African runners exhibit greater fatigue resistance, lower lactate accumulation, and higher oxidative enzyme activity

1 Medical Research Council/University of Cape Town Bioenergetics of Exercise Research Unit, Department of Physiology, and 2 Department of Anatomical Pathology, University of Cape Town Medical School, Cape Town 7925, South Africa; and 3 School of Exercise and Sport Science, University of Sydney, New South Wales 2141, Australia Nine African and eight Caucasian 10-km runners resident at sea level volunteered. Maximal O 2 consumption and peak treadmill velocity (PTV) were measured by using a progressive test, and fatigue resistance [time to fatigue (TTF)] was measured by using a newly developed high-intensity running test: 5 min at 72, 80, and 88% of individual PTV followed by 92% PTV to exhaustion. Skeletal muscle enzyme activities were determined in 12 runners and 12 sedentary control subjects. In a comparison of African and Caucasian runners, mean 10-km race time, maximal O 2 consumption, and PTV were similar. In African runners, TTF was 21% longer ( P