I was never able to do a single pull-up as a child. I could even do a chin-up (the variation which has the palms facing me, so that I could use more of my bicep muscles). I didn't have a very active childhood. It's a miracle I wasn't as overweight as I could have been from all the exercise that I missed out on.
I did my first pull-up as an adult after discovering the weight-assisted pull-up machine at my university gym. I started using it at a weight of around 80lbs, so that the machine would allow me to do pull-ups as if my body weighed 80lbs. lighter than it actually was. I gradually lowered the assistance weight as I progressed. After several months of use, I was able to do a pull-up with no weight assistance at all.
My previous best was 4 consecutive pull-ups. After I achieved that, I didn't practice pull-ups as much, especially after I moved into an apartment where my door pull-up bar would not fit into any of the doorways.
About 6 months ago, I finally began regular pull-up practice - minimum of 3 sets per session, 2-3 sessions a week. My max pull-up reps had decreased to 3, with the 3rd requiring noticeably more effort than the first two. It didn't help that I'd injured my shoulder twice. After a couple of months, I started doing 5 sets of at least 3 reps per session. After a few weeks of this, I was able to do 4 reps/set for some sets.
About a month ago, I'd progressed to doing 5 reps/set. And today, I did a set of 6 pull-ups for the first time in my life. My shoulder seems to be holding up. It's not pain-free all the time, but that's because it's a little "loose". I'm confident it will stabilize over time as I increase my strength.
I wasn't doing just pull-ups. I've actually been following a program called "Intro to Ring Training for Beginners". You can get this free program by visiting this page at the Gold Medal Bodies site and scrolling all the way to the bottom. It comes with a PDF and video. It could be that the Baby Muscle-Up and other exercises in the program also contributed to my improved pull-up strength.
