弯管，管子弯头
1. 弯头：knead 捏 | knee bend 弯头 | knee brace 角拉条
2. 肘管：knee 升降台 | knee bend 肘管 | knee brace 角拉条
3. 折弯：knee 弯曲处 | knee bend 折弯 | knee of saturation curve 饱和曲线的弯曲处
4. 屈膝：kneading method 揉捏法 | knee bend 屈膝 | knee chest position 爬臥
noun
1. exercising by repeatedly assuming a crouching position with the knees bent
strengthens the leg muscles