Improving Pace

It has been a consistent theme of this blog that I think my pace is improving since I switched to minimalist and barefoot running. Well, I think there is now enough data to back it up. I've been using the Nike + iPod system for a long time, with a couple disruptions (having lost my iPod, etc.). The slowgeek.com site has some great graphs for looking at the Nike + iPod data. So, what is the verdict?

I have logged 2000 kilometers since 2006, in 305 runs. The last couple of years, I haven't been very fast. I purchased my Vibram Fivefingers KSO shoes on April 15th (6 weeks ago today, as I write this). In the 16 runs I've done since then (not counting a handfull of barefoot runs, which are not logged and are significantly slower) my pace has improved dramatically. At first, some people said it was probably enthusiasm for my new gear, and simply psychological. That may well be, but I seem to be getting more enthusiastic as time goes on. I've logged 16 runs since then: 126 kilometers. Take a look at the above image, which is a snip from my Pace over Time graph. That is quite a jump and it perfectly coincides with buying the VFFs. If it's simply that I'm excited about new gear I find it surprising that I've maintained that enthusiasm over the 16 runs, and that my excitement seems to be increasing. I think something else is going on.

Another thought I've had, and that others have echoed, is that my pace is increasing because I'm running more. The data doesn't back that up either. In this image from my monthly runs graph the light red is 2009 and the dark red is 2010. In 2009 I logged nearly twice as many miles in April, and almost as many in May. But check out the Pace over Time graph above. I'm a full minute per kilometer faster now. What gives? There isn't a backlog of months of strong training this year either. I hardly ran at all this Winter.

In the short amount of distance since I took up minimalist running, it can't be all fitness improvements. Sure, I think there are benefits to barefoot running that improve the muscles in your feet and calves. But I can't see how suddenly after a regular amount of training I could see my pace jump up a minute per kilometer. I think these improvements are around increased efficiency in my gait. I've always read that the best way to improve your pace was to increase your turnover and shorten your stride. You see it in races. Several times I've been huffing and puffing up some hill, fighting the good fight, and some person comes around and pulls away doing the marathon shuffle: little quick steps, not lifting their feet high, quick turnover. I've worked on that in the past, counting footfalls per minute and trying to increase my turnover, and I think that is some of how I was so much faster in 2005/2006 (that and working out with the Santa Cruz Track Club). But with the Vibrams and barefoot running this kind of gait just comes naturally. I don't have to think about it.

The improvements I've seen have required no real changes to my training patterns, and that boggles my mind.  I'm excited by the prospect of how fast I could be if I applied myself. I feel like if I applied myself (actual speedwork, hills, consistant distance and a long run every week) I could actually close in on my 44 minute 10k PR and my 1:47 half marathon PR. I doubt I could do it for the Summerfast 10k in July, but for the first time in years I think I can run that fast again in the future.

Maybe my running will peak in my 40s instead of my 30s. If it does, I hope I'll be sitting around in 10 years saying "maybe my running will peak in my 50s instead of my 40s!" Hell, at this rate I'll qualify for the Boston Marathon before I'm 60. I'll be a shoe-in in my 80s!

Here is to a bright future as a mid-pack runner.

Cheers.

Another barefoot run

Just a quick note about my run on Thursday. Went out with a friend at lunch and decided to go shoeless again.

We did about 5km, like my first run, but no major problems with the feet. They were tender at parts, and the grass was amazing compared to the concrete and asphalt, but I didn't get the same hotspot/blister problems on my midfoot.

The crazy thing is that after my first barefoot run the skin on my foot changed significantly. The outside portion of my feet was the same baby-soft skin I had up on the high part of my arch. That first run hurt like hell by the end. I thought it might blister, but it just got puffy and tender. A week later, those tender spots are now tough, thick pads of skin, more like the balls or heels of my feet. I cruised through the run at an easy pace, and felt fine after. It was an enjoyable run. Parts of it were raining lightly, and the concrete felt cool and wet. I was a bit worried about the water softening up my feet and having problems because of it. But things were fine.

I now understand how people can run long distance barefoot. Feet are amazing. They get stronger quickly, and your running adapts to take it easy on them and land softer. Obviously they have evolved to do this, but it is amazing to me how fast it happens. After a single run, my foot was ready to go and significantly tougher a week later.

Amazing.

