just goes to show the fitness of the pro dancers.
It could be argued that there are 'types' of fitness, and the pro dancers are 'on home ground' i.e their fitness levels have always been steered towards perfomances on the dance floor (Iknow it is pretty obvious), whereas even the most athletic celebrity is asking their bodies to do very strange things, to them anyway and that takes it toll. Though in the end as Darren Gough showed last year the increased general fitness improves enormously.