Taekwondo training when you're 60+

A couple of weeks ago I received an email from an old friend -- in other words, a friend who is actually as old as I am.  He's a 68-year-old runner, and I'm a 68-year-old Taekwondo competitor.  Despite the obvious differences between the two sports, my friend wanted my thoughts on "Training for Oldsters."
   My advice, in a word, was MODERATION.  Although our brains can sometimes trick us into believing we're 25, our bodies can't be fooled.  So if we attempt to train as though we're 40 years younger, we'll most likely end up at the local physical therapy clinic . . . or maybe even in the ER.
In my friend's case, he's thinking about broadening his running experience by becoming a sprinter as well as a distance man.  Hmm.  Does a 68-year-old body really want or need sprinting?  Well, I suppose if you've been a sprinter since high school, perhaps your muscles and tendons can handle the stresses that sprinting will put on them.  But if you're setting out to become a sprinter for the first time, I hope you're 18 rather than 68.
   My friend also wondered how often I train.  Answer: seven days a week.  MODERATELY.  Three of those days are maybe what I'd call "moderate +" because they incorporate my usual workout as well as weight training.  But the other days are simply "moderate."  I spend 30-40 minutes warming up, another 15 or so stretching gently, a half hour or more practicing my Taekwondo poomsae [or forms], and a final 15 stretching.  The best stretching comes at the end of the workout, of course, because that's when the old body is really warmed up.
   Now you might be wondering what I mean by "moderate."  Well, it's impossible to get overly scientific about the definition, since you and I are different in countless ways.  Our ages are different; our experience levels are different; and our training histories are different.  Oh, and our bodies are different.  I generally keep my weight around 145, which feels just about right for competition.  But if you weigh 180 or 220, any specific advice I can offer you goes right out the window.
   That said, I can offer some general guidelines that seem to work well for me.  I'll let you -- or you and your doctor -- decide whether these markers make sense for you.
   Weight training.  I don't belong to one of those mega-gyms where serious body builders pump as much iron as they can.  I tried that once and found myself getting caught up in the competitive spirit that pervades these testosterone havens.  The result: injury.  Naturally.  You might be able to lift more weight than you should, but eventually your joints, tendons, ligaments, or muscles rebel.  So now I train in a gym located within a physical therapy clinic -- the very same clinic, in fact, where I get put back together every now and then.
   My weight-training guidelines are as follows:
      One arm dumbbell curls: 15-18% of body weight for each arm, or whatever you can lift 10-12 times using proper form.
      Triceps push-downs [on a weight machine]: 50-60% of body weight, or whatever you can do 10-12 times without struggling.  If you struggle, you end up using muscles that shouldn't be part of this exercise.
      Bench press:  40-50% of body weight, or whatever you can do 10-12 times without arching your back or dropping the bar on yourself.  I like using a bench press machine that prevents the barbell from falling on my neck.  The older I get, the more I like it.
   My primary warm-up device is a recumbent exercise bike, which I ride for 20-30 minutes at roughly 80 rpm.  Set the bike to whatever resistance level allows you to ride for at least 15 minutes without becoming exhausted.  The idea is to break a sweat, not pass out.  I like the recumbent bike because it doesn't put pressure on my lower back the way an upright bike does.  Elliptical machines are okay because they're fairly gentle on your joints, but I prefer the recumbent bike.  Stair steppers?  No way.  My lower back doesn't like stair steppers, with one exception: a machine called the Nu Step, which is essentially a seated stair stepper.  If you have access to one, by all means use it.
   Stretching: I suppose some people actually enjoy stretching, but I'm not one of them.  I stretch because my sport calls for kicking.  And if you kick hard without sufficient flexibility, you stand a good chance of pulling a hamstring muscle.  Ask me how I know.  So I stretch every day -- gently right after warming up, more intensely at the end of the workout.
   So there you have my general tips on MODERATE TRAINING.  When in doubt, do less, not more.  Build up to the targets slowly.  That way you'll stand a better chance of training without injury while making the kind of progress that anyone of any age can make.  Hey, Taekwondo isn't just for kids.   If you're a Taekwondo senior, get off the couch and go for it.