Monday, 30 April 2012

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

Running hard in a half marathon in 2009

I got back from a trip to Eugene, Oregon this weekend for the half marathon there as part of my Western States build up. So, apart from the fact that I enjoy road racing and that Eugene is Track Town USA (with the US Olympic Trials occurring around WS time), why is that a good training run for a mountainous trail ultra?

One thing that I have found over time is that the more I just run trails, the more I tend to slow down. Yes, the ability to climb and descend gets better, but the pace on easier trails goes down. And WS, like most trail ultras, has a lot of faster running in there as well as some climbs to slow things down a bit.

Apart from downhill, most people are unlikely to hit their half marathon road speed in a trail ultra, but 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 I'd suggest 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.


  1. Is half-marathon pace really close to your lactate threshold? Doubtful.

    1. One of the rough indicators of LT pace is 15 mile race pace.. So yes it is very close like 3 or 4 seconds a mile. And unless you have regular testing for LT then you probably don't know what your LT pace is so a half is a good LT pace run for MOST people.

  2. good to hear- making my half début this weekend as part of my TNF100 Aust prep (2 weeks later)....

  3. Completely agree with your view on this. Trail only running is not quite diverse enough to keep your flat road speed up. I know with my running club since I joined I can run closer to our best runners on the road, but lose out on hilly trails as iam less experienced in this environment (and am to scared to do hill repeat training sessions). I note Anton and Geoff roes don't train fast but they don't run short races

  4. If it's a race like Hardrock, i agree that Kenyan athletes wouldnt dominate without specific training,but for most mountain ultras,in my opinion, they would kill it. Most of these guys were born at altitude, they grew up and trained in the mountains at altitude and are very mentally strong. Not a bad start!

    1. But do they know how to eat right? Do they know how to pace themselves? Do they know how to decent? And do Kenyan Runners actually WANT to do stuff like this?

      With all respect for Kenyan Distance Running and the Magic it surrounds. Until there is no money in Ultra Running there are no Kenyans and therefore no specific training in the Rift Valley!

  5. I think you are making a good and interesting point but am not 100% sure what that means for my training though.

    So if I want to take the above into account and prepare for a race like the WS100

    In training:
    a) Should I be RACING a HM? (for me that's eyeballs out and as fast as possible and probably sore hamstrings for a week)

    b) Should I add efforts to my training and run 5 miles (or any other distance below 13 miles) at HM RACE pace? (which is a shorter effort and would leave me with less sore legs since it's much easier to recover from)

    c) Should I be running a HM but below an actual race effort? (that would again allow a better recovery)


  6. @Thomas,

    I would lean towards doing 4-6 miles at "actual" half marathon race pace as a workout on the road or track and then doing a half marathon race just a little slower than you could do it... like 10-15 s/mile slower and don't "kick" the last 2-3. It's that last few % that cause much of the damage.

    I think there's an aerobic benefit but also a benefit to running form.

    Sorry for inserting my 2 cents...

  7. Nice run, Ian! That was me cheering at 5K. Hope you enjoyed the race as much as the post-run Ninkasi.

    1. I did wonder who would recognize me at a half marathon and turned around but couldn't tell who'd shouted - thanks. Hope your WS training's going well.

  8. @Alex, yeah, that makes sense. I was leaning in the same direction actually. Thanks for your 2 cents!

  9. Thomas,

    You obviously don't want to overdo your training and racing and get overly tired, plus this can lead to a higher chance of injury. But racing halves and shorter distance races at full effort is generally fine, even as a training run - that's the benefit because they don't cause nearly as much damage to the body as a marathon or ultra. If you want a 13 mile tempo run then you can do that outside of an event just as easily and cheaper too. Personally I use treadmills for this and run at marginally below half marathon effort for 13 miles.

    The longer distances can also be great training runs but may need to be run a little off maximum effort if they aren't the focus event - the longer it is, the more time it'll take to recover and the higher the chance of injury if you constantly do long races at full intensity. Plus it's difficult to train if you do a lot of ultras at full effort - you'd be constantly recovering or tapering.

  10. Thanks Ian. Much appreciated!

    Good luck with Transvulcania. The clash of the titans!

  11. I'm well out of your league and a bit of a plodder but i can't agree more. I'll take it further and mix up the long stuff with all sorts of short fast fells, half's tens and cross training as well.

  12. Hi,
    I have a quick question about your blog, do you think you could email me?