Digitally recorded body-markers were strategically positioned (by independent judges) on the dancers’ major joints and body-parts.(* see note below + image above) The results showed that the modern-day average professional leg-lift-angle is around 115 degrees – though some dancers can achieve a staggering 137 degrees. But the study goes further – for not only has the angle now been quantified, it has also been compared to previous leg-lift-angles – as registered on film showing ballet dancers performing The Sleeping Beauty from 1946 to 2004. It can now be said with some degree of confidence that the angle has been increasing substantially over the years – it was only 96 degrees in 1962. The question then arises: why? And the research team go some way towards answering it :“…we conclude that the variation in leg elevation is an example of progressive, systematic change within an artistic tradition.”
See : ‘A Dance to the Music of Time: Aesthetically-Relevant Changes in Body Posture in Performing Art ‘ in PLoS ONE 4(3): e5023. doi:10.1371/journal.pone.0005023
* note : The markers were placed with the dancers’ full permission – the study procedures having been approved by UCL’s Department of Psychology ethics committee.