Road running is a fairly common recreational activity, with many marathons and half-marathons being held regularly in cities all over the world. In terms of athletics sportsmanship, the Summer Olympics and the IAAF World Championships in Athletics only hold one road running competition, the marathon. Road running is almost always held on paved road or tarmac tracks and for long distance races, which can be anywhere between 5km and 42.2km long.
Long distance running can be incredibly stressful for the bodies of athletes, particularly when races are conducted or challenging tracks with varying types of terrain. A high level of aerobic fitness is required, as well as careful examination of possible injuries. If an athlete is injured in some way and continues to run long distances on that injury, they can cause irreparable damage to their bodies. The most common road running injuries are ankles and knee injuries, consequently, many athletes will use specialized equipment such as braces, high-tech sports shoes, and breathable sportswear for running marathons. A number of preventative measures are also important and include proper hydration and diet, straps and joint braces, Vaseline to prevent chafing, and appropriate footwear.
Apart from 5km, 10km, half-marathon and full marathon races, other styles include ultrarunning, wherein competitors cover distances much farther than marathons, an example of this is the Badwater Ultramarathon in America at over 200km in length. Another interesting style is the stage or multiday races, where participants cover long distances each day within a set time, completing stages each day. Most common recreational road running events are shorter and are held for community or charity purposes. Noteworthy races include the Sydney-based City to Surf, the Round the Bays run of Auckland, New Zealand, and the World Marathon Majors events which include the Boston, London, Berlin, New York City and Chicago marathons.