I am at work, and cannot directly quote the episode or the manga chapter as it is archived at home, but Sasuke's statement was something along the lines of:

"The subtle way his chakra enters and powers his body, I can see his next movement .."

He then goes on considering how if he's been using it to avoid being struck, he should also be able to time it accordingly and attack prior to Naruto fully being in place and taking the offensive.

But, because of the translation (taken from two manga scan teams and one anime team - unsure if it was DB or AonE, I have both), it implied those echoes were more ninjutsu intensive due to the inclusion of chakra, which had it been normal motion and running, more relative to taijutsu, only stamina would have been used.