Passing the Test: A Standardised Passing Drill Provides a Valid Assessment of Cardiorespiratory Fitness in Senior Football Athletes

We aimed to assess validity of a sport-specific intermittent-variable submaximal fitness test (SMFT) as an indicator of cardiorespiratory fitness. In a 12-week repeated measures design, eighteen male senior football (soccer) players were monitored. Each week, a standardised Y-shape passing drill (practical SMFT) was administered immediately following a 4-min continuous run (criterion SMFT), with exercise heart rate (HRex) measured during both protocols. Laboratory-derived cardiorespiratory outcome measures were assessed at the start and end of this period. The repeated measures correlation between HRex from the two SMFTs was large, with a significant improvements in the relationship and model fit after controlling for total and high-speed running distances in the practical SMFT protocol (χ2=52.1, p<0.001; adjusted vs unadjusted model statistics: marginal R2=0.56 vs 0.29, Akaike information criterion=434.8 vs 477.0, root mean square error=1.63 vs 2.21%-points of HRmax). Adjusted HRex values from the passing drill showed large to very-large correlations with maximal oxygen uptake and maximal aerobic speed. A Y-shape passing drill can be used as a valid and practical assessment of cardiorespiratory fitness within the SMFT framework. We provide a correction equation to help practitioners adjust HRex for external training load, which improved the agreement with HRex measured from a criterion SMFT protocol.