Physiological Demands of a Simulated BMX Competition

Abstract

The aim of this study was to investigate the physiological demands of Supercross BMX in elite athletes. Firstly athletes underwent an incremental cycling test to determine maximal oxygen uptake (VO_2max) and power at ventilatory thresholds. In a second phase, athletes performed alone a simulated competition, consisting of 6 cycling races separated by 30 min of passive recovery on an actual BMX track. Oxygen uptake, blood lactate, anion gap and base excess (BE) were measured. Results indicated that a simulated BMX performed by elite athletes induces a high solicitation of both aerobic (mean peak VO₂ (VO_2peak): 94.3±1.2% VO_2max) and anaerobic glycolysis (mean blood lactate: 14.5±4. 5 mmol.L^− 1) during every race. Furthermore, the repetition of the 6 cycling races separated by 30 min of recovery led to a significant impairment of the acid-base balance from the third to the sixth race (mean decrease in BE:  − 18.8±7.5%, p<0.05). A significant relationship was found between the decrease in BE and VO_2peak (r= − 0.73, p<0.05), indicating that VO_2peak could explain for 54% of the variation in BMX performance. These results suggest that both oxygen-dependent and –independent fuel substrate pathways are important determinants of BMX performance.

Key words

bicycle motocross - elite athletes - intermittent sprints - buffering capacity - aerobic demand - anaerobic glycolysis

