Skeletal differences at the ulna and radius between pre-pubertal non-elite female gymnasts and non-gymnasts.

OBJECTIVE To compare skeletal parameters between the ulna and radius in pre-pubertal non-elite gymnasts and non-gymnasts. METHODS Fifty-eight non-elite artistic gymnasts, aged 6-11 years, were compared with 28 non-gymnasts for bone mineral content (BMC), total and cortical bone area (ToA, CoA), trabecular and cortical volumetric density (TrD, CoD) and estimated bone strength (BSI and SSIp), obtained by pQCT at the distal and proximal forearm. RESULTS Gymnasts had greater estimated bone strength than non-gymnasts at both sites of the forearm. At the distal forearm, the gymnastics-induced skeletal benefits were greater at the radius than ulna (Z-scores for BMC, TrD and BSI +0.40 to +0.61 SD, p<0.05 vs. +0.15 to +0.48 SD, NS). At the proximal forearm, the skeletal benefits were greater at the ulna than the radius (Z-scores for BMC, ToA, CoA and SSIp +0.59 to +0.82 SD, p<0.01 vs. +0.35 (ToA) and +0.43 SD (SSIp), p<0.01). CONCLUSION Skeletal benefits at the distal and proximal forearm emerged in young non-elite gymnasts. Benefits were larger when considering skeletal parameters at both the ulna and radius, than the radius alone as traditionally performed with pQCT. These findings suggest the ulna is worth investigating in future studies aiming to accurately quantify exercise-induced skeletal adaptations.