Static stretching during warm up: Research vs. real world sports (part 2)

(AP Photo/Fabian Bimmer)

In Part 1, exercise order and static stretch hold times were identified as dissimilarities between research protocols and the traditional warm up progression. These differences raise questions about how applicable research findings are to sport settings. Misinterpretations of results also fuel the controversy.

Recent findings on the effects of static stretching during warm up are still mixed, but more realistic stretching conditions are impacting outcomes. Stretching just prior to performance testing remains a key difference.

Research results. Recent studies (not a complete review) revealed no significant negative effects of preactivity static stretching on strength (1), force production/power (2, 3), muscular performance (4), running economy (5), tennis serve accuracy (6), or balance (7).

However, other studies did show significant negative effects on sprint performance (8), even between repeated sprints (9, 10). Force production was adversely affected by longer, but not shorter, duration stretches (11). One study showed that up to 1 minute of static stretching per muscle group with at least 4 minutes of rest after stretching did not reduce force production on vertical jumping (12), and another found no effect after 90 seconds of static stretching performed 30 seconds prior to the same skill (2).

While research is far from conclusive, shorter stretching durations and longer rest periods appear to reduce the detrimental effects found in some earlier studies. There is so much for researchers to consider that reaching definite conclusions is nearly impossible. The multiple forms of stretching and the research methods used add to the contradictory and confusing information (13).

(AP Photo/Tom Hevezi)

More confusion. Based on the static-before-testing format, scientists sometimes make practical applications that static stretching should be eliminated, or imply that only dynamic stretching should be performed. But they often ignore the option that static stretching could continue to be performed in preparation for dynamic stretching in the warm up progression.

What readers take home. Coaches and athetes may accept practical applications at face value, or zoom in only on a single point or two without reading study details. Nonresearchers often operate under the erroneous assumption that research is an oracle of absolute truth. In reality, researchers look for clues that, when taken together, attempt to explain (basic research) or improve (applied research) some specific aspect of sport performance.

(AP Photo/Kirsty Wigglesworth)

Collectively, reading the "bottom line", taking points out of context, and believing that research is foolproof open the door to misinterpretations. Ultimately, the real world reduces the body of research into one "proven fact"---static stretching before exercise is bad for you.

Case in point. The University of Nevada study (2)(see Part 1) has emerged as the flagship document that spawned a proliferation of popular articles warning of the evils of static stretching. The main point gleaned from the study was that weakened muscles after static stretching produced less force than no stretching at all. Other studies supported the breaking news that dynamic stretching is the only way to go.

Equally astonishing, however, is the news that the Nevada study revealed no significant negative effects of static and ballistic stretching on 4 of 5 measures of strength and power. The only negative effect was on a measure of power derived mathematically from vertical jump readings. The researchers were even surprised at the internally conflicting results between the two power measures, attributing the discrepancy to the coordination required for vertical jumping. The study did not involve dynamic stretching at all, but recommended it based on related literature.

Yet popular articles picked up the single negative finding only. Neither did they report that 4 other tests of strength and power were not adversely affected, nor that one was the vertical jump---the only nonlab test of power used extensively in real world sports. Further, they did not mention that stretching occurred 30 seconds before testing, in contrast to the extended time lapse of the "old school" traditional warm up that some claim to have been "disproved". Infuse a similar telephone effect about related studies, and static stretching may even be "dangerous" as the "evidence" mounts. So it goes that dynamic stretching only is the new wave in the world of warm up.

Perhaps the most important stretch to be bridged is the communication gap that spans preactivity static stretching research and real world sports. If the traditional stretching sequence (cardio-static-dynamic-performance) was a football play under review, there would be no indisputable evidence to overturn the call. Even worse, and unbeknownst to many coaches, a different play (cardio-static-performance) would have been under review by officials (the researchers).

