You are just begging to disconnect your swing when doing these things.
Loss of posture, narrow downswing, arm run off, early extension, arms getting too far inside, steep downswing, overly slow tempo, bad rhythm, over the top, under the plane, casting, flipping, gout, diabetes, cirrhosis of the liver and erectile dysfunction are all direct results of these two cliches.
1. The easiest and way to swing a golf club is to keep your width, constant arc or the distance of your hands to your chest remains fairly constant. Basically all the same thing.
2. In addition if the amount you bend at the waist/hip sockets remains constant through the back swing, down swing and through impact, that is also the easiest and most efficient.
3. It has already been proven that a slow back swing is terrible. It ruins your rhythm because you are bound to grab the club at the top. You don’t want a slow back swing or a pause at the top. What you want is to be patient in the transition and allow your body to unwind and change direction without snatching the club with the hands. Tour players have faster tempos than amateurs.
By definition, widening the arc ruins #1. Now go try and swing low
and slow without increasing the distance from your hands to your chest…or low and slow without pulling your head to the ball and increasing your bend at the hip sockets.
The answer is your can’t.
I realize what these cliches are trying to accomplish. Low and slow is to get people improve their rhythm and keep them from lifting the club off the ball.
It doesn’t work. It replaces one problem with another. It falls into the cliche category of “Do the opposite of bad.”
“Widen the arc” gained popularity when DL III (Davis Love III) came on tour with this huge arc and prodigious drives. He doesn’t widen the arc, he maintains his width. He just has long arms and a narrow chest and shoulders, so he creates a huge arc naturally.
If Craig Parry or Craig Stadler would have tried to widen the arc, they would have gotten the shanks.
Woody Austin has the lowest and slowest backswing I can think of in a Tour player and I bet his tempo is faster than every amateur that constantly says out loud, “I got quick.”