Hi All,
A scientist trained a fly to jump over a matchbox on each command of ‘jump'. Then the scientist removed one leg from the fly. He gave the command jump and the fly jumped over the matchbox. The scientist observed that even with three legs the fly could still jump the matchbox. His observations were correct and his facts were correct. He continued his experiment by removing the second and third legs. He observed that even with one leg the fly could still jump the matchbox proving that his observations and facts were correct. Finally the scientist removed the last leg. He gave the command jump and the fly did not move. He observed that when a fly had its four legs removed it became deaf. His observations were correct but his facts were wrong.
Even running a tape in slow motion or studying frame-by-frame doesn't mean we get all the facts correct.

Hi Iluv2dance
I agree that watching a dancer in slow- or frame-by-frame motion doesn't show everything:- can't see which muscles are being used, or tell for sure how much foot pressure is being used and, most infuriatingly (for me anyway)you can't hear the music at all, so the rhythm has gone (i know you can count TV frames and work out the timing, but i can tell you from experience that this is very difficult and takes AGES!!)
However, having said all that, watching dancing frame-by-frame does have benefits - expecially watching your OWN dancing in this way. It's amazing what technical howlers are uncovered. Even the best teachers can't be expected to see everything 'live' as it were.
And the scientist in me just has to point out that a fly, being an insect, in fact has six legs. But your point was well made.