Correlation analyses for leg elevation and trunk inclination angles vs. year.

1Angular values for the analysed positions were averaged across judges prior to analyses; r = Pearson correlation coefficient; N = number of images available.2HS = Highly Skilled postures: postures highly demanding in terms of balance (i.e. the ballerina is not supported by the male dancer) and/or motor constraints (i.e. leg elevation above 90–120 deg).3see an example in Figure 1 A.4see an example in Figure 1B.5LS = Less-skilled postures: postures less demanding in terms of balance (i.e. the ballerina is supported by the male dancer) and/or motor constraints (i.e. leg elevation below 90–120 deg).6see an example in Figure 1C.