A quick Googling of that suggests otherwise:

https://www.irishtimes.com/news/ireland/irish-news/one-seaso...

Aussie Rules has nowhere near as much contact as gridiron, and the kind of contact it has is rarely as full-on as in gridiron. There's no real contact in aussie rules if you're not on the ball, whereas every play in gridiron, more than half the players are slamming into each other, regardless of what's happening.

Most of the contact in aussie rules is tackling from behind, whereas in gridiron on every play you have around nine guys smashing into each other just as the quarterback receives the ball... and then all the additional contact depending on the play, including tackling like in aussie rules.

Here's a bit where they measured the force of rugby -vs- football tackles. Football is 3 times harder.

https://www.youtube.com/watch?v=W7tGY-VDx3o

Don't have much commentary on the subject and just wanted to share the vid. I'd only think that a difference like that can't really be resolved to padding.

It's a pretty unfair comparison, though I'd expect it's largely representative.

A rugby union player has to run around the pitch for 2 bouts of 40 minutes [about 40 minutes of 'ball in play' time]. According to this article - https://qz.com/150577/an-average-nfl-game-more-than-100-comm... - the average NFL match is 11 minutes of action, in [average] 4s bursts, over a 3+ hour period. Many NFL positions can optimise for muscle mass without worrying about stamina and sustained speed.

FWIW the measured tackle and at least one footage tackle [8mins 26s] in your linked video - https://youtu.be/TSc_Gxq1two - look illegal to me, lifting a player and pushing them down with head/shoulders first towards the ground (spearing, https://en.wikipedia.org/wiki/Spear_tackle) is a red-card offence.

> Many NFL positions can optimise for muscle mass without worrying about stamina and sustained speed.

Not just mass. What I often hear NFL athletes and trainers talk about maximizing "explosion" in their movements.

I'd say this is not true. The doctor from the movie "Concussion" said that Rugby, most martial arts, and lacrosse are all sports that need massive modification for those under 18. Adults can make their own decisions, he said, but these sports are demonstrably bad for brain-safety.

Rubgy has much less contact than american football. You can't just tackle people without the ball.

You're also not allowed to tackle a player without the ball in American football. You're allowed to block, but when two players come together, especially at the snap, it can be a violent collision.

Here in Melbourne there was a news article recently about some AFL players who got high on drugs and alcohol and set a dwarf alight.

It may be harder to detect chronic brain trauma in that population.

For some context, here is an article from the aftermath of that incident: https://www.theguardian.com/sport/2013/sep/03/afl-st-kilda-d...