I found and watched the original video of this. So first things first, he is using 20lb bows, which means they will be at a really slow FPS rating compared to other bows. Next he doesn't have anything on those arrows that would cause major damage to him unless they were to break and splinter, using similar tips used for archery dodgeball. Lastly he just worked on timing with multiple attempts. There are 3 other bows involved with this trick. He shoots at a target for one. Once it hits the target it activates a trigger to shoot another bow that is aimed at another target that does the same thing at a final target that shoots the last bow. With enough practice, he knew roughly where the final arrow would be flying to, and based off of the sound of the last target getting hit, he would be able to count off how soon before he needed to start catching the last arrow. So in essence it took a lot of practice and a bit of luck. But with the low FPS of the bow, it makes it a whole lot easier.
