Physiological differences between black and white runners during a treadmill marathon

Abstract

To determine why black distance runners currently out-perform white distance runners in South Africa, we measured maximum oxygen consumption (VO2max), maximum workload during a VO2max test (Lmax), ventilation threshold (VThr), running economy, inspiratory ventilation (VI), tidal volume (VT), breathing frequency (f) and respiratory exchange ratio (RER) in sub-elite black and white runners matched for best standard 42.2 km marathon times. During maximal treadmill testing, the black runners achieved a significantly lower (P less than 0.05) Lmax (17 km h-1, 2% grade, vs 17 km h-1, 4% grade) and VI max (6.21 vs 6.82 l kg-2/3 min-1), which was the result of a lower VT (101 vs 119 ml kg-2/3 breath-1) as fmax was the same in both groups. The lower VT in the black runners was probably due to their smaller body size. The VThr occurred at a higher percentage VO2max in black than in white runners (82.7%, SD 7.7% vs 75.6%, SD 6.2% respectively) but there were no differences in the VO2max. However, during a 42.2-km marathon run on a treadmill, the black athletes ran at the higher percentage VO2max (76%, SD 7.9% vs 68%, SD 5.3%), RER (0.96, SD 0.07 vs 0.91, SD 0.04) and f (56 breaths min-1, SD 11 vs 47 breaths min-1, SD 10), and at lower VT (78 ml kg-2/3 breath-1, SD 15 vs 85 ml kg-2/3 breath-1, SD 19). The combination of higher f and lower VT resulted in an identical VI.(ABSTRACT TRUNCATED AT 250 WORDS)

Are There Differences in Performance, Metabolism, and Quadriceps Muscle Activity in Black African and Caucasian Athletes during Brief Intermittent and Intense Exercise?

“…However, despite a similar resting blood lactate concentration and no significant difference in absolute power output, Caucasians had a significantly higher blood lactate concentration than black Africans during the fv exercise test from 4 kg to F Pmax + 1 kg. Lower blood lactate accumulation in black Africans (compared with Caucasians) has previously been reported during intense, continuous exercise [4,31]. However, this is the first time that this result has been reported for an intermittent sprint exercise.…”

“…Nevertheless, Coetzer et al [8] also reported that the plasma lactate concentration was significantly lower in the black African runners at two submaximal running workloads, despite an O 2 consumption similar to that seen in the Caucasian runners. Lower lactate accumulation has also consistently been reported in studies of black African runners [4,31] and elite Kenyan runners [26], compared with Caucasian runners.…”

“…Bosch et al [4] reported a higher fractional utilisation of max for the same lactate accumulation in black South Africans compared with Caucasian South African marathon runners. The findings of Coetzer et al [8] indicated greater resistance to fatigue in black South African runners than in their Caucasian counterparts, despite comparable max values.…”

“…Several studies have compared black and Caucasian responses to intense, continuous exercise [4,8,26]. Bosch et al [4] reported a higher fractional utilisation of max for the same lactate accumulation in black South Africans compared with Caucasian South African marathon runners.…”

Demographic characteristics of elite Kenyan endurance runners

“…Proposed explanations have included environmental factors (Saltin, 1996;Scott et al, 2003), psychological advantage (Baker & Horton, 2003) and favourable physiological characteristics that could be genetically conferred or environmentally determined (for a review, see Larsen, 2003). Some studies have also compared the physiological characteristics of ''black'' and ''white'' runners, reporting for the former lower blood and muscle lactate concentrations at a given exercise intensity (Coetzer et al, 1993;Saltin et al, 1995;Weston, Karamizrak, Smith, Noakes, Myburgh, 1999), better running economy (Saltin et al, 1995;Weston, Mbambo, & Myburgh, 2000) and an ability to tolerate higher fractional utilization of maximal oxygen uptake ( _ V O 2max ) (Bosch, Goslin, Noakes, & Dennis, 1990;Coetzer et al, 1993;Weston et al, 2000). However, the validity of extrapolating such findings to account for the success of East African athletes is questionable when participants have been classified into groups based primarily on skin colour, given that there are more genetic differences within ''race'' groups than between them (Yu et al, 2002).…”