RESUMEN
The purpose of this study was to examine the effects of ankle plantar and dorsal flexion on the lower extremities' dynamics and crank torque in pedaling movements. Twelve males (6 cyclists and 6 non-cyclists) pedaled at the rate of 90 and 120 rpm for a power output of 200W. Subjects were divided into two groups according to the different ankle movement patterns in one crank rotation. The first group (Gr1) showed a one time plantar and dorsal flexion movement in one rotation. The second group (Gr2) showed two plantar and dorsal flexion movements in one rotation. It was assumed that the exertion of positive plantar flexor power in the upstroke phase could provide the difference of the ankle movement patterns. The following results were shown in Gr2 as compared with Grl. 1) The positive crank torque time ratio was extended due to dorsal flexor torque produced near the top dead center. 2) Continuous muscle contraction of the same muscle was avoided and reduction in a burden was brought about due to plantar flexion in the upstroke phase. 3) Reduction of hip extensor torque was shown. These results suggest that two dorsal and plantar flexion movements in one rotation in pedaling could be a more effective pattern in terms of muscle work.