Figure 1

Cyclists completed a 2-hour cycling bout on an electronically-braked cycle ergometer which consisted of 15 minutes of continuous exercise at 60% VO ₂ peak followed by three, 10-second sprints performed at 110% VO ₂ peak interspersed with 60 seconds cycling at 65% VO ₂ peak. This protocol was repeated eight times, for a total continuous exercise time of two hours. The final sprint was to exhaustion, with the duration of the final sprint used as the measure of performance. Muscle biopsies were obtained from the vastus lateralis of the quadriceps femoris muscle group immediately prior to, and five minutes prior to the end of, the cycling bout. A blood sample was obtained from an antecubital vein every 15 minutes. Oxygen consumption (VO₂) was determined every 30 minutes.