It was previously believed that static stretching- stretching to the point of resistance and holding for a specific amount of time- prior to exercise would result in improved performance and reduced risk of injury.
A review completed by Simic et al. in 2013 examined the effects of pre-exercise static stretching on activity performance. One of the most significant findings of the study was to avoid the use of static stretching as the only warm-up activity as a negative relationship exists between stretch duration and muscular performance. On the other hand some studies have shown that static stretching during warm up may increase range of motion and reduce the occurrence of muscle strains.
Given the potential effects of static stretching as well as the negative effects it is suggested that static stretching before exercise and activity should be combined with activity specific dynamic stretching (controlled movements through limits of range of motion which mimics the Healthy Body’s movement during the activity that will be completed) to promote blood flow and warm up the muscles to be used. As well, static stretching is important to be added as a cool-down after exercise or activity to decreased muscle soreness after activity.
Reference: Simic L, Sarabon N, Markovic G. Does pre-exercise static stretching inhibit maximal muscular performance? A meta-analytical review. Scand J Med Sci Sports. 2013 Mar;23(2):131-48.