That's a great video I've seen it a number of times, but you can see that a lot of them do use thinner boards for the demonstrations.
Also, in my opinion, I think the apple on the sword bit is actually, pretty lame...the only way that would impress me is if they used real sharpened swords, half the time you see someone try it they just end up kicking the blade and knocking the apple off...if you really want to use an apple properly...find someone that can throw one up and use a spinning hook kick to turn it into applesause on the dojang wall...
Also, in my opinion, I think the apple on the sword bit is actually, pretty lame...the only way that would impress me is if they used real sharpened swords, half the time you see someone try it they just end up kicking the blade and knocking the apple off...if you really want to use an apple properly...find someone that can throw one up and use a spinning hook kick to turn it into applesause on the dojang wall...