Last October, Lai watched videos of wheelchair boxing on the internet and was inspired to try it himself. But finding somewhere to train was difficult. He says he approached several gyms but they either did not take him seriously or said it would be inconvenient.

Then he met Joey Chan Chi-sang, managing director of Everlast Fight & Fitness, and was offered the opportunity to train for free at the company's Causeway Bay gym. Boxing has since become Lai's main sporting activity and he practices twice a week.

As a precaution, Lai has an extra wheel attached to the back of his chair to prevent it from flipping over. Other modifications include leg and waist belts to secure him in the wheelchair, which remains stationary during training and fighting.

Lai says he has benefited greatly from boxing because it strengthens his waist muscles - which are crucial for the sport. He initially found it challenging because when the legs are paralysed, the waist becomes weak and this affects balance. If his back loses contact with the wheelchair, Lai says, his body may rock from side to side.

"Through boxing, I can build up these muscles and tension in that area of the body. Also, by doing any exercise, you work your heart and your lungs; you'll sweat, but your body will change."

Being half-paralysed and wheelchair-bound means that Lai cannot duck and dodge as an able-bodied boxer would. "When you're fighting with someone you have to keep punching and defending, and it gets very exhausting," he says. His physical condition also makes it difficult for him to rotate his body, so punches such as the hook and uppercut are much harder, he adds. "You have to get a sense of rhythm, and you have to train your fitness level."

Lai believes other disabled people who may not have his level of fitness could find boxing helpful because it would improve their physical and mental focus and boost their confidence. He is encouraging others to take up boxing and, since meeting Everlast's Chan, the pair have established a Hong Kong wheelchair boxing association.

"In Hong Kong, there are a few sports for disabled people. There's wheelchair basketball, wheelchair fencing and wheelchair ping pong," Lai says, and he has tried them all.

"These are more popular, but why can't there be more diverse opportunities? No matter what type of sport, we hope to get disabled people to participate more, leave their home and sickbed, and go out to do activities and re-enter society," he says.

"I will encourage [disabled people] to do boxing because even if their fitness level might not be good. It's something they can work on. I have seen that overseas there are one-armed boxers. Even just moving is a form of training."

The wheelchair boxing association has three members, but several other people have shown interest. However, Lai knows too well how inconvenient it can be. "For example, you may need special arrangements depending on the wheelchair, the weather, trainer or certain medical conditions, and many other things."

In March, Lai took part in Hong Kong's first competitive bout of wheelchair boxing, opening a scorecard of boxing and MMA fights at Wan Chai's Southorn Stadium. His opponent was another disabled athlete, Lam Tin-wing, whose main sport is rowing, and who trains with Lai at Everlast.

"I had only been training for about three months, and [Lam] had trained for about two months. So we both went from being beginners to training together, going on to fight one round, and then on to fighting in the tournament," he says. This involved three, two-minute rounds.

Before the bout with Lam, Lai was joined in a performance fight with former Mr Hong Kong contestant Otto Chan Chi-kin, who also sat in a wheelchair.

"Of course, he accommodated me during the fight because he is very fit. He's also taller and bigger than me," he says, laughing. "So it was just a friendly match."

Lai says he is keen to take part in the next tournament, in September, and the association hopes to invite wheelchair boxers from other countries such as the US, Canada or Britain for friendly fights.

Chan, who has helped train the wheelchair boxers at Everlast, was impressed with the contestants in their first tournament.

"I thought the match was quite good for beginners," he says. "[Lai] Chi-wai had already had athletic training so he learns quickly, but Lam has less physical ability."

The bout attracted a number of spectators and Chan is keen to promote wheelchair boxing at Everlast and through the new association because he has seen how it helps disabled people develop their strength and self-confidence. "It's very meaningful," he says.

Everlast charges a one-off fee of HK$500 for wheelchair boxing classes, which helps buy gloves and hand wraps. Training is offered twice a week for free. Chan says training the disabled boxers involves extra care and consideration.

"From our perspective, the most important thing is that they don't get hurt, learn the correct skills and increase their fitness levels. The trainer really needs to have basic fitness knowledge and skills. Another consideration is the student's level of fitness and whether they can withstand boxing. There will be clashes; they could pull or injure muscles."

Their abilities have to be looked at holistically, he adds, and the most important thing is that they have a goal. Beyond the physical, in boxing "you must have the mindset that you can't give up".

"The ones who come to train are pretty strong-minded people. We hope they can encourage others who are not as strong," Chan says.

Lai fits boxing training into a busy work schedule that still revolves around his first love of climbing.

His main job is coaching children and adults, including members of Hong Kong's international team. He is also a contractor for rock climbing facilities, involved in planning climbing walls, maintenance and repairs.

His motivational talks also keep him busy. Lai says he receives requests constantly but finds time to give three talks a month at most. Last month he spoke at an event in Kowloon Bay at which 1,000 people turned up.

"I give talks to primary, secondary and college students; also people in banking and finance, charity organisations - a lot of different types of groups. Usually, the company will invite me to tell my story and motivate its employees."

Lai's most important message is that of a true sportsman, and echoes Chan comment on the boxer's mindset: "Never give up."

"The second message is that you have to find solutions to the problems you're facing. I fell from the top to the bottom and became disabled, but I was still able to recover very well in one or two years. I experienced a lot of things, but I kept my confidence and faith throughout.

"I kept going forward and shaped my path. No matter whether you're disabled or not, you have to try to do the best you can. I try to express these ideas to my audience."

Lai has sporting ambitions beyond his next boxing match, having set his sights higher than the peaks he reached as a rock climber. He now wants to try paragliding.

"I'm still exploring how I can go about this sport. I'm preparing to do some tests, and hopefully I can be the first disabled person in Hong Kong to take to the sky."