As a young coach I was educated with the idea that genetic factors were the limitations to performance: “you can’t turn a donkey into a race horse”. Irrelevant statement: donkeys do not race against race horses.
More puzzling were the observations that some athletes seemed to response so well to a certain training program while others barely improved with the same program.
It’s not difficult to observe a large inter-individual variation in training responses. Nor is it hard to see ct that one-size-fits-all does not work optimally for everyone and that every individual athlete needs an individual training program or in a broader sense, an optimal environment to thrive.
In the same line of thinking is the fact that this idea also applies to nutrition: some people can eat a lot of calories without gaining weight while others can only eat a few calories and still gain weight.
Also here: one man’s superfood can be another man’s poison.
There are ways to find out what the individual response to training or diet is: coincidence, trial-and-error or taking estimated guesses. Science won’t help us a lot, as scientific research tends to average the results of individual responses. Most of the time we look at (bio-)markers of individual progress, which is also not an easy task, since there are any different variables that influence the results.
For example: for explosive sports we might look at jumping height, other strength parameters, and of course competition results, to see if our training is heading in the right direction. For many of our athletes things seem to go well, but what if an athlete stops making progress, what could be the cause? Yes, many factors can be taken into account, but one factor is difficult to judge: the genetic factor. Maybe our training program is not optimal for the specific genetic design of the athlete: physiologically, biochemically, hormonally, psychologically, etc.
Already in 1970, I wanted to perform genetic tests on athletes, but only in 2003 the human genome was unraveled and it took another 10 years for genetic testing to become feasible for coaches (reliability and pricing).
The procedure of genomic testing is simple: just have the athlete swab their cheeks. But then, trouble starts: even though the results might be accurate, the interpretation and practical meaning is not. Here are some practical hiccups: even though the genetic predisposition of the athletes is of the explosive power type (according to ACTN-3), there is still huge difference in muscle type composition between the different muscle groups in the human body.
One other methodological problem is the associations between certain qualities and the genomic design. Some labs will tell you having gene A might predicts a 80% probability of a certain quality or disease. But another lab will tell you gene A only will give you a 20% probability of the same quality or disease.
It depends on the population from which the samples are taken, since many qualities depend on environmental influences as well. So in one country one might have a gene with a 80% chance, since other environmental influences are not present or have a negative amplifying effect. While in the 20% example the same gene is expressed less in that particular population since there are positively amplifying factors like, temperature, sunlight, altitude, food, pollution, exercise, lifestyle, smoking, cultural and social habits, etc. And this might explain the difference between the 20% and 80% probability.
And there are more methodological difficulties. All of this does not decrease the value of genetic testing at all, just makes the interpretation more difficult and therefore challenging.
In sports we are not specifically looking for the risk of certain (rare) diseases. We looking for the genetic factors that associate with training and diet. These factors might show that maybe you have been training and/or eating against your genetic design and so your results are negatively affected.
The more we start to know about the human genome , the more we realize it’s not a destiny, but a set of possibilities mainly influenced by the environment. And it are those strong influences , like training and diet that we work with, every day.
A few books:
Collins, M (Ed.): Genetics and Sports; Medicine and Sport Science Vol.54, Karger, 2009.
Pescatello, L.S; Roth, S.M.(Eds.): Exercise Genomics; Humana Press, 2011.
Bouchard, C; Hoffmann, E.P.(Eds.): Genetic and Molecular Aspects of Sports Performance; Wiley-Blackwell, 2011.
Wackerhage, H.(Ed.): Molecular Exercise Physiology; Routledge, 2014.
