This is mainly for guys, because women generally lack the upper body power for unassisted pull-ups and chin-ups. Guys under age 30 can usually do at least ten, and fit guys can do more with varied grip widths.
Guys over 40, regardless of weight issues, commonly have more trouble due to muscle disuse and decay. The US military considers 20 pull-ups or chin-ups to be a perfect score for that exercise. Few Generals can do that, but I bet Mattis can.
Like all of the Big Functional Exercises, a pull-up stresses many muscle groups. Pull-ups stress upper-body muscles from hands to abs, but the greatest stress is on back muscles - the lats.
To do a pull-up correctly, you do not focus on using your arms but you focus on driving your elbows down. It's not primarily a biceps exercise except secondarily.
To work towards doing some pull-ups if you can't, here's how:
- work on raising the weights on seated pull-downs
- jumping pull-ups
- pull-ups with those rubber bands
and perhaps most important, Hangs. If you can't hang on, you can't pull yourself up. To work on hanging, you hop up to the bar with an overhand or underhand grip with your elbows down at your sides or as close to that as possible. Suspend yourself as long as you can. Your muscles will slowly (or quickly) give way, but keep suspended as they collapse.
One or two sets of three of those weekly will help you move forward towards the goal of doing just one lousy pull-up with chin above the bar. I do three sets of hangs/wk and three sets of either jumpers or band-assisted weekly. If I can get to 10 pull-ups again, I will be proud of my achievement but I doubt that I will get there. When I was young I could do 15 or more.
