A Walking Intervention Through Text Messaging

Study Overview
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Brief Summary
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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.

Official Title
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Walking Intervention Through Texting Study: A Factorial Trial

Conditions
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Physical Activity, Behavior, Overweight, Motor Activity

Intervention / Treatment
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* Behavioral: Adaptive Goals
* Behavioral: Reinforcement
* Behavioral: Static Goals


Participation Criteria
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Eligibility Criteria
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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.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 60 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Prevention
Allocation: Randomized
Intervention Model: Factorial Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Adaptive Goals with Immediate Reinforcement<br>Adaptive Physical Activity Goals, Immediate Financial Reinforcement | Behavioral: Adaptive Goals<br> <br> Behavioral: Reinforcement<br> <br> |
| Experimental: Adaptive Goals with Delayed Reinforcement<br>Adaptive Physical Activity Goals, Delayed Financial Reinforcement | Behavioral: Adaptive Goals<br> <br> |
| Experimental: Static Goals with Immediate Reinforcement<br>Static Physical Activity Goals, Immediate Financial Reinforcement | Behavioral: Reinforcement<br> <br> Behavioral: Static Goals<br> <br> |
| Active Comparator: Static Goals with Delayed Reinforcement<br>Static Physical Activity Goals, Delayed Financial Reinforcement | Behavioral: Static Goals<br> <br> |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in Fitbit-measured Steps/Day and Moderate-to-vigorous Physical Activity Between Study Arms. | 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. | Daily for 4 months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in Fitness (VO2max) Between Study Arms. |  | Baseline and 4 months | 
| Changes in Body Mass Index and Body Composition Measured by Dual-energy X-Ray Absorptiometry (DEXA) Between Study Arms. |  | Baseline and 4 months | 
| Changes to iAortic Pulse Wave Velocity Assessed With the SphymocorTM Between Study Arms. |  | Baseline and 4 months | 
| Changes to Cardiovascular-disease (CVD) Risk and Inflammatory Markers (e.g. Glucose, Insulin, Lipids, Adhesion Molecules and Hemostatic Factors) Between Groups. |  | Baseline and 4 months | 
| Changes to Self-reported Physical Activity Measured by the International Physical Activity Questionnaire (IPAQ). |  | Baseline and 4 months |