Nordström P, Nordström G, Lorentzon R
Sports Medicine Unit, Department of Orthopaedics, Umeâ University, Sweden, S-901 85 Umeâ, Sweden.
Calcif Tissue Int. 1997 Apr;60(4):332-7. doi: 10.1007/s002239900238.
The objective of this study was to evaluate the relationship among bone mineral density (BMD), physical activity, muscle strength, and body constitution, in young men with a low or moderate level of physical exercise. Another aim was to investigate whether the head is unaffected by physical activity. The subjects consisted of 33 Caucasian healthy men, mean age 24.8 +/- 2.3 years. BMDs of the total body, lumbar spine (L2-L4), femoral neck, Ward's triangle and trochanter, humerus, and head were measured using dual-energy-X-ray absorptiometry (DXA). Bivariate correlations were measured among the different BMD sites and age, weight, height, body mass index (BMI), fat mass, lean body mass, amount of physical activity (hours/week), hamstrings strength, and quadriceps strength. Significant predictors were found for all BMD sites except the head. Using all these variables, only 6% of the variation in BMD of the head could be explained, whereas 46% (total body), 31% (humerus), 17% (lumbar spine), 38% (femoral neck, Ward's), and 41% could be explained for the trochanter. Physical activity and muscle strength were found to be independent significant predictors of BMD of the total body and the sites at the proximal femur. These results suggest that at the time of peak bone mass attainment, physical activity is an important predictor of the clinically relevant proximal femur in young men with a low or moderate level of physical activity. Furthermore, since head BMD was not related to the level of physical activity, we suggest that head BMD may be used as an internal standard, to control for selection bias, in studies investigating the effect of physical activity on bone mass.
本研究的目的是评估体育锻炼水平低或中等的年轻男性的骨密度（BMD）、身体活动、肌肉力量和身体组成之间的关系。另一个目的是调查头部是否不受身体活动的影响。研究对象包括33名白种健康男性，平均年龄24.8±2.3岁。使用双能X线吸收法（DXA）测量全身、腰椎（L2-L4）、股骨颈、沃德三角区和大转子、肱骨以及头部的骨密度。测量不同骨密度部位与年龄、体重、身高、体重指数（BMI）、脂肪量、去脂体重、身体活动量（小时/周）、腘绳肌力量和股四头肌力量之间的双变量相关性。除头部外，所有骨密度部位均发现了显著的预测因素。使用所有这些变量，只能解释头部骨密度变化的6%，而全身为46%、肱骨为31%、腰椎为17%、股骨颈和沃德三角区为38%、大转子为41%。身体活动和肌肉力量被发现是全身和股骨近端部位骨密度的独立显著预测因素。这些结果表明，在达到峰值骨量时，身体活动是体育锻炼水平低或中等的年轻男性临床相关股骨近端骨密度的重要预测因素。此外，由于头部骨密度与身体活动水平无关，我们建议在研究身体活动对骨量的影响时，头部骨密度可作为内部标准，以控制选择偏倚。
