[eointierney]

Helmets have an interesting correlation with concussion. They can help a lot in cycling, hurling, and f1, but can encourage reckless collision seeking in american football for example. Contact sports are intrinsically dangerous and introducing protection from one type of damage can allow increase in other damage forms.

Avoid collisions

I reckon rugby must change the most, which is a real shame because rugby at the highest level is amazing

Though ice hockey is pretty daft