At the upper age levels, keep your lower reps limited to exercises that utilize the stronger joints.
Not the knees, not the low back, and defintely not the shoulder joints.
If you have been training steadily for years, and making every attempt to track your progress, there shouldn't be any reason that you can't use lower reps as you are pyramiding sets (in weight)--your body will have become accustomed to this and you will probably learned impeccable form.
To all of the sudden, out of nowhere, decide that you will switch to low reps with heavier weight-- after having trained more exclusively in a higher rep range with moderately heavy weights, you are just asking for problems.
Talk to bodybuilders who have been doing this for a long time. See what they have to say about lower reps (heavier weights?) and joint pain.
Most of them, if they could do it all over again, would now choose (from their past experiences) higher reps with moderately heavy weight. The pain of a damaged joint doesn't usually subside with time. It usually becomes worse with age, and limits range and mobility... oh yeah, and comfort.
I would rather live a long comfortable life without the joint pain. After a lifetime of abuse, our bodies manifest their past usage-- usually in the form of pain.
we gotta stay in this game for the long run. Right?
