Capping

The Schutzhund dog must learn to control himself
while "in drive". In basic obedience training,
most dogs are taught when they are calm and
in a low distraction environment. Usually distractions
are added later in training and the dog is expected
to ignore them. In this way the dog is gradually
de-sensitized to environmental distractions.
When clicker training we often choose a reward
that the dog enjoys but not so much that he
gets incredibly excited. This level of excitement
(or arousal to give it it's more technical behavioral
term) can be a barrier to the dog learning what
the handler requires.
Now in Schutzhund, we like the dog to work "in
drive", to be in an excited state. This helps
to get the points for power and speed that the
judges look for. It also creates a nice picture
of a dog joyfully working for his handler. The
dog must learn to work and to respond to commands
even when his primary focus is on a toy or even
a helper.

So
it is a good skill for a puppy to learn to control
his excitement or to "cap" his drive. A good
way to teach this is on the way in and out of
the house / crate / kennel. The pup is excited
to get in or out and is probably whining, clawing
or jumping at a door. To begin with, just wait
until the pup puts his front paws on the ground,
he certainly won't be calm, but at least he
is not ruining the paint work! This will be
quite difficult at the beginning, and will take
longer if the pup has already been jumping at
the door for several weeks! Gradually the pup
will learn that jumping does not earn him what
he wants. Keep the target behavior simple to
begin with, you don't want the pup to become
completely bored and out of drive before you
release him.
Later when commands have been taught, you can
give the pup a command like sit. He soon learns
that even though he is excited he must pay attention
to the handler. This of course is essential
in protection training later on but is also
very useful in normal situations, for example;
the dog may get very excited when there are
a lot of other dogs around. It is not always
practical to avoid these situations. It is also
not always possible to gradually de-sensitize
the dog to these situations. Far better to have
a dog who still pays attention to his handler
even when he is excited.