A US study used sophisticated electromyogram technology to measure muscle activity and come up with the most effective exercises for abdominals and obliques. The study compared 13 abdominal exercises, ranging from the traditional crunch to more complicated activities, using home and gym equipment. Each of the 13 exercises was ranked for muscle stimulation in the rectus abdominus (the long, flat muscle extending the length of the front of the abdomen) and the internal and external obliques (the long, flat muscles extending along the sides of the abdomen at an angle). The study found the three best abdominal exercises are:
Bicycle manoeuvre
Lie flat on the floor with your lower back pressed to the ground. Put your hands beside your head. Bring your knees up to about a 45-degree angle and slowly go through a bicycle pedal motion. Touch your left elbow to your right knee, then your right elbow to your left knee. Breath evenly throughout the exercise.
Captain's chair
This was one of the few on the "most effective" list that involves gym equipment. Start with legs dangling then stabilize your upper body by gripping the handholds and lightly pressing your lower back against the back pad. The starting position begins with you holding your body up and legs dangling below. Now slowly lift your knees in toward your chest. The motion should be controlled and deliberate as you bring the knees up and return them back to the starting position.
Crunch on an exercise ball
Sit on top of an exercise ball, feet placed firmly on the floor. Slide forward, rolling the bottom half of your bottom off the ball, until your middle back is supported by the curve of the ball. You should be positioned so that your back is at a steeper angle than your thighs so that the hip flexors are deactivated to provide a greater emphasis on the abdominal muscles. Essentially you shouldn’t be lying across the top of the ball.
You can either cross your arms over your chest or place your hands behind your ears. Do not put them behind the head or clasp them together behind your head. Crunch your upper body forward, rolling your shoulders toward your hips. Squeeze your abs at the top of the movement. Keep you neck in a neutral position. Lower yourself back to the starting position. Do not fling your head back. Breathe normally at all times.
Keep space in-between your chin and chest, so your spine stays in a neutral position.
(Study: Biomechanics Lab at San Diego State University)
A balanced set of Core and Abdominal Exercises can be found here.
