Ma Bu practice

Some issues with Ma Bu: knee and lower back pain, lack of balance.
Possible causes: not using the qua properly, trying to sit too low.

Response from He Laoshi:
Try not let your knee further then ankle, not toe.
We will use too much strength on lower back if we sit low in the beginning, practice the squat exercise holding something, try to check which muscles you use and reduce them, try to feel the qua movement only, relax where you feel pain on squat position, tell me what happens.

Response from Vova:

it's not balance, it's the structure, need train more of the leg's inner tendons and opening of kua. are you falling back?

check knees to know if the posture is right. But don't move your knees back. Knees are like litmus paper. You can check them and see if it is right. But that's all. to correct the posture check two things - kua and dang
sit on kua to have right posture, use dang to keep upright (not fall down)
because if dang is not used then either your torso leans forward or you tend to fall backwards
dang is what sifu calls arch in English
dang is chinese prononciation