I know you want to find out what is his training plan yi have to say, that this is not optimal way how to train and that it is not for naural lifters, but lets take a look what Rich Piana workout routine consists of

8 hour arm workout

This is something, which many pepple want to try, but then they never do this.

Even if you are enhanced lifter, this is something you don’t want to do every week or even every month. Your muscles can recover from it, if you’re on juice, then your joints and tendens might recover too, but your CNS won’t. This much volume is bad for your cns and steroids have pretty much no effect on your central nervous system recovery. And i’m not even going to talk, what this will do to a natural lifter. And another thing to consider is, do you really want to spend 8 hours in gym and drink 16 protein shakes? I know it might be cool to try Rich Piana workout routine, but waste your whole day and snap your s**t up durinf it is not a game, you might also start doing crossfit  😀

Is the one inch of growth possible?

If you did Rich Piana workout for 8 hours, your arms might be an inch bigger. But don’t think even for a second it is muscle gain. Your arms will be swelled and holding tun of water and probably full of glygogen. Because your body will try everything to recover. And even if you gain a bit size from this workout, you will hinder your progress. Because you won’t be able to workout for a few days after 8 hour arm workout. So if you skip two lr three days from gym, how do you want to hit every body part twice that week? If arms are truly your week point