[Picture Tutorial ~ Sit and Stand Abdomen] Mainly exercises abdominal muscles

[Picture Tutorial ~ Sit and Stand Abdomen] mainly exercises abdominal muscles. Sit on the side of the bench. Place your hands behind your hips and press them against the sides of the bench. Extend your feet outward. Then bend your feet to about ninety degrees toward the center of your body. Relax other parts of your body and focus on tightening and relaxing your abdominal muscles. Do 3 sets, reaching failure in each set, no limit to the number of reps, and rest for 60 seconds between sets.