African Runners Versus Caucasians

By Danny Mackey M.S.

            Other than a few meets outside of Europe, the track season is over.  Between Flotrack and my cable network getting the Universal Sports channel, I have lost interest of my losing Chicago Cubs and been able to watch the best athletes in the world fight it out on a regular basis.  Unlike past track seasons, U.S. distance running fans were excited to cheer on top finishes in major Golden League IAAF meets and championships. America had a number of finalists and top 8 finishes in the Men’s and Women’s 800, 1500, 5k and 10k in both the World Championships and World Athletics Final.  Just 10 years ago the US was lucky to have one athlete in either of these events.  But even with the improvement, watch any Golden League 5,000 and it is evident there is a strong dominance from one part of the globe.  This is why one of the questions I heard from my buddies while watching these meets is “why do the Africans still just dominant”? 

One argument is East Africans are tougher, train harder and are more disciplined.  Does that mean that Bekele can handle more pain and trains harder the Ritz?  Maybe.  Another argument is environment.  Growing up at an altitude of 7,000 feet and running 10km to school everyday versus growing up in Chicago and driving everywhere is very good point.  Studies have shown that even short-term exposure at altitude can affect aerobic energy metabolism and fat oxidization activity.  This ties in closely with the last argument, genetics. What we are born with regardless of toughness and environment.  (The reason I say “closely” is because genetic expression levels can be directly influenced by your environment).  Though, why is it that despite comparable VO2 max levels, slow-twitch/fast-twitch fiber proportions, fiber cross sectional area (predictor of maximum force production) and capillarization (more capillaries help oxygen transfer within muscles) the East Africians have raced substantially faster then Caucasians? 

I am more curious about the genetic differences, if there are any.  (Or maybe I want to make an excuse for my weak minded, lazy self that even though I’m trying to qualify again for the US marathon Olympic trials that I would not even make a middle school team in Kenya).  In Kenny Moore’s Best Efforts: The Long Green Line, he talks about traveling to Kenya after finishing 4^th in the Olympics.  While on a run one day, Kenny writes about thinking that only 3 guys are better than him in the world, yet he is not able to keep up with the Kenyan kids as they run to school.

            A study by Dr. Coetzer talks about traits that African runners have over Caucasians that can directly improve performance.  A common genetic indicator that can be measured in a lab is VO2 max because it provides a quantitative measure of an athlete’s capacity for aerobic ATP resynthesis.  Note the word capacity here, as it just provides a ceiling.  In a distance race, our goal is to increase our time to fatigue.  We can achieve this by having a lower accumulation of metabolites for a given pace or tempo.  Furthermore, if our plasma lactate concentration is lower at a similar percentage of VO2 max utilization, this should infer greater time to fatigue.  Plasma lactate can be lowered by a few methods.  First, simply a decreased rate of lactate formation during hard effort running.  Second could be an increased rate of lactate clearance.  The last possibility is a combination of the two.  African distance runners with a similar VO2 max to Caucasians have shown a lower accumulation of metabolites and plasma lactate levels. 

            In this study, trained 32 min 10,000 meter Caucasian and African runners with equal VO2 max levels were run in a lab to maximum intensity.  They found, African runners ran 21% longer then the Caucasian runners.  Yet RER (respiratory exchange ratio which looks at substrate utilization, a decent indicator of relative effort), VO2, and max heart rate were the same.   Though plasma lactate was significantly lower in the Africans and citrate synthase activity was significantly higher (aerobic enzyme that begins the Krebs cycle). This supports the thought that having a high skeletal muscle oxidative capacity is important for optimizing an athlete’s performance.  In a 10,000 meter race Africans can nearly run 1,200 meters longer at 98% of their max heart rate.  Applying these numbers.....remember the fast sustained effort Bekele and Tadesse used to close the last 5,000 meters of the 10,000M in the world championships?  That was Tadesse’s season best in the 5,000M and only 12 seconds off Bekele’s season best, thing about that for a minute! 

            I am sure there are other possible factors, and half the fun of watching a great race is talking about it and “why” with your friends.  But, the Africans simply being tougher may not be the case.