400 metres

The 400 metres is a track race covering one lap of a standard outdoor track, run without hurdles. It combines sprint speed with the need to manage fatigue over a longer distance.

Sprint: A footrace over a short distance run at high speed. The 400 metres is classified as a sprint, though it lasts longer than shorter sprint events.
400 metres at the Olympics: The Olympic track-and-field event in which athletes race one lap of the track. The Olympic race is the event's most prominent international competition.
100 metres: A track sprint covering 100 metres on a straight section of track. It emphasizes acceleration and top speed far more than the longer one-lap event.
Amateur Athletic Association: The governing body for amateur athletics in England, founded in 1880. Its early rules helped standardize organized athletics, including one-lap racing.
Pacing: The distribution of effort across the duration or distance of an athletic performance. Runners must avoid starting so fast that fatigue overwhelms their pace late in the lap.
4 × 400 metres relay: A relay race in which four athletes each run 400 metres. It adapts the one-lap event into a team race with baton exchanges.
200 metres: A track sprint covering half a lap, usually combining a bend and a straight. It shares curve running with the 400 metres but demands less sustained effort.
Athletics at the 1896 Summer Olympics: The track-and-field competitions held at the first modern Olympic Games in Athens. The 400 metres was among the events contested at the inaugural modern Olympics.
Speed endurance: The ability to maintain high running speed despite accumulating fatigue. It helps explain why 400-metre performance depends on sustaining speed, not just peak velocity.
400 metres world record: The fastest performances officially ratified as world records in the 400 metres. Record progress tracks changes in athletes, preparation, and competition over time.

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