Popsugar Health & Fitness Hiit Workouts Workout For Fat Loss Grab a Pair of Dumbbells, and Get Ready to Burn Fat With This 40-Minute HIIT Workout 11 December 2018 by Jenny Sugar View On One Page Photo 13 of 14 ADVERTISEMENT () Start Slideshow Share This Link Copy ← Use Arrow Keys → 13 High Knees Beginning with the right knee, run in place while lifting your knees high to the level of your waist. Engage your abs as the knees come up, and pump your arms to warm up your upper body. Lifting the right and then the left knee counts as one rep. Perform 12 reps (24 total high knees). Previous Next Start Slideshow HIIT WorkoutsDumbbell Workouts45-minute WorkoutsIntermediate WorkoutsStrength TrainingWorkouts