According to rule 144 (d) of the USATF competition rules The use of any mechanical aid, unless the athlete can establish on the balance of probabilities that the use of such an aid would not provide an overall competitive advantage over an athlete not using such aid.
Would the Aeroswift tape Galen Rupp wore in both the 10K finals and the 5K semis and Justin Gatlin wore in the 100m be considered assistance? It's not part of the uniform which has its own Aeroblades but is something that is applied like KT tape to provide an athlete with better aerodynamics and a 2-3% drop in wind resistance.
Competitor did an article on it.
http://running.competitor.com/2016/07/photos/nike-aeroswift-tape-next-big-thing-running_152812