Being a teen star is a risky profession: “They are not miniature adults.”

Yu Zidi, a 12-year-old Chinese swimmer, left the World Championships with a bronze and three-quarters place. Cooper Lutkenhaus (16), an American athlete, qualified for the World Championships in Tokyo with a time of 1:42.27 in the 800m (1:37 off the world record). The Australian Gout Gout (17) is nicknamed the new Usain Bolt, while the Japanese Sorato Shimizu (16) completed the 100 meters in ten seconds. Lamine Yamal (since 16) was one of the stars of LaLiga . And cycling broke its pyramid: Tadej Pogacar won his first Tour at 21... and is still unstoppable. Is the adolescent (or youth) spiral that sport is in a coincidence? Have standards changed? What is the risk of treating growing bodies as adults?

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José Luis López, national athletics coach, provides an overview of the debate. “These are isolated cases that draw attention. There's no pattern; we can't generalize,” he explains. “We must ask ourselves why they're good. Does it come naturally to them or have they achieved it through intense training? If it's the former, great. If it's the latter... You can burn them out,” he introduces.

The craze for teenage success seems unintentional around the world. Sergi López, who has been a swimming coach at American universities for more than three decades, attests to this. He acknowledges that "no one is forgetting that athletes complete their learning curve. There have always been those who stand out. Now we have Luka Mijatovic, who is breaking Phelps' records at 15, but he trains at a club with a good coach. It's all normal," he adds. "It's another matter that other countries use different methods. It's cultural," he asserts with conviction.

No one has forgotten that the athlete completes his learning process. Sergi López, Swimming Coach in the United States

This is where, as José Luis López suggested, the overtraining of children or adolescents comes into play. The Spanish coaches who attended the World Swimming Championships agreed that "it's very difficult for Yu Zidi, in five or six years, to continue improving his times and reach the elite." This already happened with Shiwen Ye, who won two gold medals at the 2012 London Games with two world records at age 16 and never swam that fast again.

In 2024, the Department of Sport and Science at the University of Innsbruck, headed by Michael Barth, conducted a study on the predictions of top junior athletes transferred to senior Olympic sports between 2006 and 2021 in Western Europe. The sample consisted of 13,392 athletes. The data was revealing: only 2.2% of stars between the ages of 11 and 19 repeated as adults. The younger the age, the less successful. "There is a clear error, which is predicting future performance based on current performance (...) You can predict current performance, not permanence," he concludes.

“Early talent detection processes are more efficient,” explains Dr. Jordi Ardèvol. Once detected, the process is accelerated “with specific and intense training,” he adds.

Entering the debate is physiologist Iñigo Mujica, one of Spain's leading figures, who is clear that "there have always been precocious athletes. I don't see a deliberate change; only cycling is faster than before. But we must distinguish between chronological and biological age. We must focus on the latter. The 12-year-old Chinese swimmer is biologically older," he argues.

“We must distinguish between chronological and biological age; the latter is the important one.” Iñigo Mujica Physiologist

Subjecting a developing body to overly specific training is risky. "Everything depends on whether the training is rich, high-quality, and comprehensive. It should be varied; late specialization is best, except in some sports," he explains. Otherwise, it can lead to dropout. But in many cases, everything goes the other way.

“We only see the tip of the iceberg,” emphasizes Dr. Antoni Tramullas, who elaborates: “Adolescents are not miniature adults; they are in the midst of emotional and physical development... Their injuries are not those of adults. They will never have a torn rectus femoris muscle; they will surely have cartilage and tendon problems... I find it hard to believe that if you subject yourself to that demand at 15, you can be just as capable at 30,” he reflects. “Bodies have an odometer; I don't see Alcaraz or Sinner at the age of Nadal and Djokovic, or at the intensity at which they have trained,” said Dr. Ángel Ruiz Cotorro. Mújica, on the other hand, believes that “with good training, long careers can happen.”

"What they're experiencing doesn't fit with their developmental and socio-emotional stage," warns Ana Merayo, a psychologist at The Rize and an expert in treating young athletes. "For me, the fact that they're excelling at such a young age is bad news," says José Luis López.