BONE MASS IN FEMALE VOLLEYBALL PLAYERS - A COMPARISON OF TOTAL AND REGIONAL BONE MASS IN FEMALE VOLLEYBALL PLAYERS AND NONACTIVE FEMALES

The purpose of this cross-sectional study was to evaluate bone mass in female athletes participating in an impact loading sport (volleyball) , and especially to investigate whether any changes in bone mass might be related to the type and magnitude of weightbearing loading and mus cle strength. The volleyball group consisted of 13 first division play ers (age 20.9 +/- 3.7 years) training for about 8 hours/week, and the reference group consisted of 13 nonactive females (age 25.0 +/- 2.4 ye ars) not participating in any kind of regular or organized sport activ ity. The groups were matched according to weight and height. Areal bon e mineral density (BMD) was measured in total body, head, lumbar spine , femoral neck, Ward's triangle, trochanter, the whole femur, and hume rus using dual-energy-X-ray absorptiometry. Isokinetic concentric peak torque of the quadricep and hamstring muscles was measured using an i sokinetic dynamometer. Compared with the controls, the volleyball play ers had a significantly (P < 0.05-0.01) higher BMD of the total body ( 6.1%), lumbar spine (13.2%), femoral neck (15.8%), Ward's triangle (17 .9%), trochanter (18.8%), nondominant femur (8.2%), and humerus (domin ant 9.5%, nondominant 10.0%), but not of the head and the dominant who le femur. The dominant humerus showed significantly higher BMD than th e nondominant humerus in both the volleyball and nonactive group (P < 0.05). There was no significant difference in muscle strength of the t high between the two groups. In the nonactive group, muscle strength i n the quadriceps, and especially hamstrings, was correlated to BMD of the adjacent bones (whole femur, hip sites) and also to distant sites (humerus). However, in the volleyball group there were no correlations between muscle strength and BMD of the adjacent bones, but quadricep strength correlated to BMD of the humerus. These results clearly show that young female volleyball players have a high bone mass. The demons trated high bone mass seems to be related to the type of loading subje cted to each BMD site. Muscle strength of die thigh seems to have litt le impact on BMD in female volleyball players.