[How Valid is the Performance Diagnostic in Soccer?]. / Wie valide ist die Leistungsdiagnostik im Fußball?

ABSTRACT

BACKGROUND: Assessments of physical and physiological performance tests in soccer sports are still unspecific yet. There is also a lack of scientific validation using those as a "golden standard". Concerning match performance a large deficit also exist in sports and medical science. OBJECTIVE: The aim and purpose of this multicentric and prospective diagnostic study was to evaluate the validity of current established and recommended diagnostic tests for endurance and match performance (golden standard real time of playing) in soccer. MATERIALS AND METHODS: In a prospective study protocol two German soccer teams from the fourth (n = 22) and third (n = 24) national league first underwent different tests of performance and diagnostics ahead of the competition season (tapping, drop jump, counter movement jump, speed dribbling, treadmill running test). Afterwards, match performance of each athlete was assessed by real time of playing (as a surrogate parameter) during the half season (14 and 25 matches). We finally compared test parameters with the match performance in a linear regression analysis. RESULTS: Our analysis showed no statistical relevant relationship between test parameters and match performance (r(2) < 0.10). Only the assessment in maximum of relative oxygen uptake during the treadmill test for endurance was associated with a higher amount of variance (12%). CONCLUSIONS: According to the study results there is no relevant and valid correlation between current established diagnostic tests in soccer sport and sport-specific performance. The time of real engagement during a match might be associated with a quality of performance for the single athlete. Therefore, the assessment of this match activity is the most important parameter for improving diagnostic tests in soccer. The existence of a "golden standard" is essential for validation of any tests and parameters and the development of new specific assessments. At the moment, physical performance tests have no scientific evidence in soccer sports.