Feature: Born or made?

What makes a champion? With Olympic fever running hot, this is a question that is likely to have been asked more than a few times in recent weeks both in living rooms and locker rooms worldwide.

There’s no question that the Olympian elite are dedicated to their craft, often putting in thousands of hours training to reach their peak. But is becoming an Olympian purely a matter of commitment? Could biology play a role in sorting those who stand aloft the podium from those who cheer from the stands? Can anyone potentially become a champion? Could you?

There’s clearly at least some biological component to athletic performance; we already separate many events into men’s and women’s streams, after all. (In fact, there’s only a single Olympic event where men compete directly against women: equestrian. But let’s not forget the genetics of their mounts.) However, there are also other tantalising hints that biology plays a significant role in determining who rank amongst the athletic elite.

Consider distance running: of the last five Olympic games, all but three of the 15 medallists in the men’s 10,000m event were from east Africa, either Kenya, Ethiopia or neighbouring Eritrea. Could this be a quirk of coincidence? Perhaps a matter of environment, such as a tendency to travel long distances on foot? Or maybe it’s from growing up at altitude, thus boosting red blood cell count? Or perhaps it’s due in part to genetics?

Answering this question is not only of scientific import, but would be a tremendous boon to the industry of elite sports. If it turns out that biology does play a role in determining who makes it to the podium, this is something that both talent identifiers and trainers would love to know, not to mention aspiring athletes themselves. For surely there are few greater disappointments than putting years of single-minded dedication into a pursuit only to find that you’ll never rank among the best.

Professor John Hawley, Head of the Exercise Metabolism Research Group at RMIT, is one of those who is drawing on the latest tools from the lab to uncover the biological basis of elite athletic performance. At the Human Genetics Society of Australasia meeting, Hawley spoke about the role played by genes, miRNA and mitochondria in determining who has the potential to be an Olympian, and who’s better off spectating.

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Nature/nurture

To this day, the role of biology and genetics in elite performance remains a controversial topic. Besides the spectre of fallacious racial essentialism, it also challenges the notion of human plasticity and the unbounded ability to mould and better ourselves.

There are some, such as psychologist K. Anders Ericsson from Florida State University, who believe that biology plays a only a minor part in determining who’s set to be a champion. According to Ericsson, body size is the only innate limit to potential performance, and the rest is down to training – and lots of it.

He famously proposed the ‘10,000 hour’ rule, stating that it takes 10,000 hours of training over 10 years at key stages of development in order to make an expert. Or an Olympic champion.

In a 2009 paper published in Current Directions in Psychological Science, he and his co-authors wrote that “our empirical investigations and extensive reviews show that the development of expert performance will be primarily constrained by individuals’ engagement in deliberate practice and the quality of the available training resources.”

Ericsson didn’t dismiss biology entirely, but argued that the pivotal biological components display marked plasticity rather than being hardwired at birth. In fact, he stated that the years of hard training activate “dormant genes that are contained within all healthy individuals’ DNA.”

This is an appealing prospect, at least on one level. It suggests that we all have within us the capacity to be great. All we have to do is unlock it. But it’s a double-edged sword: if someone fails to reach greatness they can only blame themselves for not training hard or long enough.

However, not everyone agrees with Ericsson’s 10,000 hour theory. And according to Hawley, there’s mounting evidence to suggest that Ericsson has seriously underestimated the role that genetics has to play in shaping a champion. “Nature versus nurture always gets a lot of airplay,” he says.

“But within the field of sport science we have amassed substantial evidence that it’s both genetic and environmental. There’s no question that elite athletes are genetic outliers, and no amount of training will make an also-ran into a champion.”

Hawley cites a paper published this year by two South African sports medicine researchers, Dr Ross Tucker and Associate Professor Malcolm Collins, who also question Ericsson’s findings. They point out that while the 10,000 hour mark is a relatively consistent indicator of expert status, amongst a wide range of fields – from chess Grand Masters, to musical ability, to athletic performance – there are large individual differences in performance achieved through training.

For example, one chess player reached master level after around 3,000 hours of practice, while another took 23,000 hours. They also found that elite athletes often reach peak levels with considerably less than 10,000 hours under their belts, with 28 per cent of Australian athletes reaching elite status within only four years of taking up the sport.

Tucker and Collins stress the role that genetics has to play in influencing sporting performance, such as genes that are associated with endurance or an individual’s maximal ability to take in and utilise oxygen – the VO₂max.

