I can understand that how the fingers hit the bottom (as far as the keys move down) can very well lead to hand or finger injuries. Also, if the GHS action is very light, the fingers hit the bottom with more force, than in the case of a heavier action digital piano. That plus the repetition factor, can result in injuries, like beating the fingers many times.
Maybe the best digitals are the ones with the weight of the keys gradually increasing, the further the note is pushed down, so the "bottoming down" becomes softer for the fingers? I assume such pianos are way above the price range of the P115.
From what I remember, it is getting a bit vague now, and been back around 6 month ago to have had a quick tickle of some different ivories in the shop while picking up some sheets. The Casio keybed bottoming out is on the softer side compared to others I tried, like CN 24, some yamahas. While Casio action is fairly light I gather, it does hit the bottom in a sort of springy
way, if that's the right way of putting it. I actually thought this was a good thing to reduce impact for me, it felt kinder to me. Anyway to me it feels good, since it is not like as if you are hitting a hard wall quite suddenly, which I felt was more the case with some others.
I don't know, such traits may or may not help the OP, not being an expert on piano actions or playing or piano injuries, just to point out I did notice it back then, and also the very first time when selecting a piano a year ago trying some different models.
TheodorN, are you referring to escapement, or that notch feeling by any chance ? Casio doesn't have that feature AFAIK, but neither do the cheaper lower and yamahas mentioned here I think. Not sure if that would help one way or another with injury ?, but more the fact that it eases transition between a real grand action and a digital action to feel more natural with escapement ? some others may be able to comment further. I haven't got a clue about that sort of thing, ready to hear the views and learn