When you do a sit-up you are performing a strength training exercise. A standard sit up begins with you lying on your back, knees bent at a 45 degree angle and your hands behind your head. You use leverage to lift yourself up until only your buttocks are touching the floor and your abdominal muscles are used to contract to lift you up and then relaxed to lower you back down. There are a number of ways to perform a sit-up: Legs straight Knees bent Using a balance ball Using a medicine ball Holding weights Hands behind your head Hands … Continue reading →