Functional strength training is proposed to enhance neuromuscular efficiency by improving force attenuation, force production, and dynamic stabilization of the entire kinetic chain during coordinated functional movements, whereas traditional strength training primarily targets maximal strength in isolated muscles. This study compared the effects of functional and traditional strength training on physical and technical performance parameters in U19 male football players. A quantitative randomized controlled trial design was employed. Thirty-three trained players were randomly assigned to a functional training group (FTG; n = 11), a traditional training group (TTG; n = 11), or a control group (CG; n = 11). During the first four weeks, all groups completed two weekly soccer sessions, while FTG and TTG additionally performed two supervised 70-minute strength training sessions per week. In the final four weeks, FTG and TTG continued strength training, whereas the CG discontinued organized training. A significant reduction (p ≤ 0.05) in completion time for the Loughborough Soccer Shooting Test (LSST-time) was observed in both FTG (p = 0.031) and TTG (p = 0.003) compared with CG. Additionally, a significant increase in body mass was observed in FTG compared with CG (p = 0.002). Both functional and traditional strength training improved technical performance during the off-season period and were effective in maintaining performance-relevant physical and technical components, supporting improved preparedness for the subsequent pre-season phase.