I'm going to stick to one easy barefoot run a week for now, the rest in the Vibram Fivefingers,  and see how it goes. Also considering signing up for the summerfast 10k to see if I can improve on my sun run time. I'm sure I can (it is a less crowded race on a flat course). But how much can I improve? I would love to get it under 50 min. Three and a half minutes should be possible, but can I do more?

Guess I should sign up for the race before I decide how fast I want to finish.

There, I'm all signed up. Saturday July 17th. 55 days. Now for the training and obsessing on times.

A couple good runs.

So far this week I've had a couple of great runs in the Vibram Fivefingers. Actually, that is a bit of an understatement. I had one pretty good run, and one fantastic run. The first run was a bit more than 10k on my out and back and then to work run on Monday morning.

I can't complain about that: longish run at a decent pace, squeezed in before work on a Monday. 10.8km at a 5:24/km pace. That is a great way to kick off the week. I'm not getting in a fast 10k every day like some people, but it put me in a great mood for a Monday.

I took Tuesday off from running and ducked out for my regular lunch run today. Man I felt fast. I knew I went out too fast but I didn't care. I figured if it felt that good then "what the heck?" I could limp in the last half if I needed too. But I felt pretty good the whole time.

The run starts with a downhill and ends with an uphill, so I guess I shouldn't sweat the slower split times too much. I hadn't felt this fast in a long time. I was passing other runners, relaxed and easy, when often I'm trying to just hold an OK pace. Early in the run I passed a couple people and felt great. But then there was an old guy with grey hair up ahead. I lost sight of him around a corner for a bit, and when I rounded the corner it was clear he was pulling away. My brain had two thoughts at the same time:

• "That old, grey-haired guy shouldn't be pulling away from me!"
• "Holy Crap! I am an old grey-haired guy!

And so it was on. I picked up the pace slightly. It must have been around 1.5km on the graph. I caught him & passed (he actually looked like he was in much better shape than me) with no problem, and he slipped way back behind me. I felt great up until about the 3km mark, when a pack of three real runners passed me. I was out of gas, and it was a bit demoralizing after having passed eight or ten runners and feeling strong. But I knew I came out too fast, and I guess pushing yourself is how you get faster, right? So I just held an OK pace around Lost Lagoon, and then tried to pick up pace once I was back to the pavement by the Vancouver Rowing Club at Coal Harbor. I had some mixed success after that, with a couple of inconsistant slowdowns. But, I didn't fall off too much. 

Going back through my stats on slowgeek.com, I was pretty shocked. The average pace for the run was 4:40/km (7:31/mile). The last time I held a pace that quick was a 4km run in October, 2006. Wow. Three and a half years? Today was a really awesome run. Fast and fun. Now I just need to keep up the pressure to make sure it wasn't an outlier. I'm hoping I can maintain the upward trend on my pace over time graph.

I'm even more excited about barefoot/minimalist running. I'm getting faster because of it, I'm convinced. Hope to get out for another completely barefoot run soon: maybe tomorrow if the rain stops.

Running Barefoot

After the enjoyable time I had at the Sun Run in my Vibram Fivefingers KSOs, and a successful and 7k run two days later, I was feeling pretty confident: not too sore, no blisters, pace increasing. I figured I've hit my goal and have transitioned to barefoot style running fairly well. But it is a slippery slope. If minimalist running in the VFFs have made my running more enjoyable, why not take it a step further and actually run barefoot?

The thing that is interesting to me is the reaction people have when you tell them you are going to run barefoot.  People are genuinely shocked that anyone would even consider it. It does seem a foreign thought at first. But when you think about it, we've been evolving for millions of years, and have only had shoes for a tiny fraction of that time. A common reaction when I point that out is "but we didn't evolve to run on pavement." While technically true, I have to call bullshit on that. Most of the world is a hard, unforgiving place full of rocks and pointy stuff. Our ancestors did not practice persistence hunting by convincing their prey to run on beaches and spongy manicured lawns. I grew up going barefoot much of the time in Nevada, and a smooth, flat sidewalk is very forgiving compared to the desert. I spent plenty of barefoot time on both. But surely that is anecdotal, right? As a doctor friend said in a Facebook comment, "Really? On pavement? Hmm." But, it turns out science is on my side with this one.

