But there's one you can stop sweating over: your stride.
Biomechanically speaking, shorter and faster strides ease the strain on your knees. (Top runners take 180 steps per minute, while everyday pavement-pounders take a slower 160-170). But if you're trying to be the most efficient runner you can be, then mastering "perfect form" may not be nearly as useful as being yourself, according to new research from Brigham Young University.
That's right. It's more cost-effective for you to fall into your body's instinctive stride than actively try to shorten or lengthen it.
In the study, published in the International Journal of Exercise Science, researchers analyzed 33 runners as they ran on a treadmill for 20 minutes.
Of those 33, 19 were experienced athletes who ran about 20 miles per week, while 14 were amateurs who had never ran more than five miles in a week. The researchers asked each participant to use five different stride lengths: their natural gait, then strides 8–16% longer or shorter than their normal stride. To keep the men and women on track, researchers played a metronome, which beeped to indicate when the runner's foot should strike the treadmill. The runners ran with masks that recorded how much oxygen they used.
Ultimately, both the skilled harriers and the weekend warriers were most efficient (they sucked in less air and thusly used less energy) when they stuck to their preferred stride.
"Many people are advocating for various 'optimal' running forms, but this study shows [that] even novice runners shouldn't try to run any different than their body naturally does," study co-author and USA Track & Field consultant Iain Hunter said in a press release. "Enjoy running, and worry less about what things look like."