Earlier quoted context omitted.
That sounds like r/imsosmart ... a simple low pass filter would be sufficient to negate the effects you talk about
Have you used a helmet before? They don't track the heads movement very well. It's not that they lag behind or anything, they just move in completely different directions willy nilly. Even tight ones will have much sharper acceleration changes as they bounce around. I regularly wear a full face helmet with tight fitment and straps and it is moving way more than my head is. Is that notsosmart enough?
Yes it does correlate directly, as in, a high acceleration will correspond to a high acceleration (maybe lower intensity, maybe low-passed in frequency) but it is a direct correlation
Yes it would be better to measure internal accelerations, but I wouldn't feel comfortable wearing a helmet that's being subject to 80G's