Both students have overcome self-doubt and poor form to firmly establish themselves in their respective Hong Kong girls' and boys' youth teams.
In August, Kenneth and the boys' team won the All China Secondary Schools Students' Volleyball (19 or under) title in Zhangzhou, in Fujian Province. In the same month, Sophie's girls' team clinched the bronze medal at the even more prestigious Asian Schools Volleyball Championship, in Vietnam.
Kenneth, 18, of South Tuen Mun Government Secondary School, and Sophie, 17, a Form Five student at Tuen Mun Catholic Secondary School, both play as setters for Hong Kong. The role involves co-ordinating team attacks by deciding which player gets to hit the ball - and where and when.
Both wore the number 3 shirts at July's All China Secondary Schools Students' Games, in Baotou , Inner Mongolia.
Kenneth, who stands 1.85m tall and plays for Yan Chai Youth, in Hong Kong's Division B men's league, was making his international debut for Hong Kong at the tournament.
Yet only two months before that, he was so frustrated that he almost gave up on his dream of playing for Hong Kong; in May, he had missed out on a place in Hong Kong's youth team at the Schools Interport Championships.
"I kept getting picked for the provisional squad, but was never good enough to make the final cut," he says. "I always missed out. I'd been thinking that maybe I should focus on my studies.
"But because there were other competitions coming up in the summer, I decided not to give up. I am so glad I kept going. So it was a lovely surprise to actually play at the Games.
"I was only a reserve player at the Games in Baotou, but was able to learn a lot by watching matches on the court side. That was really useful when I got the chance to play.
"Going to Fujian was like a dream because I knew I was in the first team - not going as the reserve."
The Fujian tournament was doubly sweet for Kenneth because Hong Kong gained revenge in the final against Hainan - the team that had beaten them in the bronze-medal match at Baotou. "That was the happiest moment for me - knowing we had won and that I had contributed," he says.
The 1.65m tall Sophie, who plays for Tuen Mun Youth, in Hong Kong's Division A2 women's league, was playing in her second successive Games at Baotou.
However, she says it took her a long time to establish herself in the team. "There are strong school teams in Kowloon and Hong Kong Island," she says. "Kenneth and I had often felt that we would never be chosen to play for Hong Kong because players from these rival teams were just too good."
Claiming the bronze medal at the Asian championships was an emotional moment for her and the rest of the team. "When we stepped onto the medal rostrum it felt marvellous," Sophie says. "We all knew we were claiming Hong Kong girls' first medal at any major tournament."
Sophie's success came after chronic health problems as a toddler, when an allergy to milk left her constantly weak and feverish. "When I went to primary school I started to run and exercise with my friends and got fitter. I touched my first volleyball in Primary Five."
Both Kenneth and Sophie praise their teachers and coaches for helping them to achieve success. Kenneth says: "My school team coach, Jacky Wu, and club coach, Chan Kin-tat, have taught me a lot about handling pressure. And my PE teacher, Lee Ying-choi, has fought really hard to improve resources for the school team. Without them, I could not have achieved what I have."
Sophie thanks her PE teacher, Wong Pik-ha. "Miss Wong has always had confidence in me and encouraged me to keep trying to make the youth team. She has been inspirational."