Superior fatigue resistance of elite black South African distance runners.
Black athletes currently dominate long-distance running events in South Africa. In an attempt to explain an apparently superior running ability of black South African athletes at distances > 3 km, we compared physiological measurements in the fastest 9 white and 11 black South African middle-to long-distance runners. Whereas both groups ran at a similar percentage of maximal O2 uptake (%VO2max) over 1.65-5 km, the %VO2max sustained by black athletes was greater than that of white athletes at distances > 5 km (P < 0.001). Although both groups had similar training volumes, black athletes reported that they completed more exercise at > 80% VO2max (36 +/- 18 vs. 14 +/- 7%: P < 0.005). When corrections were made for the black athletes' smaller body mass, their superior ability to sustain a high %VO2max could not be explained by any differences in VO2max, maximal ventilation, or submaximal running economy. Superior distance running performance of the black athletes was not due to a greater (+/- 50%) percentage of type I fibers but was associated with lower blood lactate concentrations during exercise. Time to fatigue during repetitive isometric muscle contractions was also longer in black runners (169 +/- 65 vs. 97 +/- 69 s; P < 0.05), but whether this observation explains the superior endurance or was due to the lower peak muscle strength (46.3 +/- 10.3 vs. 67.5 +/- 18.0 Nm/l lean thigh volume; P < 0.01) remains to be established.
Coetzer
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P
Liberty Life Chair of Exercise and Sports Science, University of Cape Town Medical School, Observatory, South Africa.
Noakes
T D
TD
Sanders
B
B
Lambert
M I
MI
Bosch
A N
AN
Wiggins
T
T
Dennis
S C
SC
D000328:Adult; D044383:Black People; D005080:Exercise Test; D005221:Fatigue / Q000503:physiopathology*; D006801:Humans; D007537:Isometric Contraction / Q000502:physiology; D007773:Lactates / Q000097:blood; D008297:Male; D009132:Muscles / Q000033:anatomy & histology / Q000502:physiology; D010101:Oxygen Consumption / Q000502:physiology; D010807:Physical Endurance / Q000502:physiology*; D012420:Running; D013019:South Africa; D044465:White People
D007773:Lactates