Here is an interesting write up on a U.S.archery web site called.
The BEST Method
Biomechanically Efficient Shooting Technique
A moderately low wrist position is stronger and
more forgiving when shooting lots of arrows. This wrist
position also directs the force of the bow directly
through the bones and minimizes the fatigue of holding
the wrist in an unnatural position. However, it is
common for elite archers to customize their bow grip,
often making it moderately high.
A customized grip
that aides in getting
consistent hand placement can be very valuable and if properly designed can
compensate for the normally weaker low wrist position. The grip modification shown
below will benefit the biomechanics of the bow arm, improve bow hand stability and
compensate for bow hand torque. Properly designed, the modified grip will help the
archer develop the correct hand position and consistent “feel.” The bow hand
position must be natural and never forced. The grip can be modified by adding epoxy
putty to the plastic grip and shaping it with a rasp.
To summarize, the foundation of the shot focuses on arranging the body and its component parts into the
strongest and most stable configuration possible prior to the application of internal and external forces. This is
accomplished by proper “load bearing” alignment that reduces fatigue and the potential for injury. Establishing
stability will reduce movement during the shot and increase the archer’s sense of confidence. The foundation
must, in every instance, be established precisely the same way every time to create consistency. The
foundation also sets the tone for the shot and supports the shot, making it easier to execute and thus easier to
duplicate. The design of this set of foundation positions is supported by carefully observed biomechanical and
physical principles. It is the most efficient and effective way to perform an archery shot.
( Here is a modified GMX grip )