Could someone please give me their opinion on the best approach to train the whoa command using the whistle?  I have a 1 ½ year old female GSP.  She was taught the voice whoa command off the heal command.  It worked well and I don’t have a problem with her when she is close.  I want to incorporate the whistle for times when she is out in the field.  I want to use a long blast of the whistle, one and two short blasts are already being used by different commands.  I’m thinking of two different methods but wanted to see what others thought.  The first method would be to have her go on a retrieve, blow the whistle and stop her using a line on the way to the object.  The other would be to let her roam out in the field, blow the whistle and follow it up with the whoa command.  Teaching her to whoa with the whistle off the heal command like I did with the voice command just seems a little weird (to loud for her being right next to me).  Any advice would be appreciated.