Popsugar Fitness Workouts Quick Ab Workout You Can Do at Home Tighten Your Lower Abs in 5 Minutes With This Lightning-Fast Workout March 30, 2017 by Dominique Michelle Astorino View On One Page Photo 2 of 6 ADVERTISEMENT () Start Slideshow Share This Link Copy ← Use Arrow Keys → 2 Knees and Toes: 60 Seconds Start with two high knees, bringing your right knee to your left hand, then your left knee to your right hand. Now rotate your right knee slightly outward to bring your right ankle to your left hand, then your left ankle to your right hand. Continue in this alternating pattern for 60 seconds. Previous Next Start Slideshow WorkoutsCelebrity TrainersStrength TrainingBodyweight ExercisesBodyweight WorkoutsAb WorkoutsGIF ExercisesIntermediate Workouts5-Minute WorkoutsAb Exercises