Preparation/Planning

What I found different was in the mental preparation for 100miles. Many months were spent rehearsing for the event in my head, and coming to terms with the appreciation that 100miles is pretty much double 100kms, or at least it will feel that way.
The other key thing was that DNF was not an option because it takes so long to train for 100 miles and that a second chance for this event would be another 12 months off and that was not a time I was happy to wait. So I had to adopt a no excuses mindset, prepare for discomfort and have a strategy that would get me to the finish.
Pace
When running 100m over 100kms, pacing is all important. You blow up early in a 100 miler and it’s going to be a long day at the office. This was especially relevant for GNW 100 as it was hot and humid.
My normal ultra strategy is to walk all the hills and run the flats and the downs. The trouble is that on race day you can get dragged along by the crowd and you find yourself running someone else’s strategy, not your own.

Patience
As with all things ultra running related, you need to have a pace strategy, and be prepared to adapt it to suit conditions. And for a 100mile race you are going to have to be patient, it’s just too long to rush things no matter what your ability.
For example, if it is especially hot you may want to take it easy through the heat of the day and focus on keeping hydrated, and then as the heat drops of push the pace a little. It leads us to another “P”, preservation, you simply have to preserve what you have to keep you moving forward, and this takes patience.
Perseverance/Persistence

The difference from running 100km is that the periods that you require perseverance are far longer and far tougher, and that takes immense mental fortitude. Which leads us to...
Psychology
Without doubt the biggest difference between running 100km and 100 miles is in your mindset. In fact all of the above “P’s” are basically psychologically based.
In a 100km race you will go through many mental ups and downs, and you will find your subconscious throwing up all manner of excuses for you to drop out before the finish line. In a 100mile event these ups and downs are deeper and stronger and tend to last longer. You can find you get absorbed in a mental tug of war with yourself for many hours.

So if I had to define the difference between 100kms and 100miles, I’d probably say that it’s not all that different, just a whole lot harder, far more than twice as hard. You have to be mentally tougher, more controlled, more disciplined and be prepared to maintain that for twice as long!
Happy Running!
Andy
“If you’re going through hell, keep going” - Winston Churchill
www.ultrarunning.com.au