With regard to Tiger Woods' pulled-left drives during round one of the 2012 US Masters....
With this swing, what can one expect?
In simple, non-biomechanical terms, how can the arms and hands (smaller muscles) be expected to swing the club down-the-target-line for a straight shot if the shoulders and hips are practically perpendicular to the target line at impact?
Some small compensatory moves will always be required to keep the club swinging down the target line.
If only WOODS WOULD ..... use MGS!
Tiger would not need the many compensating/re-routing positions he is forced to make with his existing swing!
He would not have a huge up-and-down movement of his body during the downswing, or the contorted-looking impact which only quick, last-minute adjustments of the hands keeps from disaster!
With MGS he would not have a deep tilt (lateral flexion) of his left side which requires a lot of compensation to undo (after all at both address and impact his right side is tilted!)
Also he would not have to have a 'fake' lifting up across the chest (adduction) of his left arm to keep it attached to his chest. With MGS it would be a more natural and much softer move! He has so many sharp angles of most of his body parts!
For a more biomechanical, qualitative-kinematic assessment, post a comment!