A racing bike? A car? No , it's a special kind of shoes called Heelys . Heelys looks just like ordinary sports shoes , but they have a wheel( 轮子 ) in the heel( 鞋跟 ) . So instead of walking , kids can “fly around in them.” "Wearing Heelys is fun and cool, " said Geng Lie , a 15-year-old boy who wore them on his first day back at Beijing's 101 Middle School. Geng said he loves the shoes so much that he wears them wherever he goes . Sometimes he even follows his parents' car to the supermarket on his Heelys! Other students think these are very cool , but some haven't been so lucky with their Heelys. There have been reports of children falling down while using the shoes , and some have been hurt . "Heelys wheels are on the heels of the shoes , so it's easy to fall , " said Liu Rui , a doctor at the Red Cross hospital , Beijing . Even worse , Liu said. "wearing Heelys for a long time could stop young people from developing their ankles( 脚踝 ) and legs."