Why are NFL players wearing padding on helmets at training camp?

Bengals linemen, linebackers and tight ends wore Guardian Caps at training camp after the NFL required the padding for some position players this preseason.

Photos: Why the Chicago Bears wear padded helmets – Chicago Tribune

Why are NFL players wearing padding on helmets at training camp

Guardian Caps NFL: What player positions are required to wear them?

What in the world are those weird-looking helmets the Saints are wearing in camp?, Rod Walker

Why are NFL players wearing padding on helmets at training camp

NFL training camps: Guardian Cap players are wearing over helmets, why

Guardian Cap Debuts at Training Camps League-wide

NFL introduces Guardian Caps across league to limit number of brain injuries in preseason

Cowboys seen wearing protective, NFL mandated Guardian Caps at

Ravens Embrace the Funny-Looking Guardian Helmets - Sports Illustrated Baltimore Ravens News, Analysis and More

What are those funny-looking soft caps on NFL helmets during camp?, Sports

NFL hopes to reduce head injuries with helmet experiment

Cowboys seen wearing protective, NFL mandated Guardian Caps at

What are those caps football players are wearing?

Is the extra white padding on their helmets for practice a new safety precaution this year? I don't recall seeing these previous years. : r/GreenBayPackers