A new study hopes to explore the genetics of the training response. This research will identify genes that predict how one’s body will react to training. This information will be useful for both the competitive athlete looking to increase performance and patient trying to regenerate fitness.
Along with motivation, coaches encounter two additional traits that predict an athlete’s future success: innate talent and ability to react to training. These two traits generate four different types of athletes. An athlete with limited innate talent and a limited ability to react to training, unfortunately, has little potential in athletics. The second type of athlete has great innate talent, but limited ability to react to training. These are the athletes in high school that seem destined for superstardom as a freshman, but fail to show significant improvement over the course of their athletic careers. These athletes are often criticized for lacking the will to capitalize on their potential, but it is easy to emphasize with the personal frustration that comes about when training fails to bring improvement. The third type of athlete lacks innate talent, but reacts strongly to training. These athletes may be able to reach the innate athlete with limited ability to adapt to training, but they must put in a lot more work. Because training is rewarding to the third type of athlete, they usually train hard, but due to limited innate ability, often fail to reach the pinnacle of their sport. It is the fourth type of athlete, with a mix of innate talent and an ability to react to training, that makeup most of the superstars of athletics.
Innate talent is relatively easy to determine. Either one has it or they do not. The ability to react to training is harder to determine. To test, one must actually participate in a training program. To complicate matters, an individual may be predisposed to react better to a specific type of training. For example, one may be able to build anaerobic muscle by lifting weights, but fail to develop aerobic capacity by swimming. Of course, the situation could also be reversed. What if one could test their ability to respond to different types of training?
In 2012 a team at the University of Miami set out to lay the foundation for a genetic test to determine an individual’s ability to adapt to training. The study is called the Genetics of Exercise and Research (GEAR). Our genes determine traits ranging from height to predisposition to cancer.Thus, it is not far fetched that genes also can determine one’s adaptability to exercise.David Epstein highlights the GEAR study for its potential to predict athletic performance in his bestselling book, The Sports Gene. This research would be useful not just for athletes, but also patients looking for programs to increase their fitness. Some of the molecular factors that were proposed by investigators in the GEAR study to play a role in defining innate adaptability to training are shown in the figure below.
One group the GEAR study initially looked at for genetic markers was a multi-ethnic cohort of women (Genomic Signatures of a Global Fitness Index in a Multi-ethnic Cohort of Women, 2013. Rampersaud E, et al.). This study looked at composite fitness improvement over a variety of fitness tests. The 12-week training program that the women participated in consisted of both cardiovascular and resistance training. Participants were all sedentary in at least the 6 months prior to the fitness program and ranged in age from 18 to 65. The subjects were divided into quartiles based on improvement in composite fitness score. Those in the top quartile were labeled high responders and those in the bottom quartile were labeled low responders.
Interestingly, the expression of 39 unique genes were found to differ between the high and low responders at baseline. The pathways implicated included oxidative phosphorylation (generating ATP fuel using oxygen and glycolysis products) and lipolysis (breaking down fat molecules). Furthermore, a gene that has been shown to predict VO2 Max following training was found to be elevated in the high responders at baseline. The gene is an androgen chaperone protein regulated by insulin. Two genes up-regulated in low responders play a role in regulating platelet responsiveness. Additional genes involved in inflammation, immunity and angiogenesis (the creation of new blood vessels) were found to differ in the low and high exercise responders.
In the next several years, the GEAR study will provide preliminary research for additional genes to investigate. It will be fascinating to see how our increased knowledge of the genetics of adaptability to exercise changes how we approach competitive athletic training and fitness conditioning.