Effects of high-intensity strength training on multiple risk factors for osteoporotic fractures. A randomized controlled trial.

OBJECTIVE: To determine how multiple risk factors for osteoporotic fractures could be modified by high-intensity strength training exercises in postmenopausal women. DESIGN: Randomized controlled trial of 1-year duration. SETTING: Exercise laboratory at Tufts University, Boston, Mass. POPULATION: Forty postmenopausal white women, 50 to 70 years of age, participated in the study; 39 women completed the study. The subjects were sedentary and estrogen-deplete. INTERVENTIONS: High-intensity strength training exercises 2 days per week using five different exercises (n = 20) vs untreated controls (n = 19). MAIN OUTCOME MEASURES: Dual energy x-ray absorptiometry for bone status, one repetition maximum for muscle strength, 24-hour urinary creatinine for muscle mass, and backward tandem walk for dynamic balance. RESULTS: Femoral neck bone mineral density and lumbar spine bone mineral density increased by 0.005 +/- 0.039 g/cm2 (0.9% +/- 4.5%) (mean +/- SD) and 0.009 +/- 0.033 g/cm2 (1.0% +/- 3.6%), respectively, in the strength-trained women and decreased by -0.022 +/- 0.035 g/cm2 (-2.5% +/- 3.8%) and -0.019 +/- 0.035 g/cm2 (-1.8% +/- 3.5%), respectively, in the controls (P = .02 and .04). Total body bone mineral content was preserved in the strength-trained women (+2.0 +/- 68 g; 0.0% +/- 3.0%) and tended to decrease in the controls (-33+77 g; -1.2% +/- 3.4%, P = .12). Muscle mass, muscle strength, and dynamic balance increased in the strength-trained women and decreased in the controls (P = .03 to < .001). CONCLUSIONS: High-intensity strength training exercises are an effective and feasible means to preserve bone density while improving muscle mass, strength, and balance in postmenopausal women.

Duke Scholars

Author William Joseph Evans Medicine, Geriatrics