by Shelly Manber (acrobat), Todd Etter, Jesse Morris
Answer: DAME COMMANDER
The aerialist is making semaphore patterns with her legs and arms. Directly decoding the strings should yield garbage. The insight is that when the aerialist is upside down, you must orient her right side up before decoding the semaphore letter. After doing that, if you organize the message into four separate groups (orientation and arms/legs) you should get four words that, when rearranged, form JUDI DENCH BRITISH TITLE, which is DAME COMMANDER (of the British Empire).
Right side up Upside Down Arms Legs Arms Legs 1 D 2 E 3 N 4 B 5 R 6 T 7 C 8 I 9 H 10 J 11 I 12 U 13 D 14 T 15 I 16 I 17 S 18 H 19 T 20 L 21 E JUDI BRITISH TITLE DENCH