Performance and hormonal responses to different training modalities in young weightlifters: a randomized controlled trial

Olympic weightlifting is a sport that requires high levels of force production, technical skill, and intermuscular coordination. The effects of strength training during adolescence on performance, anaerobic power, and hormonal responses are critically important for athlete health and development. This study investigated the effects of different strength training methods on snatch (SN) and clean & jerk (C&J) performance, anaerobic power levels, and selected hormonal parameters in young male weightlifters. A total of 32 male weightlifters participated in the study. The participants were randomly assigned to one of four groups: undulating strength training (UG) (age: 17.6 ± 1.6 years), serial strength training (SG) (age: 16.9 ± 1.3 years), maximal strength training (MG) (age: 17.3 ± 1.4 years), and a control group (CG) (age: 17.1 ± 1.2 years). The experimental groups underwent sport-specific strength training five days per week for eight weeks. The performance assessments included one-repetition maximum (1RM) tests for the SN and C&J lifts, whereas the anaerobic power was measured via the vertical jump test. Hormonal parameters were analyzed via a chemiluminescent autoanalyzer. Data were analyzed using repeated-measures ANCOVA to assess group × time effects. All strength-training groups showed clear improvements in snatch and clean & jerk performance over the eight-week period, whereas the control group showed no meaningful change. Anaerobic power values remained largely stable, with no notable pre-post differences in any group. Hormonal analyses showed that insulin, GH, TT and TSH levels did not change substantially across the intervention, while IGF-1 levels decreased in the UG, MG and control groups; however, these fluctuations were similar across groups and did not reflect a distinct effect of any specific training method. Different strength-training approaches effectively improved snatch and clean & jerk performance in young weightlifters, whereas anaerobic power showed minimal change and hormonal responses were limited, with no protocol producing distinct endocrine effects; these results underscore the need to tailor strength-training programs to individual developmental profiles to support long-term performance and athlete health. ClinicalTrials.gov NCT07088627, registered on 18/07/2025. Retrospectively registered.