Popsugar Health & Fitness Workouts Abs and Legs HIIT Workout Strengthen and Sculpt Your Abs and Legs With This World Cup-Inspired HIIT Workout 26 June 2019 by Tamara Pridgett View On One Page Photo 4 of 7 ADVERTISEMENT () Start Slideshow Share This Link Copy ← Use Arrow Keys → 4 High Knees Run in place while lifting your knees high to the level of your waist. Engage your abs as your knee comes up. Repeat for 40 seconds followed by 20 seconds of rest. Previous Next Start Slideshow Trainer TipsIntermediate WorkoutsLeg WorkoutsHIITAb Workouts30-Minute WorkoutsLeg ExercisesStrength TrainingWorkoutsAb Exercises