A Walking Intervention Through Text Messaging

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: 1. 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: 2. 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. 3. to assess participants' satisfaction with the overall program.