I'm planning to run London next year or another spring marathon. I'd like some thoughts on what training I should be doing in the next few months before starting a 16-week build up.
I currently do 20 miles a week (10-2-5-3) plus a swim. I reckon for the marathon my mileage will peak at around 40-45.
Should I stay where I am now mileage wise and increase when the 16 weeks start, or should I build a bit now? If so, when and how?