Garmin Tai Po Half Marathon

Garmin Tai Po Half Marathon

Race information

  • What? Garmin Tai Po Half Marathon
  • When? 2019-12-08
  • How far? 21.0975 km
  • Website?
  • Time? 1:41:50
  • Place? 13 / 71 in male 25 – 29


Goal Description Completed?
A under 1:40 No
B under 1:45 Yes
C complete my first half marathon Yes


Kilometer Time
1 4:43.5
2 4:20.5
3 4:33.7
4 4:39.7
5 4:50.2
6 4:40.5
7 4:49.5
8 5:00.9
9 5:03.8
10 4:30.1
11 4:48.2
12 4:41.5
13 5:01.6
14 4:52.9
15 4:55.7
16 5:12.1
17 4:50.8
18 4:41.3
19 5:20.2
20 5:14.0
21 4:28.1
Finish (my Garmin read 21.14 km) 0:31.8


After I have become a marathon swimmer in July after done a 13 km swimming race from Lausanne to Évian, I decided to temporary go back to running after a year of break in running, because I originally started swimming as a cross-training to my orienteering, and I wanted to be a balanced athlete with similar performance in running and swimming. So I decided to find a half marathon race as my next running challenge as my longest run before was 10 km.

9 weeks ago, I signed up a race on 17th November in Sheung Shui as my training target (i.e. 6 weeks of training), along with an intermediate 10 km race on 27th October in Pak Shek Kok (on the 3rd week of training). I planned to have 3 runs per week, one long run, one interval run and one medium-paced run. However, I ended up not getting 3 runs on most weeks, but only 2 in the week (interval and long run) with about 20 km / week mileage.

I completed the 10 km race in 0:46:36 which was my personal best, about 2 minutes better than before. The race on 17th November was cancelled due to de-facto war situation disrupting traffic in the region. and I signed up this race as a replacement, adding an extra 3 weeks of training time. However, in those 3 weeks I undertrained due to bad mood and illness, and also an aquathon race which I did for fun but did not fit well into my training schedule.

The first and last 5 km of this race was the same as the 10 km race which I did the PB in October. I originally targeted 115 – 120 minutes at the beginning of the training, and did my long runs at 11 km/h. However, in recent 2 weeks the weather has become much cooler than before, and on my last long training run on 2nd December, I kept 12 km/h for 20 km, and adjusted my expectation of my half marathon to 100 to 105 minutes respectively.

Here’s the summary of all my runs in the 9 weeks of training (a week is Monday to Sunday):

Week Runs Total
7 Oct – 13 Oct Wed 6.4 km interval, Fri 9.6 km long run @ 11 km/h 16 km
14 Oct – 20 Oct Wed 8.4 km interval, Sat 2.8 km sprint orienteering race, Sun 12.5 km long run @ 11 km/h 23.7 km
21 Oct – 27 Oct Mon 7.2 km 39-minute run for 721, Fri 4.8 km interval, Sun 10 km race @ 13 km/h 22 km
28 Oct – 3 Nov Wed 8 km interval, Sat 1.7 km orienteering race 9.7 km
4 Nov – 10 Nov Wed 6 km interval (not in a good shape and didn’t complete the whole set), Fri 17.4 km long run @ 11 km/h 23.4 km
11 Nov – 17 Nov Wed 5.6 km easy run @ 10.7 km/h, however Sunday race cancellation announced on Thursday, then Sun 10 km run @ 11.3 km/h 15.6 km
18 Nov – 24 Nov Wed 3.8 km interval (feeling sick, not completing the set and saw doctor on Thu), Sun 14.5 long run @ 10.3 km/h (too hot on that day) 18.3 km
25 Nov – 1 Dec Wed 7.95 km medium effort, Sun 2.5 km x 3 aquathon race 15.45 km
2 Dec – 8 Dec Mon 20 km long run @ 12 km/h 20 km (excluding race)


After my last long run on 2nd December, I stopped running for the remainder of the week, but between Wednesday and Saturday I increased my swimming amount intensity and accumulated 20 km on 4 consecutive days, which was the most swimming I’ve done in a week in this year, due to the decreased temperature (the pool temperature in the week was about 16°C – 19°C) allowing me to do hard interval training. I originally planned to have extra sleep on Saturday, the day before the race, but one of my friends who swim at about the same speed as me told me on Friday evening that he would do a training swim (probably long) on Saturday to prepare for a marathon swimming race which both have signed up which I considered the best chance for me to do my long training before the marathon swimming race next month as well, so I ended up getting up early on Saturday. Unfortunately due to dolphin encounter everyone’s attention was diverted and the swim didn’t go long, although it was really fun. So I had only about 8 hours of sleep on Saturday, and 9 hours of sleep on race day.

