Genes contributes to phenotype. Distinct genetic populations exist that can be traced via genomic information. I agree. However, as presented, these two principles are not necessarily related to one another.
The genetic uniqueness that is used to categorize populations is from non-coding, hypervariable segments of mtDNA. These segments have no phenotypic expression, are not subjected to selection or meiotic recombination, and have vastly different mutation rates from nuclear DNA. They are genetic fossils. I agree with you that to some unknown extent there is very complicated correlation between variation in the nuclear genome and physical capability. However there is nothing to suggest that hypervariable mtDNA segment mutation is consistent with the nuclear loci responsible for an individual's phenotypic expression of athletic ability. Therefore assuming that these traits follow a geographical distribution or evolutionary history is a complete shot in the dark.
Take for instance the sickle cell allele. The fact that it is present in various ethnically distinct lineages “blacks, South Americans, Southern Europeans and Middle Easterners” suggests that nuclear DNA traits don’t always correlate well with the evolutionary history suggested by mtDNA analysis.
On top of that, I'm not sure what sort of inferences a reasonable person can be made about a population's "abilities and/or limitations" based upon the frequency of a single loci mutation like sickle cell or super hemoglobin (if it is also a single loci mutation). If the hemoglobin mutation is heritable, it is likely to spread to numerous populations much the same way sickle cell has. Will the Ethiopians be good at XC skiing too?