Are champions built or born?
Whether you consider yourself a sporty type or not, the fact is we all have innate athletic ability that we can maximize to reach our own, individual personal best. This “upper limit” of athletic performance varies from person to person, since there is a large variability in an individual’s physiological adaptation to exercise. Most of us who do not play sports for a living won’t come close to reaching our ceiling, and we will be able to stay in relatively good shape with a minimum effective dose that allows us to still have lives outside the gym. Still, watching the pros whether in FIFA World Cup or the Tour de France or whatever else suits your fancy reminds us of how truly amazing the human body can be at peak performance. What is it that fundamentally distinguishes the top tier of amateurs and pros from the average gym-goer or the weekend warrior? What is the difference between an already talented athlete and a champion? Many external factors affect athletic performance, such as training, diet, skill development, climate, and other environmental and lifestyle influences. The confluence of these external factors may shape athletic development, but a key driver to being a champion is intrinsic— those at the very top have a higher upper limit based on their genetic potential.
So how different are we, really?
Or maybe the better question is… why aren’t you a pro? You may have heard that genetically we are nearly identical, sharing ~99.5%-99.9% of our DNA. Yet, the pros and elite athletes seem to have some kind of distinct genetic advantage. So, what’s right here? How can elite athletes really be so different from the rest of us? Well, we do share many similarities on a cellular level for fundamental processes (for example, reproduction or respiration). But with millions of locations in the genome where we can differ, there is a lot of room for genetic dissimilarity to contribute to large observable and measurable differences in traits. Just take a look at this picture on our Instagram of the incredible Dikembe Mutombo with a fan friend of ours. In theory, these two are nearly genetically identical but clearly small differences can make a big impact!
As we mentioned earlier, research shows a large variability in human response to exercise as well. For example, in a study by Hubal et al, 585 participants followed a 12 week resistance training program with linear periodization, and showed a huge range of muscle (biceps) growth and strength gains: the change in muscle size ranged from -2% to 59% (yes, some people’s biceps actually got a bit smaller), and the strength gains ranged from 0 to 250%! Earlier research using twins and more recent genetic association studies point to a hereditary component influencing the variability observed in athletic performance and training response. To date, over 200 genetic variants associated with various components of physical performance have been identified, with over 20 polymorphisms associated with elite athlete status in particular.
An example… genetics and muscle fiber composition
Muscle fiber composition, for example, varies considerably between individuals and is a largely heritable trait. The proportions of an individual’s fiber types in skeletal muscle affect his or her propensity for endurance (low intensity) versus power (high intensity) exercise. Type I (slow-twitch, oxidative) fibers are ideal for endurance activities since they have a high resistance to fatigue allowing you to exercise longer. Type IIa and IIb (fast-twitch, glycolytic) generate more force than Type I, but are less resistant to fatigue and are best suited to short duration, high intensity work. Type IIa fibers are an “intermediate” fiber type, using both oxidative and glycolytic pathways to produce energy. In practice, these physiological zones overlap and there are transitional regimes of fiber recruitment that may be delineated by an aerobic threshold and lactate threshold. Yet, we have some insights about genetics of elite ability in cohorts of athletes performing at a high level in sports encompassing a spectrum of aerobic and anaerobic demands: road cycling, rowing, endurance running, sprinting, rugby, swimming, cross-country skiing, triathlon, and others. For example, some notable variants that have shown positive association with endurance or power ability include ACE rs4646994 I/D, ACTN3 rs1815739 C/T, PPARA rs4253778 G/C, PPARGC1A rs8192678 G/A, ADRB2 rs1042713 G/A, and NOS3 rs2070744 C/T.
Where a competitor falls on the spectrum of power to endurance genetic potential may mean the difference between being a participant instead of a contender in a particular event. At the elite level, genetics matter when racing a 200m instead a 5km, or whether your cycling role is better suited as a sprinter or climber. Athletes and coaches are looking to leverage innate ability and train accordingly to get an edge. There is also potential of individualizing resistance training programs to maximize response to this end, and such research into personalized training is ongoing.
