(Thanks to Maghan Wilbur who graciously offered to help me shoot/model these videos at 6:30 in the morning after a training session. You earned that Pop Tart Maghan!) Sometimes you're just stuck between a rock and a hard place. Bodyweight pullups are too difficult and band-assisted pullups are either way too easy or way too hard. There seems to be a no man's land in bodyweight exercises, especially the pullup, where neither option seems to drive progress. If you require 3 or more bands to assist all your pullups, my following suggestion will probably be a better option. Certainly, adding more bands allows you to do the pullup, but at a certain point the band is doing all the work and is eliciting very little in the way of a training effect. Don't think of TRX pullups as a regression, just an exercise all their own, which can be made harder or easier depending on your personal strength levels.
The TRX pullup is the love child of the pullup and TRX row. Most people, even heavier or weaker people, can perform TRX rows and can find an angle that challenges them. Now, you can always make rows harder and there are a myriad of ways to address that, but let's face it: we all want to get better at pullups. It's a sign of strength. Plus how many weak, overweight or just plain ol' out of shape people do you know who can bust out multiple pullups? Probably not many, it goes to say that if you can do pullups you probably retain some level of athleticism.
There are four progressions shown here. In all instances, think of keeping the hips “low” and as underneath your shoulders as possible. We don't want to drive the hips up and turn this into an inverted row. This is what makes pullups so challenging, especially if you don't kip them (please don't), you don't have the luxury of tensing your body as you do in the TRX row. The free moving nature of the pullup leads to some inherent “energy leaks” and takes a lot more control to keep yourself from swinging, thrusting the hips up, or cutting reps short.
The temptation to drive the hips up will be there, just let me tell you now so you can't say I never warned you. You still want to keep the chest up, however, and then pull yourself up with the elbows out a little wider than a row, to really target the lats. From there, how you position your feet determines how much load is on the ground and therefore how much of your own bodyweight you are pulling up. You'll notice even with Maghan, who is strong, that she needs to be cued to keep the hips low as the body is always trying to make things more efficient and wants the hips to pop up.
Both Feet Flat, Legs Bent
This is a relatively straightforward setup, feet flat and about shoulder width apart. Keep the hips low, chest up and low-back as neutral as possible.
One Foot Flat
Same as above but now you are lifting one leg off the floor and extending it out to put more of your bodyweight into your hands to pull up and less supported on the floow.
You will need a box set up in front of you, or possibly brace your feet inside a squat rack. The legs are extended out in front and your are on your heels. The box keeps you from sliding forward, but more of your weight is off the floor, making this slightly more challenging than the last one-footed option.
(No there was not an earthquake in this one, I was trying to capture Maghan AND the box.)
In this position, like the last, the most minimal amount of bodyweight is supported on the box. The elevated box puts more of the weight over your center, essentially loading your upper body more and legs less, so it mimics more of the “dead hang” effect of the pullup. You want to get yourself used to this feeling so handling your own bodyweight becomes second nature.
Try these variations out and see how you like them. Remember to keep the hips low and chest up. The TRX will also need to be set up relatively high so you can hang from it without your butt trailing on the ground. Try the different progressions out and see which one challenges you but allows you to get about 6-10 reps. From there, work multiple sets until you get strong enough to progress to the next level, and from there, the real deal.