What you are talking about is likely a 'sub-concussive impact.' This is when the impact does not cause any immediate concussion symptoms but may lead to later symptoms or be part of an accumulation of sub-concussive impacts that causes full blown Post Concussion Syndrome.

There are many on this forum who have difficulty with sub-concussive impacts. I can not tolerate something as simple as shaking my head "No."

The medical industry is just starting to understand that there is very little direct correlation between impact forces and concussion symptoms. The symptoms from shaking or G forces to the brain is a very individual issue. Some brains are more sensitive than others, especially after a previous concussion that caused serious symptoms.

Remember, with concussion, it is the symptoms that matter, not the level of force during the impact or non-impact. If concussion symptoms result form the event, then you treat those symptoms as resulting from a concussion.

Hope this is understandable.

My best to you.