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.

Guardian cap' to prevent head injuries mandated for practices, CFL says

What are those caps football players are wearing?

What are those helmet pads Chicago Bears offensive linemen have been wearing at practices? – Chicago Tribune

The story behind those soft-shell puffy Guardian Caps players have been wearing

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

NFL expands use of helmet caps The Arkansas Democrat-Gazette - Arkansas' Best News Source

Guardian Caps Guardian Sports

Carolina Panthers NFL helmets training camp

Cowboys seen wearing protective, NFL mandated Guardian Caps at