Just days after his life was changed forever by an illegal hockey check from behind, high school sophomore Jack Jablonski lay paralyzed in a hospital bed determined to see the sport become safer.

Seven years later, his mission — one shared by his family and hockey leadership in Minnesota — has yielded dramatic results.

A Star Tribune review of high school penalty data from more than 18,000 games played throughout Minnesota over nine seasons reveals a significant drop in calls for checking from behind and boarding infractions. During the 2011-12 season when Jablonski was hurt, penalties were called for those types of hits almost 1,600 times, approaching one every game. Last season the number fell to less than 500 overall, a rate of about one every four games.

"I believe the game has changed and that it is a safer game," said Craig Perry, a Minnesota State High School League associate director who oversees hockey.

Jablonski's high school coach, Ken Pauly of Benilde-St. Margaret's, isn't ready to declare victory. He said he sees "a couple of dangerous hits every night" and pointed to the possibility of officials being more reluctant to call the more serious penalties because of their ability to sway the outcome of games.

Jablonski, now a student at the University of Southern California and an intern with the NHL's Los Angeles Kings, said, "It's good to see the numbers are down. Physicality is not something you want to take away from the game but you want to teach players how to be physical and, most important, to be safe."

When Jablonski was checked headfirst into the boards during a junior varsity game on Dec. 30, 2011, he symbolized every hockey parent's worst fears realized. The hit also reflected what Jablonski's parents and others described as a permissive hockey culture that had allowed dangerous levels of contact to persist.

Barely two weeks later, moving with uncommon speed, the high school league elevated two-minute minor penalties for checking from behind, boarding and contact to the head to five-minute majors. That meant offending players remained out of action regardless of how many power-play goals the opposition scored.

The midseason rule changes and the emotional response in the immediate aftermath of Jablonski's injury caused a spike in penalties for checking from behind and boarding, to nearly 800 instances for each that season. Those dangerous hits were increasing even before Jablonski's injury.

Data in recent years showing fewer calls for checking from behind and boarding reflect what on-ice officials believe are players, through years of increased emphasis by coaches, being less reckless and more respectful toward opponents. The behavioral shift is especially notable along the boards.

"When you look at the numbers and also when you watch games and talk to coaches," Perry said, "there's an agreement that we've seen a change."

But Pauly said he still "kind of jumps even now" when he sees a big hit.

"I still see enough to question, 'Is the game safer' or 'Have we moved on?' " he said.

Leaders of some officials' associations acknowledged Pauly's two primary concerns. One is that fewer checking from behind and boarding penalties could mean officials are simply calling them less often. Another is that calling two-minute penalties for cross-checking or roughing are ways for officials to avoid the ire of any coach, player or fan who doesn't want their team down a player for five full minutes.

"I'm sure there is an official or two out there afraid to pull the trigger," said C.J. Beaurline, St. Paul Hockey Officials Association president and past member of the national high school ice hockey rules committee. "We tell them, 'We can defend your call but we can't defend your non-calls or a lesser call.' "

Courage to make calls

An e-mail from the high school league to officials' associations on Jan. 16, 2012, the first day of games played under the stiffer penalty structure, stated, "If you have officials who refuse to comply, remove them from future assignments and replace with officials who are willing to enforce the rules as instructed."

Pressure on officials ebbed about a year later as the league allowed for discretion on whether contact to the head was indirect (minor) or direct (major). In addition, an automatic ejection was no longer assessed for checking from behind.

"I think then we arrived at an equilibrium everyone felt comfortable with," said Dan Walt, the Suburban Hockey Referees Association's director of officiating. "Officials have the tools to judge the degree of a penalty."

After 2½ seasons of tracking penalty data showed the numbers of dangerous penalties declining, the Minnesota State High School League sought to make its experimental model the nationwide standard. The National Federation of State High School Associations rules committee voted in favor beginning with the 2014-15 season.

Still, some officials either don't blow the whistle or they assign a minor penalty.

Minor penalties for cross-checking and roughing, supposed "out calls" for officials, are called more frequently than major penalties. Roughing penalties, after rising slightly for two seasons after Jablonski was hurt, have declined since. Cross-checking penalties have stayed relatively unchanged over the past nine seasons.

Only reviewing film of each call would determine whether officials should have called a major penalty. Bill Kronschnabel, longtime high school league director of officials, said he receives about 10 videos to review each season and the results are 50-50 whether a major penalty was warranted.

An example of Minnesota high school hockey's changed culture played out before three key members of its leadership bodies this season.

Moorhead opened its season Nov. 24 at Andover, and during overtime, a Moorhead player skated hard into the corner for the puck and checked an Andover player from behind.

Beaurline, one of the on-ice officials, said he had a clear view of the hit. He immediately raised his hand to signal a penalty and looked to see his partner doing likewise.

Perry, an Andover resident watching from the stands, quickly surveyed both officials and felt encouraged by their unanimous action.

Moorhead coach Jon Ammerman wondered whether the Andover player turned into the check. But he didn't protest when Beaurline, aware of the timing of the call, skated over and told Ammerman, "I have no choice."

"The blame has shifted to the checker, and rightfully so," said Ammerman, president of the Minnesota Hockey Coaches Association (MHCA).

Andover scored later on its five-minute power play and won the game.

Beaurline said he and the Moorhead player had "a respectful" postgame conversation and that the player "knew he had a responsibility in that situation."

Mike MacMillan, MHCA executive director, said, "Jon's comment says a lot about where the sport is today versus seven, eight years ago."

Penalties for checking from behind and boarding have been called 500 to 600 times the past three seasons. Kronschnabel called that "an acceptable standard" for a fast-paced, emotional and physical sport played by teenagers.

Staying there or lowering numbers, Kronschnabel said, is "a continual effort."

"We can't sit on our laurels and say we did what we set out to do," he said. "We're never going to take the danger out of the game, but we want to keep these numbers from sliding up."