Spatial restraints and intra-abdominal pressure

Abstract

Fifty-four National Coal Board employees participated in an investigation of the effects of spatial restraints on acceptable manual-handling capacity. The particular spatial restraints considered were limited headroom, frontal and lateral barriers, asymmetric activities and fixed or trapped foot position. Each of these conditions was examined in isolation and then in combination with one or more further restraints. The findings, particularly from the interaction studies, revealed that a space limitation in some situations would inhibit the physical activity whereas in other conditions it might well enhance it, or at least reduce the associated back stress

The predominant effect on acceptable handling capacity was found to be limited headroom where an almost linear decrement in capacity was demonstrated for roof levels down to 90% of stature, at which point the decrement began to level off

Both frontal and lateral barriers were found to inhibit lifting activities in free space but under conditions of reduced headroom their effect was generally to reduce the level of stress

Asymmetric lifting to both the left- and right-hand side of the body was shown to increase the induced stress when compared with lifting in the sagittal plane. This was found to be generally so also for conditions of restricted headroom

A freestyle foot position was found to increase the acceptable handling capacity both in free space and in limited-headroom conditions

Although a number.of conditions studied were seen to reduce the measured stress none of these could offset the dramatic effect of limited headroom in reducing the acceptable handling capacity