Background: A negative association has previously been reported between long-lasting physically heavy work and some measures of physical capacity. This relationship was further investigated in a 24-year follow-up study of 484 middle-aged men and women from the general population.
Methods: A questionnaire was administered in 1993 concerning retrospective recall of physical work loads and physical training in the time span between 1970 and 1993. Laboratory tests performed in 1993 included tests of muscle function (maximal isometric strength and dynamic endurance) and aerobic power (submaximal ergometer test).
Results: Consistent with the hypothesis, but mainly among the women, associations between long-lasting physically heavy demands and low trunk flexion strength, squatting endurance, and aerobic power were observed. In contrast, low isometric hand grip strength and low weight lifting endurance were seldom seen among those with high physical work loads, indicating a possible maintaining or training effect on the hand/arm/shoulder muscle groups.
Conclusions: Physically heavy work seems to have a different impact on different parts of the musculoskeletal system, an effect that is also different between men and women.