There are many twists in the story of how Joanne Mikl estimated the inertial properties of athletes who do somersaults. Mikl explains some of them, in this study:
“Methods Of Estimating Athlete Inertial Properties And Their Implications For The Study Of Somersaults,” Joanne Mikl, ISBS-Conference Proceedings Archive, vol. 1, no. 1. 2013.