IMPORTANT SAFETY NOTICE
Concussions can occur from impacts of varying magnitudes, influenced by numerous individual factors. If you observe any concussion-related symptoms or have any concerns about a potential head injury, immediately remove the athlete from activity and follow established concussion assessment and management protocols.
When in doubt, sit them out.
Understanding G-Force and Concussion Risk
While no single g-force threshold definitively causes concussion, research demonstrates a clear correlation: higher impact forces increase concussion likelihood, particularly when an athlete has experienced recent g-force accumulations. Studies indicate concussions can occur across a wide range—from as low as 50g to well over 100g. Younger athletes may be especially vulnerable to concussions at forces below 50g.
The science surrounding head impact exposure is rapidly evolving. While acute effects continue to be investigated, chronic g-force accumulation has been identified as a significant risk factor for Chronic Traumatic Encephalopathy (CTE). Reducing both acute and cumulative exposure should be a priority for all contact sport participants.
Key Research Findings on CTE Risk
Linear Acceleration
- Every additional 10,000g cumulative linear acceleration correlates with a 20% increased probability of CTE diagnosis.
- Among individuals diagnosed with CTE, each 10,000g increment is associated with 19% increased odds of severe CTE pathology.
- Contact athletes without CTE averaged 87,489g total exposure throughout their competitive careers.
- Athletes with low-stage CTE averaged 107,650g competitive exposure.
- Athletes with high-stage CTE averaged 148,777g competitive exposure.
Rotational Acceleration
- Every additional 1,000,000 rad/sec² rotational g-force correlates with 22% increased CTE risk.
- Among individuals with CTE, each 1,000,000 rad/sec² increment is associated with 20% increased risk for severe pathology.
- Contact athletes without CTE averaged 6.57 × 10⁶ rad/s² total rotational exposure.
- Athletes with low-stage CTE averaged 8.32 × 10⁶ rad/s² rotational exposure.
- Athletes with high-stage CTE averaged 12.26 × 10⁶ rad/s² rotational exposure.
PRACTICAL EXAMPLE
An athlete experiencing 500g of linear acceleration per week over 52 weeks accumulates 26,000g annually—a level associated with significantly increased long-term health risks. This underscores the critical importance of minimizing cumulative g-force exposure through strategic training modifications, technical refinement, and comprehensive match-day monitoring.
Age-Specific Guidance: Children (14 and under)
G-force accumulation in children should be minimized or eliminated wherever possible. Developing brains are particularly vulnerable to impact forces, and protective strategies must be prioritized.
Monitoring Principles for Youth Athletes
- Non-contact sports: Frequent green-level impacts (particularly those consistently exceeding 10g) should be documented and investigated, as contact should be minimal or absent.
- Contact sports: Monitor both frequency and intensity of all impacts. Frequent amber-level impacts warrant training adaptations, technical coaching, and exposure management.
- Red-level impacts: Require immediate athlete assessment to rule out concussion symptoms.
- Cumulative exposure: Amber and red category impacts must be minimized. Research demonstrates that regular exposure to elevated forces can affect both short-term cognition and long-term neurological health.
Traffic Light System: Children (14 and under)
Clear guidance for monitoring impact exposure in youth athletes.
While collisions in this range are unlikely to cause acute concussion, they should not be considered routine for youth athletes.
Monitor frequency carefully and minimize exposure wherever possible. Even sub-concussive impacts can accumulate over time, potentially contributing to long-term neurological changes.
These impacts require heightened attention. While concussion is not highly likely, it remains possible.
Immediately assess the athlete for symptoms or behavioural changes. If any doubt exists, remove from activity and prohibit contact until recovery is confirmed.
Amber-level collisions should be rare. Repeated exposure requires training modifications, technical coaching, and exposure management strategies.
CRITICAL: Red-level collisions must be avoided at all costs in this age group. Immediately monitor for concussion symptoms.
These impacts should never become routine. If patterns emerge, immediate collaborative intervention is required involving the athlete, parents, coaches, and medical staff.
Beyond acute concussion risk, these forces pose significant threats to long-term brain health and development.
Age-Specific Guidance: Athletes 16 and over
While older adolescents and adults possess greater decision-making capacity, comprehensive impact monitoring remains essential. We strongly recommend that a parent, partner, or trusted emergency contact have access to HIT data to support athlete safety and wellbeing.
These impacts are unlikely to cause concussion, though symptom monitoring remains important. While green-level contacts are expected in many contact sports, significant frequency trends warrant attention.
If high volumes of green impacts are observed, consider training regime modifications, technical adjustments, or match-day strategy adaptations. Sub-concussive impacts accumulate and may contribute to neurological changes over time.
While concussion remains less likely in this range, it is still possible. Monitor for symptoms or behavioural changes. If any uncertainty exists regarding head injury, remove from activity immediately and prohibit contact until complete recovery.
Amber-level collisions present significant concern due to cumulative effects on brain health. Systematic reduction remains imperative through training adaptations, technical refinement, and strategic match-day planning.
Athletes and support personnel should proactively discuss observed trends with coaching staff to implement protective modifications.
CRITICAL: Red-level impacts must be avoided wherever possible. These forces can cause concussion. Immediately assess athletes for symptoms following red-level contact.
Concussion symptoms may appear up to 72 hours post-impact. Any doubt regarding wellbeing requires immediate removal from activity and prohibition of contact until full recovery is confirmed.
Athletes should not develop patterns of red-level collisions—these pose dangers to both short-term and long-term health. Any trend in this category demands immediate collaborative intervention with coaches and medical personnel to enhance safety protocols and wellbeing.
COMMITMENT TO ATHLETE SAFETY
HIT's mission is to empower athletes, parents, coaches, and medical professionals with objective data to make informed decisions about head impact exposure. By systematically monitoring, analysing, and responding to impact data, we can work collectively to minimize both acute injury risk and long-term neurological consequences.