Some time ago, I decided to run New York with my trusty Cloudsurfers. With two weeks to go, I finally replaced them with a new pair, the old one having almost 775 km on them. Wearing one old shoe and one new shoe at the same time was quite a revelation: the old ones are really not worth using anymore. All the bounciness completely gone.

I didn’t have problems breaking them in when they were new, so I hope I won’t have problems breaking in the new ones.

They didn’t have my size in the trademark black/lime colour anymore, but “silver grey/azur” is fine with me. I took them for a spin yesterday, and tonight they’ll come with me on my 90 minutes marathon pace “final test” run.

In the beginning of 2011, I participated in a study for the “On Cloudsurfer” shoe, where their shoe was compared to the old shoes of the participants, from a physiological and a biomechanical point of view. I wrote about it here, about the first (maximum effort test) here, then a step test with my old shoe here and finally with the Cloudsurfer here.

I got the results a long time ago and wanted to wait until the overall results of the study were there as well, which they have been for some time now; I just never got around to write about it, so here goes.

In the first test, I had to run at an increasing pace until I couldn’t any more. This was the result:

(Top down: maximal velocity, maximal heart rate, maximal blood lactate concentration, maximal relative oxygen consumption)

Looks all very plausible except the VO₂ max, which seems rather high (like, much too high). The anaerobic threshold was determined as well:

(Velocity, heart rate)

But puh-lease, this pace seems extremely low. The protocol was not designed to determine the anaerobic threshold, so this statement could be expected to be not so accurate. That’s a real bummer because I hoped to gain some insight I could apply to my own training, but no.

More interesting was the comparison of the shoes. This graph compares my heart rate when running at 60% and 70% of the max velocity from above, for 15 minutes each, with my old shoes (blue curve) and the Cloudsurfer (red). My heart rate was lower when wearing the cloud surfer, but as with all statistics, a sample size of 1 is hardly lots of evidence, but still, interesting to know.

The graph below shows the run cadence, but for the higher pace with the old shoes, the sensor had some problem; my own sensor shows values around 97 strides per minute.

Finally, blood lactate concentration was measured, and again the Cloudsurfer looks better. I didn’t even seem to reach steady state with my old shoes!

The graph for running economy shows how much energy per kilogram body mass and per kilometre I required; a fairly constant value for my old shoes, increasing with the pace for the Cloudsurfer.

So my personal results suggest that my heart rate and blood lactate concentration are lower when using the Cloudsurfer. How does it look for the complete sample of about 40 runners?

The next graph shows the relative difference in heart rates (y-axis) at various velocities (x-axis); specifically, how much higher the heart rate was with the old shoes.

The dot at 11 km/h and 6% (top left) for example means that this guy, who was running at 11 km/h for the test, had a heart rate that was 6% lower when using the Cloudsurfer than when using his old shoes. Everything within the red stripe is considered to be due to the form of the day, everything below or above is considered to be “more different than what could be just due to form of the day” (my words).

Simply put, there are more outliers in favour of the Cloudsurfer than the other way around. The next graph shows the distribution of average blood lactate concentration at 60% and 70% of the maximum running speed.

The Cloudsurfer values are again lower, significant on a 5% level (i.e., the probability that this difference is just coincidence is 5%).

Finally, they checked the correlation between blood lactate concentration and heart rate, or more precisely, the correlation of the difference of each between old shoe and Cloudsurfer, for 70% of the maximum pace.

The graph has to be read like this: the dot to the far right for example was somebody who had a heart rate 15 bpm lower (x-axis) and a lactate concentration about 0.75 mmol/l lower (y-axis). People in the top right quadrant had both lower heart rates and lactate concentrations, in the top left quadrant lower concentrations but higher heart rates and so on.

The black line is the straight line that, of all the straight lines you could draw, is the one with the least distance to all the data points (“least squares fit”). The R² value indicates the correlation of the concentration and heart rate differences; a value of 1 would be “perfectly correlated”, 0 would be “no correlation”, -1 would be “perfectly anti-correlated”. In this case, “somewhat correlated”.

The biomechanical test didn’t show any significant differences between the Cloudsurfer and other shoes.

What to make of this? My personal, very short analysis: seems that people could have a heart rate and lactate concentration a bit lower than with their old shoes. The people who conducted the study said “Because we didn’t find a difference in running economy, it is hard to estimate how much the reduction of heart rate and blood lactate concentration would affect race performance.”

Now, the producers of the shoe thought “let’s say something fancy about the study” and they produced this nice video with the message “Go ahead. Save 2 beats per minute.”

Sounds fair, right? If only there wasn’t the stupid facebook ad. It says “Are you training for a personal best at Greifenseelauf [large half marathon in Switzerland]? With On, you’ll run up to 8 minutes faster (ETH study). Test now.”

Well, On, that’s exactly not what the study said. The study said “it’s hard to say what the effect would be”, so where the hell did your eight minutes come from? Pfffff…

I have put close to 600 kilometres on my Cloudsurfers so far and I use them for triathlons as well since barefoot running is quite comfortable in them. One of the cloud elements has suffered a little:

But they’re still okay to use. I’m not sure I’d be willing to pay the steep price (I got mine for free for participating in the study), but maybe when I’ll be in the US, I’ll get another pair. Maybe.

