ABSTRACT
Strandberg and Lanshammar (1981) studied the dynamics of human slipping in order to achieve biomechanical data for the prevention of slipping accidents. They simulated unexpected heel slip-ups when approaching a force plate which was lubricated with water and detergent in 76 trials (61 per cent) out of 124. The trials were categorised into two main groups, grips (85 trials) and skids (39 trials). The skids were then split into two categories, slip-sticks (16 trials) and falls (23 trials), while the slip-sticks were finally differentiated into mini-, midi-and maxi-slips. In the mini-slips the subjects were unaware of the sliding motion, in the midi-slips no apparent gait disturbances were observed, but in the maxi-slips compensatory swingleg and arm motions occurred. The peak sliding velocity was above walking speed (1 to 2 m s-1) in the skids that resulted in a fall, but did not normally exceed 0.5 m s-1 in the remaining skids called slip-sticks, where the subjects were able to regain balance. Strandberg and Lanshammar concluded that a slip was likely to result in a fall if the sliding exceeded 0.1 m in distance or 0.5 m s-1 in
velocity. The average critical slip motion started 50 ms after heel contact, when the vertical load was about 60 per cent of body weight, acting typically at the heel rear edge.
