Popsugar Health & Fitness 15-Minute Workouts 15-Minute Cardio Bodyweight Workout Cardio and Strength Training Join Forces in This Intense 15-Minute Bodyweight Workout 4 January 2020 by Jenny Sugar View On One Page Photo 5 of 5 ADVERTISEMENT () Start Slideshow Share This Link Copy ← Use Arrow Keys → 5 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. Do 40 seconds of high knees followed by a 20-second rest. Previous Next Start Slideshow 15-Minute WorkoutsBodyweight ExercisesIntermediate WorkoutsWorkouts