Vox Day nails the depressing realities of athletic decline in middle age:
This report doesn't surprise me in the slightest. One of the things I have learned about playing soccer and 3D shooters after the age of 40 is how comprehensive the physical decline is. Since most people don't compete directly with younger athletes after the age of 35 or so, it can be difficult to believe how much speed and quickness one loses. I can't imagine that there isn't a similar deterioration taking place elsewhere as well.
It is not only the top gear that is gone, but there is a also the complete absence of a first step; it's almost as if the first thing the middle-aged mind does is instead of react is to perform a quick calculation of whether or not it's likely going to be worth it to go through with the physical exertion required. One feels as if one is always going at about three-quarters speed, trying to harbor a reserve for when a complete effort will be required in order to make a difference.
I think that most people who continue to play competitive sports begin to notice this in their thirties, but it becomes more apparent once you get past your fourth decade on earth. The other thing that I've observed from playing hockey over the years is that the number of times you can really get "in the zone" and perform at a high level without really being conscious of what you're doing are fewer and farther between once you hit middle age. How you manage to arrive at that zoned state in the first place is a bit of mystery (if you could bottle that feeling you'd be a gazillionaire), but I would imagine that the reason it becomes rarer as you age is a combination of diminished physical abilities and less capability to focus as sharply mentally.