Maximum acceptable horizontal and vertical forces of dynamic pushing on high and low coefficient of friction floors

The purpose of this experiment was to investigate horizontal and vertical c omponents of maximum acceptable initial and sustained forces while performi ng push cart tasks on high and low coefficient of friction (COF) floors. Ei ght male industrial workers performed two sessions of 120 push cart tasks o n a high COF floor and one session of 120 push cart tasks on a low COF floo r. Each push cart task was 7.6 m long and initialed once a minute. A psycho physical methodology was employed, whereby the subjects were asked to selec t a workload they could sustain for 8 h without "straining themselves or wi thout becoming unusually tired, weakened, overheated or out of breath". The results revealed maximum acceptable weights of the push cart tasks on the low COF floor were significantly lower (31%) than the maximum acceptable we ights on the high COF floor. That coincided with a significant reduction in the initial and sustained horizontal forces of push (41% and 38%, respecti vely) on a low COF floor. Push durations on the low COF floor were also lon ger (62%) than on the high COF floor. Vertical forces and ratios of the ver tical to horizontal forces were not significantly different comparing both floors. Calculated slip potential and probability of slipping was borne out by the observation of repeated slipping by the subjects during pushing on the low COF floor. Ergonomic strategies should include the maintenance of s ufficient COF on floors to maximize the psychophysical pushing capabilities of the industrial worker.