“A blessing and a curse” is how Harry Aikines-Aryeetey describes the genetic quirk that means his body carries more muscle mass than the average human.
The 37-year-old was in his mid-20s and competing as a 100m sprinter for Great Britain when a team doctor became curious about his miraculous ability to recover from injuries and how little muscle mass he would lose when out of action. After conducting some blood tests, the Team GB doctor sat Aikines-Aryeetey down in his office and asked: “Have you ever heard of a myostatin deficiency?”
He had not, but everything the doctor said next made complete sense: the pictures he had seen of himself as a four-year-old with bulging biceps, the speed and power he was able to produce from a young age — all of it tallied with what the doctor said about him lacking myostatin, a protein which circulates in the blood and normally acts to limit muscle growth.
Se-Jin Lee is a US-based professor who discovered myostatin in 1997 after he and a group of colleagues had bred mice each lacking a different protein. Most died, but mice bred without the GDF-8 protein not only survived but became “freak show rodents…” as David Epstein described them in his book The Sports Gene, “They had double muscle.” Lee’s group named GDF-8 and its protein myostatin.
In his search for other species which might be affected in the same way as the mice, Lee came across a breed of beef cattle called Belgian Blue, notable for their prominent shoulder, back, loin and rump muscles. When he tested blood samples from cattle on a ranch in Missouri he discovered they had a mutation in the myostatin gene — now popularly called the ‘Hercules gene’ — resulting in what is known as “double muscling”.
Harry Aikines-Aryeetey has always had highly developed muscle mass (Photo courtesy of Harry Aikines-Aryeetey)
His search for human subjects took longer. In the early 2000s a baby boy was born in Berlin who caught the attention of a paediatric neurologist, Markus Schuelke. In The Sports Gene, Epstein describes the newborn as having “bulging biceps, chiselled calves and glutes you could bounce a nickel off”.
When the boy reached toddler-age and could easily hold 6.6lb (3kg) dumbbells out in front of him with his arms straight, Schuelke got in contact with Lee. A year later, in 2004, they published a paper in the New England Journal of Medicine introducing the world to a boy the media would nickname “Superbaby” (his true identity has been kept hidden).
“This was a heavily-muscled boy who has a mutation in his myostatin gene such that he makes no myostatin at all,” Lee tells The Athletic. “To date, this boy and his mother are the only humans that have been described with clear mutations leading to myostatin loss.
“There are other genetic variants that have been described, possibly leading to lower amounts of myostatin being made, but this is less clear. There are other individuals described on the internet who are claimed to be myostatin mutants, but none of this has made it into the scientific literature.”
Aikines-Aryeetey was not only strong from a young age — he was fast. His first memory of being quick came when he was about seven, and sprinting away from a dog who he didn’t realise only wanted to play. By 14 he’d set a European age-group best of 10.83 seconds for the 100m; by 16 he had become the first sprinter to win the 100m/200m double at the World Youth Championships when he won double gold in 2005. A year later he added World Junior 100m gold to his collection.
At that point Aikines-Aryeetey looked on track to be one of Britain’s biggest athletics hopes for the London 2012 Olympics but then, in 2007, he suffered a double stress fracture in his back which left him in a brace for much of the year. He could walk on a treadmill but not much else.
“My muscles had grown too fast for my skeleton,” he says. “That’s why I say it’s a blessing and a curse.”
Once he matured skeletally, there were other things that bore the brunt of his power. “What comes with being so explosive is a lot of tendon injuries because my muscle is so powerful that the only thing that can ‘go’ is the tendon,” he adds. “I’ve ruptured my semitendinosus (in the hamstring), I’ve ruptured my patella tendon, I’ve had a longitudinal tear of the biceps tendon. These are all things that tend to come with being as powerful as I am because of the muscle quality.”
Aikines-Aryeetey at the 2018 Commonwealth Games (Mark Metcalfe/Getty Images)
Aikines-Aryeetey has recently emerged from an eight-week stint on the BBC’s flagship entertainment programme Strictly Come Dancing, where his enthusiastic performances endeared him to the British public more than the judges.
It is a notoriously gruelling experience for contestants, but Aikines-Aryeetey was still combining it with his role as Nitro on the relaunched version of the TV show Gladiators: he joined the latter’s live tour as he exited Strictly last month.
His television commitments means that sprint training, and the work he does in the gym alongside it, has taken a back seat for a few months. “I was told I was going to lose muscle,” he says. “The last time I trained as an athlete was the first week of July, before we filmed Gladiators and then I went straight into Strictly. To make sure I was mobile and flexible enough for that I didn’t go to the gym once. And my body hasn’t changed — except my calves have got bigger!”
