Here we are again. My third time competing in the 20 km door Brussel. In the past I took part in the 2015 and 2016 editions. After the 2016 edition I declared I would stop caring about it because it is so stupidly crowded: up to 40,000 people sign up, starting across just six waves. In 2017 I was abroad when it happened. This year however, I was half considering doing it again. Since 2016 ended in, in my opinion, failure, I still had a score to settle. I was not sure I really cared enough though. Then a co-worker started taunting and challenging me. He was set on breaking my PR and becoming the best in our lab. Eventually I decided to commit and signed up, six weeks before the race itself.


Have not actually done much specificity training for this one. Instead I will just describe what I have done the past months. Base building, largely. Aiming to run 65 km per week, spread over six days. Long runs on Sunday. A tempo run if the body feels up to it. Some strides. Down weeks every fourth week. Been doing it this way as I have noticed some trouble in the past in getting safely past 70, so I have been giving my body time to catch up to things.

I also feel like I should mention I have been ensuring my long run is not too crazy in comparison to the total distance I run in a week. Specifically, I have not run more than 18 km in one run since 8 January 2017, when I ran 21.5. This would not change in the build up to this race. I know I can run 20 km and I did not believe it would add anything in particular to my training.

The 65 km per week idea started in February and went OK then. Got some tempos in, some few 100m sprints. Halfway through March I caught a fever right before having to go to Italy for a conference. I was forced to take several days off. I went to the conference while still on fever reducing meds and short on sleep. It was a bit hard on the body, but I managed to get back to running.

In April my mind was turning towards the 20 km. I did a test race on the 8th of April, seven weeks before the race. It went pretty well. Despite keeping myself under control, I managed around 4:20 pace. Of course, that race was flatter and, as it turns out, cooler temperature than the 20 km would be. Regardless, that sealed it for me, and I signed up shortly after. The rest of April went fine until the final week. My right knee had been bothering me a bit. It was not painful, just noticeable. A rusty/creaky feeling, the movement felt not necessarily smooth. I find it hard to describe. I decided to take some days off, see if it changed anything. After a few days, it was still similar and I decided to just get back to running.

For the first two weeks of May, I decided to slightly up the distance I ran: 68 km and 70 km. Peaking of sorts (hah). On top of that, the Wednesday of the second week had a sort of 31×600m workout. That one definitely tired the body out. I got through it though and squeezed out a progression long run on the Sunday of that second week too.

The next (and final) two weeks were easier, with the race on the Sunday of the second week. The distance went down a little bit (60k and 50k planned, respectively), though I still threw in a tempo on the Thursday of the first week. The first week ended with a trip to Amsterdam, which added some walking and biking. The biking tired out the outsides of my hip a little bit (left side especially), I think the rental bike must have forced me in a slightly awkward position. The week of the race was almost all recovery runs, except for Wednesday when I squeezed in a 500m sprint for a little internet competition.

Course Details

For a longer description, see the 2016 report.

Some highlights:

  • Decent net uphill in the first half
  • Add on to that three tunnels
  • More downhill in the second half
  • Easiness of second half negated by a 40m climb over the course of 1 km starting neatly around 2.5 km from the finish

Goals and Strategy

On a non-number level, I wanted to make sure my co-worker would not be the best of the lab after this race. I was OK with him breaking my old PR, but I was set on breaking it myself too and doing it better.

In actual numbers, my PR was at 1:30:40 from 2016. 2015 had been 1:30:41, I paced 2016 terribly and blew up. My co-worker’s PR was 1:33:xx from 2016. I will admit I did not feel terribly threatened by him (hubris?). I figured if he would break my old PR, it would not be by much. He on the other hand was saying his training had been better than ever and that he felt more in shape than ever before.

At the very least I wanted to PR. Besides that I figured my body could handle a 1:27:30, which would hopefully be plenty to keep him away. I had a stretch goal of 1:25 if I was feeling particularly good.

In the week of the race, two important things happened.

For the first point, let me sketch my co-worker’s running a bit. On a yearly basis, when the worst of winter is past, he starts training for the 20km, races it, and then his running consistency slowly fizzles out again. As far as I have been able to gather, he has been doing it like that for at least five years now, possibly more. The same stuff was happening this year. He started at the end of January, doing 9 km, 21 km, and then 43 km in the first three weeks. After that he hovered around that weekly distance, sometimes down to 25, sometimes up to 55. He however spreads out these kilometres over an odd choice of runs. A selection includes: not running for seven days, then running 20 km and 17 km over the course of three days; and running 57 km over the course of four days, one of the runs being 30 km.

