Cardiorespiratory Responses and Circulating Metabolite Concentrations in Male and Female Adolescents During a Simulated Duathlon

This study compared markers of the metabolic processes occurring in male and female adolescent triathletes from two age groups (over 15 years of age [O15] and under 15 years of age [U15]) during a laboratory based duathlon. Participants were tested on three separate occasions; two peak VO₂ tests on a treadmill and cycle ergometer, and a third session involved a simulated duathlon (2 km run, 12 km ride and 4 km run for the O15 groupo or 1 km run, 8 km ride and 2 km run for the U15). Data collection included performance speed, cardiorespiratory responses and blood borne markers of exercise metabolism. The performance speeds selected by the two age groups did not differ. The mean relative percentage of VO₂peak at which subjects participated were 79 ± 3, 77 ± 4 %, for the 015 males and females, and 71 ± 5 and 82 ± 2 %, for the U15 males and females, respectively. While the plasma metabolites of ammonia [NH₃] and lactate [La] were not different between age groups and sex (p > 0.05) there were however, higher concentrations recorded during the cycling phase when compared with the running phases (p < 0.05). The respective mean concentrations for NH₃ and La were 80.5 ± 5.6 μM, and 4.9 ± 0.3 μM for cycling, and 56.3 ± 2.7 μM, and 2.7 ± 0.2 μM for the combined running phases.

Key words

Adolescents - endurance - blood metabolites - self-paced - duathlon