Function
Meaning better coordination, balance and body performance. As improving the athletic abilities. No offense to some BB'ers, but, truth be told, some seem to have a hard time chewing gum and walking at the same time. Always room for improvement there. because the body is relearning those different performance functions.
Function can include better stamina (strength & endurance) through a good lifting program also.
I've always been into heavy lifting (racks, partial's,lockouts, rest/pause, etc), but do cycle training programs into thing like general BB'ing. A personal favorite for me is GVT (10X10's). Any programs will last me from 8 to10-12 weeks, in most cases. Than a week or two of rest and back to a different program all together. Extra insurance that the joints stay healthy. My larger bone structure is designed for lifting heavy things.
I've never had any serious joint or muscle related problems from lifting heavy. I have had a serious injury through football, requiring major spinal surgery while in college. Learned to respect my lower back more and have geared training programs to returning it to being stronger than ever.
Good Luck.