Regularity of muscle activities and smoothness of limb movements can be useful characteristics of walking patterns when rehabilitation training protocols are considered. Arm and leg cycling training may improve walking abilities of individuals with incomplete spinal cord injuries (iSCI). Recent studies investigated the effect of simultaneous voluntary arm cycling complemented with functional electrical stimulation assisted leg cycling (hybrid FES cycling) training on walking abilities [1]. Our objective was to find additional metrics that can characterize these changes and quantitatively support the clinical assessments of walking ability. In this paper we present new computational approaches for this purpose. We show that hybrid FES cycling can induce changes in the regularity of muscle activity signals and in the smoothness of leg movements during walking. Entropy of muscle activities and the smoothness of foot trajectory as function of joint angular velocities, accelerations and jerks are investigated in one iSCI patient who participated in low intensity hybrid FES cycling training. The entropy of EMG signals, recorded from knee flexors and extensors, decreased after the training. The decomposition of the jerk of the foot (the endpoint of the leg) into components related to joint angular velocities, accelerations and jerks, shows that the most dominant component is the one which is related to joint angular jerks. This agrees with the results obtained earlier for reaching arm movements [25], [26]. In the case of our participant, the contribution of this component to the total jerk was a bit different between the left and right legs (93% and 85% respectively). After the training, the contribution decreased with 21% on left side and 6% on right side, indicating a more balanced pattern on both sides. We conclude that the two methods, muscle activity entropy and jerk decomposition give important insight to changes into walking patterns and abilities.Clinical Relevance— This study proposes new measures to provide quantitative support for clinical tests to characterize walking ability. It illustrates this through a case study showing that the hybrid, (simultaneous) functional electrical stimulation-assisted leg cycling with volitional arm cranking training may be favorable for improving walking ability after incomplete spinal cord injury.