Do non-contact injuries occur during high-speed running in elite football? Preliminary results from a novel GPS and video-based method

Objectives: Understanding how injuries occur (inciting circumstances) is useful for developing etiological hypotheses and prevention strategies. The aims of this study were 1) to evaluate the feasibility of a method combining video and Global Positioning System data to estimate the speed and acceleration of activities leading to injuries and 2) to use this method to analyse the inciting circumstances leading to non-contact injuries. Design: Retrospective descriptive study. Methods: Injury inciting circumstances from 46 elite players over three seasons were analysed from video recordings and from external load measures collected through Catapult Vector S7 Global Positioning System. Results: In total 34 non-contact injuries were analysed. Sixteen out of the seventeen hamstring injuries occurred when players were running for (median and interquartile range) 16.75 m (8.42–26.65 m) and achieved a peak speed of 29.28 km·h⁻¹ (26.61–31.13 km·h⁻¹) which corresponded to 87.55 % of players' maximal speed (78.5 %–89.75 %). Of the three adductor injuries, one occurred whilst the player was decelerating without the ball, one occurred whilst the player was accelerating and controlling the ball at knee level, and one occurred whilst the player was performing an instep kick. Two quadriceps injuries occurred whilst the players were kicking either whilst walking or running. Conclusions: From the preliminary results reported in this study most hamstring injuries occurred when players ran > 25 km·h⁻¹ and above 80 % of their maximal speed. This study suggests that this novel approach can allow a detailed and standardised analysis of injury inciting circumstances.