Being a flexible runner can be useful. It can also make you less efficient. People most commonly stretch to relieve the muscle tightness and soreness that are a product of hard training. As this article from Competitor mentions, there’s no good reason our bodies would adapt in a way that didn’t benefit us, so do we get tight after a tough workout? Our muscles shorten because increased flexibility can actually have a negative effect on performance. Here’s how being a too flexible runner can change the way your body performs for the worse.
Think of your muscles as rubber bands. There’s something to be said for tightly pulled rubber bands. Tight bands are loaded with energy, waiting to explode. Loose bands aren’t quite as ready to propel your body in one direction or another. Static stretching, or loosening up, takes our tightly pulled rubber band muscles and makes them slack. The relaxed muscles of a very flexible runner aren’t holding as much energy or as ready to perform as the tighter muscles of less flexible runner.
Stiffer muscles are also better springs. They are better than stretched muscles at responding to impact with the ground, absorbing that energy and using it to move us forward with each step. Being good at translating energy from the ground into forward movement is necessary for efficient running. One study found that a group of runners who did static stretches before running had to make a bigger effort and had less efficiency at the start than those who had not, though the groups’ efforts eventually evened out. Increasing running efficiency is the key to faster finish times and staying injury free.
While touching your toes might not be the most powerful indicator of running performance, it is still important to be a flexible runner. Having appropriate ranges of motion around the hips and ankles will help prevent injuries, and some of the world’s best runners have been shown to have bigger ranges of motion around their hips than the rest of us. Most of us also spend a lot more time sitting, which shortens the hamstrings, and wearing shoes, which shortens the Achilles and calf muscles. Stretching these muscle groups to restore normal mobility should be part of your daily routine.
If a little stretch before or after your run feels good, keep it up. Just be sure to hold for a short time and consider using a foam roller to make those muscles feel better instead.