When Nature Trumps Nurture: Genetics and Doping

The International Olympic Committee recently revealed that several athletes used performance enhancing supplements at the 2008 and 2012 Olympic games. The IOC plans to retest additional samples that may result in more athletes joining the likes of British javelin thrower Goldie Sayers and Australian race walker Jared Tallent in receiving their Olympic medals later than deserved.

Doping, or the use of a substance for performance enhancement, is a phenomenon that dates back to the ancient Greek Olympics in third century BCE. Ancient Olympians drank alcoholic mixtures and ate hallucinogenic mushrooms and various plants in an attempt to improve performance or mask pain.

In modern history, the first cases of doping occurred in the early 20th century, however anti-doping testing only began in the 1960s (1). The rationale for doping in elite and professional sport is relatively clear cut; to gain a winning advantage over opponents in order to gain fame, money, or both. Without question, there are a significant number of cases that don’t fit this characterization (see Ross Rebagliati, Andreea Raducan, for example) however it is clear that the majority of doping is done with purposeful intention.

But what distinguishes banned substances and methods from those that are permitted? The World Anti-Doping Agency (WADA) considers doping to be the possession, use, attempted use, or trafficking of a prohibited substance or method. A substance or method is prohibited if it fulfills two out three criteria: 1) performance enhancing, 2) harmful to an athlete’s health, and 3) if it violates the spirit of sport (2). In keeping with this definition, there are numerous legal means by which an athlete can improve their performance without putting their career and reputation at risk. A simple example is that of caffeine, a stimulant which is used by as many as 3 out of 4 elite athletes (3). Other examples include carb loading and the use of altitude technology.

The simplest means of improving performance, however, is through training. Physiologists are continuously looking for ways of increasing the benefits an athlete can get from his or her time spent training. Depending on the sport, these benefits can be found in being able to maintain a large training volume without overtraining or getting the biggest improvement out of the time spent training.

An example of such improvements are evident in the optimization of warm-up for a given sport or the use of post-activation potentiation, a technique that employs an understanding of muscle physiology to increase power output (4). Although the field of physiology in its many forms is continuously improving, we are also now beginning to understand the benefits of precision training, and specialization of discipline, based on the individual abilities of an athlete. These individual abilities may be a result of one’s genetics and how a their genetic makeup interacts with their environment.

An athlete that uses their genetics to precisely identify and focus on areas of strength, or potential areas that need improvement, will be able to gain an edge over their opponents and by doing so minimize the need to use illicit performance enhancing substances. For example, erythropoietin (EPO), a doping agent used by some endurance athletes, improves the body’s ability to transport oxygen to the working muscles. Seven-time Olympic Medalist Eero Mantyranta had a mutation in the gene coding for the EPO receptor (EPOR) that rendered his body overly sensitive to the red blood cell producing effects of EPO (5). This meant his (and 29 other members of his family’s) blood was naturally doped with excess EPO, giving them an innate advantage over the competition.

Photograph of the Finnish skier Eero Mäntyranta (1937–2013) at Innsbruck Olympic Games 1964.
Finnish skier Eero Mäntyranta (1937–2013) at Innsbruck Olympic Games 1964.

There are some genetic variations, such as that of the HIF1A gene, associated with an improved ability to transport oxygen. In fact, HIF1A acts as activator of EPO synthesis at the molecular level in our cells. Although our understanding of this marker is still incomplete, an athlete with this marker may excel in endurance events more so than someone who has a different variant of the gene.

Alternatively, an endurance or multi-sport athlete with an advantageous variant in a certain area may be able to afford spending more time on other facets of their fitness to improve their overall performance. An example with respect to strength and power athletes can be found in the genes that influence muscle performance. Variations of the ACTN3 gene may affect both the structure and function of muscle and how it responds to training (6). Using this understanding of how genetics might affect muscles can help physiologists and coaches to optimize a training program for a given athlete while minimizing the draw towards anabolic agents like testosterone.

As our knowledge of the effect of genetic variants on athletic ability and responses to training progressively develops we will continue to see improvements in individualization and specialization of training and athletic ability. Although there are innumerable factors that contribute to overall performance and training outcomes the use of genetic testing may provide a small but significant benefit to an athlete. In fact, an improvement as small as 1% may be considered a meaningful difference in some athletes (7).

Although there will likely always be those who are willing to risk everything for a chance at winning, the use of our knowledge of genetics will help to provide guidance to those who wish to achieve their best results while staying within the rules.


References:

  1. Reardon, C. L., & Creado, S. (2014). Drug abuse in athletes. Substance Abuse and Rehabilitation, 5, 95–105.
  2. World Anti-Doping Agency (2015). World Anti-Doping Code 2015. Accessed 01/27/16: https://wada-main-prod.s3.amazonaws.com/resources/files/wada-2015-world-anti-doping-code.pdf.
  3. Juan Del Coso, Gloria Muñoz, & Jesús Muñoz-Guerra (2011). Prevalence of caffeine use in elite athletes following its removal from the World Anti-Doping Agency list of banned substances. Applied Physiology, Nutrition, and Metabolism,  36, 555-561.
  4. Lorenz, D. (2011). Postactivation potentiation: an introduction. International Journal of Sports Physical Therapy, 6(3), 234–240.
  5. de la Chapelle, A., Träskelin, A. L., & Juvonen, E. (1993). Truncated erythropoietin receptor causes dominantly inherited benign human erythrocytosis. Proceedings of the National Academy of Sciences of the United States of America, 90(10), 4495–4499.
  6. Kikuchi, N., & Nakazato, K. (2015). Effective utilization of genetic information for athletes and coaches: focus on ACTN3 R577X polymorphism. Journal of Exercise Nutrition & Biochemistry, 19(3), 157–164. 
  7. Hopkins, W. G., Hawley, J. A., & Burke, L.M. (1999). Design and analysis of research on sport performance enhancement. Medicine and Science in Sports and Exercise. 31(3), 472-485.

 

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