Myth Busters: Do You Need to Stretch Before Exercise to Prevent Injury?

The Claim

Many people were taught that holding stretches before a run, a game or a gym session "loosens up" muscles and protects against strains, and that skipping the pre-exercise stretch is asking for an injury.

Does Pre-Exercise Stretching Reduce Injury?

Systematic reviews have repeatedly struggled to find a protective effect. An early review of stretching before and after exercise found that stretching before exercise did not appear to produce a practically useful reduction in injury risk, based on data from two studies of army recruits in military training, though the authors noted that this finding needed testing in other settings (Herbert & Gabriel, 2002). A later meta-analysis of randomised controlled trials found no beneficial effect of stretching on sports injuries, while strength training, proprioception training and programmes combining several exercise types were associated with fewer injuries (Lauersen et al., 2014).

What Stretching Does to the Muscle Right Away

Stretching is not useless: it reliably increases range of motion for a short time, typically less than 30 minutes, possibly through reduced muscle and tendon stiffness or greater tolerance of the stretch sensation (Behm et al., 2016). The more debated question has been performance. Long static holds can temporarily reduce force output, and a systematic review found that this effect was mainly limited to holds of 60 seconds or longer per muscle, while shorter holds of under 60 seconds did not appear to compromise maximal muscle performance (Kay & Blazevich, 2012). Dynamic stretching, in which a joint is taken through a controlled range of motion, was associated with small to moderate performance improvements when performed within minutes of physical activity, while static and proprioceptive neuromuscular facilitation stretching had no clear effect on all-cause or overuse injuries and no injury data were available for dynamic stretching (Behm et al., 2016).

What a Useful Warm-Up Looks Like

The takeaway is not that stretching is harmful, but that it is not the part of a warm-up doing the protective work. Behm and colleagues concluded that stretching within a warm-up that also includes dynamic activity afterwards is reasonable for increasing range of motion without meaningful effects on subsequent performance (Behm et al., 2016). A warm-up built around gradually raising intensity, practising the movements about to be performed and, over the longer term, building strength in the tissues that carry load fits better with what the injury-prevention evidence favours.

Individual needs differ. A person who has a restriction in range, who is returning from injury or who plays a sport demanding extreme flexibility may reasonably use stretching more deliberately, and an assessment can help identify what is relevant to them.

The Verdict