The doctor is in

The following article sent by Marc Rowe essentially says that if you use imagery of doing something after you've physically practiced it well, it's more efficient when you execute it.

Nov 22, 2008
Motor Representations and Practice Affect Brain Systems Underlying Imagery:
An fMRI Study of Internal Imagery in Novices and Active High Jumpers.

Open Neuroimag J. 2008;2:5-13

Authors: Olsson CJ, Jonsson B, Larsson A, Nyberg L

This study used functional magnetic resonance imaging (fMRI) to investigate
differences in brain activity between one group of active high jumpers and
one group of high jumping novices (controls) when performing motor imagery
of a high jump. It was also investigated how internal imagery training
affects neural activity. The results showed that active high jumpers
primarily activated motor areas, e.g. pre-motor cortex and cerebellum.
Novices activated visual areas, e.g. superior occipital cortex. Imagery
training resulted in a reduction of activity in parietal cortex. These
results indicate that in order to use an internal perspective during motor
imagery of a complex skill, one must have well established motor
representations of the skill which then translates into a motor/internal
pattern of brain activity. If not, an external perspective will be used and
the corresponding brain activation will be a visual/external pattern.
Moreover, the findings imply that imagery training reduces the activity in
parietal cortex suggesting that imagery is performed more automatic and
results in a more efficient motor representation more easily accessed during
motor performance.