I'm 42, with a bum knee and a temperamental back. I wasn't much of a jumper or runner even back in the day, so I'm squarely staring down some physical limitations when it comes to my martial arts hobby (some might say obsession, but lifestyle would probably be a better word since a lot of out-of-class effort is required once you hit a certain level.) I'm taking four classes a week on average right now, two each of aikido and taekwondo.
My aikido belt is white (the lowest rank) and likely to remain so for a while. I'm relatively new at that style and it doesn't come naturally to me, but I'm no quitter. For taekwondo, however, I'm staring down the barrel at the black belt test and the proverbial shit is starting to get real. Only a couple of belts between me and black now, and they won't be easy ones to earn. My goal is to get to black belt before my 45th birthday...we'll see how that goes. I've mentioned here before that I made a big fitness push about a year ago and have maintained it so far; that's been key.
In addition to all the other craziness (usually three to four hours' worth) the black belt test includes a timed running requirement; half a mile in five minutes or less. Not a big deal for most, except inasmuch as it comes early in the three or four hours, so it can't take much out of you to get it done or you'll never make it through to the end. Not to mention the fact that for nonrunners with bum knees like me, it's no triviality. I've recently been thinking that it might not be a bad idea to start some training for that so it's no big deal come a few belts from now.
Hit the track with a stopwatch today for a few sequential test runs, just for giggles.
Half a mile: four minutes flat
Half a mile: 4:06
A full mile: 9:33
Pretty damned good for me, especially three belts ahead of time. And after 90 minutes of aikido, to boot. There's real hope and that cheers me more than I can begin to express! I may be old and creaky but damned if I'm not going to give this everything I've got.