What Muscles Are Getting Worked During a Swiss Ball Sit Up?
Increase the challenge of your situps by performing them on a Swiss ball. Also known as a stability or exercise ball, the Swiss ball provides a wobbly surface for your situps instead of the solid surface of the floor. You cannot roll off the floor like you can off the ball. To avoid rolling off the ball, your core muscles will engage to keep you upright.
You will receive the most core-strengthening benefits when you complete a Swiss ball situp using proper form. Sit on top of a ball with your knees bent and feet flat on the floor. The right-sized ball will bring the angles of your hips and knees to 90 degrees when used. Walk your feet away from the ball until you are lying face up with the ball underneath your middle and upper back. Place your hands behind your head. Point your elbows out to the sides. Lie back as you stretch your abdominals. Tighten your abdominals by pulling your navel toward your spine. Exhale and sit up high enough to bring your shoulder blades off the ball. Inhale and return to the starting position.
Before you make one move in a situp, your deepest abdominal muscle, the transverse abdominis, is already contracting. When you flatten your core by pulling your navel toward your back, the transverse abdominis tightens. This muscle rests around the inside of your abdomen like a corset. Instead of pulling the strings to tighten the corset, you contract the muscle and flatten your abdomen.
The Swiss ball situp provides the best results in your rectus abdominis muscle. The RA is the most superficial of abdominal muscles. You often see the RA as a "six pack" on the core of those who have a reduced amount of body fat. The RA contracts when you shorten the distance between your ribs and pelvis as you do when you raise your torso during the situp.
Along the sides of your abdomen, you will find two pairs of oblique muscles. These muscles are placed on a diagonal as if putting your hands in your front and back pockets. The internal and external obliques contract when you bend to the sides and shorten the distance between your ribs and hips. During the situp, the obliques act as stabilizing muscles to keep you from rolling off the ball.