UNDATED (WKZO) -- High School classes will not start until after Labor Day, but football practice begins this week with two-a-days.
Coaches in Michigan have new rules to follow to protect student athletes from concussions and from heat exhaustion.
John Johnson with the Michigan High School Athletic Association says there are new limits on practice times, on how long each session can last and limits on collision drills.
They also want coaches to know how to teach athletes to correctly tackle, block, take a block and get tackled so they can avoid injuries.
Single practice sessions are limited to three hours and there can only be one collision practice a day.
Students will not be permitted to begin practice in full gear until Friday.
Once the season starts, collision drills will be limited to two per week.
41-thousand Michigan High School athletes are expected to participate in football programs this year in Michigan, but that number has been declining, because of parental concerns over safety.