I just don't know...

1. Curl-ups:
*.基本上等同仰臥起坐：
*.Hooking-lying: 雙膝彎曲70-90度
*.雙手垂直平放
*.將肩膀碰至膝蓋即可，不必完整坐起
→因之後即靠hip flexors在作用
*.要更難度的話，可以改變手的位置：雙手置於胸前、放至頭部後方。

2. Diagonal curl-ups:
*.基本上等同第一項運動，不同的是方向性。
*.將一邊肩膀碰至另一邊膝蓋即可，不必完全坐起。
(e.g.: R't shoulder to L't knee, L't shoulder to R't knee)

3. Double knee-to-chest:
*.強調lower rectus abdominis
*.bring both knees to chest and return.
*.decreasing the angle of hip and knee flexion will increase the
diffculty.

4. Pelvic lifts:
*.hip flexion to 90 degrees, knee extended
*.lift the buttocks upward toward the ceiling
*.emphasizing the lower abdominalmuscles.

5. Bilateral straight-leg lowering:
*.begin with hips at 90 degrees, and knees extended
*.then, lower the extremities as far as possible. while maintaining
a flat back
*.then raise both legs back to 90 degrees.
*.Precaution:
if you have a problem with low back pain, spinal
hypermobility,spinal instability. Do not perform this execise.