OK so I was perusing Bicycling Magazine at the local library and came across an article call "Fast Feet".

It talks about positioning the cleat location of the SPD shoe. There are basically 3 positions.

1) At the front, right by the ball of the foot. Good for sprinting type riding
2) Slightly behind the ball of the foot. Good for criterium or something. Basically not for fast sprints.
3) At the arch. Basically way at the back of the cleat adaptor as far back as possible. Good for casual riders, commuters and touring.

My old cleat position was #1 as per most guides regarding cleat position right under the ball of my foot.
I am currently testing #2. So far mixed feeling. In fact I have developed a lower rear back ache. Although I am unsure if it has to do with the cleat repositioning or the fact that I raised my seat stem 5mm higher.

Your learned thoughts appreciated!