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

Endurance exercise performance declines with age; however, there is li ttle information on the mechanisms responsible, especially in women. W e tested the hypothesis that this performance decline in women is asso ciated with decreases in maximal O-2 consumption (VO2max), blood lacta te threshold (LT), and running economy (RE). We determined a 10-km rac e pace, VO2max, LT, and RE in 31 highly trained female runners aged 23 -56 yr with similar relative (i.e., age-adjusted) competitive performa nces. 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. T he 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 a nalyses performed on subjects pooled from groups I and II and from gro ups II and III indicated that the majority (60%) of the variability in performance for runners aged 23-47 yr was explained by the running ve locity 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 physiologic al phenomena most closely associated with declines in 10-km performanc e with age in highly trained female runners. However, the contribution s of these two mechanisms to the declines in performance are not unifo rm with advancing age.