Completed another 4 miles in the gym today. Legs and left ankle were giving me a lot of pain right from the start. I think 1 days rest after the 12 mile run may not have been enough. It was also rather hot in the gym again causing my heart rate to hit 180 before I'd done 25 minutes. I managed to keep my heart rate hovering around 170 during the 12 miles so I can only think its the heat in the gym causing the problem. Tomorrow I will have to run outside to see if there's any difference.