Maher Jaclyn P, Labban Jeffrey D, Hudgins Brynn L, Hevel Derek J, Bittel Kelsey M, Kennedy-Malone Laurie, Hedeker Donald
Department of Kinesiology, University of North Carolina Greensboro, Greensboro, NC, USA.
School of Health and Human Sciences, University of North Carolina Greensboro, Greensboro, NC, USA.
J Phys Act Health. 2024 Nov 6;22(1):112-122. doi: 10.1123/jpah.2024-0350. Print 2025 Jan 1.
Research investigating the psychological determinants of physical activity (PA) tends to conceptualize determinants as stable, trait-like factors. Growing evidence suggests that people and the processes that regulate people's behavior fluctuate over short timescales (eg, hours and days). This study explores the extent to which subject-level variability (vs stability) in determinants of PA, as well as the interaction between subject-level mean and variability in those determinants, is associated with moderate- to vigorous-intensity PA (MVPA) in older adults.
Older adults (N = 202) enrolled in a measurement burst design study with 3 data collection waves occurring over a 1-year period. Each data collection wave consisted of accelerometers and ecological momentary assessment to capture MVPA and psychological determinants of MVPA, respectively. Mixed-effects location scale modeling was first used to estimate subject-level means and variability in psychological determinants. These estimates were then used as predictors of daily MVPA using multilevel modeling.
Subject-level variability in PA intentions (β = 0.199, SE = 0.062, P = .001), self-efficacy (β = 0.133, SE = 0.064, P = .037), and planning (β = 0.154, SE = 0.062, P = .014) were positively associated with daily MVPA. Associations between subject-level variability in PA intentions and self-efficacy decreased in strength, becoming nonsignificant at higher mean levels of PA intentions (β = -0.147, SE = 0.062, P = .018) and self-efficacy (β = -0.116, SE = 0.063, P = .062).
Greater subject-level variability in psychological determinants may be adaptive for PA engagement, especially among older adults experiencing low levels of those determinants. Moving beyond mean levels to include subject-level variability in psychological determinants of PA may help to improve our understanding of the processes that drive PA engagement.
研究身体活动（PA）心理决定因素的研究倾向于将决定因素概念化为稳定的、类似特质的因素。越来越多的证据表明，人和调节人们行为的过程在短时间尺度（如数小时和数天）内会发生波动。本研究探讨了PA决定因素中个体水平的变异性（相对于稳定性），以及这些决定因素中个体水平均值与变异性之间的相互作用，与老年人中等至剧烈强度身体活动（MVPA）的关联程度。
202名老年人参与了一项测量突发设计研究，在1年时间内进行3次数据收集。每次数据收集包括加速度计和生态瞬时评估，分别用于捕捉MVPA和MVPA的心理决定因素。首先使用混合效应位置尺度模型来估计心理决定因素的个体水平均值和变异性。然后，这些估计值被用作多级模型中每日MVPA的预测因子。
PA意图（β = 0.199，SE = 0.062，P = .001）、自我效能感（β = 0.133，SE = 0.064，P = .037）和计划（β = 0.
