The aim of this study was to examine age and gender differences in isokinetic eccentric (ECC) elbow flexion (EF) and extension (EE) torques in children. Thirty-seven children participated in a 3-year longitudinal study. The average age ± SD at the first test occasion was 13.0 ± 0.3 years. Isokinetic ECC EF and EE torques at 0.52 rad · s-1, MRI determined muscle cross-sectional areas (CSAs), stature, and arm length were determined annually. Concentric (CON) EF and EE torques for the same children reported previously, enabled functional torque ratios (ECC antagonist/CON agonist) to be calculated []. In contrast to isokinetic EF torques, ECC EE torques were not significantly higher than CON EE torques (across test occasions and for boys and girls). Functional torque ratios did not significantly differ with age or between boys and girls. Multilevel modelling was used to examine age and gender effects once differences in body/muscle size had been considered. ECC EF torque was relatively greater in girls following adjustment for size. These data contribute to the understanding of differences in upper body strength performance and injury propensity during growth and maturation, suggesting CON and ECC torque development are muscle and gender specific.