It should be noted that while the research points to the importance of genetics in the context of various elite sports, this is a different question than whether we can we use these genes to actually predict talent. Sports performance is complex, and has many moving parts that need to be integrated on a systems level to be able to accurately predict success of the athlete as a whole. Individual genetic architecture will clearly play a major role, but the nature of the task, training intensities and periodization, nutrition, neuromuscular adaptations, and many other factors will contribute to success as well. The evidence is currently lacking to support talent selection based on genetic profiles alone. Right now, we can only say that a “good” genetic profile is important in the making of an elite athlete, but it is not enough to predict or guarantee athletic success.
So, what if we want to maximize our own genetic potential, even if we aren’t pros? There are things we can do to level up our fitness game and achieve our own personal best by knowing our genetics. Understanding your body’s tendencies with regards to power or endurance capacity can help guide your training to enhance your strengths and/or work to address limitations. However, your fitness genotype is only one consideration to guide your optimal training choices and it does not define your athletic identity. Do not underestimate the value of work ethic and challenging your weaknesses. Over time you will adapt to the stimuli, become more resilient and emerge stronger than before. Furthermore, training is just one part of the bigger fitness picture. This post did not go into your individual needs for recovery (nutrition and rest time) and injury risk—these also have underlying genetic associations that are important to consider, and will be covered in future posts. Recovery is as significant as training in maximizing athletic potential, and knowing how to eat and rest to complement your unique genetics can extend your fitness longevity.
When it comes to the those of us who just want to get fit and not become Olympians, consistency and long-term sustainability are crucial considerations in picking a fitness plan. There are innumerable benefits of regular physical activity not pertaining to high-performance sports, such as boosting energy, improving mood, increasing longevity, enhancing quality of life, reducing risk for several diseases, and the list goes on. Furthermore, other factors not discussed here can affect your response to consistent training over time, such as epigenetics or improvement of hormonal milieu. If you dislike your fitness plan or it is not feasible for your lifestyle, it doesn’t matter how “perfect” it is, you will never do it. Putting theory into practice means realizing that our fitness is a moving target. Our goals, life demands, medical status, and many other things that impact our choice of exercise regime will change over time. Attempting to train exactly the same way all the time will have a negative impact in the long run, no matter what your goal.
What about pros with a little “extra help”?
As an aside, this discussion has purposely not considered the effect of performance enhancing drugs (PEDs) in elite sports. Interestingly, a recent study by Seaborne et al showed epigenetic modifications during skeletal muscle growth earlier in life are “remembered”, facilitating growth later in life should there be muscle loss. This has potential consequences for athletes using drugs, since muscle growth due to pharmacological aids may have consequences lasting longer than anticipated, possibly requiring longer ban times. More research including drugs for muscle growth in this context is required to test this particular hypothesis. However, the area of sports epigenetics is fascinating and the research is rapidly increasing our understanding of how exercise stimuli can provoke epigenetic responses and modulate gene expression, giving us some control of the genetic cards we are dealt. This modulation of gene expression also applies to diet, so stay tuned for more sharing of knowledge as this exciting area continues to grow.
“Genetics loads the gun, and environment pulls the trigger.”
Could someone exist who is genetically “perfect” for his/her sport?
If you’re wondering if there could possibly be a “perfect” athlete out there, consider the 2008 study by Williams et al where they took 23 genetic polymorphisms associated with the endurance phenotype, considered the typical frequency of the “good” genotype and the odds ratio of a “perfect” genetic profile, and calculated the probability of any individual having the “good” version for all 23 variants. It turns out there is 0.0005% chance for any given individual in the world to have a “perfect” polygenic profile. So, it is extremely unlikely that a perfect endurance athlete exists. And this analysis was based only on 23 polymorphisms; larger panels of variants as the research grows make it even less likely. Basically we’re all at some kind of disadvantage, so we might as well go out and train to get fitter and stronger and work with whatever genetics we’ve got!
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