Popsugar Health & Fitness Workouts Quick At-Home Ab Workout Strengthen and Sculpt Every Muscle in Your Core With This Quick and Intense Ab Workout 6 February 2019 by Tamara Pridgett View On One Page Photo 1 of 4 ADVERTISEMENT () Start Slideshow Share This Link Copy ← Use Arrow Keys → 1 High Knees Run in place while lifting your knees high to the level of your waist. Engage your abs as your knee comes up. Pump your arms to warm up your upper body. Each time your foot makes contact with the ground, that counts as one repetition. Complete 30 reps. Previous Next Start Slideshow Trainer TipsGIF ExercisesIntermediate WorkoutsCore ExercisesAb Workouts5-Minute WorkoutsStrength TrainingWorkoutsAb Exercises