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Are Athletes Born or Built? How Genetics Influence Athletic Ability

How important are genetics in an athlete's success?

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Updated May 28, 2014

Female triathlete with male competitors in wetsuits preparing for race
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Athletic records are broken year after year, and the limits of human performance continue to be debated. Just as soon as we think something can’t be done, someone comes along and shows us that it indeed can be done. There was a time when no one thought a human could run a four-minute mile. Roger Bannister did that in 1954 and soon, many others followed. Ultramarathons, Ironman Triathlons and 24-hour races are now commonplace.

Is there any limit?

Surely there must be some limit. So what factors limit performance? Most physiologists agree that the current limits have to do with our genetics – specifically genes that regulate our cardiovascular endurance and muscle fiber type, but some factors are much more variable. Things like nutrition, motivation, environment and advances in equipment (running shoes, swim suits, skis, bicycles) all allow for dramatic improvements in athletic performance.

Genetics and Sports Performance

Genetics shape us in many ways including our potential to excel in sports. Training, diet, and other factors play a large role in developing our potential, but our genes may also limit performance. You may have the genetic potential for being a champion athlete, but if you live a lifestyle of overeating and no exercise you are unlikely to achieve that potential. On the other hand, someone with limited genetic potential can find ways to compensate and become a solid performer.

Genetics have a large influence over strength, muscle size and muscle fiber composition (fast or slow twitch), anaerobic threshold (AT), lung capacity, flexibility, and, to some extent, endurance.

One major limitation for endurance athletes is cardiac capacity, or the heart’s ability to deliver enough oxygen (via the bloodstream) to the working skeletal muscles. This, too, is largely determined by genetics.

The other limitation for endurance athletes is the ability of muscle tissue to effectively use oxygen and create ATP (adenosine triphosphate), the fuel that allows muscular contraction and movement. (see: Creating Energy for Exercise.) The efficiency of this process is measured by something called VO2 max (maximum volume of oxygen).

How Genetics Influence Response to Training

Your genes may also determine how your body responds to training, diet and other external factors.

Research on aerobic endurance shows that some people respond more to training than others. So even if you have a low genetic potential for endurance, you may respond well to training and develop your potential more completely than someone with genetic 'talent' who doesn't respond to training.

Training also increases cardiac efficiency, but the extent of this increase may depend upon genetics. Genetically gifted athletes will have a much greater response to training and will have a large increase in the number of mitochondria in cells. (The mitochondria are organelles in cells that produce the ATP, so the more mitochondria a person has, and the more efficient they are.)

Other Factors That Affect Sports Performance

Genetics appear to have less influence over characteristics such as balance, agility, reaction time and accuracy. Many of these skills can be greatly improved with the proper training.

Sports Nutrition

An athletes diet and nutrition plan has an enormous affect on his or her athletic performance. No where is this more evident that when an elite athlete "bonks" or "hits the wall" during an event. Bonking is generally a result of glycogen depletion, dehydration or a combination. Athletes can avoid this by training the body to burn fat when glycogen stores decrease and by continually supplying the working muscles with energy during an event. (See: Energy for Exercise.)

Mental Skills Training

Practicing mental skills training such as imagery, visualization, and learning techniques for dealing with performance anxiety are all skills than any athlete can learn to master with practice. These techniques, along with learning the tactics and strategies of the sport, using proper equipment and avoiding injuries are all critical factors in sports success that have very little to do with genetics.

Although many elite athletes are blessed with the right genetics for their sport and a great training routine, even recreational athletes can make the most of their abilities with optimal conditioning, good nutrition and a positive mental attitude.

Source

Bouchard, C., R. Malina, and L. Perusse (1997). Genetics of Fitness and Physical Performance. Champaign: Human Kinetics, pp. 1-400.
Bouchard, C., P. An, T. Rice, J.S. Skinner, J.H. Wilmore, J. Gagnon, L. Perusse, A.S. Leon, and D.C. Rao (1999). Familial aggregation of VO2 max response to exercise training: Results from the HERITAGE Family Study. J. Appl. Physiol. 87: 1003-1008.

Skinner J.S., A. Jaskolski, A. Jaskolska, J. Kransnoff, J. Gagon, A.S. Leon, D.C. Rao, J.H. Wilmore, and C. Bouchard (2001). Age, sex, race, initial fitness, and response to training: The HERITAGE Family Study. J. Appl. Physiol. 90: 1770-1776.

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