Triple Olympic champion Sun Yang gestures after winning the 1,500m freestyle at the China National Swimming Championships in Qingdao, Shandong province, this week. Winner of five freestyle events, the Zhejiang province native is tentatively aiming to add to his Olympic haul at the 2020 Tokyo Games.
Sun Yang cemented his status as China's top freestyler at the Chinese National Swimming Championships over the last week - but the triple Olympic champion admitted the physical toll of the sport has left him doubting his participation in the 2020 Tokyo Games.
After almost eight months away from competition following his Rio Games exertions, the 25 year-old won golds in all his events - the 100, 200, 400, 800 and 1,500m freestyle - over eights days in Qingdao, posting world-leading times in the 200 and 400.
However, he suffered for his impressive haul.
"I had a stomachache during the winter training and kept taking medicine until now. I've been eating less than a girl," said Sun, who also had to battle through back and shoulder pain in the 1,500m final.
"To keep fighting is never easy. I did feel tired, but it's good practice for me, and I'm happy that I managed to fulfill the plan," he added.
Sun's plans for the Tokyo Olympics, however, remain hazy.
China's most successful swimmer of all time, Sun topped the podium in the 400 and 1,500m freestyle at London 2012 and took 200m gold at the Rio Games four years later, despite hardly training for six months in the build-up after twice fracturing metatarsal bones in his left foot.
The Hangzhou native contemplated retirement after Rio, and while he vowed to try his best to compete in Tokyo, the thought of more years of punishing training has left him feeling uncertain.
"Day after day, no matter summer or winter, you have to get up so early and swim in the pool repeatedly. It's enough to drive you nuts sometimes," said Sun.
"During the championships, sometimes I left the aquatic center at 10 pm. All the lights were turned off and all the gates were shut. We had to find a back door to go out."
As far as the new breed is concerned, there were some encouraging signs in Qingdao.
Xu Jiayu, 21, broke the Asian record in the men's 100m backstroke with a time of 51.86 seconds, just 0.01 sec shy of the world record, and smashed his own national marks in the 50m and 200m backstroke.
"My upper-body strength has been enhanced and I'm happy that I improved my personal bests," said Xu, who grabbed silver in the 100m backstroke in Rio and won four golds at the championships.
Yan Zibei from Hubei province, also 21, set new national marks in the men's 50 and 100m breaststroke.
"I don't think too much about the Olympics, and I will try my best to improve step by step. This year, my main objective is the National Games (in Tianjin in August)," Yan said.
Eighteen-year-old Li Zhuhao, Sun's provincial teammate from Zhejiang, broke the national record in the men's 50m butterfly and pocketed three golds.
The Chinese Navy's Qin Haiyang, 17, broke two world junior records and the national record in the men's 200m breaststroke, and his time in the 200m individual medley ranks third in the world this year.
"I'm surprised I swam so fast; perhaps it's my winter training that made it happen," Qin said.
However, Qin's coach, Ye Jin, was far from surprised. "His technique has improved a lot, and I think he has a bright future," she said. On the women's side, Fu Yuanhui, 21, improved her personal best in the 100m backstroke to set a Chinese record of 58.72 sec, 0.04 sec faster than her Olympic bronze medal-winning time in Rio last year.
Most promising, perhaps, were the results of 15-year-old Li Bingjie, whose times in the 400m and 800m freestyle are this year only inferior to double Olympic champion Katie Ledecky of the US.
"Li Bingjie is only 15, and other female swimmers are very young as well," said Liu Haitao, one of China's coaches. "Their performances are satisfying, but we need to give them more time.
"I hope the youngsters can train as hard as they can and get the best possible marks at the Tokyo Olympics."