Increase in bone density. Bone hypertrophy occurs in response to physical activity. The bones in the throwing arm of a baseball pitcher and the racket arm of a tennis player are denser and thicker than the other arm. In addition, physical activity increases bone density throughout the skeletal system, not only in the bones being stressed. Bone hypertrophy is stimulated more by the magnitude of the skeletal loading than by the frequency of loading. Consequently, it appears to be greater in weight-lifters than runners. Although it occurs in response to weight-bearing exercises, it also occurs to a lesser extent in response to some non-weight bearing exercises such as cycling. Swimmers who spend much time in the water, however, may have a lower bone mineral density than that of sedentary individuals. Bone hypertrophy reduces the risk of osteoporosis. Compare bone atrophy.
Subjects: Sports and Exercise Medicine.