Ventilatory efficiency in juvenile elite cyclists

Objectives: Ventilation ( [Formula: see text] ) as a function of CO2 output, and oxygen uptake ( [Formula: see text] ) as a function of [Formula: see text] , define cardio-respiratory efficiency, although few data compare efficiency with maximum oxygen uptake ( [Formula: see text] ), or consider reproducibility. Currently there are no data for trained juveniles.

Design: Twenty-five trained juvenile cyclists (mean age 14.7 years), performed maximal exercise testing on two occasions, separated by 16 weeks.

Methods: [Formula: see text] vs. [Formula: see text] slope, oxygen uptake efficiency slope, and [Formula: see text] were measured during cycle ergometer exercise to volitional exhaustion on two occasions, 16 weeks apart.

Results: Mean (SD) [Formula: see text] vs. [Formula: see text] slope, oxygen uptake efficiency slope, and [Formula: see text] were 28.14 (3.89), 4.16 (0.73), and 75.4 (8.9) mlkg(-1)min(-1) on visit 1, and 27.92 (4.63), 4.22 (0.76), and 73.6 (9.3) mlkg(-1)min(-1) on visit 2. Good reproducibility (differences ≤2.4%), but poor correlations (r≤0.29) between efficiency and [Formula: see text] were recorded.

Conclusions: Reproducibility of efficiency measures was comparable to [Formula: see text] , however, poor associations between efficiency and [Formula: see text] suggested independence. Efficient ventilation may be of limited importance in determining the [Formula: see text] in a trained juvenile cyclist.