That ability to hold onto muscle (and build it) is something many people would be envious of. But as an athlete, Aikines-Aryeetey and his coaches have always had to manage it carefully. “As powerful as I am, it’s harder to run. I’m a sprinter, not a body builder. It gives me a lot of gifts in terms of being explosive and powerful, but at the same time, I’ve got to move this weight.”
He’s never had a coach allow him to do upper body training, which seems scarcely believable when you look at his frame, which includes arms thicker than the average human’s thighs. “They were worried I was going to put more mass on,” he says. “Even if it was from a conditioning perspective, I was allowed no upper body whatsoever. It did come as a detriment because my upper (body) mobility is pretty bad.”
It is not as straightforward as extra muscle equating to extra strength, but it does give Aikines-Aryeetey more explosive power. And speed — and by extension, explosiveness — is another side effect of a myostatin mutation, as proved by studies on whippets.
In The Sports Gene Epstein explains that since the late 19th century whippet breeders unknowingly created dogs that have single myostatin mutations, meaning that at the highest level of whippet competition, more than 40 per cent of the dogs have what is “normally an exceedingly rare myostatin mutation”. As you go down the levels, that percentage lowers until it all but disappears.
While Aikines-Aryeetey’s case has not made it into scientific literature, Lee says it’s “definitely possible” that there are other humans who are deficient in myostatin (strongman Eddie Hall has also claimed to be deficient). But given there is no compelling medical reason to monitor someone with a loss of myostatin function, there is no real reason to get tested for it — which makes tracking its prevalence more difficult.
Eddie Hall also believes he is myostatin deficient (John Phillips/Getty Images)
Establishing whether an individual has a mutation in the myostatin gene involves isolating DNA from cells in the blood and then determining the DNA sequence for the myostatin gene. That could be done in a research laboratory, at reasonable expense, but an approved diagnostic would cost considerably more.
Aikines-Aryeetey says he was diagnosed via a blood test, which Lee says can allow myostatin protein levels to be measured.
“This could be low even if he did not have an actual mutation,” he adds. This could explain Aikines-Aryeetey’s ability to build and hold on to muscle, but the clearest explanation would be “if he actually had a mutation, in which case he would be expected to be hypermuscular”.
When Aikines-Aryeetey first started talking about myostatin he would often be asked by other athletes, ‘That sounds great, how do I get that?’
“I remember looking up that you can get myostatin blockers. It didn’t look legit to me. But obviously that would have been the early days of people trying to form something. With the gene crafting wizardry happening nowadays I don’t know what people can do.”
The World Anti-Doping Agency (WADA) first added myostatin inhibitors to the list of prohibited substances in 2008. At the time, the drugs were still experimental and not yet available on the market but WADA was ready for that to change. “We now have convincing data on those drugs and what they can do,” said Olivier Rabin, science director at WADA, in 2007. “We have a duty to act as early as we can when drugs have the potential to be doping agents.”
Fast forward to 2025 and Lee warns that there are still no approved inhibitors, although many companies have developed them in clinical trials for a variety of muscle and metabolic diseases. While most of these trials have been disappointing in terms of improving clinical outcome, there has been a resurgence of interest in these types of drugs in recent years. Lee explains this has been driven partly by promising results in relation to a rare genetic condition called spinal muscular atrophy, and partly by obesity.
In March this year, an article published in Nature Reviews Drug Discovery suggested that “companies are pivoting to the larger potential medical and commercial opportunity for muscle mass preservation in overweight and obese individuals” taking weight-loss drugs.
But as yet, none have been approved for use and Lee says that “any use of these drugs currently would be very risky”. Once the drugs are approved he is concerned that “abuse by athletes will become rampant. As a complete sports junkie, I think that this would be unfortunate in terms of fair competition. As a medical professional, I worry even more about the potential health consequences for people who may abuse these drugs for unapproved indications.
“I especially worry that the focus on inappropriate use of these drugs may create roadblocks in terms of making these drugs available for many people in medical need whose lives could be transformed by the successful development of them.”
For Aikines-Aryeetey, his athletics career is drawing to an end.
At the end of last year he suffered a serious knee injury which ruled him out of competing in the second series of Gladiators. But he’s now back in training and on the day we speak he’s completed 10 reps of 100m with 90 seconds rest in between at around 13.5 seconds. It’s a repeat of a session he did earlier in the week and he can already feel the improvements. “If I do the same thing every week, each week I’ll be 20 per cent better,” he says.
He accepts that he has been given certain gifts when it comes to muscle and power, but is clear that they are not the reason for his success.
“There’s a lot of hard work and dedication that goes into it,” he says. “Lots of planning, lots of specific movements that I need to work on. You’ve got to think of your body as a bit of playdough. You’ve got to mould it into what you want and your sport really dictates how your body reacts and grows.”
