Influence of physical activity and cessation of training on calcaneal quantitative ultrasound measurements in peripubertal girls: A 1-year prospective study

The aim of this 1-year follow-up study was to investigate the influence of physical activity and cessation of competitive training on the changes in t he sonographic parameters among healthy peripubertal girls. We used calcane al quantitative ultrasound measurements. A total of 174 peripubertal Caucas ian girls aged 11-17 years (61 gymnasts, 58 runners, and 55 nonathletic con trols) were studied. Weight, height, stage of puberty, years of training, a nd the amount of leisure-time physical activity were recorded. Twenty-one s ports participants (9 gymnasts, 12 runners) discontinued their training (re tired) within 6 months from the baseline. The broadband ultrasound attenuat ion (BUA) and the sound of speed (SOS) through the calcaneus were recorded. The mean baseline BUA and SOS values of the nondominant calcaneus of the g ymnasts were 11.9% (72.6 dB/MHz vs 64.9 dB/MHz. P < 0.05) and 2.0% (1600.4 m/s vs 1569.2 m/s. P < 0.001) higher than that of the controls, respectivel y. The baseline BUA and SOS values of the gymnasts and runners were similar . The mean 1-year increase in BUA was significant in the controls and sport s participants who continued their training, whereas the change of BUA amon g the retired sports participants was not. The mean I-year increases of SOS of the runners and controls were 6.6 mis (95% CI 1.5 m/s to 11.7 m/s, P < 0.05) and 3.5 m/s (95% CI 0.5 m/s to 6.4 m/s. P < 0.05), respectively. In c ontrast, the SOS value among the retired runners declined and the 1-year ch ange of SOS was -12.8 m/s (95% CI -22.1 m/s to -3.6 m/s, P <less than> 0.05 ). The 1-year change of SOS among gymnasts was not significant. We conclude that the beneficial effect of exercise on the sonographic parameters of th e calcaneus is evident but, at least partly, temporary. The SOS value decre ases significantly soon after cessation of training and it may reflect the deterioration of the quantity and quality of bone without sufficient mechan ical loading.