04.09.2019

Performance Testing on Synthetic Turf Fields

There are many testing standards within the synthetic turf industry. One of the standards growing in popularity is the “FIFA Standard” or FIFA Quality Programme as it is officially called. FIFA implemented quality standards as far back as 2001 to ensure football (soccer) surfaces could be designated with a FIFA quality mark, meaning the surfaces were up to their standards. Revisions to these standards have occurred since then with the latest revision in 2015.

The FIFA Standard covers performance measures ranging from ball roll, ball bounce, and foot traction, to surface heat, surface planarity, and even turf yarn thickness. The commonly referenced tests within this standard are Vertical Deformation, Energy Restitution, Shock Absorption (formerly known as Force Reduction), and Rotational Resistance. These first 3 tests are completed using the Advanced Artificial Athlete (AAA – Figure 1) while the fourth test uses a mechanical torque wrench (Figure 2) attached to a weighted test foot with cleat studs (Figure 3)

USGreentech Performance Testing - Advanced Artificial Athlete (AAA) USGreentech - Performance Testing -Rotational Resistance USGreentech - Performance Testing - Cleat Studs
Figure 1 - Advanced Artificial Athlete (AAA) Figure 2 - Rotational Resistance Figure 3- Cleat Studs

Vertical Deformation is the measure of how much a surface gives underfoot. To picture this, think about planting your foot onto a concrete floor versus a trampoline. The concrete floor would have a very low vertical deformation while a trampoline would be high. Athletes want a firm surface but also some give to help protect their ankles and joints.

Shock Absorption is exactly as it says, the measure of shock absorption percentage by a surface. A lower score indicates a surface is harder and is absorbing less of the impact. This means vibration from the impact may travel back through the athlete’s legs. A higher score indicates a surface is absorbing a higher amount of the shock, with less vibration traveling back to the athlete’s legs.

Rotational Resistance is the measure of surface traction. Cleat studs are attached to a weighted device which when turned measures traction in Newton meters (Nm). A higher score indicates higher traction while a lower score indicates low traction.

Although not part of the current FIFA standard, Energy Restitution is the measure of how much energy as a percentage is returned from a surface to the athlete. A good way to think about this is to imagine running on the beach…that would be nice right about now wouldn’t it? Running over compacted wet sand will have a higher Energy Restitution meaning energy is being returned to the individual. Running over dry sand that gives underfoot will return less energy because more is being absorbed by the surface, therefore causing fatigue to the individual.

You may instinctively want your turf to score at the minimum or maximum for some of these tests, but in fact there is an ideal range according to FIFA. These ranges have been set based on scores from testing conducted on natural turf fields. Below are the ideal FIFA ranges for the tests mentioned above:

TEST Vertical Deformation Shock Absorption Rotational Resistance Energy Restitution
SCORE RANGE 4 to 11 mm 57 to 68%

27 to 48 Nm

No FIFA range

When reviewing test results, consider if the results are from a lab sample or an in-situ sample. Consider how new or how old the sample/field is. Age of turf/infill can play a factor in your results as your turf or infill can begin to degrade, compact, or simply migrate away. There are a lot of turf system characteristics to consider when designing a field. To learn more about what to consider for your upcoming synthetic turf field, call USGreentech and speak with one of our team members.

Picture of Ross Vocke, Operations Manager

Author: Ross Vocke, Operations Manager

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