I found early morning runs helped my training when i used to average 75 - 100 + mpw back in the late 1990s. They were all run at a easy pace and were 5 miles in distance, 5 - 6 times a week. These runs helped by refreshing the body from the previous nights hard session and adding a little extra mileage to improve endurance. On race days i would also do a 20 - 25 minutes run just to wake the body up and get the mind in focus for what was to come and also found this to help.