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首页> 外文期刊>Medicine and science in sports and exercise >Effect of activity and age on long bones using a new densitometric technique.
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Effect of activity and age on long bones using a new densitometric technique.

机译：使用新的光密度测量技术，可以了解活动和年龄对长骨的影响。

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INTRODUCTION: Long bone structural parameters such as cross-sectional area or area moments of inertia are useful measures of long bone mechanical properties. We implemented a three-scan densitometric method to measure structural parameters in long bones of the lower leg in vivo. The validated method was applied to investigate the relationship between activity level, age, and long bone structural parameters in women. METHODS: An aluminum phantom was used to estimate in vivo setup accuracy. In vivo precision was determined by same-day repeated measures on human subjects. For the activity study, women were recruited in two age groups (25-35, 60+yr) and two activity levels (recreational runners, nonrunners). Scans were taken of the middle third of the lower right leg; structural parameters for the tibia and fibula were determined at each scan line, averaged over the section, and adjusted by factors accounting for body size variations. RESULTS: Aluminum phantom cross-sectional area was underestimated by 4-6%, principal moments were underestimated by <5%, and principal angles were within +/-1.2 degrees. In vivo precision results (lower energy, scans spanning 60 degrees) indicated coefficients of variation for cross-sectional area (A), principal moments of inertia (Imax, Imin), and polar moment of inertia (J) of 0.52, 5.87, 2.22, and 3.82%, respectively. The activity study showed mean adjusted tibial A, Imax, Imin, and J were significantly higher in runners compared with nonrunners. There was no dependence on age. CONCLUSIONS: A three-scan densitometric method for measuring cross-sectional structural parameters in long bones in vivo was validated; accuracy and precision measurements establishes confidence limits. From the activity study results, we postulate that higher loads associated with running lead to increased cross-sectional parameters to support axial loads, bending, and torsion in the tibia.
机译：简介：长骨结构参数（例如横截面积或面积惯性矩）是长骨力学性能的有用度量。我们实施了三扫描光密度法，以测量体内小腿长骨的结构参数。经验证的方法用于研究女性活动水平，年龄和长骨结构参数之间的关系。方法：铝模被用来估计体内设置的准确性。通过对人类受试者进行当天重复测量来确定体内精度。在这项活动研究中，招募了两个年龄段（25-35岁，60岁以上）和两个活动级别（休闲跑步者，非跑步者）的女性。扫描右下腿中部三分之一;在每条扫描线上确定胫骨和腓骨的结构参数，在整个截面上取平均值，并通过考虑人体尺寸变化的因素进行调整。结果：铝模型的横截面积被低估了4-6％，主力矩被低估了<5％，主角在+/- 1.2度以内。体内精度结果（较低的能量，扫描范围为60度）指示横截面积（A），主惯性矩（Imax，Imin）和极惯性矩（J）的变异系数分别为0.52、5.87、2.22 ，和3.82％。活动研究表明，跑步者的平均调整胫骨A，Imax，Imin和J显着高于非跑步者。没有年龄依赖性。结论：验证了一种三扫描光密度法在体内测量长骨横截面结构参数的方法。准确度和精密度测量建立置信度极限。从活动研究结果中，我们推测与跑步相关的更高载荷会导致横截面参数增加，以支持胫骨的轴向载荷，弯曲和扭转。

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