SummaryStudy aim: To compare two exercise training modes on the physical fitness of 10 year-old children. Material and methods: A sample of 60 schoolboys aged 10 years were randomly divided into 3 groups: Traditional (TG), trained according to the Brazilian national curricular parameters, Maturational (MG), in which the degree of difficulty of the activities was adjusted to the level of maturity of subjects, and Control group (CG). The GreulichPyle protocol was used to assess biological maturity. The following fitness tests were applied: 5×10 m shuttle run (SHR), Burpee's test (BCT), goniometric (LABIFIE) measurement of shoulder joint flexibility (SAA), horizontal shoulder flexion (HSF), shoulder joint abduction (SJA), lumbar spine flexion (LSF), hip joint extension (HJE) [10], Sargent's Jump Test (SJT), endurance shuttle run (ESR) and 50-m run. The TG and MG groups trained 16 weeks, twice weekly. Results: The only significant (p<0.05) between-group differences were found for SJA (TG >MG) and LSF (TG >CG). Conclusions: Despite the lack of clear-cut results, biological maturation combined with chronological age should be considered when applying various methodological approaches in order to encourage the engagement in physical exercises as this would have favourable carry-over effects.