It is safe to say:

Static stretching could be detrimental if held for prolonged periods within a few minutes of sport performance.
There is no evidence for or against performing static stretching before dynamic stretching in the traditional warm up progression.
The results of stretching studies conducted in controlled lab conditions cannot replicate the complex dynamics of athletic performance. Findings must be taken with "a grain of salt" in real world sports.

For more information, check out the references below for details about the studies cited in this article. Also, see Tips for Reading Sport Research using stretching articles as examples. Reading Statistics and Research by Schyler Huck is an excellent resource for college level readers.

Comments and insights are encouraged and welcomed!!

References:

1. Beedle, B., Rytter, S.J., Healy, R.C., & Ward, T.R. (2008). Pretesting static and dynamic stretching does not affect maximal strength. The Journal of Strength and Conditioning Research, 22(6), 1838-1843.

2. Samuel, M.N., Holcomb, W.R., Guadagnoli, M.A., Rubley, M.D., & Wallmann, H. (2008). Acute effects of static and ballistic stretching on measures of strength and power. The Journal of Strength and Conditioning Research, 22(5), 1422-1428.

3. Manoel, M.E., Harris-Love, M.O., Danoff, J.V., & Miller, T.A. (2008). Acute effects of static, dynamic, and proprioceptive neuromuscular facilitation stretching on muscle power in women. The Journal of Strength and Conditioning Research, 22(5), 1528-1534.

4. Torres, E.M, Kraemer, W.J., Vingren, J.L., Volek, J.S., Hatfield, D.L., Spiering, B.A., Ho, J.Y., Fragala, M.S., Thomas, G.A., Anderson, J.M., Hakkinen, K., & Maresh, C.M. (2008). Effects of stretching on upper body muscular performance. The Journal of Strength and Conditioning Research, 22(4), 1279–1285.

5. Hays, P.R. & Walker, A. (2007). Pre-exercise stretching does not impact upon running economy. The Journal of Strength and Conditioning Research, 21(4), 1227-1232.

6. Knudson, D.V., Noffal, G.J., Bahamonde, R. E., Bauer, J. A., & Blackwell, J. R. (2004). Stretching has no effect on tennis serve performance. The Journal of Strength & Conditioning Research, 18(3), 654-656.

7. Costa, P.B., Graves, B.S., Whitehurst, M., & Jacobs, P.L. ( 2009). The acute effects of different durations of static stretching on dynamic balance performance. The Journal of Strength and Conditioning Research, 23(1), 141-147.

8. Sayers, A.L., Farley, R.S., Fuller, D.K., Jubenville, C.B., & Caputo, J.L. (2008). The effect of static stretching on phases of sprint performance in elite soccer players. The Journal of Strength and Conditioning Research, 22(5), 1416-1421.

9. Beckett, J.R.J., Scneiker, K., Wallman, E., Dawson, B.T., & Guelfi, K.J. (2009). Effects of static stretching on repeated sprint and change of direction performance. Medicine and Science in Sports and Exercise, 41(2), 444-450.

10. Sim, A.Y, Dawson, B.T., Guelfi, K.J., Wallman, K.W., & Young, W.B. (2009). Effects of static stretching in warm-up on repeated sprint performance. The Journal of Strength and Conditioning Research, 23(7), 2155-2162

11. Ogura, Y., Miyahara, Y., Naito, H., Katamoto, S., & Aoki, J. (2007). Duration of static stretching influences muscle force production in hamstring muscles. The Journal of Strength & Conditioning Research, 21(3), 788-792.

12. Robbins, J.W. & Scheuermann, B.W. (2008). Varying amounts of acute static stretching and its effect on vertical jump performance. The Journal of Strength and Conditioning Research, 22(3), 781-786.

13. Curry, B.S., Chengkalath, D., Crouch, G.J., Romance, M., & Manns, P.J. (2009). Acute effects of dynamic stretching, static stretching, and light aerobic activity on muscular performance in women. The Journal of Strength and Conditioning Research, 23(6), 1811-1819.