Junbi undo exercises follow a logical order beginning with 'range of movement' exercises for the toes and feet, then continue with the ankles, followed by the legs, torso, upper limbs and finally finish with exercises for the neck.
They are thus designed to put all of the joints through their full range of movement, exercising all parts of the body in a balanced way with a view to limbering up the joints, increasing circulation and warming up the body in preparation for hard training.
Many of these exercises are essentially martial arts techniques performed slowly and combined with a specific type of breathing so that they not only improve cardiovascular health but assist in the learning and 'grooving' of practical techniques.
They also serve an important function in mentally preparing you for a hard training by starting slowly so that training intensity builds in step with your level of physical arousal.
Thus even on those days when you don't really feel like training by the end of the warm-up phase you're glad you came along!
In addition to warming-up the body these exercises function as conditioning exercises to improve flexibility.
Finally, cooling down exercises are done at the end of a training session with a view to restoring heart-rate, breathing and circulation to normal rates and to relax and stretch the muscles to minimise post-exercise stiffness and soreness.