The default attitude to head impacts in most sport has been react when something bad happens. A player goes down, an HIA is performed, a decision is made on the side of the pitch. That process is necessary but it’s not enough on its own.
The problem is that almost none of the head loading an athlete experiences over a career produces an immediate clinical event. Most of it accumulates quietly, across thousands of small impacts that no one is logging. If long-term outcomes are even partially explained by total exposure rather than by individual concussive events, then the thing we should be measuring is all the impacts, all the time, not just the ones that hit the medic’s notebook.
Three reasons measurement is now realistic
- The sensors got small. Instrumented mouthguards can be worn for an entire season without anyone noticing them. Earlier generations of headgear-mounted sensors were too obvious and too inaccurate to be deployed at scale.
- The data pipelines got faster. Once a model can return a per-region strain estimate in milliseconds, you can run it on every impact rather than reserving it for the handful that make it into a research dataset.
- The questions got sharper. Cohort studies are starting to ask not just did this player have concussions but what was their cumulative head-impact dose by position, by minute on the pitch, by training year. That kind of question only has answers if someone collected the data.
Three things measurement does not do
Brain-exposure monitoring isn’t a substitute for the rest of the safety stack. It does not:
- Diagnose. That stays with the clinician.
- Decide. No threshold automatically removes a player. Numbers prompt conversations; they do not end them.
- Predict the future. A perfectly normal season is not a guarantee of future health. A heavy season is not a sentence either.
What it does do is give athletes, coaches, parents, and clinicians an objective record they didn’t have before. That record is the foundation on which everything else gets built — better return-to-play protocols, smarter rule changes, more honest career decisions, and ultimately the kind of dose-response evidence that will let the next generation of athletes make informed choices about how much of this risk they’re willing to carry.
The point isn’t to make sport safe. The point is to make it understood.
Sources & further reading
- The FA — Concussion guidelines for football.
- If in doubt, sit them out — UK Concussion Guidelines for Non-Elite (Grassroots) Sport (2024).
- Stemper, B. D. et al. (2019) — Comparison of head impact exposure between concussed and matched control football athletes. Annals of Biomedical Engineering 47. — Cumulative exposure, not just single hits, separates concussed from control athletes.
- Patton, D. A. et al. (2023) — Quantifying head impact exposure, mechanisms and kinematics using instrumented mouthguards. — What season-long iMG monitoring actually captures.