Associations Between Self- and Coach-Efficacy Expectations and Physical Performance Following Small-Sided Game...

This study examined the effects of SSG-based program on sprint and intermittent endurance in youth football players, and explored the relationships between players' and coaches' expectations, physical performance, maturation, and training adaptations. Fifty-two U14-U15 players were allocated to a control (CG) or experimental group (EG). Both groups completed two weekly football sessions, in which the EG performed an SSG-based protocol within the regular training sessions. Sprint performance (20 and 30-m), 30-15 IFT velocity (vIFT), and pre-intervention expectations were assessed. The SSG-based program resulted in improvements in sprint performance and vIFT in the EG compared to CG (time × group interaction, p ≤ .02). The EG showed small improvements in sprint (≈3%) and moderate in vIFT (≈4%). Age and maturation were associated to physical performance but not with players' or coaches' expectations. Players' expectations were moderately associated with sprint and vIFT (ρ≈ 0.30-0.60), whereas coaches' expectations just to vIFT. Alignment between players' and coaches' expectations was observed for speed and endurance, but not for technical, tactical, or overall efficacy. Pre-intervention expectations did not predict training-induced adaptations. SSG-based training was associated with improvements in selected physical performance measures in youth football players, while discrepancies between players' and coaches' efficacy expectations may have implications for talent identification processes and warrant further investigation.