BMX bikes are a special kind of low bike, with smaller wheels than normal, that can be used for racing. They are designed to be very light weight but also very robust, as well as streamlined for speed. They are also known for being easier to perform tricks with than normal bikes.
BMX stands for bicycle motocross, which refers to the origin of the sport: children saw motocross races on the TV in the 70s and wanted to emulate them. Since they had no motorbikes of their own, they used their bicycles to race around similar dirt tracks to the ones they had seen. Today the sport is notable for being one of the few sports that is taken part in almost exclusively by the under-10s. Although there are a few older professional BMXers, most good ones move on to other cycling or motorcycling sports.
Among children today, BMXes remain one of the most popular kinds of bikes around, even if they do not compete in competitions, and BMX magazines are some of the biggest-selling hobbyist magazines. This was a surprise to many, as the sport was considered pretty much dead in the 80s and early 90s, only to undergo a dramatic revival in the mid-90s that is still going on now....