Sun's journey back to the pool has been anything but easy. After serving a 51-month suspension, he returned to competition last summer, drawing enormous attention from fans and media alike.

At the National Games venue, spectators packed the stands from the preliminary heats to the finals, cheering his every stroke. On Sina Weibo, where he commands over 30 million followers, his post upon arriving in Shenzhen quickly garnered nearly 30,000 likes.

Although he didn't reach the podium in the 400m final, his name still appears beside the Asian and national records — a quiet yet powerful reminder of the glory he once brought to the pool.

Yet Sun must now accept that, with age, his performance is no longer at its peak. In the heats, he ranked eighth — only 0.1 seconds ahead of ninth place — barely qualifying for the final, where he swam in lane eight instead of his once-customary center lanes. All seven of his rivals were born after 2000.

In a previous interview with Sina, Sun admitted he had anticipated this. He returned to competition to assuage his passion, not a thirst for titles — doing so knowing full well that there would come a day when he could no longer be a champion.

"Even if one day I no longer hold Olympic or world records, I still have Asian and national records," he added with a small smile. "I've already achieved what most athletes can only dream of. I'm lucky — one of the fortunate few."

Despite his age, Sun continues to train with the intensity of athletes two decades his junior. Weighted sessions, ten sets of 800m swims — the workload remains immense. "At 34, the biggest difference is that places that never used to hurt now start to ache," he said. "To keep up, I have to work ten thousand times harder."

Cai Li, coach of the Zhejiang provincial swimming team, praised Sun's perseverance. "At his age, maintaining this level of training and competition is extraordinary," Cai said. "Very few athletes worldwide can do what he's doing."

Sun's focus now extends beyond personal victory. "When I was young, I wanted to win China's first men's swimming gold medal," he reflected. "Now, I want to break another barrier — to see how far an older athlete can go."

He hopes to adjust his training methods to better suit his physical condition, emphasizing longevity and adaptability over pure speed.

For Sun, retirement is not yet on the horizon. He knows his best days may be behind him, but his passion endures. "To achieve something great, you must go through storms and waves," he said. "That's what makes an athlete truly remarkable."

And when the time does come to step away, he knows exactly how he wants it to happen. "Whatever I do, I must see it through," he said firmly. "I want to end my career in the pool — even if I lose, even if I fall, it will be in the water."