I am enjoying the 5x50 so much, though I did have a few doubts about exercising every day as I have had dinned into me that you have "rest days" between runs which has always meant actually sitting down for me
Then I found out that my niece runs twice a day every day!! As she's half my age I decided that once a day every day was fine for me - though I don't think it will ever become running every day
Although my legs feel permanently a little tired over the past 8 days I haven't had any stiffness or soreness - today is a a trail run W7R1. Wish me luck, the sun is shining just now but there is still ice on the pond. Roll on spring.