Two Ways To Run Faster

When thinking about running speed, it becomes obvious that there are two components.

One is how fast the legs are switching, that is, stride rate (also known as cadence). The other is how long each step travels, that is, stride length.

Everything else that a runner does, such as posture, upper body movement, breathing, etc. are all meant to increase either stride rate or stride length, thereby increasing the speed.

Now then the how-to-run-faster question becomes a multiple-choice problem. To increase the speed, a runner can either

  1. Increase the stride rate,
  2. Increase the stride length, or
  3. Increase both

From my reading of discussion threads and blog articles, there are many debates among runners regarding optimal stride rate. There are several articles that seem to suggest that optimal stride rate is 90 strides per minute (180 steps per min). Does that mean if I were to increase my speed, I have to increase my stride length?

Let’s figure it out by analyzing my own interval training data, where I vary my running speed.

How am I varying my speed? Is it by controlling stride rate, or stride length, or both?

Thanks to my stride sensor, I have the following data from my interval training the other day.


Red line is showing the stride rate (cadence) on the left Y axis, and purple line is showing stride length on the right Y axis. What’s interesting is that as I increased my running speed, I increased both stride rate and stride length. (This was done on a treadmill while controlling the speed. I remember the initial speed was at 6 miles/hr, and I jumped to 10 miles/hr. If you do the math, you’ll notice that my stride sensor was reporting my speed a bit lower. I’ll talk more about that later.)

When I increased the speed from 10 to 10.5 miles/hr toward the end (two wider peaks), I was increasing stride rate instead of stride length on the top end of the speed.

On the lower end of speed, when I slowed down to 4 miles/hr walking pace around the last two peaks, I was modulating my stride rate while keeping my stride length constant. This meant that my jogging (about 6 miles/hr) stride length is just about the same as my walking (about 4 miles/hr) stride length. What accounted for slower speed was my stride rate, which dropped from mid-80’s to low-60’s.

This is easier to see when stride rate is plotted against the speed.


In the above graph, the X axis is showing the stride rate (cadence), the Y axis is showing the speed, and the color of each circle is showing the stride length, where the darker the color, the longer the stride length is.

Most of my interval running had the stride rate between 85 and 95. And the speed within this stride rate zone was primarily controlled by stride length.

This shows I’m using my stride rate to vary my speed at the lower end, and primarily using the longer strides to pick up speed at the higher end. But in the very top end, I tend to rely on stride rate to increase the speed even further.

If I were to plot out these three phases, they would look like the following.


Yellow is the walking to jogging where I’m varying stride rate with minimum stride length. Orange is the jogging to running where both stride length and stride rate are increasing. Red is the final phase where stride length is staying constant yet stride rate is increasing by a bit.

It is interesting that increasing stride rate is where I can gain the last bit of speed. Reading about how a professional runner used higher stride rate in the home stretch to win a race, I somehow feel validated.


18-Mile Run

Yesterday was my 18 mile run.

It started out great. I have been watching how to improve my stride length by folding my legs faster and bringing my feet closer to my butt, and it must have helped in the beginning. I was doing about 8:15 minute a mile, and felt great.

Oh, I should also mention that I learned a lesson from my 17 mile run, and ate a banana before heading out. It must have counted for something.

Going up to San Ramon was a breeze. I was doing about 8:25 minute a mile all the way up to 9 mile mark. In fact when I reached my half way mark, I felt like I could go for another mile to make it 20 mile run. At least that’s what I felt like at that time.

It was nice going until about Mile 13.
After that, my legs turned into bricks.

Coming back was a different story. Starting 13 miles, I could feel that my legs were getting wobbly. Breathing and upper body were okay, but my legs were getting heavier and not moving. I thought I was switching my legs at the same pace as the first half, but on my watch it was showing 9+ minute per mile pace. Even when the road was clear, each crosswalk gave me an excuse to stop and wait for the light to turn green. When it turned green, I jogged. In my mind, I was already visualizing how good it would feel to lie down on the couch and kick up my feet.

By the time I got to the final 3 miles, I barely jogged. Mostly it was walking, and waiting for the light to change.


Comparing it with the earlier week, it was not much different. I remembered how difficult it was at the end of my 17 mile run. Yesterday’s run was no better.


I now think that I must have depleted glycogen. For my 18 mile run, I was out on the road for 2 hours 49 minutes. I should have gotten some snack, either energy gel or sports drinks. All I had was three 10 oz bottles, and a banana that I had before the run. Looking back, the banana that I ate before the run must have kicked in during my run because at the mid mark I felt like I could go for 20 mile run.

So I ordered some energy gel for the first time. I read online that you should eat a gel every 1 hr or about every 6 miles or so. Boy, no wonder I felt out of energy. I was running close to 3 hours without any snack.

Let’s see what kind of difference energy gel will make on my next long run.


Stride Sensor

After I tried Garmin Forerunner 225, I realized how much training data I will be missing if I did not measure treadmill running. Although I ended up not keeping Forerunner 225, I remember how it tracked cadence as well as estimated distance without GPS tracking. I say estimated because it often got the distance off, but considering that it was measuring my steps while strapped on to my