Cardiorespiratory fitness (CRF) is significantly related to current and future physical and psychosocial health in youth making it an important indicator in the measurement and surveillance of population health. The aim of this research was to explore metaanalytical techniques with aggregate published health-related criterion-referenced cutpoints for 𝑉 ̇O2peak in youth developed using the 20 meter shuttle run test (20mSRT) and explore age, sex, prediction equation, country, and health indicator related differences.We included thirteen articles representing 114,145 children and youth aged 6-18 years across 18 countries who completed the 20mSRT. Significant heterogeneity was demonstrated across all sub-group analyses. This may be explained by direct and indirect variables related to each co-factor and the pooling of data within the studies disregarding age and maturation of the participants or health outcome definition.Future research needs to use standardized approaches and include sex-, age-, and culturally diverse cut-points to reduce heterogeneity between studies.iii Justin Lang, and Dr. Paul Peters, for their commitment to seeing me through this project. I greatly appreciate their dedication, guidance, and time they put in to advise me on my journey. Additionally, I would like to thank Dr. Brooklynn Fraser and Dr. Grant Tomkinson, for their help and advice as I was developing my thesis topic while working with them on the systematic reviews.I would like to give a thank you to the very helpful members of the CHEO CRU,