Have started the programme last week. Yesterday was day 3. I have also done quite a bot of walking this week too and my legs have been aching a bit but I wanted to carry on anyway. After one of the running sets I started walking and had a dreadful pain in the back of my right ankle. Not so bad when I ran. I completed the podcast anyway. This morning I am struggling to move with it (beyond usual stiffness) and getting up/down stairs hideous. Have taken ibuprofen. What is it? Why is it? What can I do to ease it and prevent it? Any help gratefully received.