Impact Safety

Preventing concussions in sports has become a national priority.

The science is clear: 1 in 5 concussions results from head to surface collisions. And now the largest study of chronic traumatic encephalopathy (CTE) to date found that the cumulative force of head hits absorbed by players in their careers is the best predictor of future brain disease. Meaning EVERY IMPACT COUNTS.

How we test impact safety

Only infilled turf over a quality shock pad can reach player safety ranges found in natural grass. We know this from the data collected from the Gmax test, the HIC test, the foot impact test, and measuring that same data over the life of the turf. This gives a more comprehensive picture of how the field is performing from an impact safety standpoint both when new, and during it’s use.

Gmax with Triax Data

This test method covers the measurement of surface hardness. It does not correlate with head injury. Landing on a harder surface transmits more energy to the body so common sense would tell you that a “softer” surface would be better. It’s applicable to natural and artificial playing surfaces. It drops a 20 lb flat missile from 24″. Gmax is a good measurement when used in conjunction with HIC, but as a stand alone test it is not a total measurement of safety. A quality natural grass field will produce a Gmax typically below 115 G’s.

Head Injury Criterion

The HIC test correlates with the likelihood and severity of a head injury. It has been used for decades in the auto industry and for playground surfaces, and was adopted by ASTM for athletic fields in 2018. The HIC impact test drops a 10.1 lb. hemisphere projectile (curved like a human head) multiple times from increasing heights and determines the surface’s Critical Fall Height. The higher the Critical Fall Height, the safer the surface. A good natural grass field will produce a minimum critical fall height of about 6 feet or higher.

Advanced Artificial Athlete

This test simulates the heel strike of an adult running athlete in stride. In other words, it measures the softness or hardness underfoot during play on a field. A great natural turf field hits the “sweet spot” of being firm underfoot while producing very low Gmax and high Critical Fall Height. This is why quality natural turf is the benchmark for quality artificial turf.

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Natural Turf Gmax and HIC

Natural turf produces Gmax levels typically below 115 Gs, and HIC values well below the 1000 threshold.

Synthetic turf with sand rubber over stone

Synthetic turf without a shock pad may produce Gmax levels that appear acceptable, but fails the Head Injury Criteria levels by a lot, resulting in a significantly higher risk of serious head injury and a higher cost to the Brain Savings Account of each impact.

As the field ages, the differences are obvious

Maintaining safety levels for the life of the turf is paramount with the investment in a synthetic turf field. Below compares an 8-year old field without a Brock shock pad with one that uses one. Remember, the goal is to achieve a HIC value below 1000.

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Dartmouth Football has been a pioneer of safety innovation for nearly a decade. With the late Coach Teevens at the helm, Dartmouth football eliminated all player-on-player tackling in practice. In 2016 they continued their safety mission by installing a Brock Shock Pad System for their Artificial Turf Field.

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Ready to Build a Safer Field?

1 in 5 concussions results from head-to-surface contact.
Learn how Brock shock pads bring impact levels in line with natural turf.

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Frequently Asked Questions About Impact Safety

Impact attenuation matters because it describes how the complete synthetic turf system manages energy when an athlete contacts the surface. Testing helps field owners understand how the surface responds to impacts when the field is new and as it ages.

No, a shock pad cannot prevent every concussion or eliminate the risk of injury. A properly selected shock pad is engineered to improve impact attenuation and help the field maintain more consistent performance throughout its useful life.

HIC testing for an athletic field evaluates the impact response of the complete playing surface and calculates the Head Injury Criterion under prescribed test conditions. The test uses a rounded impact device to help assess how the surface performs during a simulated head-to-surface impact.

Critical Fall Height is the maximum tested height at which a surface remains within the specified HIC criterion. A greater Critical Fall Height indicates that the tested system provided more impact attenuation under those specific test conditions.

Gmax testing measures the peak acceleration produced when a flat impact device strikes the playing surface. It is commonly used to evaluate surface hardness and track changes in a turf system’s impact-attenuation performance over time.

No, Gmax does not directly measure or predict an athlete’s risk of a head injury. Gmax measures surface impact attenuation under specific conditions and is most informative when reviewed with HIC and other performance data.

HIC and Gmax should be evaluated together because they examine different aspects of surface response. Gmax helps characterize surface hardness, while HIC testing provides additional information about the impact response associated with a rounded, head-shaped test device.

The Advanced Artificial Athlete test evaluates how a sports surface responds under a simulated running heel strike. It helps measure the firmness and impact response athletes may experience underfoot during play.

A Brock shock pad supports impact performance by adding a purpose-engineered layer beneath the turf. This layer is designed to help the complete field system manage impact energy and maintain more consistent performance as the turf and infill age.

An artificial turf field should be tested as a complete system because turf fibers, infill, shock pad, base construction, installation, age, and maintenance can all influence impact performance. Evaluating one component alone does not provide a complete picture of how the field performs.

Impact testing is important as a field ages because infill can compact, fibers can wear, and system performance can change over time. Periodic testing helps owners identify trends, address maintenance needs, and make informed decisions about field performance and replacement.

A synthetic turf field should be tested according to applicable standards, warranty requirements, governing-body guidance, and the facility’s risk-management plan. Testing at installation establishes a baseline, while periodic testing helps document how performance changes over the field’s life.

Architects and field owners should request HIC, Critical Fall Height, Gmax, and underfoot-performance data for the complete proposed system. They should also review testing conditions, field-age data, maintenance requirements, warranties, and independent documentation.

Brock’s impact-testing documentation includes technical data, field comparisons, product specifications, and information about HIC, Gmax, and underfoot testing. Contact Brock to request the documentation relevant to your field design or specification.

Do you have more questions about Impact Safety?

A Brock specialist can help answer any questions you might have about Brock’s Impact Safety.

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