Department of Health, Exercise Sciences, & Recreation Management, University of Mississippi, 215 Turner Center, Oxford, MS 38677, USA.
Aging Clin Exp Res. 2012 Dec;24(6):657-62. doi: 10.3275/8758. Epub 2012 Nov 26.
It is unknown if the site-specific muscle loss of ageing muscle is associated with accelerometer-determined daily step count and/or intensity of physical activity. The purpose of this study was to examine the relationships between accelerometer- determined physical activity and lower body muscle size in women.
Forty-eight women aged 52 to 76 years had their muscle thickness (MTH) measured by B-mode ultrasound at seven sites on the anterior and posterior aspects of their upper- and lower-leg. Daytime physical activity was measured using an accelerometer on 30 consecutive days and the total duration of each level of exercise intensity (light-PA, moderate-PA and vigorous-PA), average step count, and physical activity-related energy expenditure were calculated.
Age was inversely correlated with anterior 30% upper-leg MTH (r=-0.296, p<0.05), but not with other measured MTH sites. Light-PA was not significantly (p>0.05) correlated with measured lower body MTH. However, moderate-PA was correlated (p<0.05) with lower-leg MTH, while vigorous-PA was correlated (p<0.05) with lower-leg and anterior 30% upper- leg MTH. Following adjustment for confounding factors, the anterior and posterior lower-leg MTH was positively correlated (p<0.05) with duration of moderate- PA and vigorous-PA, as well as average step count.
Thus daily moderate and vigorous physical activity was associated with higher muscle mass in the lower leg, but not in the upper-leg muscle, suggesting that the site-specific upper-leg muscle loss may not be prevented or attenuated by daily physical activity.
目前尚不清楚衰老肌肉的特定部位肌肉损失是否与加速度计测定的日常步数和/或身体活动强度有关。本研究的目的是检查加速度计测定的身体活动与女性下肢肌肉大小之间的关系。
48 名年龄在 52 至 76 岁之间的女性，通过 B 型超声在其上下肢前后面的七个部位测量肌肉厚度（MTH）。在 30 天的连续时间内，使用加速度计测量白天的身体活动，计算每种运动强度（轻度 PA、中度 PA 和剧烈 PA）的总持续时间、平均步数和与身体活动相关的能量消耗。
年龄与上肢前 30%MTH 呈负相关（r=-0.296，p<0.05），但与其他测量的 MTH 部位无关。轻度 PA 与下肢 MTH 无显著相关性（p>0.05）。然而，中度 PA 与小腿 MTH 呈正相关（p<0.05），而剧烈 PA 与小腿和上肢前 30%MTH 呈正相关（p<0.05）。在调整混杂因素后，前后小腿 MTH 与中度 PA 和剧烈 PA 的持续时间以及平均步数呈正相关（p<0.05）。
因此，日常中度和剧烈身体活动与小腿肌肉质量较高有关，但与上肢肌肉无关，这表明特定部位的上肢肌肉损失可能无法通过日常身体活动来预防或减轻。
