the rubber is precisely what blocks the flow of electrons to-and-from ground. another way to discharge or recharge is by petting an animal that has been running around barepawed.

i think that the bigger the animal, the more charge u can exchange with it. maybe that's why people like to ride horses and elephants. 

I'd say it's not very practical, but my lifting shoes are very wide and have a very hard bottom. I'm pretty grounded. This summer when it gets warm, i may even start lifting barefoot because I have hard rubber mats. 

Aardvark

Is it impractical where you live? I've certainly lived places where it would be a really bad idea.