^ but they don't 'measure' it in the article, they're not even coming close! it's just a lot of brouhaha about angles, based on almost randomly selected, low resolution pics.
however, huntingyou offered two good clips that actually do give an idea of how to measure racquet head speed (not to be confused with acceleration, of course; also, it has to be noted Roger's clip is an abstraction and Rafa's seems to be distorted a bit by having a low fps count - high speed cams would work wonders here). the relevant moment of course is quite short - the time of contact between strings and ball. so the racquet head speed for that moment would have to be measured - and with the right equipment and setting, yes it can be.
however, go back and read what BS said - you misquote him in saying that rh speed can't be measured at all - he's saying that it's a "near impossibility" to measure it "on average". now that makes a whole lot of difference, and i reckon it's true because each measurement would require a whole lot of calibration, perfect lighting, the high speed cams, some serious calculating; also, there's so many different shots and situations (positioning, movement, shot choice etc), all of which affect the accelaration and speed, that there's no real way to compare these player v player.
so i think in the end, as you said - you're free to disagree with what had been said regarding Roger's or Rafa's speed; and you might also notice that at no point did anyone deny that Novak has tremendous rh acceleration, just that some people couldn't quite "trust" you on his numbers being superior to Rafa and Roger's.
