Runners: Protect your legs with fewer distractions

Runners often seek distraction from the task at hand. Whether it be music, texting, daydreaming, taking in the sights, or propping a book up on the treadmill, more often than not a distraction is welcome. But, researchers from the University of Florida have recently discovered those distractions may lead to injury.

"There isn't a lot of research that looks at the connections between cognitive stressors, or distractions, and injury risk, says Daniel Herman, MD, PHD; assistant professor at University of Florida Department of Orthopedics and Rehabilitation and lead investigator in the study. "This is an important topic to study as runners commonly attend to distractions such as music, crowd noise, or other runners."

Dr. Herman's team looked at the effect of auditory and visual distractions on 14 runners to determine what effect, if any, these distractions would have on things such as how much a runner breathes per minute and how much of that oxygen is utilized by the body, heart rate, the amount of energy expended, running rhythm, the length and width of steps, the speed in which runners apply force to their bodies, and the force the ground applies to the runners' bodies when they come in contact with it.

The runners -- eight men and six women -- were all injury free at the time of the study, and they were approximately 26 years old. On average, the runners logged 31 miles each week.

Dr. Herman's team had each participant run on a treadmill three separate times. The first time was without any distractions. The second time added a visual distraction, which consisted of the runner concentrating on a screen displaying different letters in different colors with the runner having to note when a specific letter-color combination appeared. The third time added an auditory distraction similar to the visual distraction, with the runner having to note when a particular word was spoken by a particular voice.

When compared to running without distractions, the participants had faster application of force to their left and right legs (called loading rate) with auditory and visual distractions. They also experienced an increased amount of force from the ground (called ground reaction force) on both legs with auditory distractions. Finally, the runners tended to breathe heavier and have higher heart rates with auditory and visual distractions than without any distractions at all.

"Running in environments with different distracting features may adversely affect running performance and injury risk," explains Dr. Herman. "Sometimes these things cannot be helped, but you may be able to minimize potentially cumulative effects. For example, when running a new route in a chaotic environment such as during a destination marathon, you may want to skip listening to something which may require more attention -- like a new song playlist or a podcast."

Dr. Herman's team will continue to investigate the potential relationship between distracted running and leg injuries, including the characteristics of runners who may be more or less susceptible to this effect, and any effect this relationship has on different training techniques that use auditory or visual cues.