Popsugar Fitness Body Weight 32 No-Equipment Ab Exercises You Can Do on a Mat Heat Up Your Core With 32 Small-Space, On-the-Floor Ab Moves You Can Do Right on Your Mat 31 March, 2020 by Maggie Ryan View On One Page Photo 23 of 32 ADVERTISEMENT () Start Slideshow Share This Link Copy ← Use Arrow Keys → 23 Straight-Leg Sit-Up Begin on your back with your legs straight and arms raised toward the ceiling. Roll up to sitting, focusing on the abs rounding the back. Roll back down to the mat slowly, one vertebra at a time. This completes one rep. Previous Next Start Slideshow Body WeightBodyweight ExercisesCore ExercisesAb ExercisesWorkouts