Postural sway during quiet standing is the resultant action of various destabilizing forces acting on the body and actions by the postural control system to prevent a loss of balance. Human postural sway is a stochastic process and can be represented in terms of the fluctuations of center of pressure (COP) under the feet of a quietly standing subject (Chiari et al., 2000; Chow and Collins, 1995; Collins and De Luca, 1993, 1994, 1995; Ohira and Milton, 1995; Peterka, 2000; Sabatini, 2000; Yao et al., 2001).
In this paper we present the observation where 10 healthy subjects of mean age 25 are examined to find out a relationship between postural sway during quite-stance and perturbation with and without muscle fatigue. We also observe the effect of vision on postural sway on both normal and fatigued conditions.
Human control of upright body posture involves inputs from several senses (visual, vestibular, proprioceptive, somatosensory) and their central interactions. Multiple sensory systems of human body are involved in tandem for controlling quite standing. Studies show that there is an indirect and presumably cognitive relationship between visual effects on posture control and their intersensory interactions (BLMLEA. et al, 2006).
During quite stance position, center of mass (COM) is stabilized over base of support by using low level muscular movements and body sways around the point of support like an inverted pendulum (Johans ...