The ergonomic argument against the straight shaft is based on the fact that if you look at a straight shaft detector set-up from the side, then draw a line from the inside bottom of the arm cup through the center of the handle, that line projects out to a point well above (in front of) the junction of the shaft with the coil.  This results in torque (twisting) when you initiate or reverse a swing with the coil.  This force must be resisted by your body.  It also introduces twisting strains on th