What is the move following the American Foxtrot curved feather, his legs appear to be in locked position at the end of this move?

It's a Curved Back Feather, which is essentially a Curved Feather with man and lady switching parts. So the man's 6th step is nearly identical to the lady's 3rd: Back in CBMP, very small step.

Of course it's not necessary to dance these two measures in succession. Either one can be taken in isolation, and preceded and followed by any number of figures. A Curved Feather is often followed by a regular (non-curved) Back Feather moving toward diagonal center. Natural and Reverse Twinkles also work, as does 4-6 Closed or Open Right Box (i.e. Running Finish). You can even use some of the walking bronze figures (e.g. Back Basic). And of course, you can open up a world of options if you venture outside the syllabus -- Outside Spin, Outside Swivel, Tipple Chasse, etc.

Precedes to the Curved Back Feather include all of the same figures that precede the Natural Twinkle, such as 1-3 Open Right Turn, 1-6 Twinkle to Pivots, or even a RF Passing Backward Change if taken at a corner.

Regards,
Jonathan

The combo of.. Curved Feather to Back feather to Feather Finish.. Known as the The " Prince of wales ". One of the most clasic Foxtrot Amalag/variations, and great for developing and refining technique .

Wanna create " swing " in your FT ? then practice that combo

I have not got the latest Technique Book. In mine there is no Curving Feather.I do understand that any turn or curve has Sway. Question. In the latest Technique Book is the first step of a Curving Feather a straight step. Therefor no Sway until the second and third steps. What does it say?.

According to the IDTA book (Guy Howard) you are correct. The sway on the three steps of the Curved Feather is/are:

1 St
2 R
3 R