It was the middle of October in Stockholm, and Holger Rune was worried about his hamstring.
He had felt a twinge, during his quarterfinal win over Tomás Martín Etcheverry at the Nordic Open. He had gone to a local hospital for a scan. He had been told it was a small tear. Don’t worry, he remembers the physicians telling him. A thorough warm-up before his semifinal against Ugo Humbert of France and it would be just another niggle, the kind that so many players were carrying deep into the 11-month tennis season.
The next day, Rune led 6-4, 2-2, 30-40. He moved to his left to return a wide serve from the left-hander, and then to his right, to get to a routine forehand.
“I felt a loud pop,” Rune said during a recent interview. “Every time I see the video I can hear it also, the pop. It’s pretty loud and I was like, ‘OK, what is that?’ It felt like my heel kind of disappeared.
“I looked straight at the ground. I was like, ‘Did the ground break?”
The court was intact. Rune’s left Achilles tendon was not. A brutal injury for anyone, but especially for a tennis player with designs on greatness in a sport that requires quick cuts and explosiveness on nearly every point.
After shock and adrenaline let Rune hobble to his chair, a trainer examined him. He told Rune that he had to retire from the match. The 22-year-old Dane, as feisty and stubborn a player as there is, tried to stand up and test it.
“I couldn’t push off,” he said. “The connection from the calf muscle to the tendon was not there.”
Rune and his team quickly decamped for Monaco, where a full examination confirmed a full tear. Then he went to Copenhagen for surgery, with a future that once seemed so bright now in doubt.
Not for him.
“I am 100 percent going to be back stronger than ever,” Rune said. “I can build myself exactly how I want to when I come back.”
Rune being Rune, he is also determined to beat the traditional nine-to-12 month recovery. That’s how long it took Kevin Durant, the future NBA Hall of Famer, to get back. Jayson Tatum, the Boston Celtics star, is following a similar timeline. Four-time NFL MVP Aaron Rodgers returned to New York Jets practice 77 days after his tear in 2023 and had designs on a rapid return, but did not play again for over a year.
Rune has also turned his rehabilitation into an Instagram documentary, memorializing the stages of training and the emotions in a series of videos that may yet become a triumphant montage — or a live-action demonstration of the deleterious economic and social pressures of modern sports.
There he is sitting on a padded bench in Monaco, smacking balls fed to him by his coach, Lars Christensen.
There he is in the weight room, as Marco Panichi, the former trainer for Novak Djokovic and Jannik Sinner, tortures him with bench presses and medicine balls and weighted bags during his first weeks back.
There he is in a fitness lab in Qatar, with wires taped to his calf to stimulate the muscle. Anything he can do to add strength and make this process go more quickly, he is willing to try. Team sport athletes have salaries and support systems, Rune said. Tennis players eat what they kill. Sponsors watch a top athlete go down with a career-threatening injury and their eyes can drift to someone else fit to play.
Just before New Year’s Eve, he was standing with two feet on a tennis court for the first time in 10 weeks.
“I’m trying to maximize every day of my life to get back and to get back safe, to not have any risk again,” Rune said. “That can definitely be done before nine to 12 months.”
The limits of the human body may have something to say about that timeframe, and Rune’s surety of his transformation into the player he was before, and, he hopes, much more besides.
“It’s basically a year of your career before you come back. And sometimes a little bit longer,” said Mark Drakos MD, a foot and ankle surgeon at the Hospital for Special Surgery and the team orthopaedist for the New York Mets and Knicks, who is not treating Rune.
“Sometimes, they are not the exact same as they were before.”
That is exactly what Rune wants. Just not in the way that Drakos intend it.
Whatever damage his Achilles tendon and the musculature around it have endured, Rune’s confidence is intact, as is his surety that he is going to join Carlos Alcaraz and Jannik Sinner at the top of the game, as he looked set to do after stunning Novak Djokovic to win the Paris Masters at the end of 2022. He rose to world No. 4 by the following summer, but never looked sure of his tennis identity.
