Lie on your back on the yoga mat, keep your lower back on the ground, cross your arms on your chest, lift your head slightly, fix your neck, miniaturize your chin, and lift your legs together so that your thighs are perpendicular to the ground and your calves are perpendicular to your thighs to keep your body stable. The lower back always touches the ground and the neck remains fixed. Your abdominal force drives your upper back to roll up, while keeping your legs bent toward your chest, and stop at the apex to feel the compression of your abdominal muscles. Then, actively control the speed and slowly regain your attention during the action.