Popsugar Fitness Workouts 5-Minute HIIT Workout Warning: This 5-Move, 5-Minute Workout May Destroy You October 3, 2017 by Michele Foley View On One Page Photo 3 of 5 ADVERTISEMENT () Start Slideshow Share This Link Copy ← Use Arrow Keys → 3 High Knees Run in place while lifting your knees high to the level of your waist. Engage your abs as the knee comes up. Pump your arms to warm up your upper body. If this move is too hard on your knees, try doing butt kicks instead. Previous Next Start Slideshow WorkoutsCardio WorkoutsBodyweight ExercisesNo-Equipment Cardio WorkoutsIntermediate Workouts5-Minute Workouts