This football player from the 1920s hardly looks fired up for the gridiron. Could it be he realizes his soft leather helmet is better suited for keeping his noggin’ warm than protecting it?

Given what we now know about football and concussions — players get hurt even during practice — it's hard to believe it took so long for helmets to evolve from glorified caps-with-earflaps to the modern headgear players are required to wear today. For example, even though the first plastic football helmet was invented in 1939, the National Football League (NFL) didn’t require players to wear helmets of any type until 1943. It took another six years for the NFL to adopt plastic helmets.

The next few decades brought face masks, protective visors and air bladders inside helmets to soften blows. Perhaps the coolest helmet technology advance came in 2011: a chin strap with a light-emitting diode that changes color to reflect how hard a player was hit, allowing medical experts to identify concussions sooner.

Related: Should You Let Your Son Play Football?

Angela is a Pulitzer Prize-winning digital editor with more than 15 years of experience delivering news and information to audiences worldwide. Prior to joining SafeBee, she was the features editor for at The Boston Globe, overseeing health, travel, entertainment, business and lifestyle coverage. Before moving to features, she was the news and homepage editor, covering stories such as the Boston Marathon bombing, Red Sox World Series victories, presidential elections, a papal inauguration, and more. Her favorite safety tip: Clean your phone! The average cell phone has 18 times more germs than the toilet handle in a men’s restroom.