I usually do 1 set of 6-8 reps with heavy weights and increase the weight each time I go to the gym. I push to muscle failure. Sometimes, I'll have to stay with the previous weight because of stamina or whatever, but usually am back to the heavier weight the next session.

I'm a very senior gal, and have been doing this on and off since 2009, and I have osteopenia and really believe that my weight training has helped me avoid osteoporosis.

There are times though when I do like to vary my routine though with some lower weight/higher reps, but I always go back to lower reps/higher weights.