HIIT intervention
The HIIT intervention was a 12-week high intensity interval training workout that consisted of home-based HIIT sessions prescribed by the telephone counselor. The content of the HIIT sessions were determined based on exercises the participant could confidently engage in (e.g., regular push-ups vs. knee push-ups vs. wall push-ups). Participants in the HIIT condition were told when PA should be stopped for safety reasons in order to minimize risk to the participant. The goal was to engage in four PA sessions per week including three HIIT sessions and one moderate intensity continuous session. The moderate intensity session was included to allow for a comparison of affective responses during the HIIT and moderate intensity sessions. Ten percent of the HIIT sessions were audiotaped and reviewed by the PhD-level project director to ensure fidelity to the telephone sessions. The project director completed protocol checklists when listening to the sessions.The HIIT intervention included telephone calls delivered by a master’s level health coach who is a trained personal trainer and holds an American College of Sports Medicine Certified Exercise Physiologists