Evaluation of a goalkeeper-specific motor coordination assessment in youth football

Talent identification and development (TID) in football can be enhanced through objective assessments of talent predictors. Yet, available instruments rarely consider the unique demands of goalkeepers (GKs). During early phases of talent development, considering a GK's giftedness relating to, for example, different abilities (e.g. motor coordination), can complement views on highly specialized GK-specific attributes (e.g. technical skills). Therefore, this study aimed to evaluate a GK-specific motor coordination assessment to support TID in football at early developmental phases. Six tests were designed to assess ball control relevant to GKs. Their content and face validity were confirmed by independent experts (N = 8). The assessment was evaluated with GKs selected for the German Football Association's TID program (U12-U15; N = 120). This study examined the assessment's test-retest reliability and agreement, the structural validity, and the concurrent validity. The overall test score demonstrated good test-retest reliability, although some individual tests showed lower coefficients. Additionally, limited agreement between repeated measurements due to considerable measurement error as well as issues with the structural validity of the test battery were identified. Nevertheless, the findings support the assessment's concurrent validity as higher-rated (i.e. more talented) GKs outperformed lower-rated individuals. Yet, the test battery's diagnostic accuracy is not high enough to justify individual decisions for talent selection. Overall, these findings support the consideration of motor coordination as a talent predictor in youth GKs and emphasize the assessment's potential to enhance coaches' evaluations. The identified psychometric weaknesses in some individual tests provide impetus to further optimize the test battery.