Effects of Resistance Training and Walking on Cardiovascular Disease Risk in African-American Women

HORNBUCKLE, L. M., P.-Y. LIU, J. Z. ILICH, J.-S. KIM, B. H. ARJMANDI, and L. B. PANTON. Effects of Resistance Training and Walking on Cardiovascular Disease Risk in African-American Women. Med. Sci. Sports Exerc., Vol. 44, No. 3, pp. 525-533, 2012. Purpose: The study's purpose was to evaluate the effects of walking (W) and walking plus resistance training (WRT) on cardiovascular disease risk factors in inactive middle-aged (49.0 + 5.5 yr) African-Americanwomen (body mass index = 34.7 + 6.4 kg.m(-2)). Methods: Body composition, blood pressure, HDL cholesterol, triglycerides, glycosylated hemoglobin (HbA(1c)), C-reactive protein, and fibrinogen were measured before and after a 12-wk exercise intervention. Subjects were randomly assigned to one of two training groups. The W group (n = 25) was instructed to increase daily pedometer-measured walking to >= 10,000 steps per day, whereas the WRT group (n = 19) was given the same walking prescription plus supervised resistance training 2 d.wk(-1). A two-way repeated-measures ANOVA with an intention-to-treat analysis was performed to examine changes between groups. Significance was accepted at P <= 0.05. Results: Both groups significantly (P < 0.001) increased walking (W = 5453 +/- 2119 to 6845 +/- 2279 steps per day, WRT = 4823 +/- 1758 to 6859 +/- 2012 steps per day). WRT significantly (P < 0.001) increased both upper (100 +/- 15 to 113 +/- 18 kg) and lower (102 +/- 20 to 116 +/- 25 kg) body strength compared with W. WRT significantly decreased waist circumference (94.8 +/- 12.3 to 92.9 +/- 12.0 cm, P = 0.021) and total fat mass (42.6 +/- 11.1 to 41.8 +/- 10.8 kg, P = 0.036) compared with W. WRT also significantly decreased pre- to postintervention body fat (45.8% +/- 6.2% to 45.3% +/- 6.2%, P = 0.018), HbA(1c) (5.9% +/- 1.2% to 5.6% +/- 1.0%, P = 0.028), and mean glucose calculated from HbA(1c) (122 +/- 39 to 114 +/- 32 mg.dL(-1), P = 0.028), whereas W showed no changes. Blood pressure, HDL cholesterol, triglycerides, and C-reactive protein were not affected by either intervention. Conclusions: Although both interventions increased steps per day, WRT was more effective in improving several body composition measures and glucose control in 12 wk. WRT may be an important addition to a lifestyle intervention aiming to facilitate reductions in cardiovascular disease risk factors in overweight and obese African-American women.