The use of individualized speed and intensity thresholds for determining the distance run at high-intensity in professional soccer

As with other match analysis systems, ProZone (R) uses an absolute speed threshold to identify running speeds at ohigh-intensityo. In this study, we examined the use of an individualized high-intensity speed threshold based on the speed at the second ventilatory threshold (VT2speed) for assessment of the distance run at high-intensity during matches. Ten professional soccer players completed a maximal treadmill test to determine VT2speed. Match data were identified by means of the ProZone (R) match analysis system. The distances run at high-intensity during matches were calculated using the default value (19.8km center dot h-1) and VT2speed. Differences between VT2speed and the default were analysed using a non-parametric median sign test. The distances run at high-intensity were compared with a paired t-test. The median VT2speed was 15km center dot h-1 (range 14-16km center dot h-1), which was less than the default (P0.01). Mean distance run at high-intensity based on the default and VT2speed was 845m (s=296) and 2258m (s=707), respectively [mean difference 1413m; P0.001 (95% CI: 1037-1789m)]. The high-intensity running speeds based on the second ventilatory threshold are substantially less than that used as the default within the ProZone (R) match analysis system, thus the distance run at high-intensity can be substantially underestimated.