This is sort of a modified sit-up. To start, lie on the floor with your knees bent at an approximately 45-degree angle.
Rest your head on the ground with your hands resting on your thighs. Your arms should be straight. To begin, raise your hands up so that they are roughly parallel to your thighs. Keep your arms straight.
Next, raise your upper body off the ground in a crunch movement bringing your hands up and over your knees. Pause for a one count at the top, slowly return to the starting position and repeat.
Push Over Knees Sit Ups Exercise - Start Position
Push Over Knees Sit Ups Exercise - Finish Position