Effects of impact‐loaded sport training on bone bending stiffness and BMD in young females (706.16)

Abstract

BLACKGROUND: Participation in high‐impact loading or odd‐impact loading sports is associated with higher bone mineral density (BMD) and bone mass. OBJECTIVE: The objective of this study is to compare the impact of sport training in long‐distance running, soccer and volleyball practice on BMD and bone bending strength in female athletes, 18‐24 years old.METHODS. 57 trained female athletes participated in this study. They were 22 soccer players (SOC), 22 long‐distance runners (RUN), and 13 volleyball players (VOL). Their ages were 19.1, 20.5 and 21.5 yr for the SOC, RUN and VOL, respectively. Sport training history was: 13, 11 and 10 yr for the SOC, RUN and VOL, respectively. Mean height, weight and BMI were 163 cm (±4.7), 59.8 kg (±4.1) and BMI 22.6 kg/m2 (±1.9), respectively. We also recruited 23 non‐athlete females, age 22.6 ± 0.5 yr, as control subjects. Bone bending stiffness was measured using a Mechanical Response Tissue Analyzer (MRTA, NASA‐ARC, CA), an in vivo technique expressed as EI in Nm2. EI was measured at the ulna and tibia. BMD was measured using a Duel‐Energy X‐ray Absorptiometry (PIXI‐DXA, in g/cm2) at two skeletal sites: heel and wrist.RESULTS. There are no differences in height, weight and BMI between the groups, except that VOL were significantly heavier and taller than the other groups. Tibia EI (TEI) of the RUN (122.7±89 Nm2) were significantly lower (p<0.05) than VOL (228±89 Nm2), but not SOC (152±89 Nm2) and CON (85±89 Nm2). RUN has the lower ulnar EI (UEI=30.7±14 Nm2) relative to SOC (44±14 Nm2) and VOL (44±14 Nm2). VOL has significantly higher TEI (228.3±89 Nm2, p<0.05) compared with SOC, RUN and CON. Heel and wrist BMD of the SOC and VOL are 7% to 9.5% higher (p<0.05) than the RUN and CON.CONCLUSION. Volleyball training exhibited greatest osteogenic adaptation in tibial EI compared with RUN and CON, but not in ulnar EI or heel and wrist BMD. Distance running did not induce high osteogenic adaptation in the tibial EI or heel BMD. The mechanism for these changes in bone EI and BMD is unknown.