Every once in a while when doing a max 15-30 second sprint towards the end of an hour of power ride I get this in my right ear. It feels and sounds like when your ear is filled with water. Never had it happen in a race which is strange. I googled and from what I can gather may be caused by holding your breath when straining. A small air bubble is the culprit.
Anyone else? Insight? It usually resolves itself with in an hour after the sprint.