METHODS FOR DETERMINING HIP MOVEMENT IN SEATED CYCLING AND THEIR EFFECT ON KINEMATICS AND KINETICS

In a previous paper (Neptune & I-lull, 1995), a new video-based method (ASIS) for locating the hip joint center (HJC) in seated cycling was shown to be more accurate than tracking a marker placed over the super ior aspect of the greater trochanter (TRO). The main goal of the prese nt study was to see if the conclusions presented in Neptune and Hull ( 1995) may be applied to other cyclists. Lower limb kinematic and pedal force data were collected from 7 cyclists at nine combinations of ped aling rate and work rate. ASIS produced significantly different hip jo int movement patterns than TRO, which resulted in significantly differ ent power and work calculations developed by the intersegmental hip jo int force, at all combinations except one. A significant quadratic tre nd was evident as a function of pedaling rate, and a significant linea r trend was evident for work late. At naturally preferred pedaling rat es (similar to 90 rpm) and lower work rates (<225 W), the hip joint mo vement was minimum. Under these conditions, the fixed hip assumption i s least prone to error.