Popsugar Health & Fitness Workouts HIIT Cardio Exercise The 13 Best HIIT Cardio Exercises to Strengthen Your Entire Body and Boost Your Stamina 7 December 2018 by Tamara Pridgett View On One Page Photo 3 of 12 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. Previous Next Start Slideshow Trainer TipsBodyweight ExercisesHIITCardioWorkouts