The maintenance of an upright position is attributable to adaptation in response to unconscious oscillations which, alternating with rest periods, make gravity act intermittently on them.

This complex neuro-physiological process is entrusted to the Postural Tonic System, a set of communicating structures that fight against gravity, opposing external forces and allowing balance by guiding movement.

2 different types of sensory impulses:

• exteroreceptors (touch, sight, hearing) – these collect information that comes from the surroundings
• proprioceptors –  these perceive and recognise the position of the body in space and the level of muscle contraction

analyse and encode the sensory information tied to mechanical, thermal, or chemical stimulation of a part of the body.

The information is then transferred, through the ascending sensory pathways, to the spinal cord and to the regions of the brain that process it, determining perception.

So, the strategy selectors – the cognitive processes that rework the data received by the receptors – produce specific postural responses that modify the state of contraction of the kinematic muscle chains and consequently osteoarticular balance.