You'd be hard-pressed to find a treadmill runner who isn't tethered to their smartphone (or dinosaur iPod), running with their head cranked back to watch sports recaps on TV, or flexing their multitasking skills by texting mid-run.
And while the distractions are a welcomed reprieve from the monotony of the "tread shred"—hell, even outdoor runs—new research from the Association of Academic Physiatrists suggests that runners who bombard themselves with more visual and auditory distractions are more inclined to suffer leg injuries.
In the (admittedly extremely small) study, researchers corralled 14 runners—injury-free, about 26 years old, who logged approximately 31 miles each week—and put them through three test trials. During the first run, the runners were left alone. During the second, the runners concentrated on a screen that displayed varying letters in different colors; participants had to note when a specific letter-color combo flashed across the screen. And for the third test, runners had to indicate when a particular word was spoken by a certain voice.
Compared to running without the distractions, men and women who contended with visual and auditory distractions experienced faster loading rates and greater force impact from the ground, which in turn means more force absorbed by the body. The runners also tended to breathe heavier and have higher heart rates, which eats up more oxygen and urges you to use more energy.
All of these factors also influence your running rhythm—the length and width of your strides, which can throw off your typical cadence and momentum, further upping your odds for injury. And when your brain has too much stimuli to process—everything from chatty gym goers to a busy running route, music to daydreaming—your training and focus suffer.
Yeah, we know: "Sometimes these things cannot be helped," lead study author Daniel Herman, M.D., Ph.D., noted in a press release. "But you may be able to minimize potentially cumulative effect. For example, when running a new route in a chaotic environment [like] a destination marathon, you may want to skip listening to something which may require more attention—like a new song playlist or a podcast," he suggests.
Focus on regulating your breathing, re-checking your form, and keeping your mental focus sharp. At the very least, stick to a familiar playlist. You might just unlock some new personal bests as a result.