The purpose of this study was to evaluate the relationship between forceplate inaccuracies and joint torques during running. Instrumented gait analysis data were collected on a single subject running above ground. A Monte Carlo analysis was performed using 60 simulations. In each simulation, joint torques were computed as the ground reaction force (GRF) data were perturbed. Errors in joint torques were larger for proximal joints compared to the distal joints. These errors in joint torques were due more to inaccuracies in the GRF magnitude than the center of pressure (COP) measurements. Clinically, these results may be used to determine a priori the forceplate accuracy needed to measure a desired difference in joint torque between patient populations.