Well here's an FTM's input (I hope I'm doing it right).
Being cursed with a body that is unnaturally feminine in a wide variety of ways (including the index finger:ring finger ratio, I'm the only person I've witnessed that has an index finger about a centimeter longer than the ring finger....apparently excessively feminine....whatever) I was surprised to "fail" this test.
I held my palms flat against my thighs and slowly rotated them forward and the side of my hand as well as the entire arm stuck to my body. If I held my arm freely in the air though, there was a very visible bend of my forearm outwards where my upper arm ended. However, one thing I did notice is that where the elbow is is also where my waist and skinniest part of my body is so it was just like a jigsaw where the elbow was unnaturally bendy but my waist accommodated for this by getting skinnier. Perhaps this this small-waist and bendy-elbow is all connected?
Hope this helps, if I did this wrong please let me know D: