2. Exercise purpose: to improve the muscle strength and endurance of the target muscle.

3. Instrument name: rectus abdominis trainer.

4. Action name: sitting posture and belly rolling.

5. Design principle: In the process of sitting and belly rolling, go up against the resistance, and in the process of resisting the resistance, the body makes a spinal flexion. Because the centripetal contraction of the target muscle has the function of bending the spine, the action is consistent with the function, so the target muscle can be exercised.

6. Body position: sitting in the seat; Feet on the ground, legs naturally open; Pelvic neutral position, scapula neutral position, chin slightly retracted, eyes looking straight ahead, ears, shoulders and buttocks in a straight line from the side; The waist is close to the baffle; Hold the handle of the instrument with both hands closed, and the big arm is close to the top of the baffle.

7. Action trajectory: from top to bottom, and then from bottom to top.

8. Range of motion: make the rectus abdominis fully contract downward, and the original weight plate will not collide when it is upward.

9. Safety tip: Always keep your head stable, don't bend your head to cause excessive pressure on the cervical spine, and keep your waist close to the baffle and pelvis in a neutral position.

10. Breathing and speed: exhale when descending, with a speed of 2-4 seconds; Inhale when rising, with a speed of 2-4 seconds.