are the shoes that the athletes will wear on the track and we have seen some superfast times. may people are wondering whether it is this springy, bouncy track we have or whether the heat having it run quicker or whether it is potentially these super shoes or super spikes they are calling them. let s get a little bit more on them now. we spoke to geoff burns, a biomechanics researcher at the university of michigan, an expert in running shoe technology and a runner himself. he explained how this works. it s a really highly responsive foam and a stiff plate going through it. so, you know, all shoes, running shoes, have foams, but this next generation of foam is what we call it more compliant and more resilient. so, that means it squishes down more and squishes back more. sarah, what action can we look forward to today?
sydney mclaughlin has taken gold and smashed her own world record in the women s 400 metre hurdles shaving almost half a second off the old mark. there were five personal bests in the race, giving you an indication of what a high calibre contest it was. one of the hot topics in the athletics at tokyo is shoes. a new generation of running spikes with rigid plates and cushioning foam are some say a significant factor in the consistent breaking of records we re seeing in tokyo. supporters call it a revolutionary advance after years of stagnation. critics think it s a form of mechanical doping. geoff burns is a biomechanics researcher at the university of michigan, an expert in running shoe technology and a runner himself, he s been speaking to our correspondent lucy hockings, who is in tokyo. it s a really highly responsive foam and a stiff plate going through it.