Med Sci Sports Exerc. 2021 Jun 1;53(6):1179-1187. doi: 10.1249/MSS.0000000000002571.
Physical activity benefits bone mass and cortical bone size. The current study assessed the impact of chronic (≥10 yr) physical activity on trabecular microarchitectural properties and microfinite element analyses of estimated bone strength.
Female collegiate-level tennis players (n = 15; age = 20.3 ± 0.9 yr) were used as a within-subject controlled model of chronic unilateral upper-extremity physical activity. Racquet-to-nonracquet arm differences at the distal radius and radial diaphysis were assessed using high-resolution peripheral quantitative computed tomography. The distal tibia and the tibial diaphysis in both legs were also assessed, and cross-country runners (n = 15; age = 20.8 ± 1.2 yr) included as controls.
The distal radius of the racquet arm had 11.8% (95% confidence interval [CI] = 7.9% to 15.7%) greater trabecular bone volume/tissue volume, with trabeculae that were greater in number, thickness, connectivity, and proximity to each other than that in the nonracquet arm (all P < 0.01). Combined with enhanced cortical bone properties, the microarchitectural advantages at the distal radius contributed a 18.7% (95% CI = 13.0% to 24.4%) racquet-to-nonracquet arm difference in predicted load before failure. At the radial diaphysis, predicted load to failure was 9.6% (95% CI = 6.7% to 12.6%) greater in the racquet versus nonracquet arm. There were fewer and smaller side-to-side differences at the distal tibia; however, the tibial diaphysis in the leg opposite the racquet arm was larger with a thicker cortex and had 4.4% (95% CI = 1.7% to 7.1%) greater strength than the contralateral leg.
Chronically elevated physical activity enhances trabecular microarchitecture and microfinite element estimated strength, furthering observations from short-term longitudinal studies. The data also demonstrate that tennis players exhibit crossed symmetry wherein the leg opposite the racquet arm possesses enhanced tibial properties compared with in the contralateral leg.
身体活动有益于骨量和皮质骨大小。本研究评估了慢性（≥10 年）身体活动对小梁微观结构特性和估计骨强度的微有限元分析的影响。
选用女性大学生网球运动员（15 名；年龄=20.3±0.9 岁）作为慢性单侧上肢身体活动的个体内对照模型。使用高分辨率外周定量计算机断层扫描评估桡骨远端和桡骨干的球拍臂与非球拍臂之间的差异。还评估了双侧胫骨远端和胫骨骨干，并纳入越野跑运动员（15 名；年龄=20.8±1.2 岁）作为对照。
球拍臂的桡骨远端的小梁骨体积/组织体积增加了 11.8%（95%置信区间[CI]：7.9%至 15.7%），小梁数量、厚度、连接性和彼此之间的接近度均大于非球拍臂（均 P<0.01）。结合增强的皮质骨特性，桡骨远端的微观结构优势导致在预计失败前的负载中，球拍臂与非球拍臂之间的差异为 18.7%（95%CI：13.0%至 24.4%）。在桡骨干，球拍臂与非球拍臂相比，预计失败时的负载增加了 9.6%（95%CI：6.7%至 12.6%）。在胫骨远端，两侧之间的差异较小，但与球拍臂相对的腿的胫骨骨干较大，皮质较厚，其强度比对侧腿增加了 4.4%（95%CI：1.7%至 7.1%）。
长期增加身体活动可增强小梁微观结构和微有限元估计的强度，进一步证实了短期纵向研究的结果。数据还表明，网球运动员表现出交叉对称性，即与球拍相对的腿的胫骨特性比对侧腿增强。
