Guest post: Half marathon time trail

by Mollie Millington | Jun 16, 2021 | guest post, running

Running a half marathon PB

For 14 weeks I trained to run a PB for the half marathon. That being said, achieving a PB was not going to be too hard given that this was the first time I have properly trained for a race. I had run a couple of half marathons in the past, but only ever in long training runs (the first time I tried the distance, I paced myself to come in at just under 2 hours so that I could tick a sub-2 hour half off the list). I was excited to see what I could achieve when I committed to a goal.

On Saturday 29th May, with the help of a friend who had kindly offered to pace me, I ran a half marathon PB (TT) of 1 hour 42 mins and 18 seconds!

I missed both my A goal (1 hour 38 mins) and my B goal (1 hour 40 mins) but, all things considered, I was actually very pleased. Here are some of my reflections on the effort on the day, and on the training that came before it.

Training to a plan was great for accountability:

I have not always been a runner; I only really took it up a couple of years ago as part of an effort to lose weight. Until this training block, I had always just gone out to run 5k or 10k (or whatever distance Mollie had convinced me to tag along for) without a purpose or a goal. Some friends and I arranged our own virtual 5k TT during lockdown and I did a few intervals in preparation but didn’t follow a plan; I underperformed on that day and was extremely frustrated with myself! After that experience, I was determined to train properly for this half marathon so I signed up to a Garmin training plan that I could download to my watch.

Having the structure of being told what workout to do each day was a massive help and I made sure I didn’t miss a session. It actually made running way more fun because I knew what I had to achieve in each session and so I was never tempted to slack off when things got tough.

That being said, I followed the plan to the letter and I am not sure the latter weeks of the plan suited me perfectly. I felt that the plan switched from hard intervals, speed work and long runs to tempo/goal pace runs too early. Next time I will be in a better position to make my own decisions about the design of the plan and I will probably do a bit more mileage and have a bit less of a taper.

Easy runs to heart rate were a game changer:

For the entirety of the training block, the plan suggested my easy paced runs (including the weekend long run) should be between 5.16 – 5.54 p/km which at first, compared to my previous tactic of just going out and running at a moderate pace, felt pretty slow. As a result, I ran the easy paced runs and long runs at the start of my plan towards the top end of this pace interval. However, half way through the training, after reading more and more about running to heart rate, I decided to run these sessions to 130 bpm and forget about the pace.

This made a huge difference. Although I was able to run relatively comfortably at 5.16 p/km, when I slowed down a bit (to meet the 130 bpm goal) I recovered a lot quicker and felt less physically tired. This helped to go harder in the interval and speed work sessions; and within a few weeks, I was able to run at 5.20 p/km at 130 bpm.

Working full time and training is hard:

As I’ve already said, I stuck to my training plan religiously; but balancing training with a full time job is not straightforward. I work in the finance industry and regularly work 10-12 hours per day sat at a laptop. This means that it can be difficult to find the time to squeeze in three sessions of 40-75 minutes during the week. In the end, it took a combination of flexibility/opportunism (for example, being prepared to run at 9pm at night or squeezing in an intervals session between meetings) and a very understanding partner (who didn’t complain about having to do more than her fair share of cooking and household admin to allow me to get more running in).

Getting enough running in on top of work also impacted on my sleep. I often found that I was faced with a choice of getting enough sleep or having enough down time in the evening. Choosing to end the day with at least a couple of hours of television, or reading, meant that I regularly got a bit less than 7 hours sleep; and towards the end of the 14 week training block I really noticed I was feeling a bit fatigued.

Conditions are a huge factor in performance:

Between February and early May the weather in London was relatively cold, which meant that the vast majority of my training was undertaken in conditions between 3 – 12 degrees celsius. In these conditions, I had never had to think about the impact of heat and consequently had never tested my nutrition and hydration strategies outside of this range.

On race day the weather started at 16 degrees in the shade at 10.30am, rising to over 20 degrees by 12.30pm with close to 70% humidity. This was a lot hotter and humid than anything I had run in during the preceding 14 weeks – I had missed perfect conditions by 3 days. I considered changing the plan and setting off earlier to reduce the heat, but that would have meant throwing off my morning routine and running the risk of needing the bathroom mid-race.

Long story short, I kept to the originally planned timings and figured that I would deal with slightly hotter conditions. In hindsight, this was probably unwise. In training I had progressed to a point where I could comfortably run large intervals at race pace with a heart rate of between 150-160 bpm, however within a couple of kilometres of starting the race my heart rate had rocketed to over 160 bpm. Part of this could have been nerves, but I suspect a large part of it was the heat. And in the heat, I was never able to get my heart rate down again (my average heart rate over the race was 169 bpm).

When you think you are done, there is definitely more left to give:

After spiking my heart rate early in the race, after 9 km I felt much worse than I should have done. Until then I had been able to keep broadly to race pace (4.40 p/km) but I started to realise that I was unlikely to be able to maintain this for another 12 km. I asked my friend who was pacing me to take off 5 seconds p/km in the hope that if I was able to recover a little then I could make it up in the final few kms when I didn’t have to worry about preserving energy.

The course I had chosen was a 5.77 km loop through the Olympic park, along the canal, and around Hackney marshes. At the start of the fourth loop, I hit a wall. I had heard people talk about hitting a wall when running long distances, but I had never experienced it until then. Having run 17 km, with only 4 km to go, I suddenly felt like I wasn’t going to be able to make it to the end. My right hip was starting to hurt with every step, one of my abs was cramping, and mentally I wasn’t in a good place.

Even being so close to the finish, I started to think about the prospect of stepping off the course and conceding defeat. I’m really glad that my friend was pacing me, because one of my biggest thoughts to counter the negativity was that he had travelled across London to run for me (even carrying my water) and therefore I couldn’t let him down by stopping.

According to my Garmin/Strava, I managed to keep the pace at around 5.00 p/km for the next 2 kms; although in the moment I had lost all ability to think about anything other than the distance counting down (which seemed to take an age) and continuing to put one foot in front of the other. The second to last km was the slowest at 5 minutes 23 seconds but for all I knew it could have been 7 minutes – I was in that much pain! When it came to the final 200m I tried to pick up the pace or even sprint, but immediately my calves started to cramp up and I hobbled the last hundred metres before collapsing at the side of the path.

A combination of the heat and potentially not enough water meant that the last few km were harder than I had ever imagined, but I can safely say that I got absolutely everything out of my body. Whilst it wasn’t quite the time I was hoping for, I am pleased with the effort and I learned a lot of valuable lessons from both the training and the race itself.

It’s now time to spend a few weeks relaxing, focussing on some other sports such as cycling (without feeling guilty that it’s not on the training plan), and running just for fun; until I decide on my next challenge!