By Martin Quin Pollard BEIJING (Reuters) – Feeling cooped up by the Chinese capital’s partial COVID-19 lockdown earlier this year, which shut gyms, parks and other venues, Beijing resident Mina Zhao came across surfskating on social media and decided to give it a try. Zhao, 40, who loves to ski, was an instant devotee, getting her husband and son involved in surfskating and even introducing it to dozens of fellow mothers who have gone on to buy their own boards. “I think for my work, even for my life, skateboarding is having a positive effect,” Zhao said, adding that it has helped her lose wei…