With the help of running group as well as a few holidays, I finally accumulated 40km/week of mileage for the 1st time. However, the increase in mileage is not gradual which prone to injury. Joining this running group, the pace is around 7~8min/km (comparing to ~6+min/km that I usually did) because of a few ultra runners in the group.
I have been controlling myself for not following the mileage of other runners.
The day before the last 8km run, the muscle of both of my legs a giving me strange feeling on and off. So, I will just off for the next 5 or 6 days and hope for the best.