We challenge the tradition of fitness testing in schools on the basis of purpose, procedures and outcomes. A number of assumptions about validity of selected tests are raised. The need to be able to track fitness through childhood into adulthood is challenged with limited scientific evidence of longitudinal tracking. Supporters of wide-scale fitness testing of children in schools include researchers whose intention is to promote public health awareness and policy. But a variety of confounding factors can affect field-based testing and lower the confidence in intra and inter group comparisons. Confounders include variability in motivation, familiarisation, external conditions, group dynamics, self-efficacy in testing, and perceived value of testing and likely outcomes. With acknowledged limitations, a more appropriate context for fitness testing for young people who have a strong commitment to physical activity may lie more in a professionally delivered sports-specific setting rather than in large-scale school-based testing. Given the less than desirable participation in activity outside of school and the distressing prevalence of childhood overweight and obesity, it is unlikely that fitness testing experiences will provide children with much needed positive encouragement for lifelong physical activity. Alternative strategies for school-based assessment of the promotion of child health through physical activity are proposed.