This trait appears to be heritable, and is highly predictive of athletic performance. These genes don’t rigidly determine whether someone is bound to be a gold medal contender, but they do play a role that can’t be overlooked in who has the potential to be a contender.

“Genes set the ceiling for an individual’s absolute level of performance ,” says Hawley. “But training determines how close you get to reaching that ceiling.”

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Finding the ceiling

A study recently completed in Hawley’s lab set out to find out where that ceiling might be for different individuals, the results of which he shared at the HGSA meeting. He was particularly interested in whether there any ways of looking at various biomarkers – particularly concerning those cellular powerhouses, mitochondria – and predicting how different people would respond to exercise training.

He and his colleagues took a handful of healthy young males – all fit but none athletic – and had them perform a standardised bout of endurance exercise before taking blood and muscle samples. They then scanned for the levels of signature genes that are triggered by exercise.

One gene was of particular interest: PGC-1α. This is gene that operates as a “master switch” for mitochondrial biogenesis and is known to play a role in energy metabolism. Interestingly, there was little or no increase in PGC-1α after exercise in some subjects, while others saw up to a 12-fold increase. This would prove a telling difference.

Hawley then had the subjects undertake a 10 day intensive training regime to see how far they would improve in metrics such as VO₂max and a battery of lab-based ‘performance’ tests. Unsurprisingly, they all improved their fitness levels in response to the training, but there was a mix of ‘high responders’ and ‘low responders.’

And lo, when looking at the original gene samples they took, they saw a correlation between variation in performance improvements and variations in levels of PGC-1α after their initial exercise session.

This suggests that variations in the exercise-induced activation of PGC-1α might influence the degree to which someone will respond to exercise. High activation, and you’re likely to benefit from the exercise a lot more, and maybe even reach champion level. Low activation and you might train and train and train and never be competitive.

Another study also reinforces Hawley’s finding, except this time it tracked the abundance of key microRNAs (miRNAs). The study from 2010 was conducted by Peter K. Davidsen from the University of Copenhagen and colleagues, and took 56 healthy men between the ages of 18 and 30 and put them on a 12 week resistance training programme to specifically build muscle. They also controlled for other environmental variables like diet.

Like Hawley’s study, their performance at the end of the programme varied: some added 1 kg of lean muscle, and others added up to 5 kg. The question was: why? “If that’s what’s happening with the same training program, and the external stimulus is the same and the diet is the same, what the heck is going on?” says Hawley.

The researchers then separated out eight of the high responders and nine of the low responders and looked at variation in miRNA expression. They found that many abundant miRNAs were unaffected by the exercise, but a few did show a substantial effect. Four miRNAs in particular stood out, including two that are known to play a role in lean body mass and in muscle fibre composition.

It seems the miRNA levels were differentially affected by the resistance training, and these miRNAs then played a significant role in helping to build new muscle in those individuals who expressed them in abundance. Short on the miRNAs, and the training was simply less effective.

“So there’s no question in my mind that the genetics provide the base and ultimately how high the ceiling is, but then training, nutrition, sport science support and socio-economic factors come into play,” says Hawley.

The next stage for Hawley is to see if he can find a way to spot the key biomarkers for athletic performance that is somewhat less invasive than a muscle biopsy. As such, he’s working with researchers at ANU and in Singapore to develop a simple finger-tip blood test that can be administered with minimal discomfort. That would greatly simplify the job of spotting whether an individual is likely to respond well to training.

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Picking winners

The field is still relatively young, but Hawley believes a deeper understanding of the biological factors that underpin elite athletic performance, and an increase in simple, easy-to-administer biomarker tests, will have a profound effect on many sports.

Presently talent identification is as much an art as a science, but that may well change in the near future. Hawley predicts that in as few as five years time, biomarkers might become a standard part of the talent identification arsenal – although it’ll never entirely replace the intuition of expert coaches in spotting potential champions.

And just as genetics is opening the door to personalised medicine, it may also open the floodgates to personalised training as well. If a youngster registers as having an abundance of the right mix of genes for swimming, they might be steered away from the paddock and into the pool.

However, Hawley recognises that there are a slew of ethical issues to be overcome when it comes to handling the biological side of athletic performance, many of which have yet to be broached by the sporting community.

And when it comes to the ethics of running a test and picking potential winners (or losers), he has mixed feelings. “I don’t have too much of a problem with that as a scientist. But as a parent... These are questions which will need to be asked and probably sooner rather than later.”