Evaluating the feasibility and efficacy of a home-based combined high intensity interval and moderate intensity training program for increasing physical activity among low-active adults: A randomized pilot trial

BACKGROUND: High intensity interval training (HIIT), which includes short bursts of high-intensity physical activity (PA) followed by recovery, can increase PA by addressing time barriers and improving PA enjoyment. The purpose of this pilot study was to examine the feasibility and preliminary efficacy of a home-based HIIT intervention on PA. METHODS: Low active adults (n = 47) were randomly assigned to a home-based HIIT intervention or wait-list control lasting 12 weeks. Participants in the HIIT intervention received motivational phone sessions based on Self-Determination Theory and accessed a website that included workout instructions and videos demonstrating proper form. RESULTS: The HIIT intervention appears feasible based on retention, recruitment, adherence to the counseling sessions, follow-up rates, and the consumer satisfaction survey. HIIT participants reported more minutes of vigorous intensity PA at six weeks relative to control (no differences at 12 weeks). HIIT participants reported higher levels of self-efficacy for PA, enjoyment of PA, outcome expectations related to PA, and positive engagement with PA than the control. CONCLUSIONS: This study provides evidence for feasibility and possible efficacy of a home-based HIIT intervention for vigorous intensity PA; however, additional studies are needed with larger samples sizes to confirm efficacy of home-based HIIT interventions. TRIAL REGISTRATION: Clinical Trials Number: NCT03479177.