Is static stretching before exercise good for athletes?

Static stretching before exercise is a controversial topic in the field of strength and conditioning. For several years, many athletes and coaches have incorporated static stretching into the warm-ups of their athletes. Some include static stretching because they feel it is important to prevent injury. However, recent research shows that static stretching before activity may not be all it's cracked up to be! This article will review some of the research and expert advice about static stretching.

PERFORMANCE
Several researchers have determined that static stretching before activity can inhibit and/or decrease the isometric Maximum Voluntary Contraction of muscle (Behm et. al, 2001), 1 Repetition Maximum (Kokkonen et al.), and muscular endurance (Kokkonen et al.).

Fowles et al. (2000) determined that intense and prolonged stretching of the plantar flexors (calf muscles) decreased force production for up to an hour after the stretching protocol. Motor unit activation, however, recovered 15 minutes after the stretching protocol.

Interestingly, Rosenbaum and Henning determined that static stretching might actually improve force development as long as it is followed by a a general-warm up, such as ten minutes of running.

So why does force production decrease after static stretching? Several theories exist. A popular theory has to do with "slack;" The Muscle and/or the muscle tendon become stretched and cannot contract as quickly because the extra stretch must be "taken up" before the peak muscle tension can be reached. A good way to think of this is when you are trying to pull something with a rope - before the object will move, you have to take up the slack in the rope. Taking up the slack in the rope takes time. Since power is the ratio between force production and time, the extra time it takes to "tighten" the rope results in a decreased power.

INJURY PREVENTION
While some researchers have argued that static stretching before activity may prevent injury, many more researchers have determined that it does not (Van Mechelen et al., Macera et al., Gliem and McHugh). Shrier (1999) tallied the number of research articles in favor of static stretching versus not in favor of static stretching, and found that out of 138 articles only 12 research designs used control groups and at least 8 of those studies suggested that stretching before exercise would either increase or make no difference in the rate of injury.

Shrier (1999) suggested four explanations for the failure of pre-exercise stretching to prevent injury. a. Energy absorption by muscle is a factor in injury prevention. Increased flexibility is not associated with an increased absorption of energy. b. Most injuries occur during the eccentric portion of a movement, and may occur during a normal range of motion - meaning, a range of motion that would not be affected by stretching. c. Stretching may cause damage to muscle on a cellular level. d. Static stretching affects muscle by dulling the perception of pain, therefore increasing tolerance for pain during stretching.

CONCLUSION
According to current research, it appears that static stretching before exercise is neither beneficial for performance nor injury prevention. However, more research needs to be conducted with people of various skill levels to determine if differences exist among elite athletes versus the general population in regard to reaction to static stretching. Additionally, more well-designed research is needed for contribution to the current body of literature.

QUESTIONS

Q: I am coaching an athlete who insists upon static stretching before activity. What should I do?! I don't want to argue and endanger my job, but I don't want the athlete to perform badly or I'm in trouble too!

A: Rosenbaum and Henning (1995) determined that force development that was compromised by static stretching returned to normal after 10 minutes of running. Researchers have suggested that, based on the evidence of Rosenbaum and Henning, dynamic movements performed after static stretching might compensate for the decrements created by static stretching. Therefore, try to give your athlete a warm-up in which they static stretch first, followed by nonfatiguing, dynamic, and progressive movements that are similar to the sport activity they are warming up for.

Behm, D. G., D. C. Button, and J. C. Butt (2001). Factors affecting force loss with prolonged stretching. Appl. Physiol. Nutr. Metab. 26(3): 262–272.

Fowles, J. R., Sale, D. B., & MacDougall, J. D. (2000). Reduced strength after passive stretch of the human plantarflexors. Journal of Applied Physiology, 89(3), 1179-1188.
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Gliem and McHugh.

Kokkonen, J., Nelson, A. G., & Cornwell, A. (1998). Acute muscle stretching inhibits maximal strength performance. Research Quarterly for Exercise and Sport, 69(4), 411-415.

Macera, C. A., Pate, R. P., Powell, K. E., et al (1989). Predicting lower-extremity injuries among habitual runners. Archives of Internal Medicine, 149: 2565-2568

McMillian, D. J., Moore, J. H., Hatler, B. S., & Taylor, D. C. (2006). Dynamic vs. static-stretching warm up: The effect on power and agility performance. Journal of Strength and Conditioning Research, 20(3), 492-499.

Rosenbaum, D., and Henning E.M. (1995). The influence of stretching and warm-up exercises on Achilles tendon reflex activity. Journal of Sports Science, 13(6), 481-490.

Shrier, I. (1999). Stretching Before exercise does not reduce the risk of local muscle injury: A critical
review of the clinical and basic science literature. Clinical Journal of Sports Medicine, 9(4), 221-227.

Van Mechelen, W., Hlobil, H. & Kemper, H. C. (1992). Incidence, severity, aetiology and prevention of sports injuries. A review of concepts. Sports Medicine, 14, 82-99.