Lifting capacity at 24 weeks of pregnancy: a case contrast between a women in a physically demanding job and one in a sedentary job
Buckley, N, Innes, E, Davison, K & Gilleard, WL 2011, 'Lifting capacity at 24 weeks of pregnancy: a case contrast between a women in a physically demanding job and one in a sedentary job', paper presented to Ergonomics Australia - HFESA 2011 Conference, Northside Conference Centre, Crows Nest, 7-9 November.
Background: Pregnant women are encouraged to maintain their pre-pregnancy physical activity levels, including their activities of daily living. Heavy lifting is an activity of daily living currently restricted in pregnant women; though the literature reviewing occupational activities indicates that heavy lifting during pregnancy in developed nations does not warrant mandatory restrictions, as the risks to mother and child are minimal. Lifting capacity during pregnancy has not been specifically investigated. Furthermore, it is unclear whether lifting capacity in pregnancy is more closely related to perceived capacity, as it is in injured populations or physical activity levels as it is in healthy populations.
Aims: To (1) evaluate lifting capacity in three ranges of motion and two lifting frequencies during pregnancy; (2) evaluate perceived lifting capacity during pregnancy; (3) compare perceived and assessed lifting capacity relative to levels of physical activity (PA).
Method: Case studies of two women at 24 weeks pregnancy with different current physical work demands. PA during the preceding three months was assessed using an adapted Kaiser Physical Activity Survey; lifting through three ranges and two frequencies was assessed by the EPICRehab Lift Capacity test; and perceived lifting capacity was determined by self-report.
Results: Leisure-time PA levels were similar in both participants, however occupational PA levels were different (8.17 and 8.00; 3.11 and 2.33, respectively). Lifting capacity through knuckle-to-shoulder and floorto- knuckle ranges were similar in both participants, however their perceived lifting capacity was different. The participant with greater occupational PA consistently overestimated her lifting capacity (mean difference: +7.51 kg (occasional lifts), +3.78 kg (frequent lifts)), whilst the woman with lower occupational PA consistently underestimated her capacity (mean difference: -4.32 kg (occasional lifts), -2.27 kg (frequent lifts)).
Conclusions: The findings of the present study need to be confirmed in a larger sample of pregnant women. Lifting capacity appears to be more closely related to leisure-time PA levels rather than perceived lifting capacity in these healthy pregnant women. Maintaining a physically demanding job during pregnancy may predispose a woman to overestimate her lifting capacity and being in sedentary employment may predispose a woman to underestimate her lifting capacity.