Genetic analysis companies are forging alliances with personal trainers, chiropractors, and coaches around the world to market genomics tests that they say can help athletes at all levels tailor their workouts to their DNA.
They have struck deals with the Baylor University football team in Texas, with soccer teams in the English Premier League and in Egypt, and with an elite training facility in Arizona for top track and field athletes, including several who competed in the Rio Games.
Yet there is little science to back up the claims that a genetic analysis could identify if a particular athlete is, say, predisposed to benefit from a certain type of exercise, prone to tendon injuries, or wired to have trouble recovering from tough workouts.
Such tests "have no role to play in talent identification or the individualized prescription of training to maximize performance," according to a consensus statement published last year in the British Journal of Sports Medicine, signed by two dozen experts in genomics and sports performance.
Or as Harvard geneticist Dr. Robert Green puts it: "The notion that they're somehow tailoring these recommendations on the basis of your DNA is nonsense."
That hasn't stopped such claims from proliferating. The number of companies selling fitness-oriented consumer genetic tests grew to at least 39 last year, nearly double the market size in 2013. They're part of a booming industry of lifestyle-oriented consumer genetic tests, which purport to use your DNA to tell you everything from how to eat to which supplements to take to what kind of wine you'll like.
Companies marketing these tests, which generally cost a few hundred dollars, say they're aware of the field's limitations.
"We deliberately under-claim everything. We do not want to overstate what genetics can do," said Andrew Steele, product head for UK-based DNAFit — and a bronze medalist in track in the 2008 Beijing Games.
How coaches use the information is up to them, "because there's no data to say that you should use them in one way or another," said Dr. Paul Billings, the chief medical officer of Berkeley, Calif.-based Kinetic Diagnostics, which until recently sold a $400 genetic test for athletes but has stopped taking orders as it refines its business model.
Marketing in gyms and an NFL stadium
Despite the limitations of genetic analysis, other companies are still pushing these tests as powerful tools that can give athletes a winning edge.
Recreational athletes are one key market: "The lowest hanging fruit … are the millions of people who are trying to do something" about their weight or fitness, said Kurt Johnsen, CEO of Texas-based Simplified Genetics, which sells "Simply Fit" tests for $249 and $499.
Companies are also moving full-speed ahead in courting coaches and personal trainers.
Johnsen, a former yoga instructor, said his company is negotiating a deal with a chain of fitness clubs that would add the Simply Fit test to a premium gym membership. He wouldn't name the gym, but he said it's a national chain.
"Is your workout working?" asks a Simply Fit brochure, which Johnsen said he uses to present the test to potential customers in the fitness world. The brochure promises that once the test has "provided you with the most accurate information for your genotype, you will be able to reach your fitness goals with our thorough reports of what to DO, EAT, and TAKE."
Athletigen, meanwhile, is in the planning stages of a partnership with Baylor football that would use players' genetic data to design personalized training programs. The company touts its use of "cutting edge sports science" to help athletes "reach their highest levels of performance." (Baylor didn't respond to repeated requests for comment.)
Meanwhile, Orig3n, a Boston-based biotech with a side business selling consumer genetic tests, is using the cachet of a top NFL team to market its services. An Orig3n booth inside Levi's Stadium, where the San Francisco 49ers play, collects blood from fans for medical research — and sells a $149 do-it-yourself genetic test kit that promises to give you "unprecedented insights about your fitness potential."
To sweeten the deal, you'll also get entered into a contest to win a signed 49ers football, helmet, or jersey.
Brent Schoeb, the team's vice president of corporate partnerships, didn't respond to questions about the science behind the genetic tests, except to say that "our goal is to ensure that Orig3n generates positive brand awareness through the relationship."
Notably not participating in all the genotyping: 49ers players themselves.
— ORIG3N Inc (@ORIG3N_Inc) September 16, 2016
Gathering evidence to back up advice
As proof that they're on to something, the testing companies point to a small but growing body of scientific literature exploring how genetic differences contribute to individual strength, flexibility, speed, and propensity for injuries. And some companies say they're steadily gathering additional evidence to back up their advice.
