At the very best, they can achieve equal results in cardiovascular scores, such as those I've mentioned. However, in overall relevant elements of fitness, they should be at a disadvantage in agility, flexibility and potentially strength and power due to loss in flexibility and the possibility of injury. So overall, there is no advantage at all to being an older tennis player, physically speaking.
Regarding Murray, that's generally what happens when one gains muscle mass and loses fat. I've seen it happen 1000 times.
Right, and that disadvantage is being lessened as athletes are finding more and more ways to prolong their physical peaks, recover from serious injuries, etc etc. My point is that advantage younger players used to have isn't as big anymore.
As for Murray, well you may well be right lol. I do agree with you that the younger generation could work a lot harder.