Quantitative ultrasound of the tibia and radius in prepubertal and early-pubertal female athletes

Background: Physical exercise during childhood has been shown to enhance bone mineral density, thus reducing the risk of osteoporosis. Objective: To examine bone properties, as measured by quantitative ultrasound, in prepubertal and early-pubertal female athletes engaged in impact and non-impact sports. Design: Survey. Setting: General community. Participants: Twenty-five acrobatic gymnasts, 21 swimmers, and 21 control subjects. Athletes had been training for at least 1 1/2 years. Main Outcome Measure: Bone speed of sound (bilateral) at the distal radius and the midtibia. Results: Gymnasts were significantly shorter and lighter than swimmers and control girls (P <. 001) but had a body mass index similar to that of swimmers. Adiposity was lower in athletes than in controls. Speed of sound did not correlate with measures of body size. Higher mean ± SD radial speed of sound values (nondominant side) were observed in gymnasts (3764 ± 104 m/s; P = .045) than in swimmers and control girls (3732 ± 99 and 3721 ± 83 m/s, respectively). Mean ± SD tibial speed of sound values (non-dominant side) were similar in gymnasts and swimmers (3629 ± 87 and 3619 ± 78 m/s, respectively) and higher in the athletic groups than in the control group (3516 ± 127 m/s; P < .001). In all 3 groups, no differences were observed between dominant and nondominant sides in the radii or tibias. Conclusions: Physical exercise, impact and nonimpact, is related to enhanced bone properties, as measured by quantitative ultrasound. Longitudinal studies using various modes of bone evaluation are necessary to determine the long-term effect of various types of exercise on bone properties.