Bone Abstracts

Participation in high impact sports during growth increases bone quality. Gymnasts have previously displayed increased bone mass and strength at both the upper and lower limbs compared with controls. However, it is not yet understood how bone microarchitecture is affected by gymnastics participation, and if this differs based on gymnastics discipline. Therefore, the objective of this study was to investigate the influence of gymnastics discipline on bone microarchitecture in a youth cohort using high-resolution peripheral quantitative computed tomography (HR-pQCT).

Seven artistic and 18 trampolining and tumbling (T&T) gymnasts were recruited. Gymnasts were male and female 16–24 years. HR-pQCT was used to determine bone microarchitecture, specifically total volumetric bone mineral density (Tt.BMD), cortical BMD (Ct.BMD), trabecular BMD (Tb.BMD), total area (Tt.Ar) and cortical thickness (Ct.Th) of the radius and tibia. Finite element analysis estimated apparent bone strength. Muscle strength was determined by grip strength and Biodex dynamometers. The gymnastics-specific non-dominant limb was used for all procedures. Independent sample t-tests and two-way ANOVAs compared group means.

At the radius, artistic gymnasts had bigger bones (Tt.Ar +30%), greater bone density (Tt.BMD +18%; Tb.BMD +36%), higher Ct.Th (+12%) and superior bone strength (+57%) than T&T gymnasts (P<0.05). While there was a trend for artistic gymnasts to have enhanced microarchitectural parameters at the tibia, significant differences between groups did not emerge (P>0.05). Furthermore, gymnasts displayed enhanced bone quality compared to our normative population. There were no significant muscle strength differences between gymnastics groups, and no interaction effect for gymnastics discipline and sex (P>0.05).

Compared with T&T gymnasts, artistic gymnasts had bigger, stronger and denser bones at the radius. Trends for advantageous microarchitectural parameters displayed in these gymnasts are likely the result of the increased mechanical loading observed at the wrist. While both gymnastics disciplines are associated with high ground reaction forces on landings, the trampoline likely dissipates the ground reaction forces observed at the wrist of T&T gymnasts. In addition, many T&T skills do not involve wrist contact with the trampoline or sprung floor. In conclusion, gymnastics discipline influences bone microarchitecture on a skeletal site-specific basis at the radius, but not the tibia.