HIIT stands for High-Intensity Interval Training. This term was created years ago in exercise science to describe carefully scripted intervals of high-intensity cardiorespiratory exercise coupled with specific rest intervals. This workout includes multiple modes of cardio including stepping, jogging, sprinting, and throwing using multiple joints and planes of motion. The combination of upper and lower body movements makes this workout very effective. The workout design makes it easy to pace yourself, so it’s appropriate for all fitness levels.