The comparison of peak impact force values across surfaces for the group of subjects demonstrated no significant differences in magnitude of force. DISCUSSION: For some subjects, the maintenance of similar peak impact forces for different running surfaces was explained by observed kinematic adjustments. For example, when running on the surface providing the least impact absorption, an increased initial knee flexion was observed for some subjects, suggesting an increased lower extremity compliance. However, for some subjects, sagittal plane kinematic data were not sufficient for the explanation of peak impact force results. It appears that the mechanism of adaptation varies among runners, highlighting the requirement of individual subject analyses.

 They throw a grave warning at the end because the "sagittal plane kinematic data" didn't look the same for all subjects, but the fact remains that they didn't find a significant differences in magnitude of force no matter what the running surface was. So, I've cherry picked a google search above, but there seems to be a growing consensus in the data. I'll sum it up with a quote from Danial Lieberman at Harvard:

Most people today think barefoot running is dangerous and hurts, but actually you can run barefoot on the world's hardest surfaces without the slightest discomfort and pain. All you need is a few calluses to avoid roughing up the skin of the foot.

And now I'm going to digress and complain about science, briefly. Many of the interesting studies I've found cost lots of money to read.  This seems wrong to me and may be leading me in the wrong conclusions. </rant>.

OK, back to my run. Yes, people think it is weird. People think it is odd enough that I run in the VFFs. I often get questions like "how much cushion do they have?" and "how much arch support do they have?" Of course the short answer in none for both. But people think I'm crazy when I say that there is plenty of data that those things are counterproductive. I can't fault them. I think of all the years I repeated the "fact" that you needed a stability shoe if you pronate too much. So now that minimal running had opened my eyes to barefoot-like running, I figured I needed to get out for a run with no shoes at all. I keep finding proponents of barefoot running talk about how the direct feedback of your feet on the ground forces you to change your gait and run better. So off I went.

I wanted to stay focused, so I didn't bring the iPod, or anything else: just my running shorts and a shirt. It was a beautiful day & I started a light, easy pace. The sidewalks near our office were recently redone in preparation for the Olympics, and they are pretty fancy. By fancy I mean contain crushed glass. I never really thought about it before, but was concerned about this 4 steps into my run. It is rounded like pebbles though, so not too bad, But I'd never thought about it before. So my immediate impression was that running without shoes definitely changes your perception and your gait. Trust me, when you are running on rocks, glass and concrete you land very gently. I tried to focus on relaxing my foot, spreading out the load and not letting the pressure build up in any one place during landing or toe-off. In the first block I was a bit worried about the ball of my left foot, but once I got onto a smooth sidewalk everything mellowed out a bit. At a stoplight another runner said "Hey, you forgot your shoes!" and then "I bet you get that a lot." I told him that he was the first, as it was my first barefoot run, but I'm sure I'll hear it more if I keep it up.

Once I hit the seawall by Canada Place I got into a bit of a groove. I wasn't pushing myself and was at a slower pace than usual, but I was running and relaxed. My feet felt fine. It was a bit like a dynamic, random shiatsu massage. I could feel every detail of the surface. That feedback had me changing things a bit. I was focusing on a gentle footfall, with the outside part of the balls of my feet softly landing a split second before the rest of my foot settled in, and then a gentle lift at toe-off, not pushing with the toes themselves. At a few different points I was able to step off the path and run in grass for awhile. Wow. After running barefoot on concrete for a couple kilometers you would not believe how nice a soft lawn feels! But what was more amazing was my gait changed. Instantly I was making more use of the heel: not pounding, but letting much more weight settle on it, and pushing through the toe-off a bit more. After the gentle, careful gait on the pavement the grass felt fast. I had the urge to sprint. But, my first footfall on the concrete landed cat-like and gentle, but very precise. The concrete didn't feel that bad, but the grass lets you drop your focus a bit. You can let your feet flop down a little, and not be so exact with how your foot strikes  lands (you do not strike the ground barefoot like you can in a shoe). I got a few comments from other runners, the most common being "ouch!"

But nothing really hurt during most of this run. My goal was to go for a very short run and turn back early if I got too tender. But things probably went too well. I wound up going more than 2.5 kilometers before I turned back, making for a more than 5 kilometer run. I felt fantastic when I started back for the office, but at some point I started to feel less than fantastic, with a fair bit of distance to go. I made it back, but I have new respect for the term tenderfoot.

