I will go with what others have said as far as Poser.  T Pose is also the default for motion capture, as it lets the computer scan the points in a fixed positon - most that I have seen do not use inner thigh points but do need the arms raised and just extrapolate the rest of the legs.

Personally, the pose in your drawing looks awkward, whereas T Pose reminds me of a few calesthenic (spelling?) starting positions.

"The four count windmill.  Ready . . . begin!"