Leg strength comparison between younger and middle-age adults

Although a risk of occupational musculoskeletal diseases has been identified with age-related strength degradation, strength measures from working group are somewhat sparse. This is especially true for the lower extremity strength measures in dynamic conditions (i.e., isokinetic). The objective of this study was to quantify the lower extremity muscle strength characteristics of three age groups (young, middle, and the elderly). Total of 42 subjects participated in the study: 14 subjects for each age group. A commercial dynamometer was used to evaluate isokinetic and isometric strength at ankle and knee joints 2 × 2 (age group (younger, middle-age, and older adult groups) × gender (male and female)) between-subject design and Post-hoc analysis were performed to evaluate strength differences among three age groups. Post-hoc analysis indicated that, overall, middle-age workers' leg strengths (i.e., ankle and knee muscles) were significantly different from younger adults while middle-age workers' leg strengths were virtually identical to older adults' leg strengths. These results suggested that, overall, 14 middle-age workers in the present study could be at a higher risk of musculoskeletal injuries. Future studies looking at the likelihood of musculoskeletal injuries at different work places and from different working postures at various age levels should be required to validate the current findings. The future study would be a valuable asset in finding intervention strategies such that middle-age workers could stay healthier longer. Relevance to industry: The leg strength value reported in the study may be used for alarming both middle-age workers and managers to be aware of possible MSDs due to shortfall in muscular strength, and managers to recommend limits for manual tasks involving lower extremity.