PROGRESSIVE JUMP AND LOWER BODY RESISTANCE TRAINING HIP BONE MASS IN PREMENOPAUSAL WOMEN

Abstract

259 We studied the effects of one year of progressive high-impact (jump) and lower body resistance training on hip, spine and whole body bone mineral density (BMD) in 30-45 year old healthy, premenopausal women. Forty-five women participated in the training program and thirty-seven women (age = 39±5yrs; height = 166.4±6.5cm; weight = 66.7±10.6 kg) completed twelve months of exercise training (retention = 82%). Twenty-eight women were recruited as controls and twenty-six women (age = 41±3yrs; height = 165.1±9.7); weight = 66.8±13.4 kg) completed the year control period (retention = 93%). Controls were matched to the exercise group on hip BMD, age and weight. Baseline values of anthropometric and bone variables were not significantly different between exercisers and controls. Anthropometric variables did not change over the one year intervention. The training program was held three times per week and consisted of 100 jumps and 100 repetitions of a combination of resistance exercises: squats, front, side and back lunges, per session. Intensity of jumps and resistance exercise was increased via the use of weighted vests, and was expressed as a percentage of body weight (%BW). Jump and resistance intensity was progressively increased over the first ten months, and remained at 10%BW for jumps and 13%BW for resistance exercises for the final two months. Pre- and post-training measurements of the greater trochanter (GT) and femoral neck (FN) of the proximal femur, lumbar spine (LS), and whole body (WB) BMD (g/cm2) were measured via DXA Percent change, standard deviations, and significance values are shown in the table below:TableWe conclude that one year of jump and lower body resistance training significantly increases trochanteric bone mass in adult premenopausal women and, if maintained, could reduce fracture risk in later life. Supported by NASA GSRP and LifeFitness graduate student awards.