You move in a complete vertical pace giving the movement pattern "fixed" preventing your stabilizers from functionally stabilizing the external load in the same perspective it would stabilize in the real world, preventing smith machine movements from being exercises for "functional strength".
If you would get strong in the smith machine and return to free weights, your anterior delts wouldn't be able to perform at optimal performance due to the smith machine bar being weightless, you wouldn't be able to stabilize the weight to yourself due to weak stabilizers.
The fixed movement pattern limits your body to a single plane of motion, preventing it from working in the three planes it works in everyday life (saggital, transverse, frontal). The OH Press is in the frontal plane, involving abduction, adduction, inversion, eversion, depression and elevation, these movements are limited with a fixed movement pattern.
Your shoulders joints being limited to a movement pattern that is unnatural to it's environment is the best way to enforce energy, not prevent it.
<message edited by MVP on Saturday, June 27, 2009 8:34 PM>