[Supine Crunch] mainly exercises the rectus abdominis muscles. Lie on your back on the mat, with your lower back close to the mat, your legs bent at about 90 degrees, and your feet on the ground. Place your hands on both sides of your head, open your arms, contract your abdominal muscles to slowly move your chest upward and forward to the highest point, and then slowly lower it to the starting position. Note: Keep your abdominal muscles tight at all times, do not use force on your hands, exhale when you go up, inhale when you go down, and keep your lower back close to the mat.
