Therapeutic effect of hybrid training of voluntary and electrical muscle contractions in middle-aged obese women with nonalcoholic fatty liver disease: a pilot trial

Abstract

Sechang Oh,1,4 Tsuyoshi Maruyama,2 Kiyoshi Eguchi,2 Takashi Shida,1 Emi Arai,1 Tomonori Isobe,1 Yoshikazu Okamoto,3 Junichi Shoda1 1Division of Medical Science, Faculty of Medicine, University of Tsukuba, Tsukuba, Ibaraki, Japan; 2Division of Rehabilitation, 3Division of Diagnostic Radiology, University of Tsukuba Hospital, Tsukuba, Ibaraki, Japan; 4Japan Society for the Promotion of Science, Tokyo, Japan Background: Exercise training is an effective therapy for nonalcoholic fatty liver disease (NAFLD). Hybrid training (HYB) of voluntary and electrical muscle contractions was developed to prevent disuse atrophy during space flight. HYB can be applied to obtain a strength training effect accompanying articular movement. In this pilot study, we aimed to investigate the therapeutic efficacy of HYB in NAFLD.Methods: A total of 15 middle-aged obese women with NAFLD who had no improvement in serum alanine aminotransferase levels and/or liver fat deposition after 12 weeks of lifestyle counseling participated in an HYB program. HYB of the quadriceps and hamstrings was conducted for 20 minutes twice a week for 24 weeks.Results: NAFLD patients showed attenuated intramyocellular lipid levels in the quadriceps after the HYB intervention (-15.5%). Levels of leptin (-17.4%), tumor necrosis factor-α (-23.2%), and interleukin-6 (-30.5%) were also decreased after the intervention. HYB led to a significant body weight reduction (-4.7%), which in turn was associated with a significant decrease in serum alanine aminotransferase (-35.8%), gamma-glutamyl transpeptidase (-21.6%), ferritin (-16.0%), oxidative stress (-17.8%) levels, and insulin resistance values (-2.7%).Conclusion: In NAFLD, HYB exerts an antiobesity effect and attenuates liver dysfunction and insulin resistance in association with an increase in muscle strength and a decrease in ectopic muscle fat. Therefore, HYB has great potential as a new type of exercise therapy for liver disease in patients with NAFLD. Keywords: exercise, muscle, nonalcoholic fatty liver disease, obesity, oxidative stress, ectopic fat