get your @$$ into the gym!

yeah you're getting old but it's prolly because you're allowing yourself to.[8D]
Powerlifters don't even start hitting their peak until their late 30s and they're putting 800 pounds over their heads! I think with a little workout now and then you can manage 60 or 70!
In all seriousness, go see a doctor, get yourself checked out (make sure your ticker is good, your bp is normal, cholesterol, etc. ) and start an exersize regimen. You'll be amazed at how much just a few hours of exersize a week (jog a mile three days a week, pull ups, pushups, dumbbell curls or better yet join a gym.) will make a difference in your injury rate.