Introduction Physical activity involving weight bearing or jumping is beneficial per se to bone mineral accrual in children. However, there is large evidence that sports involving high impact loading (i.e., generated ground reaction forces greater than or equal to 3 times body weight) tend to produce a better overall osteogenic response than sports without impact loading (i.e., generated ground reaction forces = 0 times bodyweight). The aim of this study was to compare the effect of different impact loading sports on bone quality and body composition of pre-menarcheal athletes. Methods Thirty pre-menarcheal girls (aged 11.1±1.33[SD]y) participating in volleyball (VOLLEY, n=10) and artistic gymnastics at high (HGYM, n=10) and low (LGYM, n=10) intensity training underwent total body DXA analysis. Body composition (bone mineral content [BMC], fat-free soft tissue mass [FFST], fat mass [FM], and %FM) was assessed by dual-energy X-ray absorptiometry (DXA) at the total body and regional (arms, legs, trunk) level as well as specific axial skeleton sites (thoracic and lumbar spine, pelvis). Normality of data was assessed with the Kologorov-Smirnov test. Comparison of the three groups of pre-menarcheal athletes was performed with univariate ANOVA taking “group” as the within-subjects factor. Post-hoc analysis used Bonferroni’s correction for multiple comparisons. Statistical analysis was performed with SPSS v.16. Differences were considered significant when P≤0.05. Results After adjusting for body size, total body composition measurements were all significantly (p<0.01) different in the three groups of pre-menarcheal athletes. VOLLEY had lower BMC and FFST, and greater FM and %FM vs. both HGYM and LGYM. The main difference between LGYM and HGYM was greater %FM in the former. Similar results were found at the regional level (but for similar BMC in the legs) and at lumbar spine and pelvis. Linear regression analysis showed that a model using FFST mass the as independent variable is able to explain more than 90% of variance in total body less head BMC in the whole group of impact loading athletes, whereas introducing %FM in the model did not improve its predictive power. Discussion The findings of this study provide evidence that greater bone mineral accrual takes place in pre-menarcheal impact loading athletes participating in artistic gymnastics vs. volleyball and the dose of impact loading activity mainly affect %FM; moreover, results suggest that BMC in the weight-bearing skeleton is strongly.
File in questo prodotto:
Non ci sono file associati a questo prodotto.