I wish to survey the board for advice on my long run day. I am presently training for a 20K in early December. In the past I have had developed overuse injuries quite easily when doing runs of 15-17 miles while prepping for marathons. For the last 3 weeks I have been breaking my weekend long run days up into morning and evening sessions e.g. 8 and 4, 9 and 4, 10 and 3, etc and plan to continue this for the rest of my build-up, getting to about 10 and 6 max. Will this be as beneficial to me as doing the mileage continuosly?? Or am I deceiving myself?? Does a double run day sometimes increase an athlete's chance of developing injury?? I know the answers to this question are somewhat individual but any general advice would be appreciated...thanks.