The science is clear. The research is consistent. And yet for most coaches – whether they run a junior ice hockey programme in Finland, a grassroots football club in Ireland, or a competitive floorball team in Sweden – the question of what to actually do about athlete brain health can feel abstract and unanswered.
The posts in this series have covered the mechanisms of concussion across multiple sports, the science of sub-concussive events, and the long-term consequences of repetitive head trauma. But knowledge without action is not enough. This post is different: it is a practical guide specifically for coaches – covering what head impact tracking is, why it matters at training level, what tools exist, how to use the data, and what concrete changes you can make to reduce your athletes’ cumulative brain load without compromising the quality or intensity of your programme.
Why coaches specifically need this information
Coaches are the most important figures in athlete brain safety. Not because they are doctors – they are not, and this post is not asking them to be. But because coaches make the decisions that determine the vast majority of an athlete’s head impact exposure:
How many full-contact training sessions happen per week
How many repetitions of contact drills are performed
How long practice sessions run
Whether athletes who seem “fine” after a collision are held out or sent back in
What culture exists around injury disclosure – whether athletes feel safe saying they do not feel right
The athlete who experiences a concussion in a match and is assessed by a team doctor or physiotherapist is a relatively rare event. The athlete who absorbs 40, 80, or 150 sub-concussive impacts across a week of training and three matches – and never once sees a medical professional about it – is every athlete on every contact sport team in the world.
The coach is the gatekeeper to that exposure. And the first step to managing it is being able to see it.
What does tracking head impacts actually mean?
Tracking athlete head impacts means collecting objective data on the forces acting on an athlete’s head – during training and competition – so that the information can be reviewed, compared, and acted upon.
The specific data that modern head impact sensors capture includes:
Number of events: How many times did the head experience a force above a meaningful threshold? This is the most basic measure of volume – how much exposure occurred.
Magnitude of events: How forceful were the impacts? Measured in linear acceleration (g-force) and, in more advanced sensors, angular acceleration (rad/s²) – the rotational force that science identifies as the primary driver of brain tissue damage.
Impact g-load and accumulation of angular forces (AUC): A combined metric that accounts for both the magnitude and the duration of force, giving a more complete picture of the total energy each event delivered.
Frequency and proximity: How close together in time did the events occur? Research consistently shows that impacts and events clustered in time are more concerning than the same number of impacts and events spread across a longer period. The brain needs time to recover between insults, and rapid sequences of impacts and events may not allow that recovery to occur.
Cumulative load: The accumulated total of all the above metrics across a session, a week, or a season. This is the single most important number for long-term brain health management.
The critical insight from the research is that cumulative load is what drives long-term brain disease risk – not the single dramatic event, but the relentless accumulation of smaller forces that never individually produce a symptom. Many studies have found total number of impacts to be significantly correlated with changes in white matter integrity, cognitive impairment, and measurable neurological changes. Tracking that accumulation is the only way to manage it responsibly.
The two levels of tracking: what is available to coaches today
Level 1: Observational tracking – no technology required
Before any technology is introduced, coaches can begin a form of head impact tracking today using nothing more than structured observation and a simple recording system.
What to observe and record:
After every training session and match, note the following:
Any event where a player received or delivered a significant head impact or event- collision, fall, heading duel, or accidental contact.
Whether the player appeared dazed, checked out, or briefly slowed after the event.
Whether the player reported any symptom, however minor – headache, neck stiffness, feeling “off”.
A rough estimate of how many such events occurred across the session.
This is not a substitute for objective sensor data. It is better than nothing, and it begins building the habit of paying conscious attention to brain load as a distinct category of athlete monitoring – alongside distance covered, physical load, and technical performance.
Limitation: Observational tracking massively underestimates the true number of head impact events. Research consistently shows that athletes, coaches and athletic trainers observe only a small fraction of the actual impacts athletes experience, particularly the lower-magnitude sub-concussive events that produce no visible response. This is not a failure of attention – it is a fundamental limitation of the human observer.
Level 2: Sensor-based tracking – objective, comprehensive, and now accessible
Head impact sensors worn during training and competition solve the observational problem entirely. They do not get distracted, do not miss events on the far side of the field, and do not only register the hits that produce a visible reaction. Every significant head acceleration event above the sensor’s detection threshold is captured, timestamped, and stored – automatically, for every athlete wearing a sensor.
The data is then available to the coach through an app and web dashboard, providing a session summary and cumulative history that turns the invisible into the visible.
This technology has existed in research settings for over a decade. It is now accessible to grassroots and competitive athletes, teams and sports clubs at a price point – ACT Head Impact Tracker head sensor Pro at €199,90 per sensor with a free app – that makes it a realistic tool for teams at every level, not just professional organisations with sports science departments.
