No Need to Spend a Fortune Tone and Sculpt a Six Pack and Build Core Body Strength. An Adjustable Ab Bench allows much more than Sit-ups and Crunches. A Simple Ab Bench versatility to Strengthens Multiple Muscle Groups. Do Exercises to Develop the Erector Spinae Muscles with Trunk Extensions, Train obliques with Russian Twists, Develop Deep Core transversus abdominis with Leg Lifts and Flutter Kicks. Add Intensity to these Exercises by Adding Weighted Resistance. Make Crunches more Challenging by Changing the Center of Gravity: Arms Crossed on Chest, Fingers Laced Behind Head or Most Challenging, Arms Fully Extended Straight Overhead.