This study focused on functional electrical stimulation (FES) to assist production of voluntary movement for gait rehabilitation of hemiplegic subjects. Movements during walking under the low stimulation intensity FES with voluntary effort of dorsiflexion (vL-FES) condition were compared with those under conditions of no stimulation, low intensity FES only and FES. Electrical stimulation was applied to assist ankle dorsiflexion in the swing phase. Gait movements were measured with wireless inertial sensors. It was shown that the vL-FES condition produced partly similar angle pattern with FES condition. It was also suggested from shortened stride time and increased inclination angle range of the thigh that walking speed increased under the vL-FES and FES walking conditions. However, electrical stimulation started at the heel off decreased plantar flexion of the foot at around the toe off. It was considered that the vL-FES condition could be useful as a method of rehabilitation using FES, and that plantar flexion control by FES or modifying the timing of applying electrical stimulation for ankle dorsiflexion had to be studied.