The air temperature on race day was 13°C, which was cool enough that overheating was not a concern in sleeveless and shorts. Last time when I did my 10 km race in the same location, I took a metro and a bus from my home to the race venue when my motorcycle was out of order after getting hit from the back in September. This time, the metro station has been completely destroyed in the war and my motorcycle has been repaired, so I rode my motorcycle to the race venue. I had enough time to deposit my luggage and do a full warm-up routine before I entered the start zone.


Kilometres 1 to 5

The first 5 km were run from Hong Kong Science Park to Tai Po. km 1 was a warm up, 12.7 km/h. I went a bit too fast in km 2, originally targeted 13 km/h but ended up 13.8 km/h. I tried to maintain 13 km/h in km 3 and 4, and got 13.1 and 12.9. As I felt that 13 km/h was not sustainable, I planned to reduce to 12.5 km/h in km 5, and got 12.4 km/h.

Kilometres 6 to 9

As we entered Tai Po, the course had some turns and slopes in order to cross the road and river.

I planned to reduce further to 12 km/h in km 6 to further recover from the too-fast-running in the first 4 km, but immediately at the 5 km point there was a downward slope which accelerated me back to near 14 km/h, then after a few hundred metres an upward slope slowed me down to about 10 km/h, and ended up 12.9 km/h on km 6. There was another downward slope at the 6 km point which accelerated me back so I targeted 12.5 km/h in km 7, and ended up 12.4 km/h. As the slopes in the previous km seriously disrupted my rhythm, I decided that I should just stay with 12 km/h for a few km afterwards, and got 12 km/h in km 8. km 9 was run in Mui Shue Hang Playground, however it was not completely flat but it had a little gradient which made my speed uneven, and got 11.8 km/h. The first turning point was about 8.7 km.

Kilometres 9 to 13

After the turning, the course was mostly flat along Lam Tsuen River apart from a few little slopes, so I targeted 12 km/h, gradually increasing to 12.5 km/h along that stretch of the course. However, km 10 had a slightly downward gradient which I made 13.3 km/h, then 12.5 km/h in km 11. then 12.8 km/h in km 12. Just before 13 km I decided to have a rest stop as I did in every training run at a water station which I made my only hydration along the course, and got 12 km/h in km 13 including the rest.

Kilometres 13 to 16

After the rest stop came the 2nd turning point in Tai Po Waterfront Park, however I found that I could no longer get up the speed on the stretch before the rest stop, and started to find it increasing difficult to keep at even 12 km/h. I made 12.3 km/h in km 14 and 12.2 km/h in km 15. In km 16 there was an upward slope and I decide that I would mentally give up keeping 12 km/h and walked that slope, hoping that the download slope afterwards could bring me back the speed, and I only got 11.5 km/h in km 16.

Kilometres 16 to 21.1

This was the final part of the race where we ran back from Tai Po to Science Park.

I tried to keep my speed brought from the download slope in km 16, but it didn’t help much as I started to become tired, and got 12.4 km/h in km 17. I tried if I could push to 13 km/h in km 18 and ended up 12.8 km/h. I looked at the watch and at that time I had no hope to chase for 100 minutes finish so I just gave up mentally and km 19 and 20 became a jog for me, and got 11.2 and 11.5 km/h. As I entered the final km, I started to give all my remaining out for the finish, and got 13.4 km/h in km 21. I crossed the finish line at 1:41:50 (unofficial).


My legs were not destroyed in the race that I could still walk away, unlike when I did my first 17 km training run on my 5th week of training which my legs got painful for a whole day afterwards even my training run was only at 11 km/h, compared to 12.5 km/h in today’s race. However, I still felt that I was undertrained for the race despite getting a good result within my adjusted expectation for my first half marathon.

I didn’t think about running a marathon before the race as a proper marathon training will need around 4 or even 5 runs per week with about 40 – 50 km weekly mileage, which I can’t even make 3 runs most of the week now when I’m training for marathon swimming at the same time. However, as I felt good after the half marathon, I now believe that I can train for a full marathon using similar methodology with what I trained for the half marathon and what I trained for marathon swimming, and training to run a full marathon also seems like a good break in the off season of marathon swimming as well, so I started looking at race calendars next year to choose a marathon which is flat, and fits well within my marathon swimming plan. Eventually I’ve registered the Seoul Marathon on 22nd March next year, which is known for its flat course good for making a PB, i.e. 15 weeks from the half marathon, and 10 weeks after the 14 km marathon swimming race “Cold Half” which I’m doing next year.

I’m at the training peak for the marathon swimming race next year as the weather has already cooled to a good level, so I’m currently focusing on swimming now, and my run training is now in recovery mode after the half marathon which I will just get back to about 3 runs, about 20 – 30 km weekly initially gradually before the marathon swimming. Afterwards I will scale back my swim training and do less long swims, and mainly work on short speed sets instead as I want to get my swimming faster to the level of 1:40 for 5 km comparable to my half marathon result (5 km is half marathon swimming), which I currently expect 1:50. That will make some time out for me to start the serious marathon training, upping to 4 – 5 runs with about 40 km mileage per week for about a month and a half.

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