Road running is the sport of running on a measured course over an established road (as opposed to track and cross country running).
These events normally range from distances of 5 kilometers to longer distances such as half marathons and marathons, and they may involve large numbers of runners or wheelchair entrants. Road running is part of group of road events known as "road races".
Road running may offer those involved a range of challenges and interests such as dealing with hills, sharp bends, varied surfaces, inclement weather, and involvement in a large group. Aerobic fitness, or the ability of the body to use oxygen, is important to help complete the long distance. Anaerobic fitness, the body's ability to respond when there isn't enough oxygen for the muscle, is helpful when encountering hills and providing energy for a sprint at the finish.
The impact of running on roads puts more stress on the feet, knees and lower back than running on dirt or grass. It can compensate by providing a consistent, level surface.