Résumé
Purpose: This study aimed (1) to determine whether paced breathing (synchronization of the expiration phase with poling time) would reduce the metabolic rate and dictate a lower rate of perceived exertion (RPE) than does spontaneous breathing and (2) to analyze the effects of paced breathing on poling forces and stride-mechanics organization during roller-ski skating exercises. Methods: Thirteen well-trained cross-country skiers performed 8 submaximal roller-skiing exercises on a motorized driven treadmill with 4 modes of skiing (2 skating techniques, V2 and V2A, at 2 exercise intensities) by using 2 patterns of breathing (unconscious vs conscious). Poling forces and stride-mechanics organization were measured with a transducer mounted in ski poles. Oxygen uptake (VO 2 ) was continuously collected. After each bout of exercise RPE was assessed by the subject. Results: No difference was observed for VO 2 between spontaneous and paced breathing conditions, although RPE was lower with paced breathing ( P < .05). Upper-limb cycle time and recovery time were significantly ( P < .05) increased by paced breathing during V2A regardless of the exercise intensity, but no changes for poling time were observed. A slight trend of increased peak force with paced breathing was observed ( P = .055). Conclusion: The lack of a marked effect of paced breathing on VO 2 and some biomechanical variables could be explained by the extensive experience of our subjects in cross-country skiing.