How to quickly reduce abdominal muscles?

Prone knee flexion exercise 1, the starting position is like doing push-ups. Put your hands directly under your shoulders, keep your legs straight, hold your hands on the ground and keep your body in a straight line. 2. Contraction of abdominal muscles, slowly pull the left knee forward as far as possible, and be careful not to bow. Then go back to the original position, change your right knee and start over. This exercise takes 1 minute. Cross movement 1, stand up straight, put your feet together and put your hands behind your head. 2. Turn your head slowly, slowly lower your right arm and lean to the left. At the same time, slowly lift your left knee as if to touch your right elbow. Return to the original position, and then change the opposite arms and knees. Do this action alternately on both sides for 2 minutes. Frog movement 1, supine, feet together, knees naturally valgus. Put your arms naturally behind your head and elbows outward. 2. Pull the abdomen towards the spine and lift your feet, head and shoulders as much as possible. Don't put your chin on your chest, keep this action for 2 seconds. Repeat 1 min.