For the past 20 years, static muscle stretching has gotten a bad rap. Once considered an essential part of any sport or warm-up exercisestatic stretching has now been almost entirely removed from the image.
This movement follows extensive research showing that static stretching – where we stretch and then hold the muscle at an extended length for seconds or minutes – can reduce muscle strength (reflected by things like lifting weights), power (eg jump height), running speed, balance and other abilities for a short time after the stretch.
To put the research into context, the average decrease in performance (decreased strength, power, speed) after static stretching across all studies is approximately three to five percent. That might not seem like a lot, but if you consider the sprinter Usain Bolt beat Justin Gatlin by 0.8% and André de Grasse by 1% at the 2016 Olympics, it’s safe to say that a 3-5% deficit could change a life. So, at first glance, it might seem reasonable to remove static stretching from the image.
However, it seems that many of these studies were not designed to answer the specific question of whether stretching affects performance when used in a warm-up, or at least we were able to draw conclusions to the contrary. to actual evidence.
A second look at research
In our recent research review, we found that these studies tell a different story.
When looking only at studies where participants performed muscle stretching as part of a full sports warm-up – that is, when low-intensity exercises are performed before a static stretch of less than 60 seconds per muscle, and exercises specific to higher intensity sports are performed after stretching — then static stretching as part of this full warm-up has no significant effect on actual performance. For example, the average change in sprint speed was -0.15%.
So why for 20 years have we been told that static stretching should be removed from the warm-up?
A major problem is that most research studies have asked participants to stretch much longer than most athletes do during a warm-up. Professional athletes can only stretch 12 to 17 seconds per muscle, on averagebut most research studies have asked participants to stretch each muscle for more than a minute, with some studies imposing 20 or even 30 minutes of stretching.
Additionally, participants’ performance is often tested almost immediately after the stretches, as athletes still complete an additional warm-up and then do other things, such as listening to the coaches’ final instructions, finalizing preparations, or singing a national anthem. When these tasks are included in studies, the negative effects of static stretching are not observed.
Nocebo effect
It’s also important to remember that study participants are often college students, and these students have often learned during their studies that static stretching can lead to impaired performance. That is, there is the possibility of a nocebo effect (negative placebo). In one study, uneducated college students seeking static stretching they were told that stretching would actually improve performance (they were primed for a placebo effect). This instruction resulted in an increase in muscle strength after static stretching.
Thus, the power of the mind can play an important role in determining whether stretching is good or bad. Additionally, when asked immediately after a warm-up, team sports athletes reported feeling more likely to perform well when muscle stretching was included only when omitted. Preparing the brain for exercise may therefore be as important as preparing the muscles.
The case of stretching
If stretching does not improve performance, why include it?
The most obvious reason is that stretching increases range of motion of the joints by its effects on the muscles and the nervous system. That is, there is an enhanced ability to move with ease during activities such as sprint running, hurdling, being placed in extreme wrestling positions, tall gap in dance or gymnastics, football, hockey and other activities that require an enhanced range of motion.
Additionally, most muscle and tendon injuries occur when the muscle is stretched during vigorous activity. Muscle stretching not only increases the range of motion in the joints, but also allows the muscle to exert more force when it is longer. Our review found that this effect is seen even in studies showing loss of strength measured when testing short muscle lengths. Together, these changes can reduce the risk of injury.
But that’s not the end of the story, as muscle stretching has other benefits too. We can use stretching as a form of self-diagnosis, checking different areas of the body for pain or tightness before or after sport and exercise. In addition, muscle stretching can decrease muscle tone, heart rate, and blood pressurereduce anxiety and improve function of our blood vessels. Thus, stretching can play an important role in maintaining cardiovascular health and promoting relaxation.
So static stretching is back, but with some caveats. The advantages of static stretching before exercise seem to outweigh the disadvantages when stretching is incorporated into a full warm-up and when the duration is reasonable (less than 60 seconds per muscle group).
