Watch first 3 minutes if the video and you'll find out it's not true (assuming all his sets are shown in the vid), not to mention Jackson didn't say "I'm too tired for pullups", he said "I can't do pullups". Besides if you're even semi-proficient at pullups you can crank out at least one rep no matter how much pulling volume you've done prior. And let's not forget that his recovery abilities are massively enhanced