A GPS system can export dozens of variables per session. Most of them never change a decision. This guide explains what a GPS measures, what each of the metrics that matter most in football tells you, and why the numbers mislead if they are not handled with care.
What a GPS measures (and what it does not)
A sports GPS records the player's position many times per second and, from that, works out distance, speed and acceleration. Almost all devices also include an accelerometer, which picks up impacts and changes of direction.
It measures external load: what the player did. It does not tell you how they coped with it; that is what internal load is for, such as session RPE. And it has limits on accuracy: it is less reliable for very short efforts and sharp accelerations, and there, 10 Hz devices were more valid and reliable than 5 Hz ones [1].
The key metrics
- Total distance. The volume of the session. It says little about intensity: 6 km of jogging and 6 km with lots of sprints are very different sessions.
- High-speed running distance. The distance covered above a speed threshold: the intense part of the volume, the part total distance hides.
- Sprint distance and number of sprints. The same, above a higher threshold.
- High-intensity accelerations and decelerations. Every burst and every braking action has a cost. In elite competition, high-intensity decelerations were more frequent than accelerations in almost every team sport studied, and football showed the largest difference [2]. They weigh heavily in small-sided drills, where total distance is misleading because it is low.
- Minutes of exposure. The basis for reading everything else.
Why the numbers mislead
- There is no universal "high-speed" threshold. A systematic review concluded that there is no consensus on absolute thresholds in football [3]; a classic value is 19.8 km/h, the one used in Premier League analyses [4]. If the threshold changes, the numbers are no longer comparable.
- Every system measures differently. Two devices can give different numbers for the same run, and a software update can shift the results [5, 6].
- Bad readings happen. An impossible speed spike from a poor signal can ruin a player's top speed and everything worked out from it.
- Without context, the data confuses. A winger and a central defender have different profiles, and what matters is how each player compares with themselves and with what was planned.
That is why GPS data really pays off when it is lined up with the training plan and with internal load, not when it sits in an exported report.
GPS with CTBrain
- GPS data is lined up with the plan, drill by drill, so you can see what each drill produced and which planned drills have no data.
- Each player's reference top speed is based on the 95th percentile of their readings, not their peak, so one bad reading cannot distort it.
- The external load ACWR is worked out automatically for every player, with 28 days of history before it is shown.
- All of it alongside internal load (RPE) and the wellness each player reports in their app.
More on how it all fits together in the guide to training load monitoring.
References
- Varley MC, Fairweather IH, Aughey RJ. Validity and reliability of GPS for measuring instantaneous velocity during acceleration, deceleration, and constant motion. J Sports Sci. 2012;30(2):121–127. doi:10.1080/02640414.2011.627941
- Harper DJ, Carling C, Kiely J. High-intensity acceleration and deceleration demands in elite team sports competitive match play: a systematic review and meta-analysis of observational studies. Sports Med. 2019;49(12):1923–1947. doi:10.1007/s40279-019-01170-1
- Gualtieri A, Rampinini E, Dello Iacono A, Beato M. High-speed running and sprinting in professional adult soccer: current thresholds definition, match demands and training strategies. A systematic review. Front Sports Act Living. 2023;5:1116293. doi:10.3389/fspor.2023.1116293
- Bradley PS, Sheldon W, Wooster B, Olsen P, Boanas P, Krustrup P. High-intensity running in English FA Premier League soccer matches. J Sports Sci. 2009;27(2):159–168. doi:10.1080/02640410802512775
- Malone JJ, Lovell R, Varley MC, Coutts AJ. Unpacking the black box: applications and considerations for using GPS devices in sport. Int J Sports Physiol Perform. 2017;12(Suppl 2):S218–S226. doi:10.1123/ijspp.2016-0236
- Buchheit M, Simpson BM. Player-tracking technology: half-full or half-empty glass? Int J Sports Physiol Perform. 2017;12(Suppl 2):S235–S241. doi:10.1123/ijspp.2016-0499