The effect of load carrying and floor contaminants on slip and fall parameters.

A study was conducted to provide set-up values of an important biomechanical parameter, heel velocity, for slip resistance testers. Four different floor surfaces (with or without oil contaminant) were prepared for ten subjects with each walking at a fixed velocity while carrying five different loads. Stride lengths were also measured to find whether a significant difference existed between a carrying method typically used in industry (two-handed carrying of a load in a tote box held directly in front of the body) and previously used load carrying techniques (backpack and front-back pack systems). A programmable slip resistance tester was used to measure dynamic coefficient of friction with conventional set-up values for heel velocity. The results showed that the conventional set-up value for heel velocity is valid for dry floors but is too low on oily floors because faster transfer of body weight was seen owing to decreased stride length. On oily floors, heel velocities of 60 to 140 cm/s would be recommended. An abnormal gait pattern, short stride length, was seen on oily floors or with heavy load carriage because subjects adjusted their stride length for a better stance.