Thank you, California, that is very helpful. I initially read about the Agon/therapy/choreography connection in either an online review of the film or interview with Nancy Buirski, but darned if I can find the source now!
From a different angle, there's a review of the film that refers to Balanchine creating movements for Tanny to use as part of her Pilates-based therapy. Consumed as he was by the desire to rehabilitate her, it would be surprising (to me, anyway) if that drive didn't find expression in specific choreography (as Croce suggests, above). Here's a link to the review: http://m.theepochtimes.com/n3/305291-afternoon-of-a-faun-movie-review/
Edited to add: I just saw sandik's post - good to know it's discussed in the film.