• References

• 1 Bailey SJ, Wilkerson DP, Dimenna FJ, Jones AM. Influence of repeated sprint training on pulmonary O2 uptake and muscle deoxygenation kinetics in humans. J Appl Physiol 2009; 106: 1875-1887
• 2 Bertucci W, Hourde C. Laboratory testing and field performance in BMX riders. J Sports Sci Med 2011; 10: 417-419
• 3 Billaut F, Bishop D. Muscle fatigue in males and females during multiple-sprint exercise. Sports Med 2009; 39: 257-278
• 4 Billaut F, Davis JM, Smith KJ, Marino FE, Noakes TD. Cerebral oxygenation decreases but does not impair performance during self-paced, strenuous exercise. Acta Physiol (Oxf) 2010; 198: 477-486
• 5 Billaut F, Smith K. Prolonged repeated-sprint ability is related to arterial O2 desaturation in men. Int J Sports Physiol Perform 2010; 5: 197-209
• 6 Bishop D, Bonetti D, Dawson B. The influence of pacing strategy on VO2 and supramaximal kayak performance. Med Sci Sports Exerc 2002; 34: 1041-1047
• 7 Bishop D, Edge J, Goodman C. Muscle buffer capacity and aerobic fitness are associated with repeated-sprint ability in women. Eur J Appl Physiol 2004; 92: 540-547
• 8 Bishop D, Girard O, Mendez-Villanueva A. Repeated-sprint ability – part II: recommendations for training. Sports Med 2011; 41: 741-756
• 9 Bogdanis GC, Nevill ME, Boobis LH, Lakomy HK. Contribution of phosphocreatine and aerobic metabolism to energy supply during repeated sprint exercise. J Appl Physiol 1996; 80: 876-884
• 10 Boning D, Klarholz C, Himmelsbach B, Hutler M, Maassen N. Causes of differences in exercise-induced changes of base excess and blood lactate. Eur J Appl Physiol 2007; 99: 163-171
• 11 Carr AJ, Hopkins WG, Gore CJ. Effects of acute alkalosis and acidosis on performance: a meta-analysis. Sports Med 2011; 41: 801-814
• 12 Carre F, Dassonville J, Beillot J, Prigent JY, Rochcongar P. Use of oxygen uptake recovery curve to predict peak oxygen uptake in upper body exercise. Eur J Appl Physiol 1994; 69: 258-261
• 13 Chen MJ, Fan X, Moe ST. Criterion-related validity of the Borg ratings of perceived exertion scale in healthy individuals: a meta-analysis. J Sports Sci 2002; 20: 873-899
• 14 Dascombe BJ, Reaburn PR, Sirotic AC, Coutts AJ. The reliability of the i-STAT clinical portable analyser. J Sci Med Sport 2007; 10: 135-140
• 15 Duffield R, Dawson B, Goodman C. Energy system contribution to 400-metre and 800-metre track running. J Sports Sci 2005; 23: 299-307
• 16 Dupont G, McCall A, Prieur F, Millet GP, Berthoin S. Faster oxygen uptake kinetics during recovery is related to better repeated sprinting ability. Eur J Appl Physiol 2010; 110: 627-634
• 17 Gastin PB, Lawson DL. Variable resistance all-out test to generate accumulated oxygen deficit and predict anaerobic capacity. Eur J Appl Physiol 1994; 69: 331-336
• 18 Girard O, Mendez-Villanueva A, Bishop D. Repeated-sprint ability – part I: factors contributing to fatigue. Sports Med 2011; 41: 673-694
• 19 Hanon C, Leveque JM, Thomas C, Vivier L. Pacing strategy and VO2 kinetics during a 1500-m race. Int J Sports Med 2008; 29: 206-211
• 20 Harriss DJ, Atkinson G. Update – ethical standards in sport and exercise science research. Int J Sports Med 2011; 32: 819-821
• 21 Hirvonen J, Nummela A, Rusko H, Rehunen S, Harkonen M. Fatigue and changes of ATP, creatine phosphate, and lactate during the 400-m sprint. Can J Sport Sci 1992; 17: 141-144
• 22 Howley ET, Bassett Jr DR, Welch HG. Criteria for maximal oxygen uptake: review and commentary. Med Sci Sports Exerc 1995; 27: 1292-1301
• 23 Jalab C, Enea C, Delpech N, Bernard O. Dynamics of oxygen uptake during a 100 m front crawl event, performed during competition. Appl Physiol Nutr Metab 2011; 36: 219-225
• 24 Mateo M, Blasco-Lafarga C, Zabala M. Pedaling power and speed production vs. technical factors and track difficulty in bicycle motocross cycling. J Strength Cond Res 2011; 25: 3248-3256
• 25 Overgaard K, Hojfeldt GW, Nielsen OB. Effects of acidification and increased extracellular potassium on dynamic muscle contractions in isolated rat muscles. J Physiol 2010; 588: 5065-5076
• 26 Pedersen TH, Nielsen OB, Lamb GD, Stephenson DG. Intracellular acidosis enhances the excitability of working muscle. Science 2004; 305: 1144-1147
• 27 Reis VM, Duarte JA, Espirto-Santo J, Russel AP. Determination of accumulated oxygen deficit during a 400-m run. J Exerc Physiol 2004; 7: 77-83
• 28 Smith KJ, Billaut F. Influence of cerebral and muscle oxygenation on repeated-sprint ability. Eur J Appl Physiol 2010; 109: 989-999
• 29 Spencer MR, Gastin PB. Energy system contribution during 200- to 1500-m running in highly trained athletes. Med Sci Sports Exerc 2001; 33: 157-162
• 30 Tanner RK, Fuller KL, Ross ML. Evaluation of three portable blood lactate analysers: Lactate Pro, Lactate Scout and Lactate Plus. Eur J Appl Physiol 2010; 109: 551-559
• 31 Verwaerde P, Malet C, Lagente M, de la Farge F, Braun JP. The accuracy of the i-STAT portable analyser for measuring blood gases and pH in whole-blood samples from dogs. Res Vet Sci 2002; 73: 71-75
• 32 Wasserman K, Whipp BJ, Koyl SN, Beaver WL. Anaerobic threshold and respiratory gas exchange during exercise. J Appl Physiol 1973; 35: 236-243
• 33 Zabala M, Peinado AB, Calderon FJ, Sampedro J, Castillo MJ, Benito PJ. Bicarbonate ingestion has no ergogenic effect on consecutive all out sprint tests in BMX elite cyclists. Eur J Appl Physiol 2011; 111: 3127-3134
• 34 Zabala M, Requena B, Sanchez-Munoz C, Gonzalez-Badillo JJ, Garcia I, Oopik V, Paasuke M. Effects of sodium bicarbonate ingestion on performance and perceptual responses in a laboratory-simulated BMX cycling qualification series. J Strength Cond Res 2008; 22: 1645-1653
• 35 Zabala M, Sánchez-Muñoz C, Mateo M. Effects of the administration of feedback on performance of the BMX cycling gate start. J Sports Sci Med 2009; 8: 393-400