The underlying theory behind acupuncture and related disciplines is that the body has a series energetic pathways called meridians that act as pathways for life force energy (chi).
The ancient yogis of India also believed that energetic pathways existed; the ancient name given was "nadi." (The name for life force energy in this tradition is "prana.")
When life force energy gets stuck, disease can result. Acupuncture and acupressure works by stimulating points along the meridians to move the stuck chi and bring health back to the individual.
have u been 2 india
What I find amazing is that different cultures that had no contact with eachother realised these pathways existed.