Interesting, if you like that program you should really check out project mass. Very similar concept except 3 days strength, rest, 3 days hypertrophy, rest and repeat. At first it was weird having my work out days change but you get into the rhythm

One of the reasons I can still do the weight is in large part due to my Chiropractor.

He's been able to change the way I do things so that I can continue to make gains and deal with my age.

Your pains worry me.
I crippled myself at age 23 in a plain era of stupidity. Took years to heal.
Get yourself checked out and ensure that when you're 50, the young ladies are still checking you out.

There's an interesting study going on that tracked families of weight lifters. They said it only takes a lazy generation to lose the benefits your genes have built up by being active.

They also point out that most of these people were highly active until a life changing incident. And the fact that they were active kept them alive. AND life expectancy is higher.

So keep on the health track...but know when to hit the pit stop!