Dynamic stretching
Interesting article in the Times about how static stretching, advocated by gym coaches and trainers the world over, is not only unhelpful but detrimental to performance as well.
They point to a recent UNLV study (Samuel et al 2008) that examined the effects of static stretching versus dynamic stretching (versus no-stretch control) on lower-leg performance.
Preactivity stretching is commonly performed by athletes as part of their warm-up routine. However, the most recent literature questions the effectiveness of preactivity stretching. One limitation of this research is that the stretching duration is not realistic for most athletes. Therefore, the purpose of this study was to determine the effects of a practical duration of acute static and ballistic stretching on vertical jump (VJ), lower-extremity power, and quadriceps and hamstring torque. Twenty-four subjects performed a 5-minute warm-up followed by each of the following three conditions on separate days with order counterbalanced: static stretching, ballistic stretching, or no-stretch control condition. Vertical jump was determined with the Vertec VJ system and was also calculated from the ground-reaction forces collected from a Kistler force plate, which also were used to calculate power. Torque output of the quadriceps and hamstrings was measured through knee extension and flexion on the Biodex System 3 Dynamometer at 60 degrees x s(-1). Data normalized for body weight were analyzed using five separate, 3 (stretch condition) x 2 (gender) analysis-of-variance procedures with repeated measures on the factor of stretch condition. The gender x stretch interaction was not significant for any of the four measures, suggesting that the stretching conditions did not affect men and women differently. The results of this study reveal that static and ballistic stretching did not affect VJ, or torque output for the quadriceps and hamstrings. Despite no adverse effect on VJ, stretching did cause a decrease in lower-extremity power, which was surprising. Because of the mixed results, strength coaches would be better served to use dynamic stretching before activity; this has been consistently supported by the literature.
They find no difference vertical jump or lower-leg torque strength between the conditions, but static stretching led to a larger decrease in power than dynamic (both compared to control). However, the effect, while significant, was small.
2 comments:
I thought the consensus now was that what one should do is warm up before an exercise as opposed to stretching. That stretching is good in its own right, but not necessarily as a preparation to be done before another sport.
What is dynamic stretching exactly?
Dynamic stretching is moving a limb to it's endpoint in your range of motion. Basically, look at the image. If someone was taking that person's leg and pushing it up, then that would be static stretching. This is the most common way to stretch, and you basically do it whenever you move one part of your body to stretch another. The person is dynamic stretching because they are lifting their leg as high as they can, and stretching that muscle taut using the muscles in their leg.
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