In the old days, running coaches did not try to change the way their athletes ran. The prevailing belief among coaches of the time was that each runner automatically developed the stride that best suited him or her, just by running. Nowadays, the teaching of "correct" running form is quite common. Coaches who subscribe to this practice encourage athletes to alter their stride consciously so that it looks more like an image of perfect form, a grab bag of characteristics that include a high stride rate, forefoot landing and minimal vertical oscillation (or bouncing).

The problem with this practice is that it doesn't work. In fact, research stretching from the 1960s to today has consistently shown that forcing runners to change their natural movement patterns in any way does more harm than good.

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Research Shows Adverse Effects to Changing Your Stride

In a 1982 study, for example, Peter Cavanagh recruited 10 runners and had them run at stride lengths ranging from 20 percent greater than their natural stride length to 20 percent less without changing their pace. All 10 runners consumed the least oxygen—meaning they were most economical—at precisely their natural stride length. In other words, any change to their preferred stride length made them less efficient.

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Thirty years later, a team of Swedish researchers led by Kjartan Halvorsen supplied a group of 16 male runners with visual and auditory feedback that was intended to reduce the amount of vertical displacement in their stride. It worked. All of the subjects were able to trim some of the "wasteful" excess bouncing from their stride. Unfortunately, it turned out the extra bouncing wasn't wasteful at all. "Alterations led to an increase in metabolic cost in most cases," Halvorsen confessed. In other words, changing their natural stride in this way made the runners less, not more, efficient.

When presented with such information, form-fixated coaches often raise an objection, claiming that it takes time to adjust to beneficial stride changes. That may be true, but even when time to adapt is allowed, runners still end up worse off for changing their natural form.

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