" Road racing offers competitors a variety of challenges to overcome such as hills, sharp bends, varied pavement, inclement weather, and a large group to compete against- or with. Aerobic fitness, or the ability of the body to utilize oxygen, is important to have to complete the long distances . Anaerobic fitness, that is, the body's capability at responding when there isn't enough oxygen for the muscle, is necessary to charge up hills and past competitors on the finish line. A common saying for runners is that the sport is 90% mental. Recreational running became popular due to high-profile runners such as Steve Prefontaine. Race courses are usually held on the streets of major cities and towns but they could be on any sealed road. Most road races are either 5 km (3. Marathon Running1 miles), 10 km (6. 2 miles), half-marathon (21. "

" Because jogging is inefficient, it's often associated with poor form. Joggers, or runners who are jogging, sometimes move in ways that wouldn't be done in a competitive running situation: excessively bounding into the air, landing heavily on the heel, carrying the arms too high, and so forth. For these reasons, "jogger" and "jogging" are considered derogatory terms by some athletes who consider themselves runners. Other people use the terms "running" and "jogging" interchangeably, and see nothing derogatory about "jogging". Jogging is also used for active recovery intervals during interval training. The runner who may just have completed a fast 400 meter repetition at a sub-5-minute mile pace, may drop to an 8 minute mile pace for a recovery lap. The jog might be carried out in much poorer, looser form whose purpose is to "shake out" the body and maintain circulation to eliminate the waste products of exercise metabolism. Trail Running Competitive running Perhaps the most basic of athletic contests, running races are simply contests to determine which of the competitors is able to run a certain distance fastest. Today, competitive running events make up the core of the sport of athletics. "