There is a lot of information on the internet about cleat position and power. I have not found anyone reliable to say it makes a difference. In general, the cleat is positioned on the shoe so that the pedal spindle is under the middle of the ball of the foot. I believe that some trackies move it back to get a better spin. However, minute changes in setup have a huge impact on body mechanics when riding long distances. One will pedal hundreds of revolutions and a new position will require some adaptation.