Validation of Prozone ®: A new video-based performance analysis system

Prozone® is a new computerised video system that allows the tracking of many individuals performing a sporting activity. The aim of this study was to validate the Prozone® measurement system when measuring displacement velocities on a football pitch. Six male, recreationally active, subjects participated in the study. The subjects performed a series of runs in a straight line and different directions. The following runs were performed and tracked with the Prozone® system: 60m runs, 50m curved runs (30m straight, 20m angled) at different speeds (7 km/h, 11 km/h, 14 km/h, 19 km/h, and 23 km/h), one maximal sprint of 15m and a 20m sprint with a 90 degree turn (10m straight, 10 m left or right) in different zones of the Old Trafford and Reebook Stadiums.The subjects performed the 60m and 50m curved runs at a predetermined pace with an audio velocity control. For the short distances, the subjects were asked to run as fast as possible. For all runs, timing gates data were compared to tracking data measured with Prozone ®.The average velocity recorded by the Prozone ® system during the paced runs of 60m and 50m showed an excellent correlation (r = 0.999; Total error 0.05, Limits of agreement 0.12) with the average velocity measured by timing gates. Similar correlation (r = 0.970; Total error 0.23, Limits of agreement 0.85) was recorded during the maximal 15m sprint and during the maximal 20m sprint with right or left turns (r = 0.960; Total error 0.05, Limits of agreement 0.12). The results of this study show that Prozone® represents a valid motion analysis system for analysing movement patterns of footballers on a football pitch.