It's big, it's bold and you're afraid of it. Let me tell you a secret though – the marathon 'wall' doesn't really exist.
Over shorter distances, your success in a race is mainly dependent on how fit and prepared you are physically. As the distance increases, the mental component of running increases.
By mile 20, the mental effort will take you as far as your physical fitness (which is why people who are not the fastest over shorter distances can sometimes excel over the marathon distance through grit and good race execution).
There are three main reasons why people hit the wall in the marathon, and with a bit of careful preparation, you can cruise right over Heartbreak Hill at mile 20 on Roebuck Road and sail down through Ballsbridge with end-of-race speed you didn't know you possessed.
1/ The original reason why people faded in a marathon was simple: lack of knowledge on nutritional requirements. The real wall is caused by running out of muscle glycogen. If you've done enough training, eaten well for a couple of days before the race, and fuelled along the course with gels or sports drinks, then there's no reason why you should run out of fuel.
Don't be tempted to skip aid stations or neglect your fuel intake, as once you're dehydrated and/or low in fuel, the wheels will fall off rapidly.
2/ Setting out too fast is probably the number one reason why people run into trouble towards the end of a marathon. This is where some realistic goal setting comes in.
Don't be tempted to 'put minutes in the bag' – running too long at an anaerobic pace will burn all your glycogen and tank up your legs with lactic acid so that the 20-mile crash is inevitable. If you've paced it right, there will be fuel in the tank to pick up the pace slightly for the second half.
3/ Mental fatigue can cause you to grind to a halt. The problem with most marathon training plans is that the longest run is 20 miles. Once you pass mile 20, it feels like uncharted territory. A bit of mind work prior to race day can be hugely beneficial.
I like to mentally build up the last 10k as the celebratory cruise to the finish line. As you near the finish of a big marathon – and the support in Dublin is always phenomenal – the crowd support is an enormous boost.
Instead of simply surviving in a marathon shuffle, act like the runner you are; run strong, pick up your feet and soak up the support.
And remember, folks, if you do hit the wall, keep running.
I am reminiscing about dodging the wall at my last marathon, during Ironman Sweden in August. If there's a guaranteed day to hit the wall, during an Ironman is probably that day, given the preceding niceties of a 2.4-mile swim and a 112-mile bike ride.
Despite struggling a little with nausea, I felt great during most of the marathon, but started inevitably to suffer on the last of three 14k loops on the run. I had left my marathon goals fairly loose but was holding a steady pace which would take me to the finish line at just under 11 hours if I didn't slow down – or just over if I did.
At 20 miles, I had some loud internal voices shouting at me to slow down. Instead, I concentrated hard on maintaining my stride, and slowing down as little as possible. I had to break my goals down into short recognisable distances.
By the time I reached 40k, I had minimised the slowdown enough that I could see my 11-hour goal clearly in sight, and suddenly – miraculously – my feet had wings, so that I ran the last 2k with a burst of energy, celebrating with the crowd all the way.