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People serious about exercise often stretch before and after running or vigorous exercise. This practice is designed to prevent muscular injury and cramping. Animals who run to stay alive, like gazelles, never seem to pause for a stretch, however.
In the evolutionary race between predators and prey, a split second is the difference between life and death or between hunger and starvation. This means that prey species, like gazelles, must be ready to take off at top speed in an instant. For their part, predators must accelerate rapidly if they want to eat.
So, it stands to reason that wild animals are always ready for action. This means that their muscles are constantly prepared for hard work. The muscles are “warmed up.” Prey animals are constantly on the move so that their muscles remained well-toned.
What about humans, who were both predators and prey?
Stretching and Exercise Physiology
Stretching before exercise may not be a great idea. Indeed, the scientific findings are almost universally negative. There is little evidence stretching before exercise protects against injury and it was found to increase the risk of muscle injury.
That price might be justified if stretched muscles generated improved performance. Instead, the result was consistently reduced performance: jumpers jumped lower, runners ran slower.
Gazelles may not stretch, but they do appear to be well warmed-up. Thomson's gazelles (a particular type of gazelle) have a strange habit of springing high in the air for no obvious reason, a behavior known as “stotting”. It is possible that they are keeping an eye out for danger. Or, they might be letting local lions know how fit they are so that the predators target another, less vigorous animal. Or, they could simply be warming up, doing the gazelle equivalent of jogging on the spot.
Unlike stretching, warm-up exercises have been found to reduce injury. While the quality of this evidence is admittedly mediocre, meta-analysis finds that the effects of warm-ups are consistently positive.
So, we might follow the advice of gazelles and do the warm-up exercises while avoiding stretches. Despite the fact that the adverse effects of stretching have been known to science for at least two decades, many athletes, particularly runners, continue to stretch before their athletic activity. Why?
Why Runners Won't Stop Stretching
Whenever I see a runner going through their stretching routine, I resist the temptation to tell them that they are increasing their chances of injury. No one wants a stranger telling them what to do and the reaction would not be pleasant.
More to the point, perhaps, no amount of evidence is likely to induce runners to give up the preparatory or post-exercise stretch. These are avoidance rituals that reduce the fear of injury.
Such avoidance behaviors are remarkably persistent, based on early ethically fraught avoidance experiments with dogs. In a shuttle-box avoidance setup, dogs learned to jump over a low barrier to reach the other side in order to escape being shocked once a signal light was illuminated. The subjects quickly mastered this problem and always jumped, thereby avoiding shocks.
The researchers wondered when the dogs would stop jumping after the shocking mechanism was disconnected. The answer was: never! Every time the light came on, the dog jumped. Eventually the experimenters grew bored and abandoned the experiment. This helps explain why human stretches continue two decades after scientists reported that they increased injury rates and impaired performance.
Perhaps the gazelles know better.
