Resistance Training Enhances Muscle Function and Hemorheological Properties in Middle-aged Obese Women.

PURPOSE: The present study investigated the effects of resistance training for 12-week on body composition, blood pressure, blood lipid level, cross sectional area (CSA) of muscles, isokinetic muscle function, and hemorheological properties in middle-aged obese women.

METHODS: Thirty obese women (50.79 ± 5.80 years), with no history of any injuries to the musculoskeletal system and no participating any regular exercise program, were included in the present study. All participants were randomly assigned to a control group (CON, n = 15) or an experimental group (EXP, n = 15); but two participants in the CON voluntarily withdrew because of personal reasons, and thirteen participants in the CON finally participated. The EXP underwent resistance training program composed of warm-up, main resistance exercise (bench press, preacher bench biceps curl, barbell rowing, dumbbell shoulder press, dead lift, barbell squat, seated leg extension, and lying leg curl), and cool-down. Main resistance exercise was consisted of three sets of 8-10 repetitions (reps) performed with 80% of 1-RM. The training frequency was 80 min, 3 days per week for 12 weeks. The CON maintained their daily lifestyle without training. All participants underwent body composition (weight, body mass index, lean body mass, fat mass, and %body fat), blood pressure (systolic blood pressure, diastolic blood pressure, mean arterial pressure, and pulse pressure), blood lipid level (triglyceride, total cholesterol, high-density lipoprotein cholesterol, and low-density lipoprotein cholesterol), cross sectional area (CSA) of muscles (quadriceps CSA, hamstring CSA, and total thigh muscle CSA), isokinetic muscle function (peak torque, relative peak torque, mean power, and total work in quadriceps femoris and hamstrings), and hemorheological properties (erythrocyte deformability and erythrocyte aggregation) were measured before and after 12-week of training.

RESULTS: The EXP showed a significant decrease in fat mass (p = .018) via 12-week of resistance training. Also, the EXP yielded more significant improved muscle function including peak torque (p < .001), relative peak torque (p < .001), and total work (p = .001) in quadriceps femoris and total work (p = .018) in hamstrings. Regarding hemorheological properties, the EXP showed a significant increase in erythrocyte deformability (p = .001) via 12-week of resistance training. However, there was no significant change in blood pressure and muscle CSA parameters via 12-weeks of resistance training.

CONCLUSION: The present study verified our resistance training program shows greater muscle strength and endurance, decreasing fat mass, and improving hemorheological properties such as erythrocyte deformability.