GMAX testing is a test fundamentally designed to ensure that a field is performing the way it should with respect to impact attenuation or shock absorption.

  • It measures how many G’s of force a field can absorb upon impact, and how many are returned to the athlete.
  • A high GMAX test value means the field is absorbing less impact, and returning more force to the player (resulting in a potentially dangerous situation), than a low GMAX test value.
  • The American Society for Testing and Materials standard test consists of a guide tube that’s about 2.5 feet tall and a 20-pound, cylindrical weight that falls through the tube. An accelerometer mounted on the weight measures how rapidly the missile decelerates or stops.
  • That flat-faced “missile” is connected to a small device that records the velocity as the missile hits the surface, the G-forces that are experienced during decelerations, and more.
  • GMAX performance on a synthetic field can vary based on the amount and composition of infill material, how much the carpet has worn over time and whether the infill material has become contaminated.
  • Concussion safety is one reason for GMAX testing. But it’s more focused on determining the risk of skull fractures and broken bones.

Read More: GMAX: Testing Your Turf