“8 minutes”… come on!

Not pictured: socks. Because I tested sockless running in my On Cloudsurfers to check if I can use them for triathlons.

Verdict: yes. Actually very comfortable!

On Monday I finished my part of the On Cloudsurfer study, I did the second submax test. This time with a calibrated footpod, the pace should be accurate now.

Running on a treadmill is so lulling that I almost tripped when I bumped into the front end of the thing while on it. I survived, though.

I was among the first to have finished the complete study, so I’ll have to wait for a few weeks until there are results. Especially my results, can’t wait for the analysis! I’m also curious to see what the outcome is concerning the shoe, I’ve been really happy with it so far.

On Monday, I had the second physiological test of the study for the On shoe where I’m participating. The shoe’s now named “Cloudsurfer”, because it’s not the only model anymore: there’s the a bit heavier “Cloudrunner” for asphalt and long runs, and soon there’ll be a fast and light “Cloudracer”. Interesting.

The test on Monday was done with my old shoes (Asics Gel Nimbus 10); the new ones are up next Monday. Based on my results from a week ago, I had to run for 15 minutes at 60% of the max pace reached then, and then 15 minutes at 70% of that pace. Again, my foot pod shows speeds that are too high; the faster pace was not sub 4 minutes, but about 14 km/h (4:17 min:sec/km). I calibrated the pod Monday evening, so next Monday should be more accurate.

Every five minutes, blood was taken from my earlobe for lactate measurements. The effort was not very hard, but I was looking forward to the short breaks because it’s really mind-numbing to run on a treadmill. I was not far away from some kind of trance!

This morning, I did the biomechanical part of the study: running across plates measuring impact forces and being videotaped, with my old shoes, the new shoes and with bare feet. It took just about 25 minutes and I have no idea what the outcome was. But I know that the biomechanics lab has a very dusty floor!

I can hardly wait to learn about the results of the study. On the one hand I’m really interested in the outcome: can you really engineer a shoe that lets you run at the same speed as with another shoe, but with a smaller effort? And are the impact forces on your foot actually reduced by this seemingly simple damping system?

Even more interesting to me are of course my lactate threshold results because I can use them directly to determine my training zones. I must read my training bible until then so I can immediately come up with an awesome training plan for 2011!

Monday was the first day of physiological testing for the On shoe study where I participate. It was a maximum effort step test: after a few minutes warm-up on the treadmill, some (rather fast) pace was set and then increased every minute until I couldn’t go any faster.

I was hooked up in all ways imaginable: cadence sensor, heart rate monitor, blood sampling, spiroergometry (analysis of breathing gas composition). I was even fastened to the treadmill itself in case I’d trip or something. Happens probably sometimes with these all-out effort tests. I was allowed to wear my own foot pod, but I’m pretty sure it’s not well calibrated. I can’t run at 22 km/h for a minute! (That’d be 4:24 min/mi.)

Anyway, I’m looking forward to learning about the results, especially the lactate threshold heart rate so I can use them for my training. Unfortunately this will only be after all the tests are finished, but on the bright side, that’s in three weeks already.

In an effort to train more goal oriented instead of randomly, I recently did a Conconi test to get an estimate of my lactate threshold heart rate. I’m pretty sure the results are not very accurate, so I didn’t use them for my training.

Two weeks ago, I stumbled over a tweet: “Looking for test runners”. I had a look at what they were looking for, and I matched all the criteria: male, between 20 and 50, at least 40 km running per week, can sustain 14 km/h for 10 km. So I went to the kick-off event where the shoe company, On Running, introduced themselves and their shoe (see picture). The idea of the cushioning elements is to absorb vertical and horizontal forces, whereas traditional cushioning focuses on vertical only. Check out this neat video for details. I’ve put a bit more than 40 km on the shoe since I got it and I can’t say if it’s a revolutionary new feeling yet, but they certainly feel good.

Anyway, the guy behind the shoe is pretty credible: Olivier Bernhard is multiple Ironman champion and three times duathlon long distance world champion. Today, he’s working as a triathlon coach – and shoe developer, as it seems.

The study is conducted by ETH Zurich, my old university (can’t say it often enough); more precisely, the Institute for Biomechanics and the Exercise Physiology group (joint chair with the University of Zurich), which means I can believe that’s a scientific undertaking and not just some marketing stunt.

The bottom line is this: I got the shoe (CHF 270.- when bought) for free, and I’ll undergo four tests. First, I’ll walk/run across a plate measuring forces in all directions with bare feet, with my old running shoes and with the On; this will also be filmed with something like five cameras. Then, I’ll do a lactate threshold test including spiroergometry ($$$ when paid for) to determine my LT, and afterwards to submaximal tests with my old and the new shoe. And all for free!

The LT test will be on Monday in the morning, I’m a bit nervous about that, because it’s an all-out effort. But I’m really looking forward to learning about my values and how I can use them for my training!