Birth

In the internal martial arts the term 'pre-birth' refers to the natural condition of suppleness and flexibility you started life with.
A baby does not have sore knees, a bad back or arthritis.
The limbs can move comfortably within their natural range of motion.

Hands

Over-use and wrong use of the hands can cause immobility and arthritis.
Main culprits:
• Computer mouse
• Mobile phone 
• Tapping a touch screen
• Unnecessary application of force
• Gripping too hard
• Knitting 
• Sewing 
• Repetitive activity
• Using a keyboard
• Playing video games