A reader comment to Sunday's article on the impact of Minnesota's youth sports concussion law did a fair job of summarizing the potential downside of the law.

The comment is inaccurate in some respects, because the new law wouldn't have had any direct bearing on this situation. The Minnesota State High School League had already adopted strict guidelines on when to remove potentially concussed athletes from play. One provision is that "no athlete should Return to Play (RTP) or practice on the same day of a concussion." It's also important to clarify that concussions don't require blows to the head. A hit to the midsection could cause an athlete's head to whiplash so violently that the brain would bump against the inner surface of the skull.

But the philosophical point this coach made is an important one: Once you set zero tolerance policies on anything, there are bound to be cases in which people are mistakenly penalized by them. The state's youth sports concussion law certainly did swing the pendulum toward caution and safety. It wouldn't surprise me at all to hear tales from other frustrated coaches who lost players at crucial moments in games or tournaments due to questionable injuries.

Of course, a major reason for these laws and policies is to remove the return-to-play decision from the coaches and the athletes themselves who have at least some incentives to rush back to into games before they are healthy. Sports parent Beth Wynne -- whose daughter, Shannon, was featured in Sunday's story -- said her older twin boys suffered concussions in hockey, and Shannon suffered a concussion in soccer last fall that left her recovering at home for more than a month. In each instance, her children tried to downplay their injuries.

"All three kids minimized everything, as kids will do," she said, "because they want to play."

The majority of states now have youths sports concussion laws in place. Minnesota will play a key role in assessing the pro and con impact of these laws. Dr. Leslie Seymour, an epidemiologist for the Minnesota Department of Health's Injury and Violence Prevention Unit, has received a five-year federal grant to study their impact.

Seymour has already gathered some interesting figures on young athletes treated in Minnesota ERs or admitted to hospitals due to sports concussions. The number appears to be rising faster among boys than girls, and also among younger athletes (10-14) than older athletes (15-19). Concussions are rising in competitive sports, even as they are tapering off among children in recreational activities such as bicycling. It remains unclear whether the increasing speed and violence of youth sports is resulting in more injuries, or whether more injuries are being recognized now than they were in the past.

Seymour has also assembled data on spinal cord injuries in athletes such as Jack Jablonski, the Benilde-St. Margaret's hockey player who was paralyzed after being checked into the boards earlier this year. She found 117 spinal cord injuries suffered by athletes in Minnesota between 1993 and 2011. The annual number hasn't changed much. Two-thirds involved athletes 19 and younger. Most occurred in football (35) followed by hockey (21), wrestling (20) and skiing (19). The lone fatality among athletes who suffered spinal cord injuries involved a diver, according to her state data.