So the news we have all been waiting for has arrived… at last FIFA has officially allowed GPS in competitive matches.
FIFA first permitted GPS to be used in the (male) U20 World Cup New Zealand 2015 and the Women’s World Cup Canada 2015. Following this press release, which you can read in full using the above link, we wait with baited breath to see when and how it will filter through the associations and leagues. And of course, if it will be accepted by coaches and players in the match day environment. For me this could be an absolute game changer for Sport Science support in professional football.
GPS data is based on point to point location analysis calculated by the devices locking on to satellites orbiting the Earth. [To read more on the science behind GPS and accelerometers go to the earlier blog post: Inside the GPS Unit]. The visibility of the satellites and consequently the quality of the data are affected by the environmental surroundings. So the built up stands at stadiums have the potential to reduce the reliability of the data we will now be able to collect.
Catapult Sports believe they can improve this reliability by also making their latest unit GNSS (Global Navigation Satellite System) enabled, which provides access to the Russian satellite system as well as the American:
GPS companies allow you to access data on how many satellites were locked onto a device during a session and perhaps the development of using GPS in competitive matches emphasises the need for us to use this function. We will also need to carry out validity and reliability research for GPS specifically in the stadium environment. [To revisit GPS validity and reliability research available see this summary in a previous post: GPS Validity & Reliability – A Collection of Independent Research Findings.]
For me the best consequence of this decision is to finally be able to fill in the massive holes for consistently tracking individual training and game load.
The differences between match day semi-automated camera systems e.g. Prozone and GPS are widely reported. Variations as large as 40% in sprint distance have been published in the literature (Randers et al, 2010; Harley et al, 2011). Many clubs, including ourselves, have conducted in house comparison testing and found the differences unworkable. Martin Buchheit has tried to present formulae for integrating different tracking systems in football to overcome this variance (https://mart1buch.files.wordpress.com/2014/06/buchheit-integrating-different-tracking-systems-in-soccer.pdf).
But the logical solution has always been to allow GPS in games. This of course is not new to our friends in rugby union, rugby league or AFL who have been using it in competition for many years.
We will be able to track parameters over time for individuals for their loading. Totals, averages and rolling workloads, which have been shown to link to fitness/freshness, fatigue and injury risk, will be more accurate.
We will be able to objectively assess match demands with the same system that we assess training demands and rehabilitation progressions with. Our GPS match data will no longer only be from in-house games or lower intensity preseason friendlies, but will capture competitive matches across the entire season, including the performances that matter the most.
We will have access to GPS and accelerometry specific variables during matches. The validity of deriving accelerations and decelerations would seem to be greater when it is measured by a wearable device rather than a camera system. The focus of analysis appears to be focussing on these explosive variables more and more. It will also give access to accelerometry based variables, such as Player Load and IMA (Inertial Movement Analysis) in Catapult, during a match setting.
We will have more consistent performance data to benchmark Academy players against. Currently, comparing GPS Academy data to Prozone First Team data makes this very convoluted. We will also have consistent GPS match data for players who progress through Academies and into the First Team.
Beyond that there will be scope for the modelling and maybe even the prediction of performance…
Recent research highlights all of this potential. It paves the way for us to carry out research such as this from other sports:
To replicate research like this from Academy level at Senior level:
To expand research like this beyond preseason friendlies and into the competitive season:
Hopefully and most importantly the biggest impact of this ruling will be on the applied work and influence we can have in house on injury prevention and performance in senior, professional football.