The reason why west africans are overrepresented in sprinting and East Africans in long distance, is contra Syed, significantly due to innate advantages. Syed mentions that similar genes occur within all groups, but omits that they occur in different frequencies, hence the group differences. For example, ACTN3:
"Few genes are known to be decisive in determining life outcomes. Nutrition, training, and other genes matter. But the evidence that this gene significantly influences athletic ability is strong.
Now look at the frequency of the R and X variants in different populations. According to data published seven years ago in Human Molecular Genetics, the relative frequency of the X allele is 0.52 in Asians, 0.42 in whites, 0.27 in African-Americans, and 0.16 in Africans. If you break out the data further, the frequency of the XX genotype is 0.25 in Asians, 0.20 in European whites, 0.13 in African-Americans, and 0.01 in African Bantu. Conversely, the frequency of RR (the genotype for speed and power) is 0.25 in Asians, 0.36 in European whites, 0.60 in African-Americans, and 0.81 in African Bantu. Among Asians, you can expect to find one RR for every XX. Among whites, you can expect nearly two RRs for every XX. Among African-Americans, you can expect more than four RRs for every XX."