MAXIMAL OXYGEN-UPTAKE, ANAEROBIC THRESHOLD AND RUNNING ECONOMY IN WOMEN AND MEN WITH SIMILAR PERFORMANCES LEVEL IN MARATHONS

Sex differences in running economy (gross oxygen cost of running, C-R) , maximal oxygen uptake (VO2max), anaerobic threshold (Th-an), percent age utilization of aerobic power (% VO2max), and Th-an during running were investigated. There were six men and six women aged 20-30 years w ith a performance time of 2 h 40 min over the marathon distance. The V O2max, Th-an, and C-R were measured during controlled running on a tre admill at 1 degrees and 3 degrees gradient. From each subject's record ed time of running in the marathon, the average speed (<(nu)over bar>( M)) was calculated and maintained during the treadmill running for 11 min. The VO2max was inversely related to body mass (m(b)), there were no sex differences, and the mean values of the reduced exponent were 0 .65 for women and 0.81 for men. These re suits indicate that for runni ng the unit ml.kg(-0.75).min(-1) is convenient when comparing individu als with different m(b). The VO2max was about 10% (23 ml.kg(-0.75).min (-1)) higher in the men than in the women. The women had on the averag e 10-12 ml.kg(-0.75).min(-1) lower VO2 than the men when running at co mparable velocities. Disregarding sex, the mean value of C-R was 0.211 (SEM 0.005) ml.kg(-1).m(-1) (resting included), and was independent o f treadmill speed. No sex differences in Th-an expressed as % VO2max o r percentage maximal heart rate were found, but Th-an expressed as VO2 in ml.kg(-0.75).min(-1) was significantly higher in the men compared to the women. The percentage utilization of f(cmax) and concentration of blood lactate at <(nu)over bar>(M) was higher for the female runner s. The women ran 2 days more each week than the men over the first 4 m onths during the half year preceding the marathon race. It was conclud ed that the higher VO2max and Th-an in the men was compensated for by more running, superior C-R, and a higher exercise intensity during the race in the performance-matched female marathon runners.