Age differences and changes in sprint swimming performances of masters athletes.

Sprint swimming speeds were compared in cohorts of masters swimmers ranging from 25-29 to 65-69 years of age in 1976. The cross-sectional comparisons were repeated for the same cohorts in 1981. The ten fastest performers in the United States in each cohort were obtained for women (n = 1407) and men (n = 1437) in 50-yd and 100-yd races for each of the four competitive strokes. Results showed the greatest decrement in performance with increasing age for the butterfly stroke. The slowing with age was unaffected by the length of the race. The results supported the hypothesis that age differences in performance are due primarily to differences in muscle strength. As in previous studies, changes in performance with age in the same cohort were substantially smaller than differences between cohorts.