Purpose: To investigate the effects of eccentric exercise on lower body skeletal muscle mass during rapid body mass loss induced by bariatric surgery. Methods: All participants began 6 to 8 weeks after undergoing Roux-en-Y gastric bypass (RYGB) or sleeve gastrectomy (SG). Skeletal muscle mass (SMM) in the lower body was measured via magnetic resonance imaging (MRI); additional exercise measurements included muscular strength and functional capacity. Quality of life was measured using Short Form 36 (SF-36). Nineteen females (age = 37.6 ± 9.8 yr, height = 164.4 ± 7.2 cm, mass = 106.9 ± 15.6 kg) were randomly assigned to 1 of 3 groups: eccentric exercise (EEX; n = 6), concentric exercise (CEX; n = 7), or standard-of-care control (CON; n = 6). Exercise groups performed 30-minute lower-body exercise sessions 3 times per week for 16 weeks. Each month the exercise tests were evaluated. At the end of 16 weeks, all participants performed the final exercise tests, received a final MRI scan, and completed the SF-36 questionnaire. Results: Thirteen individuals completed the study. All groups lost mass: CON: 21.4 ± 3.7 kg (p < 0.001), CEX: 19.9 ± 4.0 kg (p = 0.001), and EEX: 21.8 ± 3.3 kg (p < 0.001). SMM decreased in all groups: CON: 0.77 ± 0.5 kg (p = 0.18), CEX: 1.19 ± 0.6 kg (p = 0.06), and EEX: 0.90 ± 0.5 kg (p = 0.09). The skeletal muscle loss in percent of total mass loss was 3.7 ± 4.1%. All measures of muscular strength showed no difference, except for a small decrease in dynamic (60°·sec-1) strength in the eccentric group. Functional capacity and physical quality of life increased significantly in all groups (p < 0.05). Conclusion: SMM loss still occurred in the lower body regardless of resistance training, but the loss was less than what was previously documented. Improved postsurgical functional capacity and physical quality of life may be due to a reduction in fat mass and maintenance of muscular strength during the period of rapid mass loss.



College and Department

Life Sciences; Exercise Sciences



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Eccentric, bariatric surgery, skeletal muscle mass, magnetic resonance imaging



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Life Sciences Commons