This study analyzes the associations of socioeconomic status (SES), health, and physical activity with maximal isometric strength in 75-year-old men (n = 104) and women (n = 191). Maximal isometric strength was measured with dynamometers; the forces were adjusted using body weight. The maximal forces for women varied from 66% (trunk flexion) to 73% (knee extension) of those of the men. SES was not associated with muscle force. For men the trunk forces and elbow flexion force correlated negatively with the number of chronic diseases, index of musculoskeletal pain, and self-rated health. For women all the strength test results correlated with self-rated health; the other health indicators showed significant correlation with trunk extension force only. For both sexes the physically more active exhibited greater strength. The index of musculoskeletal symptoms explained the variance on trunk force factor in both sexes. It was concluded that a higher level of everyday physical activity and good values in the state-of-health indicators were the most important variables explaining greater strength among the elderly.
The authors are with the Department of Health Sciences and Gerontology Research Centre, University of Jyväskylä, Finland. Request reprints from T. Rantanen, Dept. of Health Sciences, University of Jyväskylä, PO Box 35, SF-40351 Jyväskylä, Finland.