Muscle force strategies in relation to saddle setback management in cycling

The correct cycling posture consists in both enhancement of the performance and avoiding injuries related to a badly adjusted posture. In particular, several authors underlined that the most common injuries encountered by road racing cyclists (i.e. patellofemoral pain, biceps femoris or quadriceps tendonitis) are related to a badly adjusted fore-aft saddle position (De Vey Mestdagh 1998). The forward-leaning lower limb configuration of the cyclist changes with fore-aft saddle position. Although external cycling power is produced mainly by muscles that span the ankle, knee and hip joints (Martin et al. 2000), these postural constraints probably influence the amplitude and the pattern of muscle forces. Therefore, the changes in muscle coordination strategy related to saddle setback management directly affect lower limb’s ligament and bone-to-bone forces. The purpose of this study was to estimate the effect of changes in fore-aft saddle position on individual muscle forces produced by the cyclist. The main hypothesis was that for a given external power output, a forward position would lead to greater knee extensor muscle forces.