I did w5r1 then had a sore back and a bad cold. I've had a 4 day rest and decided to try again but instead of continuing on with w5 I've just repeated w1r1 as a warm up.Pleasantly surprised by how easy I found it after my beginning struggle! Just shows how far this thing can improve your fitness. Now waiting to see if my back hurts tomorrow. All being well I'll be back on the programme for my next run. Wish me luck!