Biological Sciences: Reflex Balance

THE notion of “balance” ordinarily implies some underlying insecurity or liability to loss of equilibrium. Thus a pencil set up on its butt end may be technically in stable equilibrium, yet, because the centre of gravity lies some way above the relatively small area of support, we speak of the condition as one of “precarious balance”. The situation of a man standing erect is somewhat similar, though here the posture is maintained by muscular activity which is reflexly adjusted to counter the effects of forces that might disturb the equilibrium. These adjustments are usually so successful, and falling is consequently so unusual, that we tend to forget the inherent insecurity of the posture.