Laying Torso Twist
Trains the internal and external obliques, the muscles on either side of your torso.
How to do it:
Lie on your back, with your knees bent at a 90-degree angle and your feet flat on the floor. Squeeze a light 2 to 5-pound medicine ball or a thick phone book tightly between your knees.
1. Lay your hands next to your buttocks then slowly raise your head, shoulders, and feet off...