Chicago - it's my kind of town!

But nothing could have prepared me for the sense of excitement and trepidation as myself and wife Alison stood on the start line.

We waited with thousands of others in our starting wave, gazing at the magnificent Chicago sky line, wondering what the next few hours (and a bit) were about to bring.

I had written three key words on my hand that Neil Featherby and I had spoken about leading up to the race to try to guard against the excitement taking over. I couldn’t afford to waste energy on quick miles in the early stages as I would pay for it in the latter miles.

‘Intelligence’, ‘patience’ and ‘strong’ were all etched on my left hand whilst my daughter, Lara, wrote ‘power up’ on my right. I decided against asking my son, Logan, to write anything fearing he might use it as an opportunity to ask for some food.

These words were so important during the race. I needed to start the race intelligently and be patient to try and not burn through too many matches during the first half of the race.

I felt so good in the early miles at the 8:10 minutes per mile pace I set off at. Despite the interrupted training thanks to an Achilles issue, I was quietly confident I could hold that pace.

I waved goodbye to Alison, who was in far better marathon shape than me and I just hoped she could stick to a race plan that would bring her in under 3:30.

It all felt incredibly easy with the adrenaline coursing through me. It always does in the early stages of a marathon, but I had to stay focused. I was manually lapping my watch each mile as the skyscrapers play havoc with the GPS in Chicago. I made sure I fuelled and hydrated properly during the early miles whilst also debating when I could dive into a portaloo to go to the toilet. I decided against relieving myself on the start line as many people did in full view of the poor people going round collecting the discarded clothing.

The first 10 miles flew before the first pang of fatigue, but I could see my heart rate was still where it needed to be. By halfway I took another gel and still felt pretty good and confident I could hold the 8:10 pace.

There was plenty to look at and keep my mind distracted from what was to come. As I passed the United Center where the Chicago Bulls play I was thinking of Michael Jordan and how much I would have loved to have seen him play.

I was still feeling good by mile 18, which was a great sign as in every other marathon the wheels had begun to fall off. Not today; I was staying strong… but I was about to be tested.

By mile 20 I was feeling okay, but there was certainly more and more internal dialogue taking place, both good and bad.

When I asked myself the question whether I could push on from here, I knew that wasn’t realistic and thank goodness I didn’t.

When I looked at my watch at the end of mile 20, ‘8:22’ flashed up. Oh. Suddenly everything didn’t feel quite so easy and the legs weren’t turning over like they were a few miles ago. There was some turbulence ahead.

We went through the Chinatown part of the course and all the smells which would normally make me feel hungry were starting to make me feel unwell. The thought of having any more gels, or even water, was nauseating.

I concentrated and really tried to kick on but my next mile was another 8:22. This felt really hard now for a mile at that pace but I couldn’t panic. I was slowing and mentally on the ropes… ‘stay strong, Mark’… you’re not walking today.

The next few miles weren’t pleasant. I turned my watch face off so I couldn’t see my current pace. No good could come of it so I just got my legs turning over as quickly as I could.

One of 3:40 pace groups overtook me at mile 24 and I found something. I suspected they had started ahead of me in my wave so I knew if I stuck with them then I could bring this home in 3:30-something. I let the power of the group take me in the 25th mile and the crowd noise was starting to build again as we neared the end.

My spirits were lifting. I dared to put my watch back on elapsed time to check how long I had to play with as I entered the 26th mile.

My marathon maths calculated that I could actually walk from here and get under 3:40, but I told myself: ‘Remember Mark, you’re not walking today!’

The atmosphere was amazing as I neared the end and the Chicago skyline once again provided a fitting backdrop to the occasion.

After the 26th mile we entered the notorious finish where there is ‘a hill that isn’t a hill… but is a hill when you’ve run 26 miles’…

My legs complained as I ambled up the slightest of gradients. It probably would have been quicker to walk but then I came round the corner into the home straight.

I wasn’t able to mount a sprint finish but I also wanted to enjoy the moment.

Despite Achilles problems, my dog nearly dying just before we came out to a Chicago, falling down my mother in law’s stairs a few days before we left, managing the stress of getting the family out to America feeling well; I hadn’t been broken.

I had made it… and in a time I am proud of - 3:38:08.

I’ve no doubt there’s more to come, but I had done the best I could in the circumstances - that’s all I ever look to do.

I stumbled back to the hospitality tent to get back to my family. There was the odd stop on the way where I thought everything swishing around my stomach was going to make an appearance.

A packet of salty crisps sorted me out and I checked my phone to see how Alison had got on to confirm she had achieved what her training block had deserved - a sub 3:30. I genuinely couldn’t be happier to lose the ‘Marathon Champion’ status in the Armstrong household.

A very good day at the office and now there is only one more thing to do… plan the next one.