I've always loved running around barefoot. This is a surprising advantage for kendo. Most people who take up the martial art get horrible blisters on their feet or even just have the skin split open and bleed. I think it's the tsuri-ashi steps, where you brush the balls of your feet against the floor as you move, which is a whole lot of friction when combined with the demure Japanese version of the rocker step employed by Western sword arts. For me, who regularly walks across gravel, asphalt and barnacles unshod, it's never been a problem. In fact, I think the kendo has helped me walk barefoot better, because the skimming the ground step is a great way to test the terrain and make sure you don't get stabbed in the foot by a sharp rock.