Maintaining upright balance requires continuous integration of sensory information and motor adjustments [1][2]. The three main sensory systems involved are the visual, vestibular, and somatosensory systems [3][4]. Visual input provides information about the environment and body orientation. The vestibular system senses head motion and position via the semicircular canals and otolith organs. Somatosensory receptors, particularly in the lower limbs, detect pressure and movement [2][5].

To maintain balance, this sensory information is continuously mapped onto motor responses that adjust the body’s center of mass over the base of support [1][6]. For example, stretch signals from the calf muscles initiate reflexive contractions to restore equilibrium after body sway [3][5]. Higher motor centers also make anticipatory postural adjustments prior to voluntary movements [2][4]. With age, deficits in vestibular, visual, and proprioceptive function contribute to impaired balance [1][6].