PURPOSE: Examine the acute hormonal and cytokine responses to free-weight resistance training in trained prepubertal and pubertal male children. METHODS: Prepubertal (n = 21
age 11.4 ± 1.1 years
Tanner I-II) and pubertal male children (n = 20
age 15.8 ± 0.7 years
Tanner III-V) conducted a moderate-intensity free-weight resistance training program to failure with venous blood sampling before (pre), immediately after (post) and during the recovery phase of the program (post-15,-30 min). Growth hormone (GH), insulin-like growth factor-I (IGF-I), cortisol, testosterone, IL-6, and TNF-α were analyzed in serum samples. Biological maturation was assessed according to the stages of the Tanner scale. RESULTS: There was a significant time-by-group interaction in IGF-I response (p = 0.044
η CONCLUSION: These data suggest that acute testosterone and IGF-I response following resistance training differ between trained prepubertal and pubertal male children. Moderate-intensity resistance training performed to failure may thus have different effects in trained prepubertal and pubertal male children, which should be considered when giving training advice. TRIAL REGISTRATION: Clinical trials number: NCT05022992.