EDIT: A week or so after this test was finished I concluded that the hangboard which the participants used was slightly wider than a typical pull-up grip, and therefore I must advise you take the following with a grain of salt. In the near future I'd like to do a re-test on a pull-up bar rather than a hangboard, at which point I'll re-post the results for you all.
Last week I conducted a test at my local climbing gym to determine the correlation between one-arm pull-ups and two-arm weighted pull-ups. I tested four people who could do one-arm pull ups as well as six others who could not do one-arm pull ups. The group of people who could perform one-arms were all male. Interestingly enough, within the entire group, only one actively trained pull-ups, and he could also perform a one-arm. For those who don't climb and are training for the elusive one-arm, it's a little bit of a slap in the face considering most of these guys got to a one arm without doing any sort of weighted training.
Here are the results:
- Of those who could perform a one arm, every subject could lift 62% of their body weight in addition to their body weight.
- Of those who could perform a one-arm, the highest percentage of body weight lifted in addition was 74% (astoundingly, by someone who never trains pull-ups).
- This subject also had the highest total weight lifted, 122.5lbs added.
- The highest percentage of body weight lifted without being able to do a one arm was 50% .
Conclusions: For climbers and non-climbers alike, I think this is useful information for those looking to someday do a one-arm pull-up. Weighted pull-ups are valuable for training the one-arm, but these results show that by no means do you have to pull an additional 100% of your body weight to do a one-arm. I think this goes to show that while weighted pull-ups are beneficial, once you reach around the 60% body weight mark it's better worth your time to start training the one-arm muscles more specifically.
Thank you to everyone who participated in the test: Ray, Matt, Andrew, Alex, Kim, Sean, Sarah, Kenny, John and Adam.