Va does indeed apply to all controls
YESmake up yor mind
As they say in "Little Britian", "Yes, but....." and the kicker is in the "but" - no pun intended. Va is certainly used as a benchmark for the design of all controls (aileron, rudder and elevator) but the prevailing pilot view that you can sit there pushing and pulling from one stop to the other while at Va is where you can come to grief big time. For those inclined look up FAR 23 at
www.faa.gov - there is a lot of information on the requirements to get your head around, but a very good and simple pilot speak paper discussing this issue can be found at
http://www.flightlab.net/pdf/8_Maneuvering.pdf