Notes
I was planning to do a 13M to see if I can finish it within pace 10, unfortunately I started too fast in the beginning and got really tired at 7M. I started to kick high around 8M, and I thought, Jesus, with this heart rate, thanks god if I can finish a 10M! at 9M I thought, it's good enough, maybe I should stop here. then I look ed at the gps, say, wait a minute, with this pace, I could finish a 10M in at most 10minutes, that's too far to go. OK, 10M is the final result of negotiation, and it's not too bad.
this 10M is much easier than my first 10M, endurance is much better. and legs and knees are ok.