Difference in pace between asphalt and trails

I pretty much copied and pasted this issue from my blog.

Here's an observation from yesterday's and today's run. I do almost all my running on
trails, but I've run on asphalt for the past two days. I find that my
pace on asphalt is faster without any extra effort. It's tough to say
how much faster, but I'm guessing it could be as much as a ten second/mile
difference, which would make a considerable difference over 26.2 miles. This leaves me with an issue for this fall's marathon. The
Nov. 20th Bucks County marathon that I had planned to run (but haven't
signed up for yet) is a trail marathon (hard gravel, non-technical,
similar to what I train on). My other option is Philadelphia, which is
the same day. I've already run Philly, which was my fastest marathon
ever and the site of my BQ. I had wanted to run Bucks County to do
something different, and because logistically it would be a little
easier. If however, running on trails is going to cost me time, than I'd
probably prefer to go back to Philly, as my goal for this year's
marathon is recapture the BQ. I'd be interested to see what folks thought about this.

I rarely do any running on trails, but when I have my times are definitely slower. Even if I run on sandy or hardpan dirt roads I am slower. I guess for me I am paying attention to my footing more and become a little tentative or my feet end up slipping around a little. If I was shooting for straight time, I would opt for the paved road.

I agree with your observation, Seth. I can feel it taking slightly more effort on trails than blacktop. If the fastest time is your goal run it on blacktop.

I ran Ridge to Bridge Marathon last fall which was almost all on hard-packed road, and I think my pace was a bit slower than if it had been on the actual road even with the downhill portions of the course. That being said, many runners use the Towpath Marathon (Cleveland-Akron) and the NCR Trail marathon (MD) for BQs even though the courses are all on gravel trails. I think it is because they are smaller and logistically easier for many to navigate. Didn't Chris run his last and very successful marathon on a gravel trail course? That, too, might be a case to run the Bucks County race.

If it isn't too difficult, could you possibly run on the course some weekend? I know that Bucks County is not really that far from you and it could assist you with this very important decision.

I think it will slow you down a little (although 10 seconds per mile seems a little steep), but your legs are also going to take less pounding than they would on asphalt, so that will work in your favor. I've run a few marathons on packed limestone and I think in the end, it had no impact on my time. I really did feel like my legs stayed fresher throughout the race because of the lesser impact of the limestone.

I really think that it depends on what type of trails you are running on. Overall I would say that running on trials can slow you down. The main reason is that you really have to think about your foot placement on a trail. I know that when I'm running on roads there is no thinking ( for the most part) about foot placement and stride.

The last two weekends I have done my runs out on some technical trails in Michigan and there is no doubt that it is a completely different type of running compared to running on the roads. Not only are the grades on the hills very steep but I have to consistently focuses on were I'm going to place my feet. At times I would have to change were my stride while in mid stride due to having to place my foot somewhere else.

So I think that as for how much trails will slow one down vs the roads would have to deal with what type of trails you are running on easy, moderate, hard and very technical.

I will be posting more about my experience of my trail runs in my blog this week.

Seth Harrison wrote:...as my goal for this year's
marathon is recapture the BQ. I'd be interested to see what folks thought about this.

Is Bucks County Marathon a certified course?

Schuey wrote:I really think that it depends on what type of trails you are running on. Overall I would say that running on trials can slow you down. The main reason is that you really have to think about your foot placement on a trail. I know that when I'm running on roads there is no thinking ( for the most part) about foot placement and stride.

The last two weekends I have done my runs out on some technical trails in Michigan and there is no doubt that it is a completely different type of running compared to running on the roads. Not only are the grades on the hills very steep but I have to consistently focuses on were I'm going to place my feet. At times I would have to change were my stride while in mid stride due to having to place my foot somewhere else.

So I think that as for how much trails will slow one down vs the roads would have to deal with what type of trails you are running on easy, moderate, hard and very technical.

I will be posting more about my experience of my trail runs in my blog this week.

Mr MattM wrote:

Seth Harrison wrote:...as my goal for this year's
marathon is recapture the BQ. I'd be interested to see what folks thought about this.

Is Bucks County Marathon a certified course?

Matt, they're expecting it be officially certified any time now. That's the main reason I haven't signed up yet.

