G-Max is important to consider when installing an athletic surface for athletes.

A field’s level of shock absorbency is tested by using a unit of measurement called the g-max, where one “g” represents a single unit of gravity. The peak acceleration reached upon impact of two objects, such a football player and the synthetic turf surface, is the maximum number of g’s a field is able to absorb.

A field with a higher g-max level loses its ability to absorb the force — and places more impact on the athlete during a collision, while a surface with a lower g-max absorbs more force, lessening the impact to the athlete. Using ASTM F1936 test method, g-max readings shall not exceed 200 at each test point. With proper maintenance, a synthetic turf field should have a g-max of well below 200. The g-max guideline in the STC’s Guidelines for Synthetic Turf Performance is “below 165” for the life of the synthetic turf field.