Neuromuscular electrical stimulation during recovery from exercise: a systematic review

The use of subtetanic low-intensity neuromuscular electrical stimulation (NMES) for the purpose of promoting recovery from exercise has increased in recent years. The aim of this systematic review was to assess the effects of NMES on exercise recovery. A computerized database search of PubMed, CINAHL Plus, Sport Discus, and Cochrane Library electronic databases was conducted for the time period of January 1, 1970 to March 8, 2012. Only studies that used healthy uninjured humans and motor threshold electrical stimulation compared with at least one other recovery modality for the purpose of promoting recovery from exercise were eligible for selection. Thirteen studies satisfied the inclusion criteria and were included for analysis (11 randomized crossover trials, 1 randomized control trial [RCT], and 1 classified as other [OTH]). A quality assessment rating of the studies was performed using an extended version of The Cochrane Collaboration's tool for assessing risk of bias. Because of the heterogeneity of the study protocols, a qualitative review (best evidence synthesis) was performed for all outcomes, whereas the results for blood lactate (BLa) were also included in a meta-analysis. Eight studies were classified as high quality, 4 as medium quality, and 1 as low quality. Three studies found a positive outcome for a subjective measure of muscle pain, 3 for BLa, 1 for lowering creatine kinase, and only 1 for a performance parameter. The meta-analysis showed no evidence in favor of NMES vs. active (ACT) and mixed evidence vs. passive (PAS) recovery for BLa. In conclusion, although there may be some subjective benefits for postexercise recovery, evidence is not convincing to support NMES for enhancing subsequent performance.