Parrott Predictor

To log my miles I'm using David Hays Excel workbook. In it there is a theory from a Coach named George Parrott that you can't run a marathon faster than the combined times of your fastest 26.2 miles in a weeks training. The workbook automatically calculates this. With the addition of my 5 and a bit mile recovery run this morning this figure was 3hr 22min 56secs. Ok this is the fastest theoritical I could run a marathon but at this stage of training I'll quite happily take it. It was especially welcome today as I needed a bit of a lift after yesterday's demoralising run.