His forehand would break down too easily, especially on quicker courts. He went through high-profile coaching swings with Patrick Mouratoglou and Boris Becker and played drastically different types of tennis, sometimes match to match. He started losing matches he should have won, especially at Grand Slams, through 2024. Barring a stirring comeback win over Flavio Cobolli at the French Open, the biggest events in the sport became exercises in frustration.
2025 was his annus horribilis long before he ruptured his Achilles, despite reuniting with childhood coach Christensen and finding stability there. Rune fell ill at the Rotterdam Open in February, before going to Acapulco for the Mexican Open, where he and a few players got food poisoning. In March, he came down with a throat infection at the BNP Paribas Open in Indian Wells, but still made the final. Jack Draper steamrolled him.
Then, two days before the Monte Carlo Masters in April, he started vomiting. Doctors found a lingering infection in his stomach, which was treated, and he bounced back to win the Barcelona Open by outlasting a hampered Carlos Alcaraz.
Then he felt sick again, at the Madrid and Italian Opens. He went home for tests. His throat was still infected. More antibiotics. The French Open. He did OK there. Then five months of quarterfinals and might-have-beens later, out of nowhere in Stockholm: The pop.
Dr. Drakos said that roughly 80 percent of people who rupture their Achilles never feel anything before it happens, which is just one reason it’s a nightmare injury.
“I’d much rather tear my anterior cruciate ligament than tear my Achilles,” Drakos said.
The ACL is like a rope. Surgeons have gotten pretty good at replacing it, and with modern rehabilitation techniques, athletes can reach their previous levels.
The Achilles tendon is the spring that connects the foot to the calf. Drakos compared it to a slinky, the spring-like toy. Stretch out or tear a slinky, and it’s pretty hard to figure out how to make it new again.
As soon as the Achilles tendon tears, the muscles around it retract and begin to atrophy. The tendon usually takes about six weeks to heal, and another six weeks to regain its elasticity back. And then patients can start using it to strengthen the calf — but they have to be careful not to stretch out a recovering tendon. That produces a stretched-out slinky.
Holger Rune is determined that his Achilles tendon injury will not define his career. (Linnea Rheborg / Getty Images)
“We haven’t really found out a way to speed up our biology of muscle and tendon healing despite newer techniques,” Drakos said.
Rune is going to do all he can to try, he says, without sacrificing safety.
He said he gave himself two or three days to be sad, and then returned to the life and career that he has to continue. He said he gets his perfectionism from his father and his ambition and hunger for his mother. Those qualities have come in handy during this trying time.
He craved the structure that a successful tennis career requires, so he set one up for his rehab.
He likes to sleep in, a rarity during a normal season, so he starts with activation exercises around his foot and Achilles around 11 a.m.. At noon, the loading and weight work begins, working the way up the legs until 1 p.m. He takes a short rest and then does eye exercises and concentration work.
Lunch happens at 2 p.m. An hour later, he does upper-body training and core work. That lasts 90 minutes. He then heads home for physiotherapy and laser treatments on his scar. He follows that with blood flow resistance training, wrapping bands around the muscles to make them feel like they are doing more work than they are actually doing, in an attempt to accelerate regeneration.
He will eat a protein-rich dinner, relax a bit and go to sleep. Then he does a version of that all over again the next day.
He is also using the time with Christensen to establish the tennis identity that he has never truly had. He is already talking to Christensen about his plan for when he returns to the court. He wants to seize this time away as an opportunity, to create a different player than the one he was before the injury.
Everyone knows how Sinner plays, how Alcaraz plays. Even Rune can’t describe Rune, thanks to his propensity for aggressiveness one match and passivity the next — and not by design.
“When you see the best players in the world, Roger Federer, Rafael Nadal, Novak Djokovic, Andy Murray, all these players, you could always see. This is Federer playing. This is Nadal playing,” he said.
“I want to create the Holger Rune game. So someone watching tennis is like, ‘OK, this is his game, always.’”
The Achilles tendon may have ruptured, but the confidence is right where it has always been.