Lie on your back, the abdomen and thighs are at 90 degrees, the thighs and calves are at 90 degrees, the body is like a flying fish, and things can be put under the calves. This action looks simple, but to really get the best training effect, you need to "compress" the abdominal muscles with the contraction force of the abdominal cluster, and the action is very short. When doing this, the upper back is off the ground, but the lower back is still close to the ground. The action is just to press the abdomen, bend the spine, and make the chest ribs close to the pelvis. It is just to make the abdominal muscles in a "peak contraction" state, pause for a while, then control the tension of the abdominal muscles, slowly stretch and restore the spine.

Note: The position of hands has a direct influence on the pressure of abdominal contraction.

Usually, there are three different placement positions:

1, hands are naturally straight (relaxed) in physical test.

2. Cross your heads and hold them in your chest (middle)

Step 3 put your hands behind your neck (difficult)

1. Accurate method: put your hands gently on the back of your neck and ears to avoid the neck from being pressed inward.

2. inaccurate method: hold the back neck tightly with both hands, bend the back and press the neck column inward with both hands.