Physiological Response to Professional Road Cycling: Climbers vs. Time Trialists

The purpose of this study was to identify possible physiological differences between professional cyclists who show best performance in hill climbing (“climbers”) and those who excel in time trials (“time trialists”). To this end, professional, top-level climbers (C; n = 8; age 26 ± 1 yr; height 176.0 ± 2.0 cm; body mass 63.6 ± 2.2kg) and time trialists (TT; n=6; 27 ± 1yr; height 181.6 ± 1.7 cm; body mass 72.3 ± 2.3 kg) were required to perform two laboratory exercise tests on a cycle ergometer: a) a maximal exercise test (ramp protocol) and b) a constant load test of 20-min duration at ∼ 80 % of VšO₂max. Capillary blood lactate concentration and several gas exchange variables were measured during the maximal tests while determinations made during the submaximal tests also included: pH and bicarbonate concentration [HCO₃ ^--] in venous blood, and electromyographic (EMG) recordings from the vastus lateralis muscle to estimate root mean square voltage (rms-EMG) and mean power frequency (MPF). Both the maximal lactate concentration in capillary blood and VšO₂max were greater (p < 0.05) in C than in TT (6.6 ± 0.9 mM vs. 5.0 ± 0.4 mM, respectively, and 78.4 ± 3.2 ml ×kg^--1 × min^--1 vs. 70.5 ± 2.4 ml × kg^--1 × min^--1, respectively). Higher mean venous blood pH and [HCO₃ ^--] (p < 0.05), rms-EMG (p < 0.01) and MPF (p < 0.05 at 10 and 15 min of exercise and p < 0.01 at 5 and 20 min) were recorded in C throughout the submaximal tests. Our findings suggest that in top-level professional cyclists, climbing performance is mainly related to physiological factors (VšO₂max normalized for body mass, anaerobic/buffer capacity, motor unit recruitment) whereas time trialists tend to achieve greater absolute power outputs. It would also seem that other “technical” requirements of the sport (i. e. pedaling efficiency probably related to biomechanical factors etc.) may be associated with successful time trial performance.

Key words:

Cycling, physiology, lactate, ventilatory threshold, EMG.

References

• 1 American College of Sports Medicine (ed) .Guidelines for exercise testing and prescription. Philadelphia; Lea and Febiger 1986
• 2 Arendt-Nielsen L, Mills K R. The relationship between mean power frequency of the EMG spectrum and muscle fiber conduction velocity.  Electroencephalogr Clin Neurophysiol. 1985;  60 130-134
• 3 Burke E R. Physiological characteristics of competitive cyclists.  Physician Sports Med. 1980;  8 79-84
• 4 Chicharro J L, Carvajal A, Pardo J, Pérez M, Lucía A. Physiological parameters determined at OBLA vs. a fixed heart rate of 176 beats · min^--1 in an incremental test performed by amateur and professional cyclists.  Jpn J Physiol. 1999;  49 63-69
• 5 Conconi F, Grazzi G, Casoni I, Guglielmi C, Borsetto C, Ballarin E, Mazzoni G, Patracchini M, Manfredini F. The Conconi test: methodology after 12 years of application.  Int J Sports Med. 1996;  17 509-519
• 6 Coyle E F, Coggan A R, Hopper M K, Walters T J. Determinants of endurance in well-trained cyclists.  J Appl Physiol. 1988;  64 2622-2630
• 7 Davis J A. Anaerobic threshold: a review of the concept and directions for future research.  Med Sci Sports Exerc. 1985;  17 6-18
• 8 Faria I E, Faria E W, Roberts S, Yoshimura D. Comparison of physical and physiological characteristics in elite young and mature cyclists.  Res Quart Exerc Sport. 1989;  60 388-395
• 9 Faulkner J A. Physiology of swimming and diving. In: Falls H (ed) Exercise Physiology. Baltimore; Academic Press 1968: 415-445
• 10 Green H J, Patla A E. Maximal aerobic power: neuromuscular and metabolic considerations.  Med Sci Sports Exerc. 1992;  24 38-46
• 11 Helal J N, Guezennec C Y, Goubel F. The aerobic-anaerobic transition: re-examination of the threshold concept including an electromyographic approach.  Eur J Appl Physiol. 1987;  56 643-649
• 12 Lucía A, Carvajal A, Alfonso A, Calderón F J, Chicharro J L. Breathing pattern of high competitive cyclists during incremental exercise.  Eur J Appl Physiol. 1999;  79 512-521
• 13 Lucía A, Hoyos J, Carvajal A, Chicharro J L. Heart rate response to professional road cycling: The Tour de France.  Int J Sports Med. 1999;  20 167-172
• 14 Lucía A, Pardo J, Durántez A, Hoyos J, Chicharro J L. Physiological differences between professional and elite road cyclists.  Int J Sports Med. 1998;  19 342-348
• 15 Lucía A, Sánchez O, Carvajal A, Chicharro J L. Analysis of the aerobic-anaerobic transition in elite cyclists during incremental exercise with the use of electromyography.  Br J Sports Med. 1999;  33 178-185
• 16 Lucía A, Carvajal A, Boraita A, Serratosa L, Hoyos J, Chicharro J L. Heart dimensions might influence the occurrence of the heart rate deflection point in highly trained cyclists.  Br J Sports Med. 1999;  33 387-392
• 17 Moritani T, Muro M. Motor unit activity and surface electromyogram power spectrum during increasing force of contraction.  Eur J Appl Physiol. 1987;  56 260-265
• 18 Padilla S, Mujika I, Cuesta G, Goiriena J J. Level ground and uphill cycling ability in professional road cycling.  Med Sci Sports Exerc. 1999;  31 878-885
• 19 Saltin B, Astrand P O. Maximal oxygen uptake in athletes.  J Appl Physiol. 1967;  23 353-358
• 20 Saris W HM, van Erp-Baart M A, Brouns F, Westerterp K R, ten Hoor F. Study on food intake and energy expenditure during extreme sustained exercise: The Tour de France.  Int J Sports Med. 1989;  10 S 26-S 31
• 21 Swain D P. The influence of body mass in endurance bicycling.  Med Sci Sports Exerc. 1994;  26 58-63
• 22 Weston A R, Myburgh K H, Lindsay F H, Dennis S C, Noakes T D, Hawley J A. Skeletal muscle buffering capacity and endurance performance after high-intensity interval training by well-trained cyclists.  Eur J Appl Physiol. 1997;  75 7-13