Why are there so many falls? In part, it is because we fail to understand the complexity of same-surface slip-and-fall accidents. We assume that people fall because the floor is slick, because they are clumsy or careless, or because they step on a foreign object. These assumptions lead to investigations that are one-dimensional and to repeated accidents at the same location.

To understand causality and to determine responsibility for an accident, the investigator usually eliminates many possible causes. But people can fall for numerous reasons. Reasons include the interaction of the walking surface with shoes; the environment, along with its distractions; and the physical and mental limitations of the victim.

Most movements involve the expansion and contraction of muscles in relation to joints and bones. People use levers to move their bodies. When we understand the patterns in which these levers work, we can determine the cause of deformities and incapacitates of a person in an accident. We cannot assume, however, that abnormal patterns of movement are responsible for an accident. 

Walking and most other motions of the whole body involve the body's center of mass. This theoretical area, commonly called "the center of gravity" (COG), is the balance point around which a movement operates. While complex measurements are necessary to determine the exact location of the center of gravity, it is estimated that the COG in the average person who is standing is about 55 percent of the distance between the floor and the person's height.

The COG changes during various activities and postures, and also varies according to the build of the person. In walking, the center of gravity is carried alternately over the right and left foot. The average human walking pattern is called "striding bipedalism" because we stand and walk with two feet in contact with the walking surface.  

Each step begins with the weight supported for the trailing foot. We swing the striding foot forward and begin to transfer our weight forward to the heel. Our weight rolls toward the toes as our momentum carries us forward, and we begin to swing the alternate leg forward. As the pace increases, an instance of instability occurs between steps at the moment when our weight is transferred to the leading foot.

Essentially, walking results in successive losses of balance. Clayne Jensen, a motion expert, divides the human stride into three parts: propulsion, swing, and catch and support. (C. Jensen, Applied Kinesiology and Biomechanics (1982).) When speed increases to running pace, only one foot is in contact with the surface at a time.

These methods of walking are generally thought to be incorrect because they are less efficient, but they should not be considered unsafe unless evidence shows they prevent the individual from maintaining balance. Stride and balance can also be affected by the inner ear, medication, and disorders of the central nervous system.

Conscious Control

Ordinarily, we do not consciously recognize changes in the walking surface. As we walk, we scan about 10 to 20 feet ahead of us. Our observations operate below the level of the conscious mind.  Most slip-and-fall accidents are caused by unexpected changes in the walking surface. To become aware of the hazard, the change must impinge upon our consciousness in some way.

 Individual Rights

When walking in a public place, we have the right to be advised of any hazards we are likely to encounter. If we choose to proceed with full knowledge of a hazard, we assume at least some risk. If the hazard has been knowingly or carelessly disguised, an accident can be expected.

A man visiting a public park broke his leg in a fall as he tried to descend three wooden steps to a lower level. His foot had slipped on a defect in the leading edge of a step. The public parks department investigated the accident and painted the steps with a bright orange paint to call attention to the stairs. unfortunately, the paint covered the defect in the step, and, two weeks later, a woman broke her hip when her foot got caught in the same defect.

The walking surface should be evenly illuminated and should have a brightness level of at least 20 foot candles - a basic quantitative unit of light measurement. And the contrast (ratio of dark to light) should be no less than 3-1 and no more than 20-1. The measurement of luminosity and contrast requires a simple photographic light meter calibrated to read in foot candles.

An example of the usefulness of photographs can be shown in the case of a woman who fell while walking through a bank. An examination of the photographs showed what had been missed during previous inspections of the scene: a dip in the floor, where a wall had been removed, which could not be seen from the area of traffic flow used by the victim.