Investigation of the effects of speed-based training on force-speed profiles and some parameters in 15-16 year old child football players

The purpose of this study was to examine the effects of velocity-based resistance training (VBT) on vertical jump performance, force–velocity characteristics, and anaerobic power outputs in young soccer players aged 15–16 years. A total of 60 players from the same club participated in the study and were randomly assigned to either the experimental group (VBT) or the control group. Over the eight-week intervention period, the experimental group performed a VBT protocol individualized through bar-velocity feedback, whereas the control group continued their regular training. Vertical jump performance was assessed using the Optojump system, bar-velocity and derived force–power variables were obtained using a Vitruve Linear Encoder, and anaerobic performance was evaluated via the Running-Based Anaerobic Sprint Test (RAST). Findings indicated significant improvements in the experimental group compared to the control group in countermovement jump height, peak velocity, main velocity, mean power and 1RM values (p < .05), with large effect sizes. Additionally, significant enhancements were observed in RAST peak power and mean power variables for the VBT group. These results suggest that VBT, particularly when applied with low velocity-loss thresholds, can effectively improve explosive power, force–velocity characteristics, and repeated-sprint performance in adolescent athletes. In conclusion, velocity-based training may serve as an efficient and individualized training strategy that enhances neuromuscular adaptations in young soccer players within a relatively short period and can be considered a complementary approach to traditional resistance training methods.