With the sketch behind us, let us get on to the actual important news. The weekend before the race, he decided he should do a 20 km run at 20 km race pace on Friday evening followed by hunting for a 4.5 km segment of mine on Sunday morning. Wednesday he tells me his foot hurts, even when walking (the foot had been nagging him already about a month ago). Thursday he comes into the office on crutches. The pain was too much to walk on and he was going to the doctor later that day. He still had hopes for Sunday, I just hoped he was not going to be dumb enough to run on that. Side note: I have also done dumb stuff in my running training, most of us have probably been there. I however did try to warn him almost every time we talked about running, so I feel like I can be free in what I say about it now.

As for the second important thing, the weather prediction was terrible. The entire week was not that hot and had plenty of rain and thunderstorms. The Sunday prediction for the race, however, was around 24C at the start with not a cloud in the sky and a high of 29C. Not my kind of temperature. The race organisers said there would be three water curtains to help with the heat. The news outlets all started putting articles online how to survive a day like that. We barely ever reach 30C here, so this was a big deal. The day before the race, the weather was about the same as the weather was predicted to be on the day itself. I decided to do my planned recovery run, starting 30 minutes past what would be the starting time. It sucked, I suffered, it ruined my confidence for the race. At this point, I was going to be happy with a PR.

The final plan was: do the first 10 km at 1h30 pace (4:30 per km), then see what (if anything) I can do in the second half.

Pre-race Logistics


To be more kind to my body, I decided to work from home on Friday. I tried to make sure I drank more water than usual to stay extra hydrated (is that even a thing?). There was no run planned this day.


I usually need quite some sleep (9 hours+) and am sadly also not very good at sleeping. Despite my attempts to fall asleep, I only got about 6-7 hours in. I hoped I could make it up the next night.

As mentioned in the previous section, the weather on Saturday was pretty much the same as what was predicted for Sunday. I ran at 10:30 (30 minutes past the race’s start time) to get an idea of what to expect. As above: it sucked, I suffered, it ruined my confidence for the race.

The rest of the day was not kind to me either. Every time I got up out of the couch, I had a head rush and felt dizzy. I was still drinking quite a bit of water, but my body was not happy. I wondered if I got dehydrated after all. I was not sure what else I could do besides all the water drinking I was doing. I was not sure it was dehydration at all.

I finished the day with my usual pre-race dinner of spaghetti bolognese.

I had trouble falling asleep.


I woke up at 7:00 (3 hours till race start), only getting in about 7 hours of sleep again. I decided to help wake me up by blasting up beat classic Belgian songs. It helped and they would stay on till I left around 8:30.

I had two and a halve plates of the leftovers which was, in retrospect, maybe just a bit too much for a race. A burp during the race briefly brought up a tiny bit of it to the back of my throat. Nothing else of it directly bothered me though, I think.

Besides that it was a matter of drinking enough water and using the toilet often enough. We left at 8:30 to catch the metro to be at the race area around 9:15. The girlfriend was not racing, but was kind enough to come along and carry some water for after the race and a change of clothes.

There was a brief distraction due to a goose family ending up in the crowd. The police helped the troublemakers on their way though.

Another agent was present outside this view. Someone else told me they had seen five agents discussing the goose situation earlier.

I made sure my watch was on the data screens I wanted. The Forerunner 225 only has two screens with up to the three fields each. I picked Time-Distance-HR and Avg Pace-Lap Pace-HR. Due to GPS discrepancies, the average pace field would prove largely useless. After some last small sips of water, I went into my wave’s corral around 9:30. For once, entrance to the corral seemed to actually be checked properly. There were even some policemen accompanying the race official in case someone would start complaining. Next I did a short warm-up jog in the area. Some clouds were showing, but afterwards I still went to hide under one of the trees to ensure I kept cool enough.

Soon, the Bolero by Maurice Ravel started playing. The 20 km door Brussel always uses this ~15 minutes long classical song as the final build up to the start. I kept my head focused on the race and did some knee lifts and similar things to keep the body moving. When the Bolero ends, the Belgian anthem starts playing, not many races in Belgium do this. I used it to get a bit more hyped and everyone’s clapping helped get me further in the right mindset. By the end of it, I noticed a few rain drops were falling from the sky, which gave me back some of the confidence I had lost in the warmth the day before. The few lost drops would stop again immediately, but it was what I needed to fully focus on not worrying. The gun went off and everyone started slowly walking or jogging to the start line, which is a bit of a bottleneck.


