speed between the 60th and the 80th meter) by Usain Bolt. Speed over increasing distance based on world record times (see :Category:Athletics (track and field) record progressions) Types Track Track running events are individual or relay events with athletes racing over specified distances on an oval running track. The events are categorized as sprints, middle and long-distance, and hurdling. Road Road running takes place 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 scores of runners or wheelchair entrants. Cross-country Cross country running takes place over the open or rough terrain. The courses used for these events may include grass, mud, woodlands, hills, flat ground and water. It is a popular participatory sport and is one of the events which, along with track and field, road running, and racewalking, makes up the umbrella sport of athletics. Vertical The majority of popular races do not incorporate a significant change in elevation as a key component of a course. There are several, disparate variations that feature significant inclines or declines. These fall into two main groups. The naturalistic group is based on outdoor racing over geographical features. Among these are the cross country-related sports of fell running (a tradition associated with Northern Europe) and trail running (mainly ultramarathon distances), the running/climbing combination of skyrunning (organised by the International Skyrunning Federation with races across North America, Europe and East Asia) and the mainly trail- and road-centred mountain running (governed by the World Mountain Running Association and based mainly in Europe). The second variety of vertical running is based on human structures, such as stairs and man-made slopes. The foremost type of this is tower running, which sees athletes compete indoors, running up steps within very tall structures such as the Eiffel Tower or Empire State Building. Distances Sprints Sprints are short running events in athletics and track and field. Races over short distances are among the oldest running competitions. The first 13 editions of the Ancient Olympic Games featured only one event – the stadion race, which was a race from one end of the stadium to the other. There are three sprinting events which are currently held at the Olympics and outdoor World Championships: the 100 metres, 200 metres, and 400 metres. These