Hutchinson T M, Whalen R T, Cleek T M, Vogel J M, Arnaud S B
Life Sciences Division, NASA Ames Research Center, Moffett Field, CA 94035-1000, USA.
Med Sci Sports Exerc. 1995 May;27(5):745-50.
To determine the factors in daily physical activity that influence the mineral density of the calcaneus, we recorded walking steps and the type and duration of exercise in 43 healthy 26-to 51-yr-old men. Areal (g.cm-2) calcaneal bone mineral density (CBMD) was measured by single energy x-ray densitometry (SXA, Osteon, Inc., Wahiawa, HI). Subjects walked a mean (+/- SD) of 7902 (+/- 2534) steps per day or approximately 3.9 (+/- 1.2) miles daily. Eight subjects reported no exercise activities. The remaining 35 subjects spent 143 (2-772) (median and range) min.wk-1 exercising. Twenty-eight men engaged in exercise activities that generate single leg peak vertical ground reaction forces (GRFz) of 2 or more body weights (high loaders, HL), and 15 reported exercise or daily activities that typically generate GRFz less than 1.5 body weights (low loaders, LL). CBMD was 12% higher in HL than LL (0.668 +/- 0.074 g.cm-2 vs 0.597 +/- 0.062 g.cm-2, P < 0.004). In the HL group, CBMD correlated to reported minutes of high load exercise (r = 0.41, P < 0.03). CBMD was not related to the number of daily walking steps (N = 43, r = 0.03, NS). The results of this study support the concept that the dominant factor in daily physical activity relating to bone mineral density is the participation in site specific high loading activities, i.e., for the calcaneus, high calcaneal loads.
为了确定日常身体活动中影响跟骨矿物质密度的因素，我们记录了43名年龄在26至51岁之间的健康男性的步行步数以及运动类型和时长。采用单能X线骨密度仪（SXA，Osteon公司，瓦西阿瓦，夏威夷州）测量跟骨的面积骨矿物质密度（CBMD，单位：g/cm²）。受试者平均每天步行7902（±2534）步，约合每天3.9（±1.2）英里。8名受试者报告无运动活动。其余35名受试者每周花费143（2 - 772）（中位数及范围）分钟进行运动。28名男性参与了能产生单腿峰值垂直地面反作用力（GRFz）达到或超过2倍体重的运动（高负荷者，HL），15名报告的运动或日常活动通常产生的GRFz小于1.5倍体重（低负荷者，LL）。HL组的CBMD比LL组高12%（分别为0.668±0.074 g/cm²和0.597±0.062 g/cm²，P<0.004）。在HL组中，CBMD与报告的高负荷运动分钟数相关（r = 0.41，P<0.03）。CBMD与每日步行步数无关（N = 43，r = 0.03，无统计学意义）。本研究结果支持以下观点：日常身体活动中与骨矿物质密度相关的主要因素是参与特定部位的高负荷活动，即对于跟骨而言，是高的跟骨负荷。
