Greater medial-lateral regularity for treadmill vs. outdoor running observed in males but not females

Differences in running biomechanics between males and females and between stable and unstable surfaces may have implications for overuse injury. The purpose of this study was to determine whether differences in biomechanical patterns between running surfaces depend on sex. A Principal Components Analysis approach was used to identify major modes of variation within an accelerometer signal during treadmill and sidewalk running for males and females. Treadmill running was characterized by greater regularity and less variability than sidewalk running, however, females maintained a more consistent side-to-side running pattern even as the surface became more unstable.