Adaptive goal setting and financial incentives: a 2 x 2 factorial randomized controlled trial to increase adults' physical activity

作者：Adams Marc A^*; Hurley Jane C; Todd Michael; Bhuiyan Nishat; Jarrett Catherine L; Tucker Wesley J; Hollingshead Kevin E; Angadi Siddhartha S

来源：BMC Public Health, 2017, 17(1): 286.

DOI：10.1186/s12889-017-4197-8

• Adaptive interventions
• Reward
• Goals
• mHealth
• Pedometer
• Fitbit
• Text messaging

Background: 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).
Methods: A 4-month 2 x 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.
Results: 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.
Conclusions: 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.

• 出版日期2017-3-29