The Perfect Pull-Up
Whether you want to view pull-ups as weight-lfting or as a calisthenic, it is a strength-builder for the entire upper body. The problem is that many middle-aged people have trouble doing reps without assistance. Does assistance really help over time?
A couple of years ago we had a one-month push-up challenge, and it worked for those who kept with it daily. The goal was 100 push-ups/day by the end of the month (not 100 at once, but 100 daily). Turned out that it was quite do-able with good results even for push-up beginners - and for women. Their reps got longer, and their muscles got tougher.
There are a couple of women I see in the gym doing 20 pull-up reps. They look fit, but neither muscular nor skinny.
A 60-day 100 pull-up challenge might work too, but I do not know how to begin it for those who cannot do a single one.