Most would probably agree that stretching is an important part of a well-balanced fitness routine, but exactly when should you stretch? Before or after your workout? Both? Neither? To tease out the pros and cons, let’s take a look at what the fitness literature has to say about these options.
Stretching Before Exercise
If you’re like most, you’re probably convinced that stretching before exercise is important for the prevention of injury. Would it surprise you to learn that the scientific evidence does not support this theory?
The confusion appears to have arisen as a result of the type of studies and evidence used as a basis for this recommendation. As explained in the editorial,1 “Stretching Before Exercise: An Evidence Based Approach,” published in the British Journal of Sports Medicine in 2000:2
“Clinicians are under increasing pressure to … practice evidence based medicine. Although some authors argue that only research from human randomized clinical trials (RCTs) should be used to determine clinical management, an alternative is to consider the study design (RCT, cohort, basic science, etc) as one of many variables, and that no evidence should be discarded a priori.
In other words, the careful interpretation of all evidence is, and has always been, the real art of medicine. This editorial explores these concepts using the sport medicine example of promoting stretching before exercise to prevent injury.
In summary, a previous critical review of both clinical and basic science literature suggested that such stretching would not prevent injury. This conclusion was subsequently supported by a large RCT published five months later. Had the review relied only on previous RCT data, or even RCT and cohort data, the conclusions would likely have been the opposite, and incorrect.”
The paper goes on to list a number of observations that refute the idea that stretching before exercise makes you less prone to injury, including the following:
- Most injuries occur during eccentric contraction within normal range of motion; therefore, increasing your range of motion before exercise is unlikely to prevent injury
- Even mild stretching can cause damage at the cytoskeletal level
- Stretching appears to increase pain tolerance, which could encourage injury
As noted in the paper, “It does not seem prudent to decrease one’s tolerance to pain, possibly create some damage at the cytoskeletal level and then exercise this damaged anaesthetized muscle. Of note, there is no basic science evidence to suggest that stretching would decrease injuries.”
No Useful Benefit of Stretching Before Exercise
Later reviews seem to support what the featured editorial is saying. For example, a 2002 systematic review3 in the BMJ, which included five studies that assessed the effects of stretching before and after exercising on post-exercise muscle soreness, concluded that “Stretching produced small and statistically nonsignificant reductions in muscle soreness” after a bout of exercise.
This finding applied whether the stretching was done before or after exercise. Data from two army studies included in this BMJ review also showed stretching before exercise failed to reduce the risk of injury.
Another review paper,4 published in the Journal of Athletic Training in 2005, also analyzed data from studies using military recruits, concluding that “the combined risk reduction of 5% indicates that the stretching protocols used in these studies do not meaningfully reduce lower extremity injury risk …”