Influence of trajectory and gender on pushing-pulling forces when maneuvering beds in actual hospital paths

This study aimed to characterize type and magnitude of the forces required to transfer a non-powered bed along an actual hospital path. Experimental tests were performed on 20 non-professional operators who were required to move a bed along a 50 m path segmented into initial, straight, turn and maneuver phases. The forces exerted by right and left limbs in the longitudinal and transversal directions were acquired using a custom measurements system, together with velocity and acceleration of the bed. The results showed that the initial phase is the most demanding in terms of both peak and mean pushing force (222 N and 68 N respectively) with women characterized by significantly higher mean values (75 N vs. 62 N of men, p < 0.001). Also, a qualitative analysis of the right/left limb contribution, revealed the existence of an oscillatory trend with relevant asymmetries. Such results suggest a possible exposure to biomechanical risk due to axial twisting of the torso. Further studies are needed to clarify whether the gender-related differences are either due to different handling strategies or to peculiar biomechanical/physiological features.