Hybrid training of voluntary and electrical muscle contractions reduces steatosis, insulin resistance, and IL-6 levels in patients with NAFLD: a pilot study

Background Physical inactivity is a risk factor for the development of non-alcoholic fatty liver disease (NAFLD). "Hybrid training", a training that involves both voluntary and electrical muscle contractions, causes beneficial alterations in muscles even after short durations of exercise. The aim of this study was to investigate the therapeutic efficacy of hybrid training in patients with NAFLD. Methods Thirty-five patients with NAFLD who were resistant to lifestyle counseling were assigned to a hybrid-training group (n = 12) or a control group (n = 23). In the hybrid-training group, quadriceps and hamstrings were contracted voluntarily or electrically for 19 min twice a week. In the control group, patients received lifestyle counseling. The therapeutic efficacy of the hybrid training was evaluated after 12 weeks of the intervention. Results Serum alanine aminotransferase (ALT) levels and hepatic steatosis grade were significantly decreased in the hybrid-training group compared to that of the control group (-14.1 +/- A 5.8 vs. 3.5 +/- A 5.4 IU/mL; P < 0.05, -0.67 +/- A 0.19 vs. 0.09 +/- A 0.06 grade; P < 0.01, respectively). No significant changes were seen between the two groups in skeletal muscle mass. The decreases in homeostasis model assessment of insulin resistance (HOMA-IR) value and in serum IL-6 levels were significantly greater in the hybrid-training group than in the control group (-6.2 +/- A 3.2 vs. 0.4 +/- A 0.6; P < 0.05, -3.1 +/- A 1.1 vs. 1.1 +/- A 0.5 pg/mL; P < 0.01, respectively). Conclusion Hybrid training of voluntary and electrical muscle contractions improved hepatic steatosis and reduced insulin resistance and serum IL-6 levels in NAFLD patients who are resistant to lifestyle counseling.