Author(s): VICARI, D., GIUSTINO, V., BOCA, G., ZANGLA, D., CABEZA DE VACA GALLARDO, S., BERRAL-DE LA ROSA, F., ZENTI, L., SCROFANI, G., SEDITA, A., BATTAGLIA, G., BIANCO, A., Institution: UNIVERSITY OF VERONA , Country: ITALY, Abstract-ID: 2567

INTRODUCTION:
Cyclo-cross is a winter cycling discipline that takes place on mixed circuits (i.e., asphalt, dirt, grass, mud, ice, snow) with natural and artificial obstacles (i.e., barriers, steps) that require cyclists to dismount and carry their bikes. This discipline combines strength, endurance, riding skills, explosive power, and running ability. These characteristics require specific demands than other cycling disciplines. The aim of this study was to evaluate the physiological demands of a simulated cyclo-cross competition in young cyclists.
METHODS:
Seven young cyclists (age: 13.6±0.5 years) were recruited. Each cyclist was assessed on the own bike after a bike fitting. In the first test session, each cyclist performed a ramp test starting at 2.5 W/kg, increasing by 15 W/min until exhaustion. A gas analyser (Cortex, MetaLyzer 3B) was used to assess the VO2max. In the second test session (1 week later), each cyclist performed a simulated cyclo-cross competition after 20 minutes of warm-up at a self-selected intensity. During the simulation, each participant was verbally encouraged to perform as best as possible. Power Output (PO) and Heart Rate (HR) values were monitored. The simulation, with the technical characteristics of a cyclocross track, was a 1000 metres circuit to be repeated five laps. The PO and HR parameters were expressed as a percentage of each participant’s VO2max power and HR (i.e., %POVO2max, %FCVO2max), previously calculated in the laboratory.
RESULTS:
The mean of %POVO2max and %FCVO2max of all 5 laps were 76.3% and 90.2% respectively. There were significant differences in the %POVO2max (p=0.002) and in the %FCVO2max (p<0.001) among laps. Post-hoc test revealed a significant decrement in %POVO2max between lap 1 and 2 (p<0.05), between lap 1 and 4 (p<0.05), and a significant increment between lap 2 and 5 (p<0.05) and between lap 4 and 5 (p<0.05). For the %FCVO2max values, post-hoc test showed a significant increase between lap 1 and 2 (p<0.05), between lap 1 and 3 (p<0.05), between lap 1 and 4 (p<0.05), and between lap 1 and 2 (p<0.05).
CONCLUSION:
The %POVO2max and %FCVO2max parameters followed two different trends during the 5 laps. While PO showed an initial decrease after the first lap followed by an increase in the fifth lap, HR increased progressively from the first lap onwards. These results highlight that in cyclo-cross, internal and external load parameters cannot be overlapped and may not fully describe the physiological demands of this discipline. The intermittent nature of obstacles, dismounting phases, and running parts probably contributes to this dissociation between cardiovascular and mechanical responses (1).

References
1. Smekal G, von Duvillard SP, Hormandinger M, Moll R, Heller M, Pokan R, et al. Physiological Demands of Simulated Off-Road Cycling Competition. J Sports Sci Med. 2015;14(4):799-810.