Performance changes in champion swimmers aged 30 to 84 years.

Performance changes in champion swimmers aged 30 to 84 years were examined using both longitudinal and repeated cross sectional designs. When single cross sectional slices of the data were analyzed, decrements in performance with advancing age were found, similar to those reported in older track athletes. When the same individuals or cohorts were followed over time, the changes were found to be substantially smaller. The results also showed greater age changes in short, anaerobically-swum races than in longer, aerobically-swum races.