From recent studies, stretching before or after exercising does not confer protection from muscle soreness. In addition, stretching before exercising does not seem to confer a practically useful reduction in the risk of injury, but the generality of this finding needs testing. However, these studies were conducted on military recruits.
Further studies have suggested that stretching before running neither prevents nor causes injury. In fact, the most significant risk factors for injury included the following:
- history of chronic injury or injury in the past four months;
- higher body mass index (BMI); and
- switching pre-run stretching routines (runners who normally stretch stopping and those who did stretch starting to stretch before running).
However, that does not mean not to stretch prior to exercise. Stretching performed before exercise will improve the functional range of movement of a joint that the muscle and the tendon act upon. Once the stretching has been completed a warm up of 10 minutes that moves the body in the new available range of movement would then provide sufficient blood flow and for the body to adapt to the increased range of movement of the joints, and allow the body to perform at a higher intensity through a greater range of movement.
In addition, stretching on a regular basis, e.g., 3-5 days/week, away from the exercise environment may be effective in improving long term flexibility and some types of exercise performance. 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.
Herbert, R: Effects of stretching before and after exercising on muscle soreness and risk of injury: systematic review