I shot this video for The Dallas Morning News about a month ago. The G-Max test is used to determine the hardness of a playing field. Anything above a score of 200 is considered unsafe. Many schools are unaware of the test though. You can read the full story about it here: http://www.dallasnews.com/sharedcontent/dws/dn/latestnews/stories/111210dnspo1ahsgmax_hp.2212c45ea.html and here: http://www.dallasnews.com/sharedcontent/dws/dn/latestnews/stories/111210dnspogmaxsider.3f90cc6.html