Introduction: It has been suggested that fatigue during high-intensity exercise may have both central and peripheral origins. Intermittent self-paced single-leg cycling exercise offers a unique model to examine fatigue because it has previously been shown that greater leg blood flow during single-leg cycling permits higher individual-leg cycling power outputs but reduced cardiac load, compared with double- leg cycling. However, how work is self-regulated during intermittent single and double leg cycling is not known. The aim of this study was to examine the self-selected distribution of work during six repeated intermittent double and single leg cycling protocols. Methods: In a randomised counterbalanced order, eight endurance-trained cyclists (mass: 83 ± 15 kg, VO2max: 55 ± 7 ml/kg/min) performed six intermittent cycling sessions (S1-6) using either single- or double-leg cycling. The intermittent cycling protocol consisted of 3 (double) or 6 (3 right and 3 left; single) maximal 4 min intervals, with 6 min recovery between efforts/intervals. Total work and the decrement in work over consecutive intervals and throughout each minute of each interval were calculated. Participants were instructed to complete each of the intervals and each session at their highest sustainable power output. Significance was accepted at p<0.05. Results: Total work completed in each session was highly reliable (CV: mean S1-6 = 2.5 and 1.8% for single and double-leg training, respectively) and significantly greater in the single compared to the double-leg training condition (384 ± 58 vs. 330 ± 36 kJ, respectively). The decrement in work each minute during the intervals was greatest during double, compared with the single-leg training condition in S1 (4.9 ± 5.1 vs. -1.3 ± 5.2%, respectively), but was similar for the remaining trials (S2-6; 0.6 to 2.2%). The decrement in work over consecutive intervals was greater in double, compared with single-leg cycling during all training sessions (mean S1-6: 3.2 ± 3.1 and -0.2 ± 3.2%, respectively). Discussion: Following familiarisation, the distribution of pacing during the four minute high-intensity intervals was similar between the single and double leg cycling. Despite, a low per leg power output during the double leg cycling, the decline in work during repeat intervals was greater in double, compared with single leg cycling. It therefore appears that localised fatigue during high-intensity intervals may be reduced when using a reduced muscle mass, possibly by due to greater blood flow and more rapid recovery.
© Copyright 2012 17th Annual Congress of the European College of Sport Science (ECSS), Bruges, 4. -7. July 2012. Veröffentlicht von Vrije Universiteit Brussel. Alle Rechte vorbehalten.