The Latest Research on Stretching Before Exercise
The evidence on stretching continues to evolve, but many athletes, exercisers, and conditioning coaches either can't or don't keep up with the most recent information, are confused by conflicting research, or simply don't want to change their routines, regardless of the evidence. All you have to do to confirm this observation is to watch the pre-game warm-up activities of many high school, college and professional teams.
In its latest 2007 edition, the Gatorade Sports Science Exchange published a summary of the findings on stretching before exercise. The report was written by Karl Fields, M.D., University of North Carolina; Craig Burnworth, M.D., Elon University (NC); and Martha Delaney, M.A., Greensboro (NC) Area Health Education Center.
The data they present includes a review of 35 studies on stretching, flexibility, and warming up, from 1985 through 2006. Key points are below.
- Traditional stretching routines performed during warm-up procedures before exercise can increase flexibility for a short time, but there is little scientific evidence that such routines can improve exercise performance, reduce delayed-onset muscular soreness, or prevent injuries.
- Stretching on a regular basis may be effective in improving flexibility and some types of exercise performance, and it may reduce the risk of injury, but further research is needed to validate this concept.
- Passive stretching for 15-30 seconds is more effective for increasing flexibility than stretching for shorter durations and is equally effective as stretching for longer periods.
- Increased flexibility is important for sports such as ballet, gymnastics, and swimming, but it may decrease running economy and may be inappropriate for line play in American football and for certain other sports activities where joint stability is critical.
- Stretching just before exercise may cause temporary strength deficits.
- There is some evidence that traditional warm-up procedures that do not include stretching may improve certain types of exercise performance and reduce the risk of sports injuries.
The authors conclude the five-page report by saying, "Clearly, stretching routines performed before exercise can increase flexibility for up to 90 minutes, but there is scant scientific evidence to suggest that such routines can improve exercise performance, reduce delayed-onset muscular soreness, or prevent injuries. It remains to be confirmed whether or not stretching on a regular basis away from the exercise environment is effective in improving some types of exercise performance or reducing injury risk."
In spite of the picture of stretching reflected in research, Fields, Burnworth, and Delaney point out that there are reasonable explanations of why some athletes and exercisers continue to participate in traditional (usually meaning static stretches in which the stretch is held for a few seconds at a point of tension, but not pain) stretches.
First, there are anecdotal accounts of their effectiveness. Second, there are valid criticisms of scientific research because a relatively small number of studies have been conducted in a few sports involving limited populations. Finally, conducting a flawless study on the effectiveness of stretching is difficult, if not impossible.