Original researchVentilatory efficiency in juvenile elite cyclists

ObjectivesVentilation (V′E) as a function of CO2 output, and oxygen uptake (V′O2) as a function of log10V′E, define cardio-respiratory efficiency, although few data compare efficiency with maximum oxygen uptake (V′O2max), or consider reproducibility. Currently there are no data for trained juveniles.DesignTwenty-five trained juvenile cyclists (mean age 14.7 years), performed maximal exercise testing on two occasions, separated by 16 weeks.MethodsV′E vs. V′CO2 slope, oxygen uptake efficiency slope, and V′O2max were measured during cycle ergometer exercise to volitional exhaustion on two occasions, 16 weeks apart.ResultsMean (SD) V′E vs. V′CO2 slope, oxygen uptake efficiency slope, and V′O2max were 28.14 (3.89), 4.16 (0.73), and 75.4 (8.9) ml kg−1 min−1 on visit 1, and 27.92 (4.63), 4.22 (0.76), and 73.6 (9.3) ml kg−1 min−1 on visit 2. Good reproducibility (differences ≤2.4%), but poor correlations (r ≤ 0.29) between efficiency and V′O2max were recorded.ConclusionsReproducibility of efficiency measures was comparable to V′O2max, however, poor associations between efficiency and V′O2max suggested independence. Efficient ventilation may be of limited importance in determining the V′O2max in a trained juvenile cyclist.