Most likely if you go to the gym for weights or aerobics, that you pass by the stretching area and spend at least a few minutes following your routine of stretching various muscles. You probably believe (as do many trainers) that stretching decreases your risk of injury, and improves your performance at the gym.
But a growing number of exercise physiologists are coming to the opposite conclusion—that pre-workout stretching neither helps prevent injury nor does it improve your performance at the gym. Today we present two well-executed research studies that cast further doubt on the idea that stretching is good for you.
There are basically two types of stretching: static and dynamic. Static is the traditional holding muscle positions for often 30 seconds or more for each muscle group. Dynamic stretching involves quick motions while you are stretching; for example jumping jacks, or high leg kicks. The research studies we are discussing today only tested static stretching.
The first study was published in the March edition of Scandinavian Journal of Medicine and Science in Sports. The investigators from the University of Zagreb (Croatia) studied hundreds of previous studies regarding stretching, and, through what is called a “meta-analysis”, using sophisticated statistical methods, they analyzed all the data from these separate studies to see if static stretching was beneficial or not.
They concluded that it was not beneficial. They found that on average, static stretching reduced strength in the stretched muscles by nearly 5.5%, and the strength reduction was even worse if the individual held a certain stretch pose for over 90 seconds.
They also found that stretching reduced not only muscle strength, but also muscle power, by as much as 2.8 percent. Power in this sense is when someone needs a muscle for a sudden burst of activity, for example surging out of the start of a race, or blocking a basketball shot, or serving a tennis ball.
You might wonder why this happens and it might be this: stretching does indeed loosen muscles and tendons, but, like a lax elastic waistband in a pair of old shorts, looser muscles are less able to store energy and spring into action.
The second study was published April 2013 in The Journal of Strength and Conditioning Research. Here the researchers studied 17 young men aged 18 to 24. They checked their performance on standard barbell squats both with and without prior static stretching.
The results supported the Croatian study. Without stretching, the men were able to lift 8.3% more weight than they could with pre-workout stretching. And they also felt 23% less stable and more “wobbly” while doing the squats after stretching. The authors recommended dynamic stretching rather than static.
This post might put into question what you have thought was good for you. But this is a good thing. We should not be afraid to question, and re-evaluate, the things we do that we think are making us healthier or better performers. When a number of well-conducted research studies contradict our “conventional wisdom”, we should consider changing our old habits. This happens all the time in medicine.
But if you enjoy stretching, it’s no big problem if you want to continue. As Dr. Robert D. Herbert, professor at the George Institute for Global Health (University of Sydney) summarizes: “There is little evidence that stretching does anything important, but there is also little to be lost from doing it. If you like stretching, then do it. On the other hand, if you don’t like stretching, or are always in a rush to exercise, you won’t be missing out on much if you don’t stretch.”
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