Metrication in the United States traditional mile-based lengths. In the Olympics, athletes run 1500 meters, not 1600 meters. Running races in the U.S. are usually run in metric distances (e.g., the 100 metres dash or the 5K run), although the mile distance remains popular. But even 5 and 10 kilometer races most often have mile markers on the course, and no kilometer markers. Long-distance races are often measured in kilometers, although exceptions exist (generally 10 mile races). The marathon is referred to as a 26.219-mile race (the official marathon standard distance originally being in English units — 26 miles, 385 yards) rather than 42.195 km.
Half marathon Half marathon A half marathon is a road running event of 21.0975 km (13 mi 192½ yd)—half the distance of a marathon. It is common for a half marathon event to be held concurrently with a marathon, using almost the same course with a late start, an early finish or shortcuts. If finisher medals are awarded, the medal or ribbon may differ from those for the full marathon. The half marathon is also known as a 21K, 21.1K or 13.1 miles, although these values are rounded and not formally correct. A half marathon world record is officially recognised by the