Marie St-Vincent

Training in handling: an evaluative study.

Training programmes in handling have been one of the most used means of preventing work-related backache. The effectiveness of these programmes has not yet been demonstrated however, since they have rarely been evaluated. The purpose of this study was precisely to assess one of these programmes in the hospital sector which specifically dealt with the handling of patients. A field study was conducted and handling methods used by 32 trained orderlies were characterized using an observational grid developed and validated specifically to describe patient handling operations. The extent to which these orderlies used the handling methods taught was determined, and the observed deviations from these methods were characterized and interpreted. The results show that the handling principles taught (working with a straight back using the legs) were not frequently used in the workplace. Furthermore, the use of training was closely related to the type of handling carried out. In handling operations in which the effort includes a horizontal component (mainly those carried out in bed) the training was hardly used, while in vertical handling operations the taught principles were more frequently used. These results suggest that actual training is not well adapted to the handling of patients, particularly to horizontal handling carried out in the bed. Two main deficiencies in the actual programmes are pointed out. First, it is shown that, for reasons of physical constraints, training could not always be applied; second, the rationale of the taught principles could also be questioned, particularly the emphasis given to the use of the legs.

Sex differences in lifting strategies during a repetitive palletizing task

Forty-five manual material handlers (15 females, 15 expert males and 15 novice males) performed series of box transfers under conditions similar to those of large distribution centers. The objective of the study was to verify whether sex differences in joint motions and in back loading variables (L5/S1 moments) exist during multiple box transfers. The task consisted in transferring 24 15-kg boxes from one pallet to another (4 layers of boxes; 6 boxes/layer: 3 in the front row, 3 in the back) at a self-determined pace and then at an imposed pace of 9 lifts/min. Full-body 3D kinematic data were collected as well as external foot forces. A dynamic 3D linked segment model was used to estimate the net moments at L5/S1. The results show that the peak L5/S1 moment during lifting for females was significantly lower than for males, but once normalized to body size the difference disappeared. In general, the female workers were very close to the posture adopted by the novice males at the instant of the peak resultant moment. However, females were closer to the box than the male workers. One major sex difference was seen when lifting from the ground, with the use of interjoint coordination analyses. Female workers showed a sequential motion initiated by the knees, followed by the hip and the back, while expert males showed a more synchronized motion. The lifting strategy of females likely stretches lumbar spine passive tissues, which in turn put them at greater risk of back injuries. As observed in our previous studies, these differences between expert males, novice males and females are especially notable when the box is lifted from the ground.

Musculoskeletal Symptoms in Two Plants in the Electrical Sector.

The study consisted of describing, using a questionnaire, the musculoskeletal symptoms in two industries in the electrical sector. The questionnaire was distributed to more than 600 workers in the two industries. The questionnaire described four types of variables: usual population data (age, gender, experience, etc.), certain work variables, the regions of the body affected in the past 12 months and in the past 7 days, and the severity of the symptoms. Ten variables were used to provide a symptom severity index. In the two plants, the women reported more frequent and more serious problems than the men and the least experienced workers were the most affected. In Plant 1, the questionnaire pinpointed two work sectors, whereas in Plant 2, the problems were found not to be concentrated in a few sectors, but distributed among different jobs throughout the entire plant.