Questions I would ask being a bit of a scientist and cynic at heart.
No mention of accuracy if used in real golfers?
You can only hit up on a driver (IF you wanted to)....no question there...so it would be useless talking about iron swings in this study (unless off a high tee).
Is it the equipment that maximises the upward swing as they are designing clubs to fit it with the "idea" of hitting a driver on the upswing that has become so popular?
Did all the swings tested have EXACTLY the same approach ANGLE OF ATTACK and EXACTLY the same FACE ANGLE to compare path these other factors must be equal. Unless you have to hit up on it the get it in the air that far inside
Too many questions not answers for me