All things considered, my feet aren't too bad. I got a couple of pretty bad hot spots. I would say blisters, and maybe they are, but they are similar to what happened to my big toe on my first run in the VFFs. I have a couple spots that are puffy, red and tender. There is probably fluid deep in there, like a blister, but I don't think they are going to pop. The really interesting thing to me is where they are. My toes, heel and the pads on the balls of my feet are all fine. They have obviously been used a bit and could stand some rest, but they are surprisingly good. The hotspots midfoot outside, opposite the arches on each foot. I've been trying to figure out why. It could be a problem in form. Some of the forums around barefoot running claim that blisters are usually the skin sliding against the pavement, ant that I might be twisting the foot slightly. But I can't imagine that happening only there. But the thought I keep coming back to is that it may be a result of running in the VFFs for the last month. While they are a very minimal shoe, the pads under the balls and heels are slightly thicker than the midfoot, even on the outside. After a single barefoot run I think that may be a slight design flaw. In the first few runs my toes and the balls of my feet got some hotspots/blisters. Then they toughened up and are fine. The midfoot had less work to do, as it was slightly lifted, so it never toughened up. It is just a theory, but I have a feeling that may be part of what is going on.

Either way, I did a 5km run on mostly asphalt and concrete with no shoes at all. I enjoyed it, and feel like I learned a bit proper running form, and I'm sure my feet will come out of it stronger. I think it was a pretty successful experiment, and I will likely do the occasional barefoot run on occasion to see how it goes.

53:22

So after all that obsessing over times, things turned out fantastic. Fifty three minutes was the absolute bottom of what I thought would be possible, so I'm thrilled. It was a fun race too, despite being frustrated for some of it. Overall this was the most enjoyable Sun Run I've done.

Looking back through my times, I did 57:52 last year (guess I was misremembering that in my last post) and my training was roughly the same. My first Sun Run after moving to Vancouver was 49:32. At the time it was a bit of a disappointment, as I was more than 5 minutes slower than my PR. But, having kids and shifting responsibilities and dark cold winters compared to Santa Cruz kept taking their toll, and I got slower and slower. So, it is nice to see my pace moving in the other direction. Barefoot running (well, almost barefoot) has me excited about running again. I'm already looking forward to my next run, wondering if there is a small 10k on a faster course and if I could be in decent shape for a Fall half marathon.

I saw one other guy with Vibram Fivefingers and chatted with him a bit before the race started. He'd been training since January and was in the Vibram Sprints. There was another guy I didn't get to talk to who was actually barefoot. I want to do some barefoot runs soon. I can't imagine running a 10k with no shoes. Maybe if I switch to a Garmin GPS instead of my Nikeplus foot pod I would be more inclined to, but I love to geek out about the numbers and stats of my runs over time. As the start approached I was a bit nervous. It is further than I've ever ran in the Vibrams, and some shorter runs in the buildup left me seriously sore. Right up to the start I was worried I may have made a mistake.

But, this run was fun. After an initial quick pace down the gentle decline of Georgia Street, a couple things slowed me down. First, was the bottleneck that happens every Sun Run, as the course cuts up and through Stanley Park. This area of the race funneled 51,419 runners through a section of road that is less than 2 driving lanes wide at some points. You can't help but wind up behind a wall of slowpokes.

Then you play the game of looking for an opening, darting through it quick, and trying to pick a line through all the people, until the next time you are blocked. To make it more complicated, everyone behind you thinks you are the slowpoke and is looking for the same openings. It sounds frustrating, and it is, but it's also what makes running a big race like the Sun Run interesting. It must be boring for the elite runners up front who never have to deal with the traffic.

Not long after the crowds thin out is the brutal climb up to Burrard Bridge. That big loop is steep. That is the low point of the graph above. It is hard enough to maintain any kind of a pace faced with a hill like that. To make things worse, this is the point in the race where people who should have lined up further back in the start section decide to walk. They don't move to the right and then start to walk. They just give up: right in front of you.

What I wasn't prepared for was almost getting taken out by a hipster. Some girl with a shiny chrome lowrider bicycle, with a sissy bar and a springer front end, decided she just had to cross the street. Who knows? Maybe Urban Outfitters was having a sale on ironic t-shirts. I nearly wound up on the pavement in tangle of springs, spokes and 80's sunglasses. It wouldn't have been pretty.

But a beautiful thing about that hill is that after the brutally steep roads looping up to the bridge, the first half of the bridge is just steep enough. With the early part of the hill weeding out the non-runners, the top part of the hill makes me feel fast. I always seem to pass tons of people in this part of the run. The course is wide open at this point, plenty of room. At the top of the bridge I was in great spirits and able to hold a decent pace down the back side and for some time on the flats.

