RC100 - Round Chengdu 100K by Tianfu Greenway

RC100 - Round Chengdu 100K by Tianfu Greenway

A detailed report of RC100 FKT


6 min read


I had my first attempt of Round Chengdu 100 (RC100) by Tianfu Greenway on Oct 21, 2023, Sat.

Finish time (elapsed): 11:59:51

Youtube video: youtube.com/watch?v=ZyA3wvizO8Q

I completed the challenge without energy gel or energy bars. I had natural food for breakfast (noodle) and lunch (KFC), and had 3 bananas at about 6pm. I consumed about 5L pocari and 3L coke.


The whole attempt was a sponteneous decision. I did not have proper running gear with me when I travelled back to hometown last week. I did not even have my usual running backpack with me, let alone water flask / water bladder. In Thursday evening, I realized that there were some WeChat groups that help cyclers to connect with each other. Then I tried my luck to ask if anyone would like to support me to run the entire Tianfu Greenway around Chengdu. Feng, a cycler from Longquan answered my request.

My plan was to run the 100K (actually 98K) with a start pace of 6:00 and a decay of -4% every double the distance. The target time is 11.5 and confidence interval is between 11.5 and 12 hours.

RC100 2023 Oct plan.png

I also have a multi-target prediction that spans from 9 hours to 13 hours. If I reached a check point with a cumulative time beyond 13 hours column, I would choose to exit as my status on the challenge day was not at its norm.

RC100 2023 Oct plan multi targets.png

Race day

On the race day, Feng met me at the entrance near University of Electronic Science and Technology of China (UESTC). We loaded the bicycle and its cargo with around 7L water and some breads/ bananas.

I set out at an easy pace at 6min as planned for the first "half marathon".

At around 23K, my heart rate surged to about 150-160 when I was running 7min pace. I decided it was the moment to start supplying my body with coke -- some fast energy.

I kept running while drinking but paced down to 8-9min, and recovered after 2K.

Once I recovered, the whole morning was a pleasant 5-6min run till 45K.

I assured to myself: I already won today! I never ran beyond a marathon distance on road before. Although I had a few 100K trail finishes, the ups and downs actually helped to rotate the main muscles. We seldom keep running for more than 10K on trails to be frank.

I told myself: be cool with it, as every kilometer is an extra win going forward.

Then we reached Qing Long Hu (Green Dragon Lake) and found out the park was right beside the service area of high way. I decided to have some warm food and KFC became the choice.

I met my daughter and my parents after lunch at KFC and they ran with me for a few hundred meters at somewhat a walking pace. I set out to another 5-6min pace segment after saying goodbye to them.

The east-south of greenway and neighbouring gardens are very well built.

I enjoyed the scenary for another 10K. My cycler went to restroom for a while and was breathing rather hard when he caught up with me. I felt like a smooth flow.

Then came the first incident -- I had some ankle pains on the left. I had to stop and stretch myself out. Fortunately, the ankle issue was alleviated and never came back till the end.

At 70K, there came the 2nd issue -- I had serious blisters under the right feet. I did not have any experience dealing with blisters on the course. I could feel something under my feet was moving, but the pain from chaft was soon overridden by niggles in hamstring/ quad/ ITB.

For every kilometer after 70K, I would think about quiting once.

Then came two friends in Chengdu, one on her bicycle and one on his skate board with Action 3 cam. They were not endurance runners and they did not benefit from my blogs about running. They were old time friends who I had not met for years due to COVID. They came along simply because they were shocked at what I was doing, or at who I really was -- not the sedentary workaholic, nor the nerd at the corner of the class.

We had some good chats and time flew by quickly, all the way till 80KM.

I already had some performance loss from 70 to 80. I used to drink while running, but I chose to drink while walking during this segment. What's worse, I drank more frequently during this segment.

After sending off my friends, I kept the 7-8min pace for a few more kilometers.

I finished 84K, aka two marathons, according to my time table.

I knew I was pushing my limits, but I did not expect it arrive so dramatically.

I had a fatigue right after 84K. I had to fully stop, rest and have some food. When I started moving again, the data shocked me. My heart rate was soon 170 once I started a running pose, even at a 8min pace. For reference, I ran at 4min pace at a heart rate of 160 during a normal day.

I had to stop running and walk until 90KM.

My time predictor kept moving right, and almost reached the 13 hours margin. I was thinking about quiting.

My beacon from Strava also stopped working because it was running in the backend for more than 10 hours since the morning. I took out the cellphone. A dozen of people in WeChat group who were following my challenge gave warm congratulations, because they thought my challenge had finished if I had kept the same pace before 80KM.

I gathered all the energy and tried a hybrid walk-run from 90 to 92K. The heart rate was still as high as 170 when I ran.

There were only 5K left. Finish was not an issue anymore, sooner or later. I checked the map and watch -- there were 35min till 12 hours, which was my planned lower bound of the challenge (at a normal day).

The messages from WeChat came to my mind again. I felt that I was not running alone. People were excited to witness a grand finish. I tried to speed up and found out that the heart rate was constantly 170+ .

Then my target was not only to finish, but also to finish within 12 hours.

I emptied my mind and tried everything to maintain a 7min pace but not more.

When the public toilet beside my starting point came into sight, I knew the challenge was almost over. I had 1 minute left and started a 4:xx pace.

Then I cross the finish line at 11:59:51.


I had fatigues and muscles issues before but I never tried to maintain my heart rate at 170 for such a long distance at late stage of a race.

There are two main variables that deviate from my normal self:

  • I had donated 450ml blood 14 days before. I was not sure the implication or full recovery time. I tried the 40K moon trekker 7 days before and got a cramp after 20K even when I ran a moderate pace.
  • Chengdu is at a 500m base altitude, which may imply a few percentage performance loss as my usual training ground, Hong Kong, is at 0m elevation.

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