Computing neuromuscular control patterns that minimize acl forces during jump landing in skiing

Jump landing manoeuvres in competitive downhill skiing are typical situations leading to ACL injuries. While, neuromuscular control is considered a key injury risk factor, optimum control strategies are unknown. The purpose of the study was to compute muscle activation patterns that minimize ACL forces during jump landing using a sagittal plane musculoskeletal model of an alpine skier. First, we computed a baseline landing simulation tracking experimental data with a commonly assumed muscle coordination strategy, which minimized the sum of squared muscle activations. Second, we calculated an optimized control strategy minimizing ACL forces after initial ground contact. Using the optimized control strategy the peak ACL force could be substantially reduced from 1.13 BW in the baseline simulation to 0.13 BW. The reduction was primary caused by altered muscle activation patterns of the glutei, hamstrings quadriceps and soleus and was accompanied with only small kinematic changes in the kinematics of the skier.