Maximum acceptable forces of dynamic pushing: comparison of two techniques

The purpose of this experiment was to investigate maximum acceptable initia l and sustained forces while performing a push of 7.6 m, performed at a fre quency of 1 push min(-1) on a magnetic particle brake treadmill and a high- inertia push-cart. Eight male industrial workers performed a 40 min treadmi ll pushing task in the context of a larger experiment and two, 2 h push-car t tasks with a unique water loading system. A psychophysical methodology wa s employed, whereby the subjects were asked to select a workload they could sustain for 8 h without straining themselves or without becoming unusually tired, weakened, overheated or out of breath. The results revealed that ma ximum acceptable initial and sustained forces of pushing on the high inerti a cart were significantly higher (28 and 23%, respectively) than pushing fo rces on the magnetic particle brake treadmill. It was concluded that adjust ments to the pushing and pulling data bank by Snook and Ciriello (1991) may be appropriate if verification of this experiment yields similar results.