Asana the third limb of Hatha Yoga is a practice of the movements of the body and its limbs.
The practice of asana helps to explore the body and understand its effects on the various limbs of the body.
Pranayama, the fourth limb of Hatha Yoga, is a practice of the regulation of breath.
Prathyahara is the fifth limb of Hatha Yoga. It means to withhold the food.
All the aspects of the body, that is physical, mental, emotional, spiritual etc., change and reflect the effects of the practice.
Hatha Yoga is a highly disciplined system given by the great seers of Bharathavarsha for the welfare of humanity.