Fig. 4.

Force tracings for one subject with cerebral palsy and one subject with typical development cycling at 60 rpm showing the differences in the phasing of force patterns in relation to the position of the crank. These two subjects were of comparable body weight. Positive force indicates pushing into the pedal and negative force indicates pulling away from the pedal, and 0° represents when the crank arm of the cycle is horizontal and farthest away from the subject. As can be seen starting at approximately 270°, the forces for the subject with cerebral palsy began reversing direction from positive to negative sooner than for the subject with typical development. For these subjects, positive forces were present for 139.5° and 176.7° for the subject with cerebral palsy and the subject with typical development, respectively.