The effects of exercise on subsequent muscle function have been variously documented (e.g. Sargeant & Dolan, 1987; Rademaker et al. 1994). To our knowledge, changes in sprint performance following prolonged, non-exhaustive, moderate intensity exercise in trained, endurance racing cyclists has not been examined. We studied the effect of extended moderate intensity exercise (70 min, 65 % VO2,peak) on 30 s maximal unpaced (Wingate) performance in nine male cyclists. A modified Monark ergometer (model 814) with SRM powermeter (Julich, Germany), infinitely adjustable saddle height, racing saddle and the subjects' own pedals was used for all exercise trials. Power output and cadence were measured by use of the SRM powermeter, which measures torque directly from the crank with strain-gauges. Subjects performed two conditions: control (C) and exercise (E), both consisting of two 30 s sprints separated by 60 min of either rest or pedalling at 65 % VO2,peak, respectively. Immediately prior to each sprint, subjects worked at a controlled cadence of 100 rev min-1 for an additional 10 min. Between sprints subjects ingested 500 ml of a 12 %, or 10 ml kg-1 h-1 of an 8 % carbohydrate solution during C and E, respectively. Peak power output (PPO) measured as the highest 1 s value, mean power (MPO) and fatigue index (FI) were calculated for each test. A thumb-prick capillary blood sample was taken 3 min post-sprint to determine blood lactate concentration [Lac]post. A paired t test on the difference between first and second sprint was used to compare the effect of exercise with rest. Exercise at 65 % VO2,peak caused a significant drop in PPO and MPO when compared with the control trial, whilst FI did not change significantly from 55 ± 14 to 56 ± 13 % (P > 0·4) (see Table 1). A significant reduction in [Lac]post (P < 0·005) following the exercise trial was also observed, from 3·6 (1·2) to 6·6 (1·5) mM. An extended bout of prior moderate exercise appears to compromise both peak and average sprinting power. The mechanism for these changes in Wingate performance is unknown.
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