Should one run 400 meters at a brisk 45-second clip instead of the more leisurely 52 seconds as prescribed by the coach, he or she may accumulate an "oxygen debt." Such over-pacing can produce cramps and sudden losses of fluid and breath, a frightening experience for any runner.
例如一個四百公尺跑五十二秒的選手，教練絕不能讓他「超能」地跑四十五秒，硬性嘗試的結果會發生「超速」（over pace）的現象，這會讓選手的呼吸急促、肌肉不能收縮，甚至失水或休克。