Abstract
Participation in regular physical activity (PA) has numerous health benefits; however, as few as 10% of U.S. adults meet guidelines when device-based assessments of PA are used. The present paper presents the design and rationale for an RCT examining the efficacy of an exercise incentive program currently offered by at least three major US insurance companies, in which participants must attend a YMCA fitness facility at least 50 times within 6 months to receive an incentive. In a factorial design, incentive amount ($200, $100, $0) is crossed with a comparison of the standard gain-framed incentive program and a loss-framed incentive condition in which participants are told their membership fee is being held and will be returned or forfeited depending on their fitness facility attendance. Participants (N = 330) are randomized to gain-framed $100 incentive (n = 55), gain-framed $200 incentive (n = 55), loss-framed $100 incentive (n = 55), loss-framed $200 incentive (n = 55), or control (n = 110). Each participant is enrolled in the same condition for two consecutive 6-month periods for a total of 12 months per participant. The primary outcome is number of visits to the fitness facility over each 6-month period, verified by objective swipe-card data. Secondary outcomes include total moderate-to-vigorous PA (MVPA) over 7-day periods assessed at 3-month intervals through accelerometers (Actigraph wGT3x-BT) and self-report. Habit formation and anticipated regret are putative mediators and household income is a putative moderator of the incentive-based programs. A payer-perspective, within-trial cost-utility analysis will quantify the incremental costs per (a) quality-adjusted life year gained, (b) YMCA attendance, and (c) change in MVPA.