The effects of different exercises on regional bone density in young adult female athletes

ABSTRACT

BACKGROUND: Previous studies have suggested that regular exercise may increase bone mineral density. However, the effects on bone mineral density are different depending on the types of exercises and recent studies on the effects of different exercises on bone mineral density are insufficient. This study was conducted to assess the effects of 2 different exercises(Judo, Taekwondo) and physical fitness(back muscle strength, grip strength, broad jump, vertical jump, flexibility, sit ups) on regional BMD. METHODS: Subjects were healthy adults female volunteers aged 19 to 22 years and consisted of eight Judo athletes, twelve Taekwondo athletes, and eight nonathletic controls. We measured their bone mineral density of lumbar spine, femoral neck, femoral greater trochanter, Wards triangle, femoral shaft and distal radius using dual energy X ray absorptiometry and assessed their physical fitness. We investigated the mean differences of regional bone mineral density between the groups and the relationships between physical fitness and regional bone mineral density. RESULTS: ANCOVA revealed that there were significant differences in the regional bone mineral density between the groups. The Judo athletes group had significantly higher bone density of greater trochanter, femoral shaft, distal radius, femoral neck and lumbar spine than the control group and had significantly higher bone density of greater trochanter, femoral shaft and distal radius.than the Taekwondo atheletes group. There were no significant differences of bone density in all the regions between the Taekwondo atheletes and the control groups. Partial correlation coefficients between the back muscle strength and the bone density of Wards triangle, greater trochanter, distal radius, femoral neck, femoral shaft, and lumbar were 0.581, 0.570, 0.526, 0.502, 0.424, and 0.418, Respectively (P<0.05). Correlation coefficients between the broad jump and the bone density of femoral neck, greater trochanter, and femoral shaft were 0.577, 0.539, and 0.457, respectively(P<0.05). Correlations of the grip strength, flexibility, sit ups and vertical jump with bone density of all regions were not high(r< or=0.5). CONCLUSIONS: Different types of exercises showed different effects of bone density. The back muscle strength among the physical fitness factors was considered to be the most important predictor of bone density. In the future, further studies are necessary for the effects of other exercises on bone density.