Interval training involves alternating periods of relatively intense work and recovery. Altering the intensity and duration of the work and recovery periods allows for the production of a nearly infinite number of interval training workouts. Modern fitness programming has adopted the term “high-intensity interval training” or HIIT as a way to describe this approach to fitness and performance, and two general categories have emerged. One category is referred to as “aerobic HIIT” and the other is “body weight HIIT” or “resistance HIIT” (see Sidebar). Both involve periods of intense effort followed by recovery segments, with the primary difference being the modality of exercise. Aerobic HIIT training most often uses running and cycling to deliver the desired intensities by way of activities such as spin classes and track-based running workouts. In contrast, resistance/body weight HIIT makes use of calisthenics, plyometrics, and/or loaded lifts in training programs like Tabata, CrossFit, boot camp training, or other similar classes. Although both types of HIIT programs are used widely and research indicates the effectiveness of body weight-type HIIT programming (13), most research has focused on HIIT that primarily is aerobic because cycling and treadmill running enable more accurate assessment of work to describe the training stimulus. Therefore, this article provides an overview of common protocols and evidence-based strategies to support designing effective programming using aerobic HIIT