Jennifer Lovejoy, Arivale Chief Science Officer, PhD
Stretching as a pre-exercise warm-up dates back to grade school PE classes for many of us. But, some studies have shown “static” stretching – holding a stretch for 30 seconds to a minute or longer – might actually cause a slight weakening of the muscle, which could lead to reduced performance. This information ultimately led to expert groups, such as the American College of Sports Medicine, to recommend athletes practice “dynamic” stretching – stretching while also moving the muscle – instead of static stretching.
The problem is studies show static stretching is important for decreasing risk of injury, especially in running-based sports or activities, and supporting tendon and ligament health – suggesting static stretching is an important part of a warm-up. In addition, there’s little evidence that dynamic stretching reduces injury risk. Furthermore, previous studies that looked at the impact of static stretching on athletic performance had a number of methodological flaws, including the fact that stretching was sometimes studied as a stand-alone warm-up rather than as part of a complete warm-up the way an athlete would normally use it.
A new study published in Medicine & Science in Sports & Exercise and covered in the New York Times was designed to test the question of whether including short or moderate-duration static or dynamic muscle stretching as part of a comprehensive warm-up routine influences performance in common, high-intensity sporting tasks.
Twenty healthy young men with an average age of 21 were recruited by researchers at the Edith Cowan University in Australia. The experiment involved three different stretching conditions and a non-stretching condition, followed by exercise performance testing.
The three stretching conditions were: five-second static stretch, 30-second static stretch, and five-rep dynamic stretch. The stretching was done as part of a comprehensive warm-up, starting with low-intensity jogging and knee lifts and ending with high-intensity jogging and “test circuits” using gym equipment. Each participant received all four test conditions in random order, separated by a period of at least 72 hours for recovery.
The performance testing included a range of activities, including flexibility testing, vertical jumping, agility testing, and a 20-meter sprint run.
An important part of the study was asking participants about their expectations prior to completing the testing. Psychology plays a huge role in exercise and sport performance; if you believe something is going to positively – or negatively – impact you, it will often turn out that way. The researchers wanted to understand whether a participant’s beliefs about the effectiveness of different types of stretching would impact the results.
The bottom line: There was no change in any measure of exercise performance between any of the stretching routines when compared to a warm-up with no stretching. This was the case even though most participants believed prior to testing that dynamic stretching would benefit their performance.
It’s always gratifying to see a carefully thought-out, well-conducted study addressing an area of scientific/clinical controversy, and this is no exception. The researchers thoughtfully considered all the prior studies, assessed methodological weaknesses, and attempted to design a study that would provide a clearer answer to the question.
In any research, though, there are some limitations. One mentioned by the researchers – but not by the Times – is that the exercise testing involved a “circuit” approach where tests were done in a set order and for a set period of time. Thus, there could be a timing impact with tests done immediately after the warm-up being more influenced by stretching than those tests done at the end. However, they didn’t see any evidence of this when individual tests were analyzed.
Another limitation: The study was small and only conducted in healthy, young men. Thus, as the Times points out, it’s unclear how these results apply to women or older individuals.
Lastly, the maximum duration of stretching in the study was only 30 seconds, and some previous studies suggest it’s actually longer static stretches – a minute or more – that have a negative impact on exercise performance. It’s possible that the stretch times used in this study were too short to produce the effect.
Nonetheless, given that static stretching seems to help reduce risk of muscle-tendon injury, the current recommendations to completely avoid static stretching may need rethinking.
Many people feel more confident in their performance after stretching. If you enjoy stretching and feel it’s helpful for your workout, either static or dynamic stretching can be appropriate. If you are going to do static stretching, however, the key point is to make sure your muscles are warmed up first. Jog in place or go for a short walk and then do your static stretches. Your Arivale Coach or a personal trainer can help you develop a balanced exercise program with the appropriate types of stretching to reach your fitness goals.
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[Arivale Hot Topics address health stories currently in the news. The Arivale Clinical Team’s commentary on these news articles is not a review of the scientific evidence, nor an endorsement of a specific study, and is not meant as official medical opinion.]