Faculty of Liberal Arts and Sciences, Bunka Gakuen University, 3-22-1 Yoyogi, Shibuya-ku, Tokyo, 151-8523, Japan.
Faculty Health and Sport Sciences, University of Tsukuba, Tsukuba, Japan.
BMC Geriatr. 2017 Dec 6;17(1):280. doi: 10.1186/s12877-017-0675-1.
The purpose of this study was to examine, in a sample of Japanese older adults, the associations of objectively-assessed sedentary behavior (SB) and physical activity (PA) with performance-based physical function. The isotemporal substitution (IS) approach was used to model simultaneously the effects of the specific activity being performed and the activity being displaced, in an equal time-exchange manner.
Among 287 older adults (65-84 years), we used accelerometers to identify the daily average time spent on SB (≤1.5 METs); light-intensity PA (LIPA) (>1.5 to <3.0 METs); and moderate- to vigorous-intensity PA (MVPA) (≥3.0 METs). Physical function was assessed using five performance-based measures: hand grip strength, usual and maximum gait speeds, timed up and go, and one-legged stance with eyes open. We employed three linear regression models - a single-activity model, a partition model, and an IS model - to assess the associations of SB, LIPA, and MVPA with each of the five measures of physical function.
There were significant positive associations in the single-activity and partition models between MVPA and the measures of physical function (with the exception of hand grip strength). The IS models found that replacing SB or LIPA with MVPA was significantly and favorably associated with physical function measures.
These findings indicate that replacing small amounts of SB and LIPA with MVPA (such as 10 min) may contribute to improvements in older adults' physical function.
本研究旨在考察日本老年人样本中，客观评估的久坐行为（SB）和体力活动（PA）与基于表现的身体功能之间的关联。等时替代（IS）方法用于以等时间交换的方式同时模拟正在进行的特定活动和被替代活动的影响。
在 287 名老年人（65-84 岁）中，我们使用加速度计来确定每天平均花费在 SB（≤1.5 METs）、低强度 PA（LIPA）（>1.5 至 <3.0 METs）和中等到剧烈强度 PA（MVPA）（≥3.0 METs）上的时间。身体功能通过五项基于表现的测量来评估：手握力、常规和最大步行速度、计时起立行走和单腿站立睁眼。我们采用三种线性回归模型——单一活动模型、分区模型和 IS 模型——来评估 SB、LIPA 和 MVPA 与五项身体功能测量指标之间的关联。
在单一活动和分区模型中，MVPA 与身体功能测量指标之间存在显著的正相关关系（除了手握力）。IS 模型发现，用 MVPA 替代 SB 或 LIPA 与身体功能测量指标显著相关，且有益。
这些发现表明，用少量的 MVPA（如 10 分钟）替代少量的 SB 和 LIPA 可能有助于改善老年人的身体功能。
