A Meta-Analysis of Sampled Maximal Aerobic Capacity Data for Boys Aged 11 Years Old or Less Obtained by Cycle Ergometry.

The aim of this study was to develop distributions of VO based on measured values that exist in the literature in prepubertal boys using cycle ergometry. PRISMA guidelines were followed in conducting this research. One database was searched for peak and maximal VO values in healthy boys with mean age under 11 years old. Data were split into articles reporting absolute and relative VO values and analyzed accordingly. Multilevel models grounded in Bayesian principles were used. We investigated associations between VO and body mass, year of the study, and country of origin. Differences in "peak" and "maximal" VO were assessed. Absolute VO (Lmin) increases with age (P ~100%) but mean relative VO does not change (P ~100%). Absolute VO is higher in more recent studies (P = 95.7 ± 0.3%) and mean relative VO is lower (P = 99.6 ± 0.1%). Relative VO in the USA is lower compared with boys from other countries (P = 98.8 ± 0.2%), but there are no differences in absolute values. Mean aerobic capacity estimates presented as "peak" values are higher than "maximal" values on an absolute basis (P = 97.5 ± 0.3%) but not on a relative basis (P = 99.6 ± 0.1%). Heavier boys have lower cardiorespiratory fitness (P ≈ 100%), and body mass seems to be increasing faster with age in the USA compared with other countries (P = 92.3 ± 0.3%). New reference values for cardiorespiratory fitness are presented for prepubertal boys obtained with cycle ergometry. This is new, as no reference values have been determined so far based on actual measured values in prepubertal boys. Aerobic capacity normalized to body weight does not change with age. Cardiorespiratory fitness in prepubertal boys is declining, which is associated with increasing body mass over the last few decades. Lastly, this study did not find any statistically significant difference in the sample's mean aerobic capacity estimates using the "peak" and "maximum" distinctions identified in the literature.