A couple of years ago I visited Mammoth Lakes, California, to assist in filming Josh Cox as he performed an epic tempo run in preparation for the California International Marathon. The workout consisted of 15 miles at marathon effort at 7,000 feet of elevation. A few miles into it Cox pulled an iPod out of his shorts and completed the workout jamming to some of his favorite tunes. (A few weeks later he finished second at CIM, setting a new PR. Not with music, though. Elites are ineligible for prize money if they race with headphones.)
Earlier this year I visited Portland, Oregon, to follow Kara Goucher around for a day in connection with a profile I was writing. I ran with Goucher and her husband, Adam, around the Nike campus in the morning. In the afternoon Kara did a second run, this time indoors at home on an Alter-G treadmill. That treadmill sat in a state-of-the-art workout room that the Gouchers had designed into their newly built, 5,000-square-foot home in the hills of Northwest Portland. Included in that room was a dance-club-quality sound system. As Kara ran on the afternoon of my visit she listened to her 2011 Boston Marathon mix (she makes a special mix for every major event) at ear-splitting volume.
As I observed and listened I started to get it. I understood how a good song may alleviate the boredom of a long marathon training run, take the edge off one's suffering during a brutal interval session, or add a layer of pure enjoyment to an easy recovery jog like the one Kara was doing. Especially in harder workouts, like Josh Cox's epic tempo run, the right music almost seemed to act like a (fair, safe, and legal) performance-enhancing drug. But, of course, there's no way something as intangible as a song could change your body's physiological limits. Or could it?
Listen to the Studies
Research suggests that music really can boost athletic performance. For example, a 2009 study by researchers at Liverpool John Moores University in England looked at the effects of music of different tempos on stationary cycling performance. Twelve subjects rode bikes for 25 minutes at a self-selected intensity level on three separate occasions while listening to popular music. Without the subjects' knowledge, the tempo of the music was manipulated so that it was normal in one workout, 10 percent faster than normal in another workout, and 10 percent slower than normal in the remaining workout.
The subjects' average power output over the full 25 minutes was found to be 3.5 percent greater when the music tempo was increased. Their power dropped by 9.8 percent when the music was slowed down.
So clearly fast music is better for performance than slow music. But is music generally better than no music? Yes, according to a 2004 study done by researchers at England's Lincoln University. Student volunteers completed a muscular endurance task (holding a weight as long as they could) while listening to self-selected "motivational music" and again while listening to white noise. The subjects were able to hold the weight significantly longer while listening to music.
Listen to Your Brain
So, how can mere sounds boost a person's physical endurance? The answer to this question has to do with the brain's role in physical performance. Exercise scientists used to believe that fatigue occurred when the muscles or cardiorespiratory system hit some kind of hard physiological limit. For example, the muscles became so acidic that they stopped working properly. It is now understood that such limits are never reached. Instead, the brain imposes fatigue before these limits are reached to protect the body from serious harm.
Because the brain essentially chooses to impose fatigue based on a prediction of where the body's true physiological limits lie, the brain has some flexibility in setting performance limits. When an athlete is highly motivated, the brain will risk a bit more and allow the body to come a little closer to the point of self-harm in pursuit of better performance. All kinds of factors may influence an athlete's level of motivation, and music appears to be one of them.