Measures of body composition in blacks and whites: a comparative review

The aim of this study was to characterize Kenyan runners in regard to their oxygen uptake and blood and ammonia responses when running. Untrained Kenyan boys (14.2 +/- 0.2 years) and Scandinavian runners were included for comparison. The studies were performed at altitude (approximately 2.000 m.a.s.l.) and, for several Kenyan and Scandinavian runners, at sea level as well. At altitude sedentary adolescent Kenyan boys had a mean maximal oxygen uptake (VO2max) of 47 (44-51) ml.kg-1.min-1, whereas similarly aged boys regularly walking or running but not training for competition reached above 62 (58-71) ml.kg-1.min-1 in VO2max. Kenyan runners in active training had 68 +/- 1.4 ml.kg-1.min-1 at altitude and 79.9 +/- 1.4 ml.kg-1.min-1 at sea level, with individuals reaching 85 ml.kg-1.min-1. The best Scandinavian runners were not significantly different from the Kenyan runners in VO2max both at altitude and at sea level, but none of the Scandinavians reached as high individual values as observed for some Kenyan runners. The running efficiency, determined as the oxygen cost at a given running speed, was less in the Kenyan runners, and the difference became more pronounced when body weight was expressed in ml.kg-0.75 min-1. Blood lactate concentration was in general lower in the Kenyan than in the Scandinavian runners, and the Kenyans also had extremely low ammonia accumulation in the blood even at very high exercise intensities. It is concluded that it is the physical activity during childhood, combined with intense training as teenagers that brings about the high VO2max observed in some Kenyan runners. Their high aerobic capacity, as well as their good running economy, makes them such superior runners. In addition, their low blood lactate and ammonia accumulation in blood when running may also be contributing factors.

Aerobic exercise capacity at sea level and at altitude in Kenyan boys, junior and senior runners compared with Scandinavian runners

Comparison of body composition in black and white premenopausal women

Obesity intervention among African-American children and adolescents

Here we explain a much avoided phenomenon in the evolution of speed sports for men and women: The world records in running tend to be set by black athletes and in swimming by white athletes. We show that this phenomenon is predictable from physics. Locomotion is a ‘falling-forward’ cycle, in which body mass falls forward and then rises again. Mass that falls from a higher altitude falls faster, down and forward. In running, the altitude (L 1 ) is set by the position of the center of mass above the ground. In swimming, the altitude is set by the upper body rising above the water, and it is proportional to H – L 1 , where H is the height of the athlete. The anthropometric literature shows that the center of mass in blacks is 3 percent higher above the ground than in whites. This means that blacks hold a 1.5 percent speed advantage in running, and whites hold a 1.5 percent speed advantage in swimming. Among athletes of the same height Asians are even more favored than whites in swimming but they are not setting records because they are not as tall.

https://www.witpress.com/Secure/ejournals/papers/D&NE050301f.pdf

The evolution of speed in athletics: why the fastest runners are black and swimmers white

Racial variation in physique and body composition are of interest to sport scientists because these characteristics may be related to athletic performance, fitness, strength and injury. There is clearly variation among groups in mean somatotypes and the sitting height-stature relationship. Although differences are often emphasized, racial group distributions of variables describing physique often overlap to a considerable extent. Environment may be a factor in group differences in physique. Consistent Black-White differences are found in mean levels of variables related to bone mineralization, with Blacks exceeding Whites. It may be that the lean body mass of Blacks is of greater density than that of Whites. Gross morphological variation among groups is probably only a concomitant of variation in performance rather than a determinant of performance.

Himes Jh

Papers

Racial variation in physique and body composition.