The effects of dual-channel functional electrical stimulation on stance phase sagittal kinematics in patients with hemiparesis

Your therapist  can explain how this might help your walking/stance. Although I will never allow one to eStim my hamstring again.
http://www.jelectromyographykinesiology.com/article/S1050-6411%2812%2900200-3/abstract

Abstract 

Sixteen subjects (aged 54.2±14.1years) with hemiparesis (7.9±7.1years since diagnosis) demonstrating a foot-drop and hamstrings muscle weakness were fitted with a dual-channel functional electrical stimulation (FES) system activating the dorsiflexors and hamstrings muscles. Measurements of gait performance were collected after a conditioning period of 6weeks, during which the subjects used the system throughout the day. Gait was assessed with and without the dual-channel FES system, as well as with peroneal stimulation alone. Outcomes included lower limb kinematics and the step length taken with the non-paretic leg. Results with the dual-channel FES indicate that in the subgroup of subjects who demonstrated reduced hip extension but no knee hyperextension (n=9), hamstrings FES increased hip extension during terminal stance without affecting the knee. Similarly, in the subgroup of subjects who demonstrated knee hyperextension but no limitation in hip extension (n=7), FES restrained knee hyperextension without having an impact on hip movement. Additionally, step length was increased in all subjects. The peroneal FES had a positive effect only on the ankle. The results suggest that dual-channel FES for the dorsiflexors and hamstrings muscles may affect lower limb control beyond that which can be attributed to peroneal stimulation alone.