RELATIONSHIPS OF MUSCULAR STRENGTH TO LUMBAR AND FEMUR BONE MINERAL DENSITY IN HEALTHLY WOMEN

Abstract

1081 The purpose of this study was to evaluate the relationships of back strength, Thigh strength and handgrip strength to lumbar and femur bone mineral density(BMD) in 754 healthy women(mean age 47.29±7.96). BMD of the 2nd, 3rd, 4th lumbar vertebrae and femural neck were measured by dual energy X-ray absorptiometer (DEXA). Thigh strength and back strength were examined with cybex 6000 system and MedX lumbar extension machine, respectively, and handgrip strength was determined by handgrip dynamometer. The BMD of lumbar(LMBD) correlated with back strength(r=.53, p<.01), age(−.45,p<.01), thigh extensor strength(r=.39, p<.01), body weight(r=.32, p<.01), handgrip strength(r=.31, p<.01), and thigh flexor strength(r=.30, p<.01) and the BMD of femur(FBMD) correlated with age(r=−.43, p<.01), thigh extensor strength(r=.43, p<.01), back strength(r=.40, p<.01), thigh flexor strength(r=.3 4, p<.01), handgrip strength(r=.32, p<.01), and body weight(r=.28, p<.01). By backward multiple regression, the LBMD is affected by age, body weight, and back strength(p<.0001), and the FBMD is affected by age, body weight, thigh extensor and back strength(p<.0001). A multiple regression analysis yielded the following formula for predicted BMD: LBMD=0.9637−0.00772 × age+0.00484×body weight+0.00032×back strength., FBMD=0.7721−0.0057× age+0.0032 × body weight+0.00 18 × thigh extensor strength+0.00012 × back strength. This study suggest that there is close relationship between muscle strength and loss of bone mineral.