Wellington Half Marathon

Last Sunday I competed in the 2018 Wellington Half Marathon. I completed the race in 1:19:06. Despite being a flat course, howling northerlies made it anything but a fast race! The weather was so foul that one runner thought it was the worst weather he’d encountered in the last 20 years of entering in the Wellington Marathon!

With winds averaging 20 knots (37.0 km/h), it made a flat course slow and difficult. While Wellington is infamous for its terrible weather, this year seemed particularly bad. The average half marathon finishing time since 2010:

Year

Time

2010

1:55:59

2011

1:59:58

2012

1:57:29

2013

1:58:09

2014

1:57:39

2015

2:01:41

2016

2:01:53

2017

2:00:09

2018

2:05:05

While there’s other factors that could explain the slower finishing time, it’s reasonable to suggest that the weather was largely responsible for the 5 minute slower average finishing time.

But does wind affect everyone the same? I found an interesting paper titled The Influence of Wind Resistance in Running…. Since drag force is proportional to the square of velocity, it comes of no surprise that the faster you are trying to run, the greater the impact of wind.

Using the regression equations from the paper and a couple of assumptions (i.e., when the runner was running with no wind on a 0% incline treadmill, this is equivalent to running outside with a tail wind):

Speed (km/h)

Wind speed (km/h)

Oxygen consumption (mL/kg/min)

VO2 relative to zero wind (%)

13.5

-13.5

43.6

-2.0

13.5

0.0

44.5

0.0

13.5

13.5

47.2

6.1

13.5

37.0

55.9

26.0

16.1

-16.1

46.3

-4.7

16.1

0.0

48.6

0.0

16.1

16.1

55.6

14.4

16.1

37.0

71.7

48.0

In other words, if you were running a flat out and back course where you were either running into a headwind or a tailwind, you’d expect to run slower than the same course on a windless day! And the faster you run, the more wind affects you! The same holds true for any out and back course, where the environmental conditions (wind and wind direction) remains constant.

So how does pace themselves during a windy race? By using heart rate! From my last half marathon race, I know I can hold 176 bpm over the race. Since my max heart rate (MHR) is 189 bpm, 176 bpm is 93% MHR. I regulated my speed based on my current heart rate!

How did the race go overall? I suspect I’ve lost a bit of conditioning since trialing a Ketogenic diet for a month. While the wind did not help, I think I should have done a bit better. From my heart rate data, I should have pushed more from 12.5 km, despite predominately being into the wind. I was 76 kg on the day, had either water or electrolytes during the first three aid stations and did not eat anything on the run.

Rotorua Half Marathon

Yesterday I paced the 2018 Rotorua Half Marathon. I was the 1:20 pacer, but came in one minute too slow! Reflections on the course and my pacing are as follows…

Unlike previous Rotorua Half Marathons, this year’s one was off-road and hilly! It starts at the same place as the full marathon, but instead heads south-east towards the forest. The majority of the course is on an old gravel road. You need to watch your step carefully here: there are countless fist sized rocks and foot deep potholes scattered along the trail! There is also a kilometer of running on wet grass trail, which also has a sandy part and a muddy part! Fortunately there were no river crossings!

Part of the course is also shared with the Quarter Marathon. This makes it hard for the faster half marathon runners; in the last 7 kilometers I had to navigate through hundreds of runners coming head on. This is easier said that done as you also need to choose a path free of things that you could roll your ankle on! The elevation gain was 260m.

As part of my preparation for my pacing duties, I studied the course profile. Instead of even pacing I needed to opt for even effort. I devised a program that gave kilometer splits, given the course profile and target time while maintaining an even effort. I followed my prescribed plan during the race. Judging by my heart rate, this plan indeed resulted in an even effort. I suspect it would have been spot on, had I factored in the surfaces I’d be traversing.

