Tracy Davies said PE attendance among girls at Blackwood comprehensive, Caerphilly, has improved significantly following a relaxation of kit-related rules.
And last week the 33-year-oldpicked up the secondary school teacher coach prize at the annual Sports Council for Wales coach of the year awards in Cardiff.
Ms Davies, who collected her prize on crutches after dislocating her ankle, said: "Girls were opting out of sessions because of having to wear the traditional gear.
"Now, within reason, pupils can wear what they like - the important thing is for everyone to feel happy and comfortable."
Ms Davies, a netball player and gymnast, has introduced a broad range of PE options to the school including rounders, dance, fitness clubs and cross-country running.
Rather than focus heavily on sport at a competitive level (high-flying pupils are steered towards clubs), her aim is to encourage pupils to be active to promote health and fitness and well-being.
"Pupils will only do sport if they enjoy it," she said. "There's no point forcing them to take part."
Satu Haikala, who took the primary teacher coach award for her work at Nantmel school in Llandrindod Wells, Powys, offers her pupils a wide range of sports, and more than half of her key stage 2 pupils voluntarily take part in PE sessions out-of-hours.