As is tradition in most any race of mine, I started out too fast. In my defence, it is a bit tricky to get right. The first km is downwards for a couple 100 metre before going upwards about to the same elevation it started out at. Around the end of the second kilometre, you pass in front of the royal palace, running over terrible terrible cobbles. At this point in time I still feel fresh so the extra concentration for it is easily managed.

As we pass the first water stand, things are a bit of a clusterfuck. I somewhat easily can grab one, but someone in front of me fails to do so. I start getting his attention to share mine, but he asks someone else before he notices me. Someone else comes from behind me and asks if I he can use what I have left. I happily oblige and wish him good luck. I did not catch his bib so I do not know whether that worked out. I pass the 3k point on my watch ahead of my time schedule.

First three kilometre in 4:09, 4:19, and 4:28.

I notice someone with a rather weird running style in front of me. His legs swing somewhat sideways and it all looks rather laboured. I briefly ponder about it, but figure if it works for him, I am not one to judge. The race is softly climbing up a boulevard at this point, though everything is made more difficult by three tunnels spread throughout it. The tunnels give a brief reprieve when you enter them, but coming back out of them is a climb on top of the climbing. Not my favourite moment of the race, not the worst either though. Just past the second tunnel I notice the guy with the odd running style again. As I once again ponder his efficiency, he veers to the left side of the road and starts walking. So far for that question.

We reach the end of the boulevard around the 6 km point and turn into Terkamerenbos. I notice my GPS distance and the race signage already disagree on the distance. I blame it on the tunnels and decide I will ignore the “average pace” field of my watch in favour of doing some calculations using my total time and the race signage. I do not have that information here, so the GPS laps are all that are mentioned here. Perhaps I should have started pressing the lap button when I saw signs. Either way, I am still a bit too quickly through 6 km as well.

Kilometres four, five, and six: 4:45, 4:41, 4:24.

This forest-y area we are now in has some more shade and I try to stick to it where possible. The second water bottle stand is still clusterfucky, but slightly better than the last one. I begin to notice I am not good at drinking from a bottle while running, managing only the tiniest of sips, stressing my patience. I end up pouring most of the water on my head instead. Maybe a bit of waste as I see the first of the water curtains coming up around 7.5 km into the race. The setup is some device lying on the ground that is spraying upwards, creating a sort of fan of water. I take my hat off as we run past it in hopes of getting that extra wet too. The effects of it did not feel as significant as I hoped. Each individual water spray is rather thin. At the next provision stand only the sports drink by one of the sponsors is served. I grab one, take two sips of it and decide I do not trust it enough to down everything. I had not tested how my stomach handles it after all. A wise choice: shortly after the two sips my stomach felt rather heavy, something that would last for a km or two.

terkamerenpic I am on the left, in the Belgian tricolore shorts.

Next we make a sharp right turn to get back out of the forest. During the turn, someone on the inside suddenly stops turning, running straight into my path, getting me out of my stride. I cast an angry glance and see him start walking. I do not understand how he thought that was the best course of action. If I recall he could have more easily stepped in between the sparse bushes on the inside of the turn. Shortly thereafter, I pass the official 10 km mark. I am over a minute ahead of what I had planned. Shortly there after, my watch tells me we hit 10.

Official 10 km split: 43:51 (i.e., 4:23/km or on pace for 1:27:42).

Kilometres seven through ten: 4:51, 4:19, 4:22, and 4:26.

I thought that from here on out it would be smooth sailing on a slight descent for a while. I had misremembered. The road remains flat-ish and even throws in another climb at 11 km. It is not that bad in se, but my body started feeling the effort of running faster than what I thought was good for me in this weather. Luckily after that last bump, the descending does finally start. I am not speeding up the way I had hoped I would. Body says no. I zoned out more from here on out too, not noticing or remembering as much from my surroundings as I did before.

As I spot the second water curtain on the other side of the road (~12 km?), I veer towards it (while ensuring I do not run in front of other runners). I decide to just run straight over the device, maximising the amount of water to hit me. I exit completely drenched, but feeling a bit refreshed. In retrospect I think it was worth it in this weather.

I notice someone who, from the side, looks like someone I might know. He does not notice me. For a while I hesitate whether to say hi, but eventually I pass him without having said a word. Turns out it was not that person, so social awkwardness crisis averted.

In my zoning out, I do notice the shirt of someone in front of me. It says “follow me till the last mile”. I think he may have been a pacer before. Over the next kilometres, I will see him often as we run about the same pace.

Kilometres eleven through fifteen: 4:35, 4:24, 4:22, 4:28, and 4:26.

