PORTSMOUTH, Va. (WAVY) — Virginia Tech researchers have released new safety rating for youth helmets based on their studies of head impacts. 

Seven models earned the highest rating of five stars and the rest earned three or four. 

Each helmet went through 48 tests on dummies, covering four impact locations and three speeds. 

Lower-rated helmets tended to have front pads that were too stiff. 

To see the complete ratings for youth football helmets and other sports, go to vt.edu/helmet