Consider a study supported by DNAFit and published earlier this year. Researchers performed genetic analysis on 28 athletes from different sports and then randomly assigned them to either a high- or low-intensity training program.
Half the group was assigned to the training style that DNAFit's algorithm recommended for them based on their genes; the other half was assigned to the training style deemed inappropriate.
After eight weeks, the "matched" group performed better on measures of explosive power and aerobic fitness than the "mismatched" group. (The athletes didn't know which group they were in; nor did those evaluating their fitness.) Similar results were seen in another study on 39 soccer players, reported in the same paper.
One caveat: Such studies are often small and in homogenous populations. The study on DNAFit, for instance, looked at just male college students at a university in northern England.
And there's concern among academic researchers that genetic test companies tend to cite studies "inappropriately," using "selective quotations or taking little bit of information and extrapolating way beyond what we say," said Alun Williams, a geneticist who studies sports and exercise at Britain's Manchester Metropolitan University and coauthored the 2015 consensus statement.
Yet another problem, experts say: Associations observed in large studies of thousands of people don’t necessarily translate into useful advice for individuals.
Harvard's Green illustrates the flaw this way: Imagine that you have thousands of people. Half of them have a genetic variant linked to sprinting speed; they get green jerseys. The other half have a genetic variant associated with no advantage in sprinting; they get red jerseys.
Line them up side by side, blow your whistle, and send them off on a short foot race. On average, the runners with the "speed" marker will probably finish a few steps ahead of the runners without it. But the race will be a big blur of color, reds and greens mixed together, undetectable to the eye who's faster.
"It's the difference between a population finding where with enough people you do see a statistically significant difference, and the ability to turn around and use that as a predictive tool in an individual person," said Green, who also practices at Brigham and Women's Hospital in Boston.
— Athletigen (@Athletigen) October 25, 2016
Tailoring workouts to a genetic readout
Despite the shaky science, the promise of harnessing genetics info is tantalizing enough that some athletes and coaches are jumping in.
ALTIS, an Arizona training facility, has worked with Canada-based testing company Athletigen in recent years to genotype elite track and field athletes. Some of the athletes recently got set up with a smartphone app. It includes a dashboard where they can pull up Athletigen's interpretation of their genetic data, which might include "high sensitivity to caffeine," "normal sensitivity to saturated fats," and "normal daily calorie intake."
In a demo on Athletigen's website, coaches get a version that lets them hone in on each athlete's data. (Sample updates might include the fact that training load has been "trending up" over the past two weeks).
Athletigen CEO Jeremy Koenig emphasizes that his company isn't making recommendations on how to use the data.
That's up to coaches like Dan Pfaff.
Pfaff, the ALTIS head coach, said when he designs training regimens for some athletes, he considers whether they have genetic variants associated with more difficult recovery from exercise. If so, they might get more days off or shorter workout sessions. Or they might move practice from the track to the more forgiving grass.
How about those who might be genetically predisposed to tendon injuries? They may get a more intense daily orthopedic exam.
Pfaff speaks cautiously about the promise of genetic testing for athletes. He insists that he and other ALTIS coaches never use genetic testing to identify talent. They never make decisions based on a single genetic marker, instead pooling together, say, seven to 10 genetic markers to decide if an athlete is predisposed to have trouble recovering from exercise.
Pfaff bristles when people uniformly dismiss all companies in the space as "charlatans and snake oil salesmen," he said. But he acknowledges it's too early to say for sure if the Athletigen tests have helped his athletes.
Some athletes who have tried it have no such hesitation.
British long jumper Greg Rutherford was quoted in a press release this past spring saying that acting on the results of his DNAFit test was helping him hit "huge personal bests in the weight room."
Rutherford went on to win a bronze medal in this past summer's Rio Olympics. He's now a paid spokesperson for DNAFit.
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