| Description |
While several researchers have reported reductions in fat free mass (FFM) and muscular strength following Roux-en-Y gastric bypass (RYGB) surgery, changes in muscle and muscular strength following RYGB have received little attention. A lack of understanding about changes in FFM and muscular strength following RYGB is concerning because on average, individuals elect RYGB after they are 40 years of age, a time when loss of muscle and strength begin a natural decline. Since resistive exercise training has been used to mitigate age-related losses in FFM and strength, this study proposes to determine if a periodized, resistance training program following RYGB (a) increases muscle mass as assessed with MRI-derived thigh muscle cross-sectional area (CSA) and increases muscle quality (MQ); and (b) increases leg strength leading to more time engaged in physical activity (PA). A convenience sample of women having undergone RYGB were recruited (N = 18) and randomly placed into an intervention group (IG; n = 11) and a control group (CG; n = 7). A total of 16 women completed the study. Body composition was assessed using air displacement plethysmography to determine fat mass (FM), fat free mass (FFM), and percent body fat (%BF). Height was measured to determine body mass index (BMI). Unilateral quadriceps 1Repetition Maximum (RM) strength of the right leg was measured using selecterized leg extension equipment. Bilateral, lower body strength was measured using 3RM, 40 degree leg press. Muscle CSA was measured before and after 12 weeks of resistance training using magnetic resonance imaging (MRI). Muscle quality was calculated by dividing quadriceps strength and lower body strength by quadriceps CSA and whole thigh CSA, respectively. Physical activity (PA) was measured using accelerometers. Repeated measures ANOVA was used to analyze outcomes with significance set at p < 0.05. The 12-week periodized resistance training intervention was shown to significantly increase strength and MQ in the IG. However, no change in quadriceps or whole thigh CSA was observed. Most indices of PA did not change significantly (total steps per day, moderate to vigorous physical activity, and sedentary time), but a significant time and interaction effect was observed for light physical activity (LPA; p < 0.05). Improvements in strength and MQ are important for physical function and quality of life and offer protection against the aging process. Due to the conflicting results for muscle CSA with other research, we recommend additional studies examining muscle CSA in the future. We also suggest additional research employing objective techniques to measures PA in those having undergone RYGB. |
