The Effect of Perturbration on Balance Control in Adults

An unexpected postural perturbration is a major risk factor of falls and injuries during gait. A postural perturbration is a sudden change in conditions that displaces the body posture away from equilibrium. Reactive postural control response is an immediate ( 70-120 ms ) automatic "like reflex" response which is initiated by unexpected postural perturbration in order to maintain balance. Even among young healthy adults there could be a problem in balance performance which does not become evident untill a slip or a trip or any other sudden perturbration happens. Thus a simple test of pertubration while standing or walking can identify a problem .

This study is comparing the reactive postural control of physical education students who suffer from chronic ankle instability (CAI) to healthy students on a Perturbation Treadmill. The device consists of a treadmill mounted on a moving force plate platform. The platform moves in the medial/ lateral plains to simulate a slip and a trip in both the standing and walking phase. Their reactive postural control is tested in a few conditions: standing on both legs - eyes open and eyes closed, in tandem standing, standing on one leg and in walking. In each condition the perturbration is given every 5-15 seconds in different speed and in unexpected direction (right /left). Lost of balance control is any change in the original location of the foot in standing conditions or stepping out of the treadmill.