In many cases, the terms “slip” and “trip” are used interchangeably as the cause of a fall. However, they are distinctly different and can make a difference as to who is liable for a fall. In a true slip and fall the owner of the floor is probably the most liable, as the case will come down to the maintenance of the floor (level of floor friction). However, for a trip and fall, the owner would only be liable if there is an impediment on the floor to cause a trip. Since a trip can be caused by a misstep the fault can be placed, literally and figuratively, at the feet of the injured party. However, the question becomes how to differentiate between a slip and a trip.
There are two things to look at when trying to distinguish between a slip and a trip; the movement of the feet and the movement of the individual’s center of gravity. During a slip, a foot slides along the floor because the friction between the floor and the foot (shoe) is too low to constrain the foot. A fall occurs when the individual is unable to stop the foot from moving. During a slip and fall, the foot never stops moving until a fall is imminent. The opposite is true for a trip. During a trip, a foot comes to sudden halt due to an impediment or misstep. With one foot stopped and the body moving forward, a fall can occur.
Likewise, the horizontal movement of the center of gravity (CG) of the body can be used to distinguish between a slip and trip. The CG of the body is located slightly above the hips near the navel. During a slip, the sliding foot moves horizontally away from the CG of the body. The farther they move apart the more likely a fall will occur. During a trip, the CG of the body will move from being behind the leading foot to being in front of the leading foot.
A Biomechanic can use surveillance footage to do a video analysis of the fall to note if it was caused by a slip or a trip—putting you one step closer to knowing the true cause and if you are liable.