The Effects of Functional Electrical Stimulation Cycling on Muscle Spasticity in Individuals with Spinal Cord Injury: A Systematic Review

To evaluate the effects of functional electrical stimulation (FES) cycling on muscle spasticity in individuals with spinal cord injury (SCI) and provide recommendations for optimal FES cycling parameters to treat muscle spasticity. In this systematic review, database searches of CINAHL, MEDLINE (Ovid), PEDro, PubMed, and Scopus were conducted to identify relevant studies published up to June 2023. Studies were screened for eligibility. Those that included an FES cycling intervention, an outcome measure of spasticity, and were available in full-text English were included. Two independent reviewers extracted the data and appraised the literature via the Crowe Critical Appraisal Tool (CCAT). Of the 1782 studies identified, 16 satisfied the criteria for this review. Two-hundred and three participants were included, aged 7 to 80 years old. Ten studies identified a reduction in spasticity following FES cycling via objective or subjective outcome measures. Methodological quality was variable, with CCAT scores ranging from 19/40 (48%) to 35/40 (88%). National Health and Medical Research Council hierarchy levels ranged from II to IV. Evidence for the effectiveness of FES cycling to reduce muscle spasticity remains inconclusive. Long-term effects on spasticity were evident in moderate- to high-quality studies where FES cycling was conducted for 60 minutes, three times per week for 16 weeks. Additional research with larger sample sizes is warranted to confirm these findings. Further clarification of the optimal parameters of FES frequency, amplitude, and pulse width to reduce spasticity is required.