Effects Of Blood Flow Restriction And Neuromuscular Electrical Stimulation On Muscle And Adipose Tissue Thickness Of The Calves

Abstract

Accelerated muscle atrophy is an important factor to consider in several different environments such as spaceflight, paralysis, immobilization, and aging. Understanding optimal exercise countermeasures in such environments is therefore necessary to examine. PURPOSE: To assess muscle and adipose tissue thickness in the calves while using the unconventional training methods of blood flow restriction (BFR) and neuromuscular electrical stimulation (NMES). METHODS: Six sedentary participants (4 males and 2 females; 20.5 ± 1.4 yrs, 73.5 ± 13.8 kg) underwent 6 weeks of calf training with each leg randomly assigned to one of three conditions: 1) BFR (n=4), 2) NMES (n=3), and 3) combined BFR+NMES (n=5). A control group of seven sedentary participants (4 males and 3 females; 23.1 ± 4.3 yrs, 75.1 ± 12.2 kg) were also used. Adipose tissue thickness was measured via ultrasound and skinfolds while muscle thickness of the gastrocnemius and soleus was assessed via ultrasound. Comparisons were made using separate two-way ANOVA’s for each variable. RESULTS: A significant main effect of time was found for ultrasound measurements of the lateral (p = 0.0021) and medial (p = 0.0467) adipose tissue. A significant interaction effect was found for medial adipose tissue (p = 0.0282) with post-hoc comparisons revealing a significant increase in medial adipose tissue thickness with the BFR (p = 0.0176). No differences were found in muscle thickness for both the medial and lateral gastrocnemius, however, there was a significant main effect of time (p = 0.0025) and interaction (p = 0.0013) for soleus muscle thickness. Post-hoc comparisons showed a significant increase in soleus muscle thickness with the BFR+NMES condition (p = 0.0029) only. CONCLUSION: These results suggest that a combined BFR+NMES training condition may be a feasible method for increasing soleus muscle thickness with 6 weeks of training. Additional research is warranted to elucidate the potential use of BFR and NMES for stimulating positive physiological change in the calves. Supported by National Institute of Health grants UL1GM118979; TL4GM118980; RL5GM118978.