ACSM states that one set of 12-15 reps per major muscle group is efficient to meet most basic fitness goals. So my thoughts are that this much volume really isn’t imposing much demand for the body to really adapt, especially if the weight isn’t increased periodically. There is another question here too, is this much volume for single or multi-joint exercises? I would be concerned about overuse injuries for single joint exercises more than multi-joint. I believe this to be the case because of the synergistics of multi-joint movements, plus, I have a few half and full marathon runners who are in there late 60s and early 70s and never suffer from overuse injuries, and they run a lot of volume.
I agree with the comments from Martin, speed of movement could be a deciding factor on whether he is causing any demands to his energy systems. I would also be sure to approach the subject with the gentleman in a neutral way if you haven’t any rapport with him.
It is difficult to make a call without seeing the performance of the exercises. It is likely that he is neither doing harm nor improving fitness. I imagine there is some chance of repetitive stress, though that would be more likely if he were doing these movements on a daily basis. Which he may be, but we don’t have that information either.
I would want to know if he is lifting to VMA/failure. If he was moving quickly or slowly, controlled or not controlled, ROM used, overall mechanics both postural and in the movement, and possibly mental aspects like OCD, TBI, psychological issues, etc.
Does he appear to be in pain at any time? Have you observed him during non exercise movement?
I would be hesitant to approach a person in this type of situation without a bit more to go on. And if I were thinking about bring this up, I would invest quite a bit of time and effort to become acquainted with the person. I would want to know them better and begin establishing rapport to lay the ground work for any type of intervention into their routine. Often, just in the natural course of connecting with patrons and attempting to show that I am approachable, patrons will bring up the subject of what I think of their routines.
If do decide to become involved, be prepared to back off if the person appears to become defensive. You won’t do anyone any good if you press them and they judge you to be critical or too pushy.
It may depend on a few different factors, but I think 6 sets of
40-50 reps could be setting the person up for overuse–given his age and any orthopedic issues he may have. It also depends on how many days a week he is doing this. One question to ask and think about is what benefit is he getting with that many reps? With my older clients I generally use a rep range of about 20 max (of course it depends on many factors related to each individual).
Here are some good guidelines from ACSM on resistance training and the older adult:
Hope this helps you.