Adams Marc A, Hurley Jane C, Todd Michael, Bhuiyan Nishat, Jarrett Catherine L, Tucker Wesley J, Hollingshead Kevin E, Angadi Siddhartha S
College of Health Solutions, Arizona State University, 425 North 5th Street (MC9020), Phoenix, AZ, 85004, USA.
Global Institute of Sustainability (GIOS), Arizona State University, Tempe, AZ, 85287, USA.
BMC Public Health. 2017 Mar 29;17(1):286. doi: 10.1186/s12889-017-4197-8.
Emerging interventions that rely on and harness variability in behavior to adapt to individual performance over time may outperform interventions that prescribe static goals (e.g., 10,000 steps/day). The purpose of this factorial trial was to compare adaptive vs. static goal setting and immediate vs. delayed, non-contingent financial rewards for increasing free-living physical activity (PA).
A 4-month 2 × 2 factorial randomized controlled trial tested main effects for goal setting (adaptive vs. static goals) and rewards (immediate vs. delayed) and interactions between factors to increase steps/day as measured by a Fitbit Zip. Moderate-to-vigorous PA (MVPA) minutes/day was examined as a secondary outcome.
Participants (N = 96) were mainly female (77%), aged 41 ± 9.5 years, and all were insufficiently active and overweight/obese (mean BMI = 34.1 ± 6.2). Participants across all groups increased by 2389 steps/day on average from baseline to intervention phase (p < .001). Participants receiving static goals showed a stronger increase in steps per day from baseline phase to intervention phase (2630 steps/day) than those receiving adaptive goals (2149 steps/day; difference = 482 steps/day, p = .095). Participants receiving immediate rewards showed stronger improvement (2762 step/day increase) from baseline to intervention phase than those receiving delayed rewards (2016 steps/day increase; difference = 746 steps/day, p = .009). However, the adaptive goals group showed a slower decrease in steps/day from the beginning of the intervention phase to the end of the intervention phase (i.e. less than half the rate) compared to the static goals group (-7.7 steps vs. -18.3 steps each day; difference = 10.7 steps/day, p < .001) resulting in better improvements for the adaptive goals group by study end. Rate of change over the intervention phase did not differ between reward groups. Significant goal phase x goal setting x reward interactions were observed.
Adaptive goals outperformed static goals (i.e., 10,000 steps) over a 4-month period. Small immediate rewards outperformed larger, delayed rewards. Adaptive goals with either immediate or delayed rewards should be preferred for promoting PA.
ClinicalTrials.gov ID: NCT02053259 registered prospectively on January 31, 2014.
新兴的干预措施依靠并利用行为的变异性来随时间适应个体表现，可能比规定静态目标（如每天10000步）的干预措施更有效。这项析因试验的目的是比较适应性目标设定与静态目标设定，以及即时与延迟的非条件性经济奖励对增加自由生活中的身体活动（PA）的影响。
一项为期4个月的2×2析因随机对照试验，测试目标设定（适应性目标与静态目标）和奖励（即时与延迟）的主要效应以及各因素之间的相互作用，以通过Fitbit Zip测量每天的步数增加情况。每天的中度至剧烈身体活动（MVPA）分钟数作为次要结果进行检查。
参与者（N = 96）主要为女性（77%），年龄41±9.5岁，且均活动不足且超重/肥胖（平均BMI = 34.1±6.2）。从基线期到干预期，所有组的参与者平均每天增加2389步（p <.001）。接受静态目标的参与者从基线期到干预期每天的步数增加幅度（2630步/天）大于接受适应性目标的参与者（2149步/天；差异 = 482步/天，p = 0.095）。接受即时奖励的参与者从基线期到干预期的改善幅度（每天增加2762步）大于接受延迟奖励的参与者（每天增加2016步；差异 = 746步/天，p = 0.009）。然而，与静态目标组相比，适应性目标组从干预期开始到干预期结束每天的步数减少较慢（即不到一半的速率）（每天-7.7步对-18.3步；差异 = 10.7步/天，p <.001），因此到研究结束时适应性目标组的改善更好。奖励组在干预期的变化率没有差异。观察到显著的目标阶段×目标设定×奖励相互作用。
在4个月的时间里，适应性目标优于静态目标（即10000步）。小额即时奖励优于大额延迟奖励。对于促进身体活动，应优先选择即时或延迟奖励的适应性目标。
ClinicalTrials.gov标识符：NCT02053259，于2014年1月31日前瞻性注册。
