Pull-ups are one of the toughest body weight exercises a person can do. Unfortunately, most people do not have the required strength to complete a pull-up because that type of upper body pulling action is not too common in everyday life. The great thing about pull-ups is that they strengthen so many muscles in your back and core to help with not only improving the overall strength of your posterior chain, but they can improve your posture as well. Unfortunately, because they are so difficult to do, many people either give up or don't know the progressions that can help them build up the required strength over time.
When I first started trying to do pull-ups back in 2008, I could barely muster about 5 repetitions at a time. Now I am able to quite easily crank out 12+ reps on any given day, for multiple sets, and if I train for rep increases, my max reps would be somewhere in the 20's for a given set.
Here are my thoughts on how you too can progress to increase your pull-up strength. These progressions are based on my own personal experience as well as training clients. Remember that, like any strength exercise, you are not going to go from the couch to doing pull-ups overnight. You need to practice these at least once or twice a week for several weeks before your muscles begin to strengthen and improve noticeably.
Level 1 - Band pull-downs
The very first progression would be for individuals who are either just starting out or do not have a stable and secure pull-up bar installed. For this progression, you will need a solid bar, hook, or attachment that up high so that you can sit or kneel on the ground and mimic the range of motion of a pull-up by pulling down on the resistance bands. I recommend getting a selection of a few different bands, varying in tension, so that as you get stronger you can increase the tension of your bands to increase intensity.
Another option if you either do not have a high enough spot to secure your bands would be to do prone pulls. The only thing required here would be a secure place to wrap your band around and then you can lay prone (on your belly) and again, mimic the action of a pull-up. This is not the most ideal situation, but should help you build strength in the muscles that are used during a pull-up.
In both cases, either seated pull-downs or prone pulls, you can vary the distance from the band's attachment to increase the tension and intensity of the exercise. As I said, however, you should try and get at least a few different variations of bands so that you can have a variety of tensions to play around with.
When beginning, aim for 15+ repetitions per set, but try and create enough tension so that you are targeting, and struggling to complete, sets with lower repetitions. Ideally, you should get below 12 repetitions in order to build up strength for the next progression.
Level 2a - "Negatives"
I am grouping level 2 as two separate sub-sections so that you can choose one or the other, or a combination of the two during your progression.
Although some people recommend chair-assisted pull-ups, I actually prefer "Negatives." Chair assisted pull-ups, no matter how much you try and not cheat, there will always be cheating involved. I went through this myself. I would have a rep goal stuck in my head, and I would fight to get to that rep goal, which included more and more emphasis or weight being placed on the chair as my reps rose.
Not only that, but most people working out at home or in a gym have a pull-up bar mounted maybe 6, 7, or even 8 feet off the ground so using a chair as a weight distribution doesn't always yield the best results.
So, try "Negatives." Negatives require you to assist yourself during the concentric (up, or muscle shortening) phase of the exercise, and then using your own strength to lower yourself back to the ground during the eccentric (down, muscle lengthening) phase. Your muscles are stronger during eccentric actions so you may surprise yourself with the amount of strength and control you have lowering yourself from a pull-up. A solid 2 - 3 second count during the lowering phase should work well to help build strength.
If you are unable to complete Negatives, then try either Assisted pull-ups (below) or band pull-downs (above).
Level 2b - Assisted
I really like the pull-up assist tools that you can get now. They are a resistance band tool that hooks onto your pull-up bar at one end, and then has a loop at the other end for your foot to step into. The idea is for the resistance bands to aid your pull-ups by reducing the amount of overall weight that you are pulling. Beachbody sells one, and that is the one that I own and love, although you can find them at other retailers as well.
I'm not sure if these things existed when I first started doing pull-ups, but if they did, I certainly didn't know about them although I wish I did! Not only do they help your pull-ups, but most models come with 3 resistance bands, each with a load capacity, so as you get good at doing 3-band assisted pull-ups, you can intensify by removing a band and just doing 2-band assisted pull-ups. Also, chair assisted pull-ups work just fine at times, but they can put your body on a bit of an unnatural angle. The pull-up assist puts your body into a more similar alignment to a real pull-up, plus you have that free-floating swing you get with a regular pull-up, training you and your core to keep good body control.
Not only that, but I love having mine around for those high-volume routines where my lats and arms are so pumped up I just can't take another set of regular pull-ups so I use the assist instead. I still get my set done, but I don't have to lug my entire body up to get my chin over the bar.
I can't recommend this relatively simple and cheap tool enough!
Level 3 - Regular Pull-ups
The final stage. Don't be so concerned about only being able to do 1, 2, or 3 reps at a time when you first try full pull-ups. If you keep working at it, you will grow and get stronger over time so that you can start cranking out reps as you get better. Just have the discipline to use full range of motion and don't try and increase in reps or intensity too quickly. You will get there!
Putting it all together
The truth of the matter is that most of you will have to use a combination of the progressions above. For example, if you are just starting out, or have been at this for a while, and you can muster 5 pull-ups, don't stop there. Your set should include 5 regular pull-ups with as good of form as you can possibly get, then slip your foot into the pull-up assist (Level 2b) and do 8 more reps, or something like that. Pull-up assist with 3 bands is too easy you say? Ok, then do your 5 regular pull-ups and then use the pull-up assist with 2 bands to crank out 6 more reps.
Don't have a pull-up assist? Fine, do 5 regular pull-ups and then do 10 negatives with a slow and controlled concentric. You have options, so use them all. Just make sure you keep a workout journal and keep track of your progress so that you can try and improve on your numbers next time you come back.
Your pull-ups, like any exercise, should be based around your goals. Are you interested in being able to do 20 pull-ups in a single set? Then you should work towards repetition training. Do you want to increase muscle size and strength? Well, maybe doing 15 pull-ups per set isn't the best option for you and you actually have to add weight with a backpack or weighted belt in order to increase intensity and lower your overall reps.