Calculating Weighted Pull Ups
Whatever weight you can pull for one pull up, take the required percentage of that weight. That includes your entire bodyweight. So if you weigh 100 pounds and can do a weighted pull up with 20 pounds, your total weight is 120 pounds. If the required weight that session is 55 percent, you’d do pull ups with 55 percent of that weight, which is 66 pounds. Since you weigh 100 pounds, but only should be doing pull ups with 66 pounds, you’d need an assistive device. If you were at a gym, you could set a pull-up machine to help you with exactly 34 pounds and you would be good to go.
If you don’t have access to a machine like that, we’d recommend using a band. You don’t get exact weights with a band, so use a band that allows you to get the required number of reps without breaking, but is still challenging. If you don’t have a band available, do self assisted pull ups. Put a box under the bar so that when you stand up on the box, your chin is above the bar. Do the pull ups while on the box, trying to use your legs as little as possible.
If you happen to be able to do a heavy weighted pull up and the end percentage weight is above your body weight, simply add the necessary weight to a pull up belt or hold a weight in between your feet while doing the pull ups.