system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: What makes rugby safer, as not needing protective gears, compared to American football?

I've seen some brutal tackles in rugby, and it makes me wonder how the "health and safety department" never imposed obligatory helmet or something.
gpt
* Football is played in 10 second bursts, which allows players to expend energy at a very high levels, then recover.  A rugby player who tried that would be on the ground gasping in minutes.

* Rugby forbids blocking, which removes a lot of the contact from the game.

* Football has deep passes and returns from set formations, that have players running full speed in different directions.  Rugby has a flow where everyone is going to be running in about the same direction.

* Rugby is more of an endurance activity, which requires lighter, less muscular bodies less capable of delivering injuring blows.

* The absence of pads favors a grabbing technique over a hitting technique when tackling.