Between 6.5 and 7.5 kilometers on the course I was tired. Really tired, and it shows in my pace. There are some twists and turns there, and the course narrows again making it more crowded. But I felt beat, and was pacing myself with slower runners than I should have. It was around here I kept thinking that it was a huge mistake to mostly do 7km runs while training. I had that miserable, tired before the end of a race feeling, that sometimes means it is all going to fall apart. Around this time I got a little hot spot on my right big toe and thought it was blistering, increasing my gloom. But I snapped out of it after awhile. I was able to accelerate a couple times, before my time drifted back down.

Again my head drifted back to the times. I had decided not to look at the ipod for pace and time in case it was off. Interestingly, the iPod has a glitch sometimes where it doesn't give the voiceovers, and that happened on this run. I'm not sure if that is good or bad. It turns out the iPod read 9.34km when I crossed the finish line. I'm not sure if that would have motivated me or crushed my spirits when my ass was dragging. I'm a bit concerned with the accuracy since I switched to the VFFs. It seems my pace fluctuates more than with regular shoes, and I'm not sure if the iPod can deal with that. My pace was much more constant last year, and the accuracy was great, logging the 10k at 9.97km. I'm hoping I can get it a little closer with further calibrating, but I guess 93% accurate isn't so far off as a training tool. I love the new feature where you can calibrate a run to a known distance after the fact though. I'm not sure if this also improves the accuracy of future runs, but we'll see.

I felt good for the rest of the run, including the Cambie Street Bridge, which has been demoralizing for me in the past and I was a bit worried. But I ran strong. The toe didn't hurt. I found my wind and kicked it out up over the bridge, holding a good pace through the flats to the finnish. Can't tell you how excited I was when I saw the time on the iPod. Blissed out.

I love these goofy shoes and I'm already looking forward to my next run. Maybe tomorrow morning.

All systems go.

It is looking good for the Sun Run tomorrow. Legs and feet are fairly rested. My left foot feels good. My last 7km run was a decent pace and felt fantastic. I've had a good rest since that run. So how will it go?

I'm reasonably sure I'll finish the race without foot problems and reasonable cardiovascular fitness. If I'm right about that, it comes down to time. Thinking of time can be either motivating or discouraging with a looming race. I'll come nowhere close to my personal best, a 44:22 from six years ago when I was 20 pounds lighter and my weekly long run was over 20km. On the other end of the spectrum, I haven't yet ran a 10 slower than one hour. So where will this one fall?

My goal remains simply completing the race strong and in good barefoot form, running with the Vibrams. But I can't help to think about the time. I'll be disappointed with anything over an hour. I'm pretty sure I can do better than that. I did 58 min and change the last time I ran it.  The only run I've done recently that I know was on the money was that 4km run last Saturday. That was on a track, and calibrated after the fact to the distance. For that run I was at 5:30/km pace: right at 55 min for a 10k. But that was on a track, had no hills like the nasty climb up over Burrard Bridge or crowds to wind your way through. On the other hand, I probably wasn't pushing myself like I would in a race.

I'd be really happy with 55 min. 58 would feel like I did just fine. Over an hour will be a bit of a letdown. But, if by some miracle I can push it back down to 54 or 53 I'll feel like I really accomplished something. That is a pretty wide range of emotions for a 6 minute range, and mostly ridiculous (especially considering I've ran the same race in 48 before, and someone will win this thing in less than 30). I should just run and enjoy it. And I will.

But I can't help but thinking about the times. It is a race, after all.

Another Good Run. Bad Idea?

Had another great run today in the Vibram Fivefingers. I've been interested in what the calibration last weekend would do to my standard lunch run at work. It seems like things are more in line, and I'm still holding a decent pace. If you look back at my recent runs it looks like my calibration did reset things a bit. On my lunch loop today the run was recorded as 7.31km. The three runs prior to calibration came in at 7.71, 7.87, and 7.58. It isn't that far off, but I think the new number after calibration is closer to reality. Guess we'll see how how it logs my run in the Sun Run this weekend (assuming I can pull it off in the VFFs).

