Physiological Demands of a Simulated BMX Competition

J. Louis; F. Billaut; T. Bernad; F. Vettoretti; C. Hausswirth; J. Brisswalter

doi:10.1055/s-0032-1327657

International Journal of Sports Medicine, Table of Contents

Int J Sports Med 2013; 34(06): 491-496
DOI: 10.1055/s-0032-1327657

Training & Testing

Physiological Demands of a Simulated BMX Competition

J. Louis

¹Faculty of Sport Sciences, University of Nice Sophia Antipolis, Nice, France

,

F. Billaut

²School of Sport and Exercise Science, Victoria University, Melbourne, Institute of Sport, Exercise and Active Living, Melbourne, Australia

,

T. Bernad

³STAPS, University of South Toulon-Var, La Garde, France

,

F. Vettoretti

⁴CREPS Sud Est, French cycling federation, Aix en Provence, France

,

C. Hausswirth

⁵Research Department, INSEP, Paris, France

,

J. Brisswalter

⁶Laboratory of Human Motricity, Education Sport and Health, University of Nice Sophia Antipolis, Nice, France

› Author Affiliations

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

Full Text

References

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