The USA are not usually very medal winners in this category, despite always being well placed. Either way, their forte is athletics, and athletics competitions haven't started yet. Even so, China already has an advantage, it will be difficult to be surpassed.
The United States is not one of the powerhouses as far as Paralympics is concerned. I guess the reason is that the proportion of handicapped people in the US is lower than what they have in countries such as China and Russia (but that argument doesn't explain why the Great Britain is at no.2 in medals table). During the 2016 Paralympics, US was at the 4th position with 40 golds (China had 107 golds in comparison). However, you are right when you claim that they are very strong in athletics. 16 out of their 40 golds came from that sport.
