Evaluating the transfer effects of skill acquisition principles on performance in academy soccer players

Despite growing evidence for the benefits of skill acquisition principles (SAPs), their effects in real-world settings remain understudied. This study examined the transfer effects of SAPs on soccer players' performance. Fifty male youth players (16.54 ± 1.01 years) and eight professional coaches from an elite soccer academy participated in a within-subject design including a control phase followed by an experimental phase where coaches applied seven SAPs. Performance was assessed at four time points (T0-T3) using match statistics and a video-based test of declarative knowledge. SAP implementation and training load were monitored during all training sessions, and changes over time were analyzed with generalized linear models and t-tests. Following successful SAPs implementation (p < .01), no significant improvements were found on 12 match performance indicators between T1 and T2 or T3, although several showed delayed increases. Response time on the declarative test improved from T0 to T2 (p < .05), with accuracy unchanged. SAPs-based sessions were shorter, imposed lower external load, and elicited higher mental demand (p < .05). SAPs implementation produced clear changes in training dynamics and trends of transfer in declarative knowledge, while on-field transfer remained limited, likely requiring longer consolidation or more sensitive performance assessment measures.