Electrical stimulation has been shown to guide neural plasticity due to the interplay between afferent feedback and supraspinal input. Here, we assessed the short-term effects in spinal circuits of different peripheral electrical stimulation (PES) strategies, delivered at the common peroneal nerve below motor threshold for tibialis anterior. Specifically, we evaluated changes in reciprocal Ia inhibition (RI) before, right after, and 30 min after three different stimulation conditions during treadmill walking: 1) PES during stance phase; 2) PES during swing phase; 3) no stimulation. RI increased when PES was delivered during swing and decreased when PES was delivered during stance. On the other hand, RI remained unaltered when there was no stimulation. These results confirm phase-dependent modulation of RI when PES was delivered at different gait phases. These findings have implications for the use of PES in neurorehabilitation and imply that phase-dependent PES is necessary to guide spinal plasticity.