The purpose of this study was to identify the general and individual biomechanical response to increased vertical loading with a particular emphasis on the knee joint in running. Biomechanical analysis was performed in three different loading conditions (100%, 110%, 120% body weight) by means of a standard inverse dynamics procedure using a Vicon Nexus system and an instrumented treadmill. Increased vertical loading was accompanied by increased peak internal knee abduction moments and a small increase (0.6°) of knee adduction angles. Two adaptation mechanisms could be identified, differing with respect to the increase of peak vertical GRF and abduction moments. It might be that runners aim at maintaining their habitual joint motion path, choosing a strategy that corresponds to their capacities to resist additional external loads.