Usually, when you hear the phrase “The Big Bang Theory,” you think of a popular sitcom in its last season (No. 12), or an explanation for the origins of our universe.

But closer to home, and more important to your kids' daily life, the Big Bang Theory describes what happens to a young brain when there's violent contact between two athletes, or between any immovable object (a field or goal post) and a kid's head.

Did you know that the majority of people playing football in this country are 14 or younger?

Or that prior to a new report from Virginia Tech's Helmet Lab, no one evaluated sports helmets for effectiveness in protecting young football players from injury and concussion?

Well, thanks to their researchers, we now have that information.

Steve Rowson, the lab's director, explains: “Kids aren't just scaled-down adults. Their heads are larger relative to their necks; their necks are weaker; and their brains are still developing.”

That means a young player's head and brain might react to a hit inside a helmet differently than an adult's, which in turn influences a younger player's risk of having a concussion or other head injury.

To evaluate helmet quality, each model went through 48 tests covering impact areas and velocities using test dummies of 10-to-12-year-old boys. Five helmets earned five-star ratings. You can view the complete results http://helmet.beam.vt.edu.

The site also offers ratings for adult football, hockey, biking, and soccer helmets.