Understanding the workload demands of Cross-country mountain bike cycling using the Critical Power concept
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Objective: To examine the pacing pattern by describing the continuous workload requirements in relation to critical power (CP) of cross-country mountain bike cycling (XCO-MTB). Methods: Five male and two female nationally competitive XCO-MTB athletes (age:23± 4 years, VO2peak:71 ± 8.1 mL·kg−1·min−1) completed an official XCO-MTB race and then performed two lab tests using their own bike mounted on a cycle ergometer with their own power meter. Speed, cadence, power output, and HR were recorded during the XCO-MTB race. VO2peak and maximal aerobic power (MAP) were established, and CP were calculated using three maximum effort time trials of 12, 7 and 3 minutes. PO >CP were divided into three magnitude based zones [P] (CP up to 1.5 times CP[P1], 1.5 to 2 times CP[P2] and 2 times and above CP[P3]), and five zones based on the duration of individual segments with >CP PO. Results: During the XCO-MTB event, average speed and PO was 14.4±1.9km*h −1 and 249±63 W, respectively. Average CP was 329±74W and PO varied from 0 to 277±29% of MAP. During the race, 40±8% of race time was spent with PO >CP with mean PO equal to 76±9% of CP. Average percent of lap time spent in P1, P2 and P3 was 25±4 %, 11±6 % and 4±5 %, respectively. Total time >CP and distribution of P2-3 decreased significantly from initial rounds, with no significant changes in P1 or distribution of duration. Conclusions: During this XCO-MTB race, about 40% of race time was spent above the CP, with a reduction of high magnitude >CP actions in P2 and P3 following initial rounds. The observed highly variable pacing pattern in XCO-MTB imply the needs for rapid changes in metabolic power output during races, displaying a prominent number of separate short-lived actions with little lap-to-lap variation in duration.
Masteroppgave - Norges idrettshøgskole, 2020