THE EFFECT OF CLIPLESS FLOAT DESIGN ON SHOE PEDAL INTERFACE KINETICS AND OVERUSE KNEE INJURIES DURING CYCLING

Pedal kinetics, including the applied moment (M(2)) about an axis orth ogonal to the pedal surface and passing through the center of pressure , were measured across three shoe/pedal interface systems (toe-clip an d strap, clipless fixed, clipless float) and three workrates (150, 250 , 350 W) during steady-state cycling using specially developed multico mpatible force pedals. The applied moment (M(2)) at the pedal is an im portant contributor to the corresponding axial moment realized at the knee and has implications for studying overuse injury mechanics and pr evention of cycling-related knee pain. Data were collected from 27 kne e pain free (KPF) cyclists and 7 cyclists with cycling-related knee pa in. The largest applied moments (M(2)) were observed when clipless fix ed pedals were employed, while clipless float pedals significantly att enuated the applied moment. Cyclists with chronic knee pain exhibited M(2) patterns markedly different from the KPF group, supporting the th eory that relatively high moments, particularly internally applied mom ents during the power phase, may be related to knee loads and subseque nt overuse injury. Our general conclusion is that clipless pedal float designs quantifiably reduce applied moments at the shoe/pedal interfa ce without compromising power transmitted to the bike.