46 International Journal of Sports Physiology and Performance, 2007;2:46-57 © 2007 Human Kinetics, Inc. Fabre, Arbez, and Rouillon are with the Laboratory of Sport Sciences, 25030 Besançon Cedex, France. Perrey is with the Dept of Motor Efficiency and Deficiency, University of Montpellier, 34090 Montpellier, France. Paced Breathing in Roller-Ski Skating: Effects on Metabolic Rate and Poling Forces Nicolas Fabre, Stéphane Perrey, Loïc Arbez, and Jean-Denis Rouillon Purpose: This study aimed (1) to determine whether paced breathing (synchroniza- tion 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 condi- tions, 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. Key Words: cross-country skiing, oxygen uptake, perceived exertion, poling efficiency Interactions between locomotion and ventilation have been observed and described for varying modes of locomotion in humans, including running or walk- ing, 1-3 cycling, 4,5 rowing, 6-8 hand-rim wheelchair propulsion, 9,10 and cross-country skiing. 11,12 The observation that many activities exhibit coordination of respiratory and