LOS ANGELES (CBS) — The NFL makes a concerted effort to prevent serious injuries on the gridiron and, now, those concerns are trickling down to the Pop Warner League.

Starting this year, new rules are taking effect to protect younger players. They include no full-speed head-on blocking. Tackling drills cannot be more than three yards apart.

And there will be no more than 40 minutes of full-contact during practices.

Sports medicine experts say the changes will benefit kids.

Pop Warner is the first nationwide league at any level of football to restrict the amount of shots players can take to the head.