Nothing's normal about the way he plays. I hope you're right tho, but historically grinders have had shorter life expectancy. We all know it takes 2-3 more shots to take a point from him, he brings back balls many others give up on. This does not come free, and he's only human.
Historically the smartest players between the ears have a long life expectancy, so Nadal's high tennis IQ will put him at an advantage over his contemporaries here.
Secondly, even if he takes longer to end points, I don't think that's a problem.I think hes smart enough to balance his off court activities well enough and keep them very light so that the overall effect on his body is no more straining than the other top guys. For example he does things like golf, fishing, swimming etc off court which are not very straining and are a good balance for the body and the mind.
Thirdly, don't forget Nadal most enjoys the competition and the challenge , so he wouldn't freak out and panic one day if his ranking down. Its much much harder to lose motivation when just competing is such a high enjoyment factor. Nadal plays doubles a bit and doesn't win nearly as much but still just enjoys the challenge, so he already knows exactly what its like to not be the best.
It will be even more satisfying when hes lower ranked and not a favorite some day and end up winning a Grand Slam final. Nadal doesn't mind being the underdog so it won't faze him if hes not the king. It wouldn't surprise me if Nadal decided to become a Verdasco type player when he became older and didn't want to run so much. Now I think he gets a lot of pleasure in making the opponents suffer, testing the opponent physically, and also making them play his style of tennis.
