The Science of Running
By Alex Hutchinson Music and Injuries; Lung Power
Music and injuries
People have strong opinions about running with headphones. Some runners wouldn’t dream of leaving the house without them; others feel they create a safety hazard, because you’re less aware of your environment. Back in 2007, the governing body for running in the United States banned headphones in races, both for safety reasons and to prevent runners from getting a competitive edge. After widespread pushback, the rule was relaxed for non-elite runners the following year.
A recent study published in the European Journal of Applied Physiology offers a new twist on the debate: under certain circumstances, researchers from the University of Sassari in Italy argue, running with music might increase your risk of injury. If you can’t hear your footsteps properly, they suggest, you lose the ability to make minor adjustments to ensure that you’re landing softly.
To test this idea, the researchers asked 50 volunteers to perform a series of two-minute runs on a force-sensing treadmill. Each runner tested three different music conditions (no music, music at a moderate volume of 80 decibels and music at a loud volume of 85 decibels) at three different speeds ( 7:30 per kilometre, 6:00 per kilometre and 5:00 per kilometre), for a total of nine trials, completed in random order. The tune was Bruce Springsteen’s “We Take Care of Our Own,” chosen for its “typical rock-based time signature, texture and verse-chorus form, resembling characteristics of playlists commonly employed by runners for motivational purposes.”
Sure enough, t he vert ical “collision force” wit h each foot landing, which some researchers believe is linked to your chances of getting injured, was higher with music – but only with loud music, mainly at the slow and medium paces, and only for men. The effect of volume is easy to understand: 80 decibels wasn’t loud enough to drown out the sound of footsteps, whereas 85 decibels, which is the upper recommended limit for prolonged safe listening, was more immersive.
The effects of speed and gender are trickier to explain. One theory is that the fastest speed required more physical effort and mental attention. As a result, the presence or absence of music made less difference, because the runners were mainly focused on avoiding getting thrown off the back of the treadmill rather than listening to either their footsteps or the music. This could also explain why no effect (on average) was seen among women: since women typically self-select slower paces than men, all three paces may have been too hard for music to have much of an effect.
But there are alternative explanations, as other researchers noted in followup comments published in the journal. One theory is that the differences aren’t about the noise itself but about the psychological response to the music. Earlier studies, for example, have found that men become worse drivers when “hard rock music” is playing, but women’s driving performance is unaffected. Perhaps the men were rocking out to the Springsteen tune while the women, on average, just weren’t that into it.
These unclear and somewhat contradictory results are actually fairly typical for studies of music and running. Music, after all, is a pretty broad category that people have vastly different responses to. Costas Karageorghis, an exercise psychologist at Brunel University in Britain, has identified four key factors that inf luence a listener’s response to a given track: rhythm, musicality, cultural impact and external associations. (Here’s an example of what’s meant by external
associations: even a song with a beat, tune, and lyrics that seem motivational might have the opposite effect if it happens to be the tune that was playing in the background when your partner broke up with you.)
There are some general trends, though. Music tends to boost enjoyment of exercise, particularly at relatively modest paces, likely because it distracts your attention from feelings of discomfort. At faster paces, which take more focus to sustain, that distraction can backfire. And the new results now suggest that the distraction of music might also contribute to sloppier running form at faster paces. That doesn’t mean you need to abandon your headphones. But it adds one more reason to ensure that your tunes aren’t so loud that they completely block out the sounds of the environment – including your footsteps.
The basic rule of training is something called the said principle, which stands for Specific Adaptation to Imposed Demands. Running doesn’t give you big muscles or teach you to play the piano; it gives you springier tendons, calloused feet and a strong, f lexible, bigger-thannormal heart, all of which help you handle the specific demands of covering ground at a rapid pace on two feet. The stronger heart, in particular, is one of a whole chain of adaptations that enable you to ferry oxygen from the air to your muscles as quickly as possible.
But there’s one notable exception to this rule: no matter how hard you train, how hard you pant and how deeply you go into oxygen debt, nothing really happens to your lungs. For decades, physiologists have considered the lungs as “overbuilt,” meaning that they have all the oxygen-pumping capacity they need plus extra to spare, even during the hardest exercise. But that view is now being challenged. In a recent issue of the Journal of Applied Physiology, University of Wisconsin researcher Jerome Dempsey and two colleagues argue that there are certain situations in which the respiratory system reaches its limits – including in highly trained endurance athletes, especially if they’re female, older or visiting high altitudes.
In practice, there’s not much you can do about the size of your lungs, but it may be possible to train the muscles that inf late and def late them. Dempsey points out that respiratory muscles like the diaphragm do get fatigued during hard exercise, and they also compete for oxygen with other muscles like the ones in your legs. Training your respiratory muscles, which typically involves breathing heavily through a specially designed kazoo-like device for a few minutes each day, might help ward off fatigue for a little longer. While results of this approach under ordinary conditions have been mixed, a 2019 review in Frontiers in Physiology found that it kept oxygen levels higher and improved performance during exercise at high altitudes.
Alex Hutchinson is a Toronto journalist specializing in the science of running and other endurance sports.