Dirt Bikes and the Sport of Motocross
Dirt bikes began with those little Japanese motorcycles in the 1960's. Hondas, Kawasakis and Yamahas began to appear on the roads as "citizen's bikes." They were smaller, easier to control, less expensive and less outlaw-ish than Harleys. You'd see Men in Suits riding them to work.
Motorcycles, however, simply do not go with Men in Suits. They are, by their very nature, wild and free and at least a little bit outlaw-ish. It wasn't long until people were taking those pretty little street bikes and riding them in places they were never intended to go and dirt bikes were born.
Dirt bikes evolved into very light (usually less than 250 pounds), stripped down bikes designed for off road riding in rough terrain, up and down steep inclines, over rocks and off jumps. The sport of Motocross has evolved with them.
Motocross is a highly competitive sport where you race dirt bakes around an off road course that has turns, hills and jumps. The course is often muddy, and getting dirty is part of the grit and glory of dirt bike racing. Some motocross competitions include trick riding, too.
Dirt bike riding is physically demanding. You need upper body strength to control the bike and lower body strength to absorb the energy and g forces generated by the turns and jumps. It's also a very accessible sport. Children as young as 4 can compete on appropriately sized dirt bikes.
You don't see many Men in Suits riding dirt bikes to work these days. Instead, those men (and their wives and children) put on protective gear and take those dirt bikes out on the track where it's free and wild and dirty, a bit out-lawish - and a whole lot of fun.