As for the type of trail, it's apparently a hard gravel, non-technical surface, very similar to what I train on. It's also a very flat course. I hear everyone that it may not have that great an impact (at least not 10 seconds/mile like I had originally said), but I also don't worry too much about the toll running a marathon on asphalt takes on my legs. By the time a marathon rolls around, I've done sufficient training on trails as well as a couple of long runs on asphalt to ensure that my legs are in good shape.
When I ran the NCR trail marathon a couple of years ago, I ran my slowest marathon (that is until this past Boston), but I attribute that to being very under-trained as opposed to it being due to the surface.
I guess I'm still on the fence about this.

I was just thinking Seth that there could be a good reason for the 10 second slow down on the trail vs the road for you. Maybe it has to do with the ankle injury you had last year and the foot.

It could very well be that you feel more confident on running on the roads right now compared to the trails. You did twist your ankle pretty good last year while trail running. So just maybe you are a little hesitant while running on uneven surface even if it is not that technical or hilly your mind just might be telling you to be careful.

Just a thought I could be wrong but maybe something to think about.

Schuey wrote:I was just thinking Seth that there could be a good reason for the 10 second slow down on the trail vs the road for you. Maybe it has to do with the ankle injury you had last year and the foot.

It could very well be that you feel more confident on running on the roads right now compared to the trails. You did twist your ankle pretty good last year while trail running. So just maybe you are a little hesitant while running on uneven surface even if it is not that technical or hilly your mind just might be telling you to be careful.

Just a thought I could be wrong but maybe something to think about.

Schuey, that occurred to me as well, although since the trails I train on are well groomed, I don't think that would make a 10 sec./mile difference (although I was just estimating when I came up with that number). I think when I get home I'll see how my pace feels on the trails during an upcoming run with some miles at MP, and than compare that to a similar run that I'll do on asphalt. It's pretty unscientific, but so is everything else about the way I train.

I agree with Schuey that it really depends on the trail. If it's a flat, very mildly-technical (a few rocks here and there) trail, I'll be running faster than on asphalt, just from the enjoyment I get from trails. But most trails I run on are extremely undulating, if not mountainous, and the descents are way too technical/steep to flat-out bomb and pick up lost time. So instead of averaging ~8:00 pace for a 3hr run, I'm closer to 8:20-8:45, depending on the conditions and total elevation change.

First off, we gotta get agreement on what we are comparing here. Similar elevation profile, non-technical footing and then just how hard packed cinder/dirt compares with asphalt. Take true "trail races" out of this discussion completely. Anything with legitmately tough footing and the normal elevation changes real trails have is going to be slower....way slower. But for flatish roads versus flatish hardpack, I think at the marathon distance that it doesn't matter. I've done the York Marathon a couple of times. Here's what the whole course looks like:







My experience has been that you will be slightly faster on straight asphalt with the same effort but that is offset, as Greg said, by the softer surface and likelihood that the pounding won't beat you up as fast over the whole 26.2 miles.



For the MARATHON distance, I think it equals out to the point of being a non factor.



But I wouldn't want to run a 10K or shorter on anything but asphalt if speed is the focus. But I say you'll be fine with the non-road surface of the marathon you picked.

Chris M wrote:

My experience has been that you will be slightly faster on straight
asphalt with the same effort but that is offset, as Greg said, by the
softer surface and likelihood that the pounding won't beat you up as
fast over the whole 26.2 miles.

For the MARATHON distance, I think it equals out to the point of being a non factor.

Chris, thanks for this. Yes, the comparison has to be apples to apples, and the good thing is that the surface I train on is very similar to the surface I'll be racing on at Bucks County.

While I said previously that I don't think the pounding from asphalt will factor in significantly since my legs should be in great marathon shape by then, I'm sure that you and Greg are right that at the very least, the fact that the pounding will be less should negate any slight decrease in pace caused by running on gravel as opposed to asphalt. While I can't say how much running on a trail affected my marathon time at NCR, I can say that my legs recovered faster than after any other marathon.
I'll still see how I feel after some MP miles on both surfaces in the next couple of weeks, but based on what everyone has said, I'm still leaning towards the trail marathon at Bucks County.

go read what i wrote in your blog yesterday come on I want credit for this thought process.

Okay, if we're simply comparing surfaces, I agree with Chris, but only under racing conditions. Training runs that are based on perceived effort (easy/recovery/maybe GA), I'm still going to say that I'm faster on trails. But my running is extremely affected by what's going on in my head.

I think 5-10 seconds per mile may be a reasonable estimate. The slippage on your push off of every foot strike is going to be slightly affected. I don't run trails very often, so you would be better prepated, but I definitely would not run on crushed limestone/gravel for a goal race.

I am with Schuey if the surface needs my attention, I am out. Jerry thinks a free mind is more important than physics.