The fascicular anatomy of the sciatic nerve may not influence the muscular activity of the biceps femoris after applying percutaneous electrical nerve stimulation: a randomized clinical trial

Abstract

Background: Electrical nerve stimulation is an effective therapeutic tool in the field of rehabilitation for the management of musculoskeletal conditions. Objective: To analyze the muscle activity of the short head of the biceps femoris (SHBF) and long head of the biceps femoris (LHBF) after the application of percutaneous electrical nerve stimulation to the common fibular versus tibial nerve compartment of the sciatic nerve. Methods: Thirty-eight healthy subjects received electrical stimulation (asymmetric biphasic rectangular waveforms) through a needle in the sciatic nerve. The sample was divided into two groups in which the technique was applied to the lateral compartment versus medial compartment of the nerve, respectively. The protocol used included 5 s of stimulation at a frequency of 100 Hz and a phase duration of 350 ms, followed by 55 s of rest, for 5 min. The electrical activity of the SHBF and LHBF and the muscle strength of the knee flexors was assessed by surface electromyography during isometric knee flexion in the prone position. Results: Neither group showed significant changes (p > 0.05) in any variable after the intervention compared with baseline values. Similarly, there were no significant differences in any of the study variables when comparing both groups (p > 0.05). Conclusion: Selective stimulation of the sciatic nerve by percutaneous electrical nerve stimulation had no measurable effects on muscle activity in the SHBF or LHBF, regardless of the approach applied. Trial registration number: NCT05549700 (ClinicalTrials.gov).