Association of swing and stance leg accelerations with reaction force characteristics during the initial contact phase of running

Characterization of mechanical load under realistic conditions provides meaningful context for injury risk in runners. The purpose of this study was to determine how reaction forces (RFs) experienced immediately after foot contact were associated with swing and stance leg accelerations measured by inertial measurement units (IMUs) secured to the shank. The body weight RF impulse experienced was associated with swing and stance leg accelerations immediately after foot contact for each leg and pace (r range: 0.51-0.79). Within and across subjects, changes in velocity due to swing (?VSW) and stance (?VST) leg accelerations decreased and increased, respectfully, as change in velocity due to resultant RF impulse (?VRF) increased during initial phase of foot contact. These results indicate that accelerations measured using IMUs can provide insight to the RF encountered when running under realistic training conditions.