CrossFit Arlington Heights to Host Level 1 Certification Clinic Posted on May 13, 2010May 13, 2010 by admin It's Official! We're hosting a Level 1 CrossFit Trainer Certification Clinic the weekend of July 24th & 25th. You can register through the CrossFit main site (www.crossfit.com). Anyone interested better hurry up, this one will sell out soon! Posted in Arlington Heights WOD, Uncategorized.