The rectus abdominis (straight abdominal muscle) is one single muscle. However you can do exercises which target either the upper or the lower area of the abdominal muscle.
The Upper Part of the Straight Abdominal Muscle
Carrying out the Exercise:
Lie on your back and bend your legs to a 90 degree angle. Keep the soles of your feet on the floor. The lower back is flat on the floor. During the exercise, keep your chin slightly lifted toward the ceiling. Focus on a point in the ceiling throughout the exercise. Do not fold your hands behind your head but instead place them at your temples. If the hands are folded behind the head, there is a risk - especially for beginners - of jerking the head forwards.
Breathe out whilst you lift the head and shoulder blades off the floor! 3/4 of the back stays on the floor. Keep the head and the spinal column in a straight line! Do not pull the head forwards! Keep your focus on the ceiling. You should feel tension in your abdominal region. Hold the end position for a brief moment.
Whilst still tensing your muscles, lower the upper body back to the floor. Be careful! Do not go all the way down. Just before touching the ground you should lift your upper body again. Breathe regularly to the rhythm of your motion.
Moving up = exhale.
Moving down = inhale.
Avoid jerking the head and any swinging movements.
This exercise can also be done with your hands crossed at your chest. Be careful! Keep the head and the spinal column in a straight line!
The Lower Part of the Straight Abdominal Muscle
Lie on the floor with your legs straight up in the air so your toes are pointed toward the ceiling. Place your hands on your sides with your palms facing down. Now slightly lift the pelvis using only the lower abdominal muscles. Be careful: do not jerk or make any swinging movements.
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