I've been fighting some foot pain in my left foot, and have been trying to get enough rest between runs. It has been a little frustrating. The pain has been strange: mostly on the top of my left foot, and very bad in the morning. But, after 10 to 15 minutes I feel fine. It is unlike other pain I've had in that it goes from feeling like I'm actually injured to feeling fine in a very short time. After my April 28th run, I was a little worried. I had some significant pain. I almost skipped running last weekend, but the weather was so good... and I wanted to calibrate the iPod... and... and... and...

I think it is easy to overdo it when transitioning to the VFFs. Since I started running I've been in running shoes: almost exclusively the GEL Kayano. I have years of training, muscle memory, and a better cardiovascular system than I've ever had. In all that time my feet muscles tendons and bones have been restricted. My foot has been held in place. I've hand my natural pronation restricted. i've been heel striking, and rolling off the front of a shoe that rolls up under the toes so they don't have to flex back. And here I've mostly switched to running with a "shoe" that does none of that. I'm landing on my forefoot and softly catching the weight of my body. My foot has been compressing, absorbing energy into my arch, springing back and returning that energy to the ground while the foot rotates from the outside midfoot to the inside ball, and pushing off of the two biggest toes as they get stretched back. None of my foot is used to this. My brain loves it and my quads love it and my cardio loves it. My feet really love it, but I think they would love it much more in moderation.

So, glancing through http://birthdayshoes.com I come upon an article on Making the Transition to Minimalist Marathon Running in Vibram Five Fingers. OK, it appears I am making a very common mistake.

Well, I started out with a few small runs after my knee was feeling better, a few km's at a time and they felt GREAT! I could instantly feel the change it had made to my gait. I was running far more upright, with shorter steps and of course I was landing on my forefoot first. I had the obligatory calf pain, but as I had read this was "something we all had to go through!" ... Well, that was a big mistake! A few days later, my left foot ceased up (I later found out related to an extremely stiff calf!) and I was back to square one. Or was I? Was it due to the FF's? Was it my poor form? I was at a loss.

Yikes! That's me! Right down to the fact that it is my left foot and I have short, stiff calves.

So I've been trying to make sure I get enough rest between runs. I didn't run from Saturday to Monday (today). The rest did me good. I was no longer feeling injured, but I was worried about going out again. I actually got some butterflies before my run. But once I got on the pavement I felt great. Really great. I felt quick and confident and strong. I felt good the entire run. No issues. On the plus side, I'm only running 7km so far, not the 25km of that guy. Guess I'll need to see how I feel tomorrow. I think I've got enough rest time before the Sun Run that I should be able to run it. It's just 10k, right?

Am I making a mistake? Of course. Am I making a mistake big enough that I shouldn't do it? Lets see.

Calibration Resets Expectations.

So I went to the track a calibrated the ipod today. It seems to have taken the wind out of my sails a bit, with my actual pace a little slower than I've been reporting. Still, it is a slight step up from what I was doing before I got the Vibrams. I first did a 400m calibration walk. Then, a 400m calibration run. After that, I ran a steady, quick (for me) 4km (10 laps on a 400m track). The results of the iPod were off I tiny bit, so I calibrated that run to 4km after the fact to exactly 4km.

 I wasn't aware of that feature. So, with at least that one run perfectly calibrated, I held a pace of 5'30". So that is 22 seconds per kilometer off from the uncalibrated iPod. So that would come out to roughly 3.7 minutes slower in a 10k than my iPod thought I was.

Fairly steady pace. Not pushing too hard, but a bit faster than I've been running. Looking back, the last time I held that pace was June 10th, 2008: almost 2 years ago.

Both are pretty uninteresting graphs. But, I can take solace in the fact that my actual pace has come up a tiny bit, if not as much as I had first hoped. That said, it has been so much fun running almost barefoot I shouldn't even care about pace, despite all these graphs. After setting the 4km run, I wasn't sure that it fed that value back to improve accuracy. I hope it does. But in case it doesn't I ran another 2km calibration on the track. If I remember correctly,  when I stopped the calibration it read 1.85km.  So that would be 150m shy over 2km: 75 out of 1000 meters. 7.5% off / 92.5% accurate. That does not sound good. I've been closer with my Nikeplus accuracy in the past. I hope the second calibration got it closer to reality.

Listen to me. I sound like frickin' Rain Man, except I've probably had a math error. Someone correct me. Anyhow, the 5:30/km (8:51/mi) pace was real, it was measured. It is not very fast, but it is slightly faster than I've been, and it seems like a good place to start working on improvements.

Anyhow, glad I got out. I was faster than the 4 other runners on the track (which is kinda sad).