The descending is behind us now and I am feeling the effort more and more. It is starting to show in my splits as I have trouble holding the 4:30 pace I had planned for the first half. I get a little worried about completely blowing up. I use the final water curtain in the same manner as the second, running straight over it. Quite some water gets in my shoes now, which feels less nice. The rest of my body is very happy with the refreshment though.

It is needed too, because the worst is yet to come. The Tervurenlaan climb is coming up, hated and feared by most people doing this race. In 2015 I had quite some in the tank still and felt quite alright on it. In 2016 I was already falling apart and the climb just completely ruined me. I feared today would not be a happy memory.

We turn onto the Tervurenlaan and… things feel OK. It is going upwards, but not that bad at all. My relief is short-lived. The actual climb was still to come. Once that happens, I start slowing down more, adjusting my pace to keep my heart rate under 180. I see “follow me till the last mile” guy slowly getting away, but do not bother adjusting my pace to his. By the time we reach the top, I am ready for this race to end.

Kilometres sixteen through eighteen: 4:32, 4:35, and 5:07.

I feel that my body does not have much left to give. To keep the pace OK, I focus on tailing a woman I spotted near me. A glance at my watch does tell me that PRing should be easy now. The Tervurenlaan had trees for some shade, but now that we are past it, I feel the sun burning on my back. I flip my hat backwards and live with potentially looking like a douche. In the distance I see the monument marking the finish line. I get caught up in the moment and make a beginner’s mistake: I start my end “sprint”. There is however another 1.5 km to go. I realise this as we reach a roundabout that I know to be about 1 km from the line. I briefly slow down again, but then think “fuck it”. If there is anything at all left in the tank, then we are throwing it all out now. I overtake people, an act that is going much more smoothly than in previous editions. The crowd of remaining runners is less dense than I am used to. One of the people I pass is “follow me till the last mile” guy, which gives me some satisfaction. It took me longer than the last mile, but I listened to his shirt in the end.

Coming into the park in which the finish line is located, there are some cobbles. While they are, in theory, much easier to run on than the ones in front of the royal palace early on in the race, they give me more difficulty. My tired body has trouble quickly getting itself through that section.

finishpic Longingly looking at the finish line.

Finally the finish line itself is in sight. I use whatever else I have left and am glad to have made it in one piece. After crossing, I stumble through to get some water, a banana, and my medal. The girlfriend finds me and we walk on to get away from the crowd and to find some shade under the trees. I drop down and take over 30 minutes before I feel like moving again to head home.

passedoutpic Ded.


My official time is 1:27:59. My Strava is also available. Despite the more friendly profile of the second half, I still had a positive split: 43:51 and 44:08. That makes for a 2:41 PR. I am satisfied, but not particularly overjoyed with this. I feel like I could definitely have done much better if it were not for the warmth. My ranking seems to confirm this, I broke into the top 1000 (984th to be exact). A PR of over 1300 spots. That one does make me quite happy. For comparison, two years ago, when it was five degrees Celsius cooler and clouded, the top 1000 was just over 1:25.

Year Time Rank
2015 1:30:41 2833
2016 1:30:40 2345
2018 1:27:59 984

The injured co-worker did not run the race in the end. The doctor put him on anti-inflammation medication, though he said it might also be a stress fracture if the pain persists. Of the other co-workers that took part, none finished within fifteen minutes of me.

I posted some pictures and results on Facebook. This lead to everyone that saw me throughout the week telling me I run ridiculously fast. It is all about the point of view, I guess. I definitely need to/want to get better still.


Near Future

I am thinking I will go back to / continue with my base building. I believe it is time to try and push my weekly distance a bit further again. Hopefully my body agrees with my mind. Looking at other people, I still have quite a lot of room for improvement with my measly 65 km per week.


The half marathon distance is a bit stupid, I like my numbers round. Following that train of thought, I sort of got hooked on the idea of finding and doing various 20 km races. First major candidate for such a plan would be the 20 kilomètres de Paris on 14 October. I would have to see whether I can actually fit that into my plans without it getting disgustingly pricy, but I like the idea on the surface. I believe it is both more flat and more likely to be less warm than the Brussels one.

Next Edition

I have not decided yet whether I will take part again next year. The same two factors that made me hesitant after the 2016 edition are still in play:

  1. It is still a rather crowded affair. It was better than I remembered, because I ensured I started closer to the front of my wave and because I have gotten faster since my last edition.
  2. The weather at the end of May can be really sucky. This can ruin time goals completely.