BOSTON – North Shore sports fans would have recognized many of the former professional athletes who gathered at the State House on Tuesday, from ex-New England Patriot Ted Johnson to boxing legend Micky Ward. Yet the cause that brought them together was related to high school sports: to urge passage of a bill aimed at minimizing the effects of concussions on high school players in Massachusetts.”Our society tells us athletes are warriors,” said State Sen. Steven A. Baddour of Methuen, a sponsor of the bill who spoke at Tuesday’s conference. “But there’s no way to shake off a brain injury. Young athletes especially need time to heal.”Senate Bill 796 impacts all schools subject to the rules of the Massachusetts Interscholastic Athletic Association. The bill would increase awareness of concussions through training for school personnel and students, written information provided to student-athletes, and documentation of student-athletes’ history of head injuries.It would also set guidelines for when players can return from a concussion: Players who suffer from one cannot return the same day, and a player who suffers a concussion needs medical clearance before playing again.Those who spoke on Tuesday described the effects of concussions as potentially lasting and lethal.”After a concussion, the brain needs days, weeks, months to recover,” said Chris Nowinski, a former Harvard football player and World Wrestling Entertainment star who now heads the Waltham-based Sports Legacy Institute, an advocacy group combating the effects of brain trauma. Nowinski added that a further danger from concussions is second-impact syndrome, which leads to death.Repeated concussions may also cause a brain injury called chronic traumatic encephalopathy (CTE), or punch-drunk syndrome, said Dr. Robert Stern, co-director of BU’s Center for the Study of Traumatic Encephalopathy.”Symptoms don’t begin until years or decades after they’ve stopped (playing),” Dr. Stern said, listing such symptoms as depression, behavior change and dementia. “It’s the only fully preventable cause of dementia.”The Center for Disease Control estimated that 1.6 to 3.8 million concussions occur in youth sports and recreational activities each year. In Massachusetts, about one in five high school students suffered a concussion last year.In a phone interview on Tuesday night, Swampscott High football coach Steve Dembowski discussed the measures that his program has taken against concussions.”We use top-of-the-line Riddell helmets, they’re conditioned every year, and the kids wear mouthpieces to help that part of it,” he said. “Even though it’s a contact sport, we try to limit the speed of contact in practice.”Dembowski said that the football program sees about one concussion per season, one every 15 games.”We’ve definitely addressed it,” he said. “We’re well aware of it ? It’s the trainer’s call and the family’s personal decision.”Asked why the State Senate bill focused on high school sports, Nowinski said, “The number of people and groups involved were part of the reason. High schools were chosen because the MIAA had oversight ? It was a mechanism we could use to enforce.”Similar legislation has passed in Washington, Oregon, Virginia and New Mexico, and bills are pending in 15 states. Sen. Baddour said he hopes to get Senate Bill 796 to Gov. Deval Patrick before the end of July.The SLI has studied the effects of brain injuries by examining the brains of 15 deceased college and former pro football players. Boston-area sports fans can see evidence of the dangers of concussions in Bruins stars such as Patrice Bergeron and Marc Savard. They also have the testimony of former players like Johnson of the Patriots.”I can still put a sentence together,” Johnson said. “I’m not quite dead yet.”The 10-year Patriots player said he sustained his initial concussion in the summer of 2002 and practiced three days afterward. He played three more years. He described suffering from aggression, sleep depr