As expressions of support for injured hockey player Jack Jablonski continued to build Tuesday, the Minnesota State High School League urged hockey players, coaches and officials to eliminate checking from behind.

The league issued a memo in the wake of a paralyzing injury to Benilde-St. Margaret's sophomore Jack Jablonski during a JV game Friday in St. Louis Park. Jablonski was checked headfirst into the boards, sustaining what his doctor has called "a very serious spinal cord injury."

MSHSL director of information Howard Voigt sent a copy of the memo to media outlets.

"This situation reminds all of us in the hockey community to renew our efforts to emphasize the elimination of hitting from behind in hockey and to emphasize proper contact techniques," the note read.

It urged coaches to remind players during practice to eliminate checking from behind and emphasize proper checking and contact technique during practices. Players should be made similarly aware during games, the league said. Coaches were told to "be grateful when officials enforce the rules" that make the game safer.

The league advised game officials to "not hesitate to make the call" when they see checking from behind. They also were told to emphasize appropriate contact and checking when talking to captains and coaches.

Players were urged to "keep it clean and hit the brakes when you see the numbers on the back of the jersey," the memo said, and stay away from checking from behind situations.

Jablonski has received an outpouring of support on Twitter from friends, strangers and professional athletes via the hashtag #jabs -- his nickname -- and on his CaringBridge site. He is expected to have surgery as early as Wednesday at Hennepin County Medical Center to repair two broken vertebrae in his neck.