The project investigates how the asymmetry between the left and right side of a runner’s body is affected by exhaustion from longer distances. The ground reaction forces acting on the body will be assessed in a representative training environment on a path throughout the Virginia Tech campus. A volunteer between the ages of 18-35 can participate if he/she meets the following requirements: He/she runs at least 10 miles per week, has not had an injury in the past 12 months that has kept him/her from running for more than 2 days, and has not had an injury within the past 2 months. Eligible subjects will run two runs: a short, two-mile run, and a long, four-mile run, spaced at least a week apart. The data collected from the study will be used to see if differences in asymmetry patterns exist in an outdoor training environment between long and short runs, and if differences in asymmetry patterns exist between males and females. Please email Kristen Renner if you are interested in participating in this study.