The effect of neuromuscular electrical stimulation on function outcome measures following muscle fatigue: a systematic review

Abstract

Background: The ability to recover after bouts of fatigue caused by high-intensity physical activity is one of the greatest challenges in sports medicine and exercise science. Neuromuscular electrical stimulation has been used with the theory that it decreases blood metabolites more quickly and therefore decreases recovery time. This systematic review analyzed primary research articles that investigated functional outcomes related to the use of neuromuscular electrical stimulation as a recovery modality. Methods: SportsDiscus, US National Library of Medicine (PubMed), and Current Nursing and Allied Health Literature (CINAHL) were used to search “neuromuscular electrical stimulation” OR “nmes” OR “electric* stimulation” OR “electrostimulation” AND “recovery” OR “muscle recovery” AND “athlete*.” Articles had to contain results from functional tests following fatigue and needed to compare these results between a neuromuscular electrical stimulation group and a passive recovery or control group. Results: One-hundred sixty-two subjects participated in the 11 studies evaluated in the review. Functional outcome measures were obtained in various methods throughout the study. There were inconsistent findings between the studies, with a tendency for the intervention to be ineffective. Conclusions: Inconsistencies between the studies likely attributed to the unclear findings of the review. Several protocols were used throughout the various studies causing multiple variables that could not be isolated. Electrode placement, stimulation frequency and intensity, and functional testing protocols were the major difference between studies that led to the inconsistent findings. Although neuromuscular electrical stimulation is often used as a recovery modality, research findings are mixed regarding its effectiveness as an intervention for recovery. Level of Evidence: Level I.