Football wearables, GPS and AI: what they do for injury prevention

What football wearables measure

Most systems sold to clubs combine three sensors in a vest-mounted unit or a strap.

• Satellite positioning (GPS/GNSS). Distance, speed, time in speed zones, sprints and high-speed running. Accuracy is reasonable for longer efforts at constant speed and weaker for short, sharp changes of direction. It does not work indoors and can degrade near tall stands.
• Accelerometers and gyroscopes (inertial sensors). Accelerations, decelerations, impacts and composite 'load' scores. They capture the stop-start work of small-sided games that distance figures miss.
• Heart-rate monitors. A measure of internal load: how hard the body is working, not how much it moves.

AI appears on top of this as software that summarises the data, flags unusual values or gives each player a 'readiness' or 'injury risk' score. These scores are only as good as the sensors underneath and the validation of the model, which is where the questions should start.

External and internal load, and the free alternatives

External load is what the player does (metres, sprints, accelerations). Internal load is how the body responds (heart rate, perceived effort). Two players can cover the same distance with very different internal cost, depending on fitness, fatigue, illness or growth.

Session RPE needs a habit, not a budget: ask each player, 20–30 minutes after training, how hard the session was on a 0–10 scale, and multiply by its duration. Over a few weeks the team's normal weekly range becomes clear, and sharp jumps stand out.

What the evidence says about load, AI and injuries

The idea that injuries follow sudden spikes in load is intuitive and widely used. The research is less settled than many dashboards suggest.

• Acute:chronic workload ratio. Comparing the last week's load with the last four weeks became popular, but the literature is mixed. A 2021 editorial in Frontiers in Physiology described the evidence as controversial, with some studies finding no link in professional football and others finding associations but no safe 'sweet spot'.
• Injury prediction models. A 2022 systematic review in Sports Medicine assessed 204 musculoskeletal injury prediction models in sport. None had been externally validated, almost all were at high or unclear risk of bias, and the authors concluded that no model could be recommended for practice.
• Prevention programmes. In contrast, a meta-analysis in the British Journal of Sports Medicine found that the FIFA 11+ warm-up reduced football injuries by 39% across the pooled studies. Regular, well-run neuromuscular warm-ups have a much stronger evidence base than any risk score.

The practical reading: use load data to plan and to avoid obvious errors, such as a player going from two weeks off to three matches in five days. Treat an AI 'injury risk' percentage as a prompt to look, not a forecast. Ask the supplier how the model was validated, on which population and with what error rates; if there is no clear answer, do not let it drive selection.

Law 4 and wearables in matches

The Laws of the Game allow electronic performance and tracking systems (EPTS) in matches under conditions. According to Law 4, where wearable technology is used as part of EPTS, the competition organiser must make sure it is not dangerous and meets the requirements for wearable EPTS under the FIFA Quality Programme.

• Players, including substitutes, may not wear or use other electronic or communication equipment, except EPTS where permitted.
• Team officials may use electronic communication where it relates to player welfare or safety, or to tactical and coaching reasons, but only with small, handheld devices.
• In grassroots competitions, check the league's rules before using vests in matches; many leave it to the competition, and referees decide whether equipment is safe.

The 2026/27 Laws also allow non-dangerous items if they are safely and securely covered. That is a general equipment change, not an extension of what EPTS may do.

Before turning to AI, it pays to automate repetitive work that involves no sensitive data, such as a tournament schedule. The DorsalCUP tournament fixture generator is free, needs no sign-up and stores nothing on a server.

Young players: growth, privacy and proportion

With youth players, the most informative 'sensor' is often a tape measure. A study at an elite Spanish academy found that players growing fastest before peak height velocity had higher injury incidence and burden, and recommended monitoring both growth rate and maturity status. Measuring standing height every six to eight weeks, recording it carefully and reducing high-impact volume for players in a rapid growth phase is cheap and well grounded.

• Data protection. Heart rate, injuries and growth data are health data, a special category under UK GDPR. They need a clear purpose, restricted access and parents informed before collection.
• No public rankings. Do not display distance or sprint leaderboards for children; they reward early maturers and can push players to train through pain.
• Proportion. Continuous monitoring of under-12s is rarely justified. Minutes, RPE and growth checks cover most needs.
• Supplier terms. Check where the data is stored, who owns it and whether it is used to train the supplier's models.

For more on the warm-up and growth-related injuries, see injury prevention in youth football.

How a small club can start

1. Weeks 1–4: minutes and RPE. One shared spreadsheet: player, date, minutes, session RPE. Five minutes after each session.
2. From week 1: a structured warm-up. Use an evidence-based programme such as FIFA 11+ (or its children's version) at least twice a week.
3. Youth: growth checks. Height every six to eight weeks, recorded by the same person.
4. After a season: review. Which decisions did the data change? If none, a vest will not change that either.
5. If you add GPS: start with one squad, fix unit allocation, define three metrics you will actually use, and compare each player with their own baseline.

Plan load around fixtures, especially at tournaments with several matches in a day; the heat and hydration guide covers the summer side of that problem.

Frequently asked questions