The Evaluation of the Match External Load in Soccer: Methods Comparison.

The aim of this study was to test the interchangeability of two match-analysis approaches for external-load detection considering arbitrary selected speeds and metabolic power (MP) thresholds in male top-class level soccer. Data analyses were performed considering match physical performance of team data (1200 player cases) of randomly selected Spanish, German and English first division championship matches (2013-14 season). Match analysis was performed with a validated semi-automated multi-camera system operating at 25 Hz. During a match players covered 10673±348m of which 1778±208 and 2759±241m were performed at High-Intensity using the speed (≥16 km·h-1, HI) and metabolic power notations (≥20 watt·kg-1, MPHI). High-intensity notations were nearly perfect associated (r=0.93, p<0.0001). A huge method bias (980.63± 87.82m. d=11.67) was found when considering MPHI and HI. Very large correlations were found between match total distance covered and MPHI (r=0.84, p<0.0001) and HI (r=0.74, p<0.0001). Players high-intensity decelerations (≥-2 m·s2) coverage was very largely associated with MPHI (r=0.73, p<0.0001). The results of this study showed that the speed and MP methods are highly interchangeable at relative (magnitude rank) but not absolute (measure magnitude) level. As a results the two physical match analysis methods can be independently used to track match external- load in elite level players. However match-analyst decisions must be based on single method use in order to avoid bias in external-load determination.