Fast Running Blog

I'm starting this thread based on an observation I made regarding Sasha's Hobble Creek Splits. I noticed that his best time in the Hobble Creek 1/2 Marathon was 1:07:03. I believe this comes out to an average pace of 5:07s. I also noticed that his PR 5k splits average out to about 5:05s. I think I did the math correctly. I'm not trying to single Sasha out on this, but, is there essentially a top speed that a runner is capable of for x distances, and anything over this is a matter of training the body to maintain that pace for further and further distances? I mean, what's going on Sasha? How is it that you can run a 1/2 marathon at a pace that is essentially the same as your best 5k? Generally speaking, I can pretty much tell you that my splits change as follows. If we take my 5k time at x minutes/mile pace, my 10k will be about x minutes +15 seconds/mile, my 15k will be about x minutes + 20 seconds/mile, my 1/2 M will be x minutes + 30 seconds/mile, and my marathon will be x minutes + 45 seconds/mile. I think this is about the case regardless of the pace I'm able to train myself into for a 5k. Is this the case for most, or do elite runners get to a point where they have a top speed and then its just a matter of conditioning themselves to go that speed for a longer distance?

hobble creek is not a normal half. It is very, very net downhill.

Ahh. See what happens when us Flatlanders try to stick our noses into the business of you Mountain Folk.

Jeff - I do think your observation is generally true, though, that some people have flatter speed curves than others.    I would say that a marathon should be closer to 30 seconds than 45 seconds off a 5k pace per mile.  Part of the differential is probably what a person's top speed is, but part is probably also how much marathon specific training they do.

Hmmm.....Contrary to Michelle's suspicions, I find I have a steeper curve, not a flatter one, and I feel like I've been doing a whole bunch of marathon training for a while now.  At this point, I'd love to get my marathon time to within a 45 sec difference of my 5k time but suspect I'll be lucky to hit a 50 sec difference.  If I had to run one now, I'd probably be looking at a full 60+ sec difference at least between my marathon and 5k time.
Perhaps the answer is the ratio of Type I to Type II muscle fibers one has?  More endurance type == flatter curve.  More faster type == steeper curve. 

Dale - things are a bit more complex. To run a good marathon you need to have very solid overall body health in addition to the specific fuel storage training. Underperforming liver, for example, could annul an incredible amount of aerobic conditioning in the last 8 miles of a marathon.  My advice on bridging the gap is to eat consistently healthy, sleep consistently well, and  keep on training consistently. Your body right now is in a remedial phase transitioning from being an American runner to a Kenyan runner, if we can use this politically incorrect metaphor. That phase may last a while, and complete only partially, but there will be progress overtime. Be patient.

Jeff -  indeed Hobble Creek half is an aided course, so my 1:07:03 (which was done on a faster version of the course than what they have now, BTW, probably by a minute) cannot be compared with my 5 K performances. Nevertheless, it is not uncommon for me to run a 5 K on the same type of terrain on a bad day slower than my average pace in a half marathon on the same terrain on a good day. Even comparing apples and apples, good day for both. This year my three fastest non-aided 5 Ks have been 16:20, 16:25, and 16:28.  16:20 was done off poor sleep, in cold weather, and with little warmup. 16:25 was done on a slippery road. But nevertheless in spite of running numerous other 5 Ks I never went faster on a non-aided course, so we have to use those.

At the same time I've run a non-aided 10 K in 32:59 closing the second half in 16:16. I suspect the second half may have been slightly aided by the tail wind. But I still got 16:29 average. I've also run a non-aided 15 K on a rather off day in 50:43. That is 16:54 average. I ran a very non-aided and windy half in 1:13:19, which comes out to 17:22 per 5 K. The first 5 K in that race  was on a non-windy section, and I covered it in 16:43.

So the bottom line - not much of a difference between 5 K and half marathon, enough to where with a little of bit of good luck for the half, and a little bit of bad luck for the 5 K the half could be run at a faster pace. Some more food for thought. In the last 4 years when running over 80 miles a week I never saw my HR over 174. One time when I cut the mileage to 70 for a couple of months I managed to hit 175 on a hill in a 5 K race on a brutal course. I've never seen it any higher than that period since 2004. I have a hard time keeping HR over 168 for more than a couple of minutes in any race, even just a 5 K. Yet on a good day I can maintain 163 or even 165 in a half-marathon. 163/175 is 93%.

Why? My number one suspect is the neural drive. In 2000 my max HR was over 190. In 2002 during a treadmill test I sustained 175 fairly comfortably. Do not remember what I maxed out at, but I do recall seeing it at 178 and not being exceptionally miserable. However, it was in 2004 that I discovered that my running HR patterns have settled into their current shape (I suspect it actually happened around the summer of 2003, but I never used an HRM around that time). All this happened with no changes in the resting HR (has been the same since the age of 16), and correlated with improved performances in all distances, smaller in shorter distances and larger in longer ones. I also stopped feeling normal pain (with only very few exceptions) after workouts and races in spite of trying very hard to do my best. During the race the normal discomfort from breathing hard and burning or sore legs has been replaced with the mere frustration of seeing the competition pull away while there was nothing I could do to go faster for apparently no good reason.

I suspect that my heart could still hit 183-185 max, and be able to sustain 170 in a long race. But I would have to sustain about 5:00 pace to hold the HR of 170, and probably 4:20 for a mile to go over 180. The neural drive to do it is just not there. So I am stuck with racing at speeds that are still respectable, but below the cardio and muscular potential for a while. On the positive side of things, the risk of injury is very low, and the recovery is very fast.

Sasha, it would be so interesting for you to work with some of the respected professionals who have published in the field of exercise and sports science since, in addition to your own personal insights, you have so much data to draw from. 

Well, it's not like I am hiding from them. After all, just my own blog gets around 500 visitors a month. I've communicated with Tim Noakes and Matt Fitzgerald through e-mail. But so far I have not had anybody approach me and say - hey, I wonder what you've got, why you are the way you are, let's test you. I can see why. I would not be very interesting as an athlete with only 2:23 marathon PR on an aided course when they have plenty sub-2:12 guys to choose from. With just a BS in Computer Science I do not have any scientific credentials in the area of exercise physiology. I've never advised or coached a runner that did anything significant on even the national level. So in their book I am not "cool".

But you are pretty 'cool' in our book Sasha -- and I for one am very appreciative that you provide the blog.