PHYSIOLOGICAL DETERMINANTS OF 10-KM PERFORMANCE IN HIGHLY TRAINED FEMALE RUNNERS OF DIFFERENT AGES

Endurance exercise performance declines with age; however, there is little information on the mechanisms responsible, especially in women. We tested the hypothesis that this performance decline in women is associated with decreases in maximal O-2 consumption (VO2max), blood lactate threshold (LT), and running economy (RE). We determined a 10-km race pace, VO2max, LT, and RE in 31 highly trained female runners aged 23-56 yr with similar relative (i.e., age-adjusted) competitive performances. Absolute 10-km race pace declined with age (r = -0.83). Both 10-km performance and age were correlated with VO2max maw (P < 0.05) and with the running velocity and O-2 consumption at LT but not with RE. The runners then were divided into three age groups: group I (23-35 yr), group II (37-47 yr), and group III (49-56 yr). Stepwise regression analyses performed on subjects pooled from groups I and II and from groups II and III indicated that the majority (60%) of the variability in performance for runners aged 23-47 yr was explained by the running velocity at which LT occurred, whereas VO2max explained the majority (74%) of the variability for the runners aged 37-56 yr. We conclude that decreases in VO2max and running velocity at LT are the two physiological phenomena most closely associated with declines in 10-km performance with age in highly trained female runners. However, the contributions of these two mechanisms to the declines in performance are not uniform with advancing age.