I can't believe the huge misconceptions revolving around the use of a whip. Hey but then again if you sit and carefully watch helpers out there working with it, trying to understand what his using it for at certain points, you'll probably not be surprised.
If you just walk out there for the first time with a dog, and whack the whip, you will definitely see what the dogs nerves are like so this is ONE fundamental aspect of it but as training progresses it is to be used in a way that maintains the effectiveness. After a few sessions the dog will form an association with the sound of the whip, so in future we can use it to enable a dog to " load" as he approaches the field. So we put the dog in drive for a specific purpose. Depending on the dog, training, thresholds etc. the whip will have a different effect. A whip and its use is not directly proportional to a dog's defense. Pressure is sometimes required when correcting a bite and may be used in this instance. Dogs that show a little stress can be exposed to more stress via this but brought through that stress using the drive, thus overriding the stress factor, slowly conditioning the dog to a consecutive, higher stress factor, bringing him through it every time. Then obviously in a trial the dog's reaction to stick blows is assessed. Greatly misconstrued locally especially with very defensive dogs during the early stages of training and bite development.