Supertraining

Hi Everyone:

I'm going to repost this with a bit more detail.

At a facility where I train clients my manager approached me and asked 
if I thought a bench press or for that matter a push up should be 
executed with the upper and lower arms at a 90 degree angle and nothing 
less.

I do not believe that a bench press movement could be executed fully 
unless a violation of this idea takes place.  Of course, grip width, 
body thickness and arm length do come into the equation. 

Could you direct me to some written materials on this topic? I would 
appreciate your input. Thanks.

Mark Cotton
New Jersey, USA