Contortion Wiki

Also: Illusion kick, Free Illusion

In gymnastics, a move that appears to be a forward flip, but one foot maintains contact with the ground. The trunk and other leg pivot around the supporting hip.

https://www.fig-aerobic.com/D-264-ILLUSION_a746.html

https://www.fig-aerobic.com/D-285-FREE-ILLUSION_a749.html

https://www.youtube.com/watch?v=RVeo6QMcbW4