A Walking Intervention Through Text Messaging (WalkIT)

The purpose of this study is to develop and evaluate adaptive goal setting and feedback interventions (Adaptive Interventions) to promote physical activity behaviors and compare it to static physical activity interventions (Static Interventions) using two levels of goal setting (Adaptive Goals vs. Static Goals) and two levels of reinforcement procedures (Praise/Rewards and No Praise/Rewards) in a 2 x 2 factorial randomized controlled trial. All four groups will receive the intervention via a semi-automated text message system developed by the investigators study team. The primary aim of this study will be to: Evaluate whether the adaptive interventions result in greater change in physical activity (pedometer-measured steps/day) compared to the static Intervention groups. HYPOTHESES: Participants in the adaptive interventions will increase their steps/day more than participants in the Static Intervention groups. The Adaptive Goals and Reinforcement Group will outperform the other 3 groups. The secondary aims of this study will be to: Evaluate the effectiveness of the adaptive and static goal interventions in improving anthropometric, cardiovascular fitness, and cardiometabolic risk factors. HYPOTHESES: Participants in the adaptive interventions will show greater improvements in fitness, lean and fat body mass, and serum biomarkers than participants in the Static Intervention groups. The Adaptive Goals and Reinforcement Group will outperform the other 3 groups. to assess participants' satisfaction with the overall program.

Given this study used a 2 condition (adaptive vs. static goals) x 2 condition (immediate vs. delayed financial reinforcement) randomized factorial design we report main effects for each condition. Sample sizes for main effects will be 96 participants for each comparison (Adaptive vs. Static goals or Immediate vs. Delayed Reinforcement) as the other condition. Consistent with proper analyses of factorial designs, main effects for the goal setting conditions pool participants across reinforcement conditions, and main effects for reinforcement conditions pool participants across goal setting conditions.

Changes in Body Mass Index and Body Composition Measured by Dual-energy X-Ray Absorptiometry (DEXA) Between Study Arms.

Changes to Cardiovascular-disease (CVD) Risk and Inflammatory Markers (e.g. Glucose, Insulin, Lipids, Adhesion Molecules and Hemostatic Factors) Between Groups.

Changes to Self-reported Physical Activity Measured by the International Physical Activity Questionnaire (IPAQ).

Inclusion Criteria: women and men of all races/ethnicities living in Maricopa County, Arizona. Exclusion Criteria: be between 18 and 60 years old currently not exceeding physical activity recommendations determined by the International Physical Activity Questionnaire (IPAQ short form). not have a medical condition based on the Physical Activity Readiness Questionnaire for Everyone (PAR-Q+) that requires supervised physical activity not taking medication(s) that would prohibit a moderate intensity physical activity program have a body mass index between 25 and 55 kg/m2 not be currently pregnant or planning to become pregnant in the next 4 months not be planning to leave Maricopa County for 10 days or more in the next 4 months not planning to move from Maricopa County in the next 4 months not currently in another physical activity, diet, or weight loss program (e.g. weight watchers) have access to Microsoft Windows (XP, Vista, 7, 8) or Mac (10.5+) operating systems on computer with a USB port on a daily basis have daily access to email and the internet have a mobile phone with text messaging capabilities and be willing to send and receive up to 3-5 text messages per day.

Hurley JC, Hollingshead KE, Todd M, Jarrett CL, Tucker WJ, Angadi SS, Adams MA. The Walking Interventions Through Texting (WalkIT) Trial: Rationale, Design, and Protocol for a Factorial Randomized Controlled Trial of Adaptive Interventions for Overweight and Obese, Inactive Adults. JMIR Res Protoc. 2015 Sep 11;4(3):e108. doi: 10.2196/resprot.4856.

Adams MA, Hurley JC, Todd M, Bhuiyan N, Jarrett CL, Tucker WJ, Hollingshead KE, Angadi SS. Adaptive goal setting and financial incentives: a 2 x 2 factorial randomized controlled trial to increase adults' physical activity. BMC Public Health. 2017 Mar 29;17(1):286. doi: 10.1186/s12889-017-4197-8. Erratum In: BMC Public Health. 2017 Apr 6;17 (1):303.

Phillips CB, Hurley JC, Angadi SS, Todd M, Berardi V, Hovell MF, Adams MA. Delay Discount Rate Moderates a Physical Activity Intervention Testing Immediate Rewards. Behav Med. 2020 Apr-Jun;46(2):142-152. doi: 10.1080/08964289.2019.1570071. Epub 2019 Apr 11.