Why Run A Road Half Marathon In Training For A Trail Ultra?

By Ian Sharman

 

Sharman running in Lake Tahoe

A lot of ultrarunners focus on mountain races and therefore mainly train by running trails and mountains. That’s certainly important as training needs to be specific to whatever your goals are.

 



However, as an ultrarunning coach I’ve seen both in theory and in practice that this often leads to a runner slowing down. Yes, the ability to climb and descend gets better, but the pace on easier trails goes down. And most ultras have a lot of faster running in there as well as some climbs to slow things down a bit.

 

So, even though most people are unlikely to hit their half marathon road speed in a trail ultra, by working on the uncomfortable pace close to your lactate threshold (as a half marathon does), you force your body to adapt and be able to sustain a higher pace when on long runs. Your lactate threshold is basically the exercise intensity where lactic acid starts to accumulate in the blood, when lactate is produced faster than it can be removed. Effectively, this causes a runner to slow down so the higher this boundary can be pushed, the higher his or her sustainable pace becomes.

 

If you can make 6-minute/miles feel easier (or 7s, 9s, 11s etc) at the high end then it really helps to make cruising speed more efficient too in a really long run.

 

So why is a half marathon particularly good for this type of training? There are two main reasons for this:

 

1. Half marathon pace is fast enough to get close to your lactate threshold and push that boundary out so you can run faster, plus it is a long enough race that you have to push hard for a sustained period.

 

2. It's short enough that it doesn't take too long to recover from for a regular runner, certainly less time than a marathon.

 

Admittedly, guys with incredibly fast sub 2:20 marathon times haven't generally done as well in 100 milers as their speed would suggest. But it's the combination of the flat out speed and trail fitness that counts. Put a Kenyan Olympian on a mountainous 100-miler without specific training and they'd obviously not be bad, but they wouldn't automatically be the best unless they trained well for and adapted extremely well to the specifics of a mountain ultra (the same applies in the other direction but is more obvious to people and has been more tried and tested).

 

Speed training can be done on trails and hill work is similar in many ways, but if you like roads then they can really help as part of trail ultra training.

 

 

 

Ian Sharman is a local Bend ultrarunner and coach, best known for running the fastest trail 100 miler in US history in 12h44m. His blog includes training tips, photography and race reports from around the globe at http://sharmanian.blogspot.com/."