damage should be expected.
The duration of the stimulus [how long you hold the stretch] determines the potency of the stimulus applied [though, a high frequency can take the place of a long duration]. The durations should be about 3 - 4 minutes for each position. In this manner, stretching should be treated as a workout, not preparation for a workout.
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