The 16-year-old Kratochvil transitioned from ice hockey to swimming after losing his sight due to a serious illness about a decade ago. This change has proven successful, as he set world records in the 50 and 200-metre backstroke last year and won his first gold medal at the para swimming world championships in Manchester, in the 400-metre freestyle event.

Earlier this year, Kratochvil was named the best Czech Paralympic athlete for 2023. He is currently preparing for the Paralympic Games, which take place from 28 August to 8 September. This will be his first Paralympics, a dream he has pursued while qualifying for six events.

“I can hardly say how much I’m looking forward to it,” Kratochvil expressed during a training session at a public swimming pool in Tachov, a town of about 13,000 near his hometown of Halze," Kratochvil told AP. “I’m delighted that I’ve made the qualification times. We’ll see what happens but above all I’m looking forward to the atmosphere at the Games.”

Despite his impressive records and evident talent, Kratochvil aims for modest goals in his first Games. “For now, I’d be satisfied with a place in a final and a fifth- or sixth-place finish,” he said, adding, “I’d like to win a medal at the Paralympics one day, that’s for sure. That’s something I’ve been dreaming of since I was nine.” In Paris, he will compete in the 50 and 400-metre freestyle, 100-metre backstroke, breaststroke, butterfly, and the 200-metre individual medley.

While his classmates enjoy a two-month summer break, Kratochvil has dedicated himself to training. He swims twice a day for a total of four hours and incorporates a gym workout in between sessions. His routine also includes a 16-kilometre ride on a tandem bicycle in the evenings, with Sunday being his only day off. “That’s fine, that’s what the sport is about,” he noted.

Kratochvil’s preparations extend beyond him to his entire Olympic team, including his parents, Stanislava and Jiri. Visually impaired swimmers often need assistance staying in a straight line, but they primarily rely on “tappers” to signal when to turn or finish a race by tapping their head or back. Kratochvil’s parents have taken on this vital role.

“It’s great to work together,” Kratochvil revealed to AP. “You have to trust your tappers.” The tappers’ role is crucial for timing, which varies based on swimming styles and distances. His parents have crafted a homemade tapping device, using a three-metre handle from a fishing net with a foam ball covered by two rubber balloons. “People say we’re catching fish,” his mother Stanislava joked.

However, the parents feel more nervous than their son as the Games approach. “We could spoil all his effort and that’s the last thing we want to do,” she admitted. Currently, their lives revolve around Paralympic preparations. Due to work commitments, they alternate attending training sessions, with one of them often running approximately five kilometres around the pool to ensure they can tap at both ends.

The public pool in Tachov is quite different from the Paris La Defense Arena, where the swimming events will be held. The Tachov facility is only 25 meters long, while Kratochvil’s father created a proper starting block for him. With the nearest Olympic-size, 50-metre pool in Plzen closed for repairs, Kratochvil has planned a warm-up camp in Pardubice and intends to train at another 50-metre pool in Usti nad Labem, both more than 250 kilometres from Tachov.

Kratochvil was discovered by a coach at the swimming club in Tachov while his parents searched for a new sport after he lost sight in his second eye due to cancer, having already lost the first eye to the same illness at just one year old. Though this was a life-altering event, sports have remained central to his life.

“I always wanted my sons to do sports and be able to play an instrument,” Stanislava reflected. “It was impossible to imagine (David) would be only sitting in the corner and suffer.” Kratochvil is thrilled with his choice of sport. “What I love about swimming is that it’s a full body sport,” he said, though he admitted, “I never feel like jumping into the cold water” at the start of morning training.

In addition to swimming, he enjoys playing the guitar, piano, and accordion, has an interest in chess, and wants to learn the organ. A good student, he is particularly interested in biology and is considering studying psychology.

Despite his youth, Kratochvil qualified for the Tokyo Paralympics in 2021 but chose to withdraw, allowing a 58-year-old Czech swimmer a chance to compete, as it was likely their last opportunity. His selfless decision earned him an award from the Czech Fair Play Committee.