Effort-wise, being the 1:20 pacer was suitable and well within my ability, even on a hilly trail course like the new Rotorua Half Marathon. From races in the eight months, my average HR for the 10K, 21.1K and 42.2K events are 180, 176, and 170 respectively. With yesterday’s run, my average HR was below my average HR for a marathon! My max HR was also the same as what I average in a half marathon race. This was a surprise to me, given the steep hills on the new course.

All in all the new Rotorua Half Marathon course is enjoyable and a nice change from road running. However, I’m unsure whether it is a wise idea having off-road courses added into what has been and is a road-running event. If I were pacing for a 1:20 again on the same course, I would aim to run 4% faster on the road surfaces (equating to 3:36 min/km on the six kilometers of road).

Auckland Waterfront Half Marathon

Last Sunday I competed in the 2018 Auckland Waterfront Half Marathon. My official race time was 1:16:43. This was a great result for me: I managed to slash 3 minutes from my previous best (PB) half marathon!

The Auckland Waterfront Half Marathon is a new race that runs along Auckland’s Tamaki Drive. To reach the 21.1km distance a large portion of Tamaki Drive is covered twice. Unfortunately this meant that there was was a lot of other runners to negotiate around on the second loop. This also made it near impossible to pick up a cup of water at the aid stations! As a result, I did not hydrate properly during the race.

There was no wind or sea breeze. Next time I’d consider running with sunglasses, given the orientation of the course and the morning sun. It was between 15C and 18C with 75% relative humidity while I was out running. This gives a wet bulb globe temperature (WBGT) between 13.3 and 16.1. According to research this was a challenging environment to achieve a PB, despite the “fast and flat” course!

Notes to self: I was 77.5kg on the day. This is about 1.5kg heavier than I was two weeks ago! I was out of the country for a week a week ago and was on an untypical diet. During the race I actively monitored my heart rate (HR) and tried to keep it below 176bpm. Despite consuming less water that I would have liked, ironically I still felt bloated for most of the second half of the race. The last four kilometers were tough and it showed in my poor posture towards the end of the race.

Christchurch Half Marathon

Last Sunday I competed in the 2015 Christchurch Half Marathon! My official time was 1:20:24 and I was 59th across the finish line! This is my second official half marathon and achieved a new personal best!

My goal was sub 1:20. The plan was to maintain 3:47 min/km for as long as I could. To my surprise, I (almost) managed to maintain this pace! I carried an energy gel but I did not use it.

I enjoyed the course. It was the first time it was held in the city since the devastating earthquakes in 2010/2011. I was 79kg on the day (I have lost several kilograms since having dental braces).

Wellington Round the Bays

Yesterday I competed in the 2015 Wellington Round the Bays half marathon! My official time was 1:24:26 and I was 27th to cross the finish line! This was also my first official half marathon. It was also a long time coming – I intended to do this race five years ago but never got around to doing it!

The plan was to maintain 4 min/km pace (15 kph) until the half way mark. Depending on how I was feeling, I either step it up or hold onto this pace.  I ended up doing both! At 10.55km, my average pace was exactly 4:00 min/km. The next five kilometres my pace dropped slightly. This was most likely due to the sea breeze headwind out towards Kau Bay. Determined to maintain the target pace, I mustered the energy required to finish strong and finished the race in 1:24:26, hitting the target average 4 min/km pace!

No major complaints with my run. I stuck to my target pace and felt great throughout the race. Oddly the only muscle that was tender post race was my right tricep! I consumed one energy gel at 12 km and had three mouthfuls of water along the way. Half a cup of rolled oats before the race was adequate. I’m currently 85 kg – 3-4 kilograms too heavy!

I was not the only one from my family competing in the event. My mother also entered and finished the event, her sixth half marathon. Well done mum!

I enjoyed yesterday’s half marathon distance run. It is a long run yet not too long. Unlike full marathons, I did not ‘hit the wall’ and it never felt like a long slog to the finish. I’ll have to sign up for more half marathons in the future!