Conclusion: The helmets must be bigger, much bigger. I don't know their current thickness; maybe 2 cm? If we expand that to a cushioned 10-20cm all the way a

Conclusion: The helmets must be bigger, much bigger. I don't know their current thickness; maybe 2 cm? If we expand that to a cushioned 10-20cm all the way around their head, the force would be reduced by a factor of five to ten. I'd imagine they could head-butt all day long without damage, and football games would be much more entertaining.