Not so, according to peer reviewed medical journals:
Philip Cohen, reporting on the annual Society of Neuroscience in the November issue of New Scientist, called the new findings a “couch potatoes dream.” Researchers have discovered that imagining exercise can increase the strength of even large muscles. Using ten volunteers between the ages of 20 and 35 to imagine flexing one of their biceps as hard as possible in imaging sessions five times a week, volunteers showed a 13.5% increase in strength. There was no change for the control group who did not participate in the mental gymnastics. Additionally, the volunteers maintained their strength gain for three months following the end of the mental session.
I again submit that the best criterion for judging a script is probably it's compostion, which gives a indication of the mental fitness and age of the proposer.