Abstract des Autors

The purpose of this study was to describe the pacing strategy of experienced cyclists in a 5-minute maximal exercise bout and to describe selected physiological responses associated with this effort. Six experienced and well-trained competitive cyclists (five males, one female) with a mean (±SD) age, height, and mass of 27.0 ± 4.77 years, 174.7 ± 8.57 cm, and 71.0 ± 6.45 kg, performed a 5-minute maximal exercise bout in a laboratory on a racing cycle. Subjects were free to determine their work rate throughout. During exercise, data were collected for work rate, heart rate (HR), VO2, electromyography of the rectus femoris and vastus lateralis, oxygen saturation, and rating of perceived exertion. All six subjects selected a pacing strategy characterized by a surge in work rate in the first minute followed by a gradual decline until the last minute, when a sprint to the end occurred. Values for HR, respiratory exchange ratio, and blood lactate concentration (182.8 ± 2.8 bpm, 1.08 ± 0.07, and 15.5 ± 2.1 mmol/L, respectively) indicated that VO2 (3.6 ± 0.4 L/min) was close to or at maximum from minutes 2 to 5. Oxygen saturation dropped continuously across time, reaching <94% in the last minute, and rating of perceived exertion was 19.5 ± 0.8. Electromyographic activity of the rectus femoris and vastus lateralis was not significantly related to work rate during the bout (p > 0.05). It is concluded that work rate or pace is uneven in an all-out, 5-minute exercise bout in experienced cyclists, yet the physiological responses are near maximal in minutes 2-5. Cyclists seem to pace themselves in a common pattern in short-term stochastic exercise bouts. The possible benefits of including some stochastic exercise in the training programs of athletes might be worthy of examination. Verf.-Referat