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Why is Testing Important?

Gmax testing measures the shock absorption of synthetic turf. The results indicate how much shock an athlete absorbs when impacting the turf. As the Gmax value increases, the field becomes harder, and is less likely to absorb shock. These measurements are a fundamental tool alerting you to critical compaction issuesand the possible need of additional infill -- keeping your field safe and limiting injuries.

An average football or soccer field requires fewer than two hours for testing.  A comprehensive report is sent to you within six business days following the test. For a sample report, click here.

Gmax Test Results

Gmax values increase with high usage, compaction, and infill segregation. These values can be reduced by grooming or top dressing your field. For optimum synthetic turf playing field performance, fields should have Gmax results between 120 and 145. It’s best to have your field tested once a year by a provider that is in compliance with the American Society of Testing and Materials (ASTM) standards.

For synthetic surfaces, ASTM specifies that the reported Gmax value for all test points on a field should be less than 200 Gmax (as measured in accordance with ASTM procedures F355-A and F1936). If the standard isn’t met, the field is considered unsafe and remediation is required.

Testing Frequency

Gmax measurements are not static. On synthetic turf surfaces, Gmax values will generally increase as the field ages. This suggests that regular Gmax testing is important - but how often is often enough? Among researchers and other industry experts, there is a general consensus that an annual test is most desirable.

Remediation Services

FieldGroomers offers several levels of services that will improve the performance of the Gmax test. Most importantly is to consider implementing periodic "deep decompaction" followed by a scheduled grooming/raking program that delivers on-going prevention of field hardening. Give us a call today (317) 771-2656 for a free on-site demonstration or field evaluation and we will create a maintenance program to protect your investment and offer extended life to your field.


Frequently, we encounter reports in the media concerning poor maintenance efforts from facilities with synthetic turf fields. Most of the articles focus on surface conditions as it relates to player safety, most notably field hardness. To read an article from the WYHR television titled "Trouble in the Turf: Lack of Synthetic Turf Testing & Maintenance Puts Athletes at Risk", click here.

The report highlights the basics of in-filled synthetic turf systems, compares different maintenance programs (such as the NFL), and highlights the fact that many facilities have not maintained their fields. The report further exposes a list of public school facilities, including high schools and universities, that have no record of maintenance effort. We've also made the article available on our website, click here.