Shore Hardness is used as a measure of hardness in polymers, elastomers and rubbers. For use in Martial Arts and playgrounds for children, it is recommended to use between 50 to 55 degree Shore A flooring. If the mats are <50, they will be too soft and not durable in the long term (the logs are more likely to break apart). If the mats are >55, they are too firm, reducing impact absorption and increasing the likelihood of injury.
That's why we choose SMAI Mats, which are 50 degrees Shore A.