I run from my house in the middle of the countryside. I don't have time to drive anywhere flat and one of the reasons I'm giving this a go is that even I can fit half an hour into my schedule. But I must admit 90 seconds uphill was incredibly difficult today. My calves are burning!!!! I know I need to go slow and I'm pretty sure I couldn't manage any faster uphill, but I'm really doubtful I'll ever be able to run consistently up and down these hills for the holy grail of 20 minutes, never mind more!!!! Anyone else do this on hills? Does it get better?