How to use the data: a practical framework for coaches
Having the data is the first step. Knowing how to use it is what makes the difference.
Step 1: Establish a baseline
The first two to four weeks of using head impact sensors should be treated as a baseline period. Do not change anything about your training programme yet – just collect data. Your goal is to understand what your athletes’ head impact exposure actually looks like in your current programme.
You will almost certainly find this number is higher than you expected. Research across multiple sports shows that coaches consistently underestimate the cumulative head impact load their athletes experience. Seeing the real numbers – the total impacts per session, per player, per position, per week – is often the most important and most surprising first step.
Establish individual baselines for each athlete. Contact load varies enormously by position, playing style, and role in training drills. A central defender in football will experience a very different heading load from a winger. An offensive lineman in American football will experience far more total impacts than a quarterback. A first-line player in ice hockey will experience more body contact than a fourth-liner. Position-specific baselines allow you to identify meaningful deviations from an individual athlete’s normal load rather than comparing across different exposure profiles.
Step 2: Identify your high-load sessions
Once you have baseline data, you will be able to identify which sessions and which drill types generate the highest cumulative brain load. Across the sports covered in this series, the most common findings are:
Full-contact scrimmage sessions produce far higher loads than technique or small-sided sessions
Heading repetition drills in football generate a surprisingly high number of events per minute
Checking drills in ice hockey and rugby produce the highest per-session peaks
The final weeks before a major competition – when training intensity peaks – often show the highest cumulative loads of the season
Knowing which sessions are driving the load gives you the information to make targeted adjustments without having to change your entire programme. You do not need to eliminate contact from training. You need to be strategic about when, how often, and how intensively contact occurs.
Step 3: Compare individual athletes – and watch for outliers
The team dashboard view is where head impact tracking becomes most powerful for coaches managing a squad. When you can see each athlete’s session load and cumulative season load, patterns emerge that would otherwise be entirely invisible:
The athlete carrying an unusually high load. One player in your squad may be experiencing significantly more impacts than their position peers – because they are always in the middle of the contact drills, because their technique puts them in vulnerable positions, or simply because of how your drills are structured. Without data, you would never know. With data, you can investigate and adjust.
The athlete whose load spikes after returning from injury. A player who returns to training after a concussion or another injury often throws themselves back into contact with extra intensity. A spike in their impact load in the first sessions back is a warning sign – even if they are symptom-free.
The athlete carrying accumulated load from a heavy match schedule. A player who has played three matches in seven days may have a cumulative impact count that warrants a lighter training load in the following session, regardless of how they say they feel.
The player whose load is consistently low – but whose technique is driving high-magnitude events. Total number of impacts tells part of the story; magnitude tells another. A player who has fewer total impacts but consistently higher peak forces may be using technique that puts them at greater risk per event, and that is a coaching target.
Step 4: Adjust training loads intelligently
The research on what actually works to reduce cumulative brain load in training is clear and consistent. Coaches and support staff should invest in scientific methods to monitor the athlete’s load and detect meaningful change, always monitoring load individually and employing a combination of load measures relevant to each sport.
Evidence-based adjustments that coaches can make without compromising athletic development:
Reduce full-contact repetitions in practice. For American football, ice hockey, and rugby – the highest-load sports – World Rugby has proposed managing and limiting contact practice by monitoring contact load from the perspective of injury prevention. Their framework defines contact load as comprising intensity (magnitude of contact events), volume (total amount of contact), density (frequency of contacts), and unpredictability. All four of these dimensions can be reduced in training without reducing them in competition.
Replace some full-contact drills with technical alternatives. Many skills that are currently practised through full-contact repetition can be taught effectively through controlled contact – where the force of impact is deliberately managed – or through technical drills that develop the movement pattern without the full force.
Reduce heading repetitions in football. The evidence for heading-related brain load reduction is particularly strong in football. To mitigate potential risks of heading on brain health, a number of pragmatic strategies have been examined in scientific studies, including smaller-sided games where fewer headers are observed, reducing headers from goal kicks and corners, developing a heading coaching framework that focuses on technical proficiency, and using lower-pressure match and training balls. Heading can be practised with fewer repetitions at higher technical quality – this is both better for brain health and often better for skill development.
Monitor acute-to-chronic load ratios. The concept of the acute-to-chronic workload ratio – well established in physical load management – applies equally to brain load. A sudden spike in contact load relative to an athlete’s chronic baseline (for example, an intense contact week following a low-contact period) may represent a higher-risk scenario than a consistently elevated but stable load. Frequent monitoring is suggested to enable acute adjustments to training and competition loads.
Build brain load recovery into your periodisation. Just as coaches periodise physical load – building intensity before a competition peak and tapering before major events – brain load periodisation is the logical next step. If your competition schedule involves three high-contact games in two weeks, the training sessions around those games should be lower in contact repetitions to manage the cumulative weekly load.
Step 5: Use the data to support return-to-play decisions
Head impact sensors are particularly valuable in the return-to-play process after a concussion. Current return-to-play protocols focus on symptom monitoring – graduated exertion with no contact until fully symptom-free. Sensor data adds an objective layer.
When an athlete returns to contact training, their sensor data shows you exactly what brain load they are experiencing from day one. You can confirm that their first contact sessions are genuinely light – as the protocol requires – rather than inadvertently high. You can track how their load ramps up across the return-to-play progression. And if their load shows an unexpected spike, you have the data to make a conservative decision with confidence.
What to communicate to athletes and parents
Head impact tracking works best when athletes understand and accept it as a normal part of their training environment – not as surveillance, but as the same kind of objective measurement that GPS tracking and heart rate monitoring have already normalised in many sports.
To athletes: Explain that the sensor data helps you manage their training load more intelligently – the same way GPS data helps you manage their running load. The goal is not to find reasons to restrict their participation, but to ensure their exposure is appropriate and to identify patterns that might indicate elevated risk before any symptoms appear.
To parents of youth athletes: Head impact tracking is a proactive demonstration that the club takes brain health seriously. Transparency about what is being measured and how it is being used builds the trust that makes the system work.
On concussion disclosure: One of the most valuable side effects of head impact tracking is cultural. When athletes know that significant impacts are being recorded objectively, the implicit pressure to hide or minimise symptoms is reduced. The data removes the need for self-reporting as the sole mechanism of identification – and that cultural shift may be the most important benefit of all.
A note on what sensors cannot do
Clarity about what head impact sensors are and are not is essential for coaches using them responsibly.
Sensors are not diagnostic devices. They do not diagnose concussion. They do not tell you whether an athlete is injured. If an athlete shows signs of concussion – for example confusion, balance difficulties, appearing dazed, headache, memory problems, sensitivity to light – they must be removed from the field immediately and assessed by a qualified medical professional. This is true regardless of what the sensor data shows. Sensor data can identify that a significant impact occurred; it cannot tell you how an individual’s brain responded to it.
No universally agreed injury threshold exists for sensor readings. There is no g-force level or angular acceleration value that definitively indicates concussion in an individual athlete. Research-derived thresholds are population-level statistical associations, not individual diagnostic cutoffs. Use the data to manage load trends over time, not to make binary “injured / not injured” decisions based on any single event.
Sensors require correct attachment to produce valid data. A sensor that moves independently of the head – because it is attached to loose clothing or a helmet that shifts during play – produces inaccurate readings. Firm attachment is essential for data quality.
Getting started: practical first steps
You do not need a full sports science department, a sophisticated data analysis pipeline, or a large budget to begin tracking your athletes’ head impacts. Here is how to start:
Week 1-2: Introduce sensors to your squad. Brief athletes on what they measure and why. Establish the habit of sensor attachment as part of the pre-training routine – just like putting on their kit.
Weeks 3-6: Collect baseline data without making training changes. Review the Dashboard after each session. Note which sessions and drill types generate the highest loads per athlete.
Month 2 onwards: Begin adjusting your programme based on what the data shows. Start with the highest-load sessions – identify one or two specific drills where the contact repetitions can be reduced or replaced with controlled-contact alternatives. Monitor whether the load metrics respond as you expect.
Ongoing: Use the season-long cumulative data to inform periodisation decisions, return-to-play monitoring, and individual athlete load conversations. Share relevant data with your team physiotherapist or medical officer.
The shift that matters most
The most important change that head impact tracking enables is not a specific training modification or a particular dashboard feature. It is a shift in how brain load is conceptualised within the coaching programme – from something invisible and unmanaged, to something that is measured, discussed, and deliberately managed alongside physical load, technical development, and competition preparation.
Sub-concussive head impacts accumulate throughout the active sports career and can cause measurable deficits and changes to brain health. This is not a risk that resolves itself or remains stable if ignored. It compounds – across sessions, seasons, and careers.
Coaches who begin tracking head impacts are not just adopting a new piece of technology. They are committing to the understanding that the long-term brain health of their athletes is part of their professional responsibility – and that they now have the tools to act on that responsibility in a way that was not possible before.
There is no medication. No cure. Prevention – practical, data-driven, and beginning in training – is the only path forward. And it starts with being able to see what is happening.
ACT Head Impact Tracker is a measurement device. ACT Head Impact Tracker is not a medical device. It does not provide medical advice, diagnostics, or treatment suggestions. In case of suspected head injury, immediately and safely remove the athlete from activity and seek assessment from a licensed medical professional.
For more information, or to buy your sensor, visit