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A. Arampatzis, G. P. Brüggemann, and V. Metzler, The effect of speed on leg stiffness and joint kinetics in human running, J Biomeeh, vol.32, issue.12, pp.1349-53, 1999.

A. Belli, J. R. Lacour, P. V. Komi, R. Candau, and C. Denis, Mechanical step variability during treadmill running, Eur J Appl Physio, vol.70, issue.6, pp.510-517, 1995.

D. J. Bentley, G. P. Millet, V. E. Vleck, and L. R. Mcnaughton, Specifie aspects of contemporary triathlon: implications for physio1ogical analysis and performance, Sports Med, vol.32, issue.6, pp.345-59, 2002.

R. Blickhan, The spring-mass mode! for running and hopping, J Biomech, vol.22, pp.1217-1244, 1989.

M. Bonnard, A. V. Sirin, L. Oddsson, and A. Thorstensson, Different strategies to compensate for the effects of fatigue revea1ed by neuromuscu1ar adaptation processes in humans, Neurosei Lett, vol.166, issue.1, pp.101-106, 1994.

M. Brughelli and J. Cronin, Influence of running velocity on vertical, leg and joint stiffness: modelling and recommendations for future research, Sports Med, vol.38, issue.8, pp.647-57, 2008.

R. Candau, A. Belli, G. Y. Millet, D. Georges, B. Barbier et al., Energy cost and running mechanics during a treadmill run to voluntary exhaustion in humans, Eur J Appl Physiol Oecup Physiol, vol.77, issue.6, pp.479-85, 1998.

G. A. Cavagna, Force platforms as ergometers, J Appl Physio, vol.39, issue.1, pp.174-183, 1975.

A. R. Chapman, B. Vicenzino, P. Blanch, S. Dowlan, and P. W. Hodges, Does cycling effect motor coordination of the leg during running in elite triathletes?, J Sei Med Sport, vol.11, issue.4, pp.3-71, 2008.

O. Dalleau, G. Belli, A. Bourdin, M. Lacour, and J. R. , The spring-mass mode! and the energy cost oftreadmill running, Eur J Appl Physio/ Oeeup Physiol, vol.77, issue.3, pp.257-260, 1998.

A. Delextrat, V. Tricot, T. Bernard, F. Vercruyssen, C. Hausswirth et al., Drafting during swimming improves efficiency during subsequent cycling, Med Sei Sports Exere, vol.35, issue.9, pp.1612-1621, 2003.
URL : https://hal.archives-ouvertes.fr/hal-01765340

A. Delextrat, V. Tricot, T. Bernard, F. Vercruyssen, C. Hausswirth et al., Modification of cycling biomechanics during a swim-to-cycle trial, J Appl Biomech, vol.21, issue.3, pp.297-308, 2005.
URL : https://hal.archives-ouvertes.fr/hal-01762706

D. J. Dutto and G. A. Smith, Changes in spring-mass characteristics durLEG-SPRING STIFFNESS AND RUNNING FATIGUE between k 1 eg? kvcrto and C between one-third and two-thirds of the run were found to not influence the subject's time to exhaustion

, This study was financed by the French Ministery of Health and Sports. The authors gratefully acknowledge the French Triathlon Federation. They thank Yann Le Meur for his reading and comments. The results of the present study do not constitute endorsement by the American College of Sports Medicine. ing treadmill running to exhaustion, Med Sei Sports Exere, vol.34, issue.8, pp.1324-1355, 2002.

C. T. Farley and O. Gonzalez, Leg stiffness and stride frequency in human running, J Biomech, vol.29, issue.2, pp.181-187, 1996.
DOI : 10.1016/0021-9290(95)00029-1

G. A. Gaesser and D. C. Poole, The slow component of oxygen uptake kinetics in humans, Exere Sport Sei Rev, vol.24, pp.35-71, 1996.

. Girard-0, G. Millet, J. Slawinski, S. Racinais, and P. Micallef, Changes in leg-spring behavior during a 5000 rn self-paced run in different1y trained athletes, Sei Sports, vol.25, issue.2, pp.99-102, 2010.

A. Gollhofer, P. V. Kami, M. Miyashita, and O. Aura, Fatigue during stretch-shortening cycle exercises: changes in mechanical performance ofhuman ske1etal muscle, lnt J Spo11s Med, vol.8, issue.2, pp.71-79, 1987.

C. Hausswirth and J. Brisswalter, Strategies for improving performance in long duration events: Olympie distance triathlon, Sports Med, vol.38, issue.11, pp.881-91, 2008.

G. D. Heise and P. E. Martin, Leg-spring characteristics and the aerobic demand of running, Med Sei Sports Exerc, vol.30, issue.5, pp.750-754, 1998.

H. Hobara, K. Garni, and K. , Continuous change in springmass characteristics during a 400 rn sprint, J Sei Med Sport, vol.201, issue.0, pp.256-61
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H. Hobara, K. Muraoka, T. Omuro, K. Sakamoto, M. Kanosue et al., Leg stiffness adjustment for a range of hopping frequencies in humans, J Biomeeh, vol.43, issue.3, pp.506-517, 2010.

. Hunter-1 and G. A. Smith, Preferred and optimal stride frequency, stiffness and economy: changes with fatigue during a 1-h highintensity run, Eur J Appl Physiol, vol.1, issue.6, pp.653-654, 2007.

A. E. Kerdok, A. A. Biewener, T. A. Mcmahon, P. G. Weyand, and H. M. Herr, Energetics and mechanics of human running on surfaces of different stiffnesses, J Appl Physiol, vol.92, issue.2, pp.469-78, 2002.

S. Kuitunen, H. Kyriiliiinen, J. Avela, and P. V. Kami, Leg stiffness modulation during exhaustive stretch-shortening cycle exercise
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, J Med Sei Sports, vol.17, issue.1, pp.67-75, 2007.

H. Kyriiliiinen, T. Pullinen, R. Candau, J. Avela, P. Huttunen et al., Effects of marathon running on running economy and kinematics, Eur J Appl Physiol, vol.82, issue.4, pp.297-304, 2000.

P. B. Laursen, E. C. Rhodes, and R. H. Langill, The effects of 3000-m swimming on subsequent 3-h cycling performance: implications for ultraendurance triathletes, Eur J Appl Physiol, vol.83, issue.1, pp.28-33, 2000.

T. A. Mcmahon and G. C. Cheng, The mechanics of running: how do es stiffuess couple with speed?, J Biomeeh, vol.1, issue.1, pp.65-78, 1990.

G. P. Millet, G. Y. Millet, M. D. Hofinann, and R. B. Candau, Alterations in running economy and mechanics after maximal cycling in triathletes: influence of performance lev el. !nt, J Sports Med, vol.21, issue.2, pp.127-159, 2000.

J. B. Morin, T. Jeannin, B. Chevallier, and A. Belli, Spring-mass mode! characteristics during sprint running: correlation with performance and fatigue-induced changes. !nt, J Sports Med, vol.27, issue.2, pp.158-65, 2006.
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J. B. Morin, P. Samozino, K. Zameziati, and A. Belli, Effects of altered stride frequency and contact time on leg-spring behavior in human running, J Biomeeh, vol.40, issue.15, pp.3341-3349, 2007.
URL : https://hal.archives-ouvertes.fr/hal-01859285

A. T. Nummela, L. M. Paavolainen, K. A. Sharwood, L. Ml, T. D. Noakes et al., Neuromuscular factors deterrnining 5 km running performance and running economy in well-trained athletes, Eur J Appl Physiol, vol.97, issue.1, p.8, 2006.

L. Paavolainen, A. Nummela, H. Rusko, and K. Hiikkinen, Neuromuscular characteristics and fatigue during l 0 km running. !nt, Official Journal of the American College of Sports Medicine, vol.33, issue.8, pp.516-537, 1999.

D. A. Padua, B. L. Arnold, D. H. Perrin, B. M. Gansneder, C. R. Carcia et al., Fatigue, vertical leg stiffuess, and stiffuess control strategies in males and females, J Ath/ Train, vol.41, issue.3, pp.294-304, 2006.

J. Slawinski and V. Billat, Changes in internai mechanical cost during overground running to exhaustion, Med Sei Sports Exere, vol.37, issue.7, pp.1180-1186, 2005.

J. Slawinski, R. Heubert, J. Quievre, V. Billat, and C. Hanon, Changes in spring-mass mode! parameters and energy cost during track running to exhaustion, J Strength Cond Res, vol.22, issue.3, pp.930-936, 2008.

V. E. Vleck, D. J. Bent1ey, G. P. Millet, and A. Bürgi, Pacing during an elite Olympie distance triathlon: comparison between male and female competitors, J Sei Med Sport, vol.11, issue.4, pp.424-456, 2008.