You mean for the cutting of the tree and guy down right? I'm not to sure about the first one with the guy but if you constantly hit pause and play while he is destroying the tree I at least caught a frame where it shows very clearly a foot going across so I would say he is kicking it down crazy fast, as for the snake... Why does everyone forget about Kabuto or think that oro had to have done it? To me it is quite obvious that Kabuto summoned the snake for them.

Anyway, I think its cuz sarutobi only cut off the forearms, so he can still move from the shoulder.
Also if you move your body the arms if they are lifeless will follow so he could have just twisted his body real quick and had his arms flail out and bring death =)