Could there be a more extreme manifestation of winner-takes-all globalisation than the chasm separating Usain Bolt, the brilliant Jamaican sprinter paid £20,000-a-day for wearing clothes and the workers paid 50p an hour for making them?

While Bolt could live without Puma, its Chinese workers could not. When sports companies buy from a country like China, they bring desperately needed income for thousands of migrants fleeing abject rural poverty: being treated like a piece of meat in a sweatshop, working 12 hours, seven days a week, is still better than the alternative: starving.

But Nike, Puma and Adidas could do more to end the labour abuses that stain their reputations. True, faced with the threat of a public backlash, they are doing something: they set standards and make inspections. If factories can't cover up abuse, the firms rightly don't walk away but try to improve conditions; that something is better than nothing. But, as our analysis shows, tens of thousands making leisurewear still work round the clock in miserable workshops.

While the most egregious abuses, child labour and forced labour, are rarer now, backbreaking hours and poverty pay remain the norm. The firms can talk all they like about commitment, but they aren't paying a "living wage" (China's monthly minimum wage is £100, the living wage £160). If they did – and threatened not to put new work into places that ban trade unions – they could market truly no sweat goods; it might add 30p to a pair of trainers.

What can shoppers do? In its last thorough audit, Play Fair ( clearingthehurdles.org/response-chart) found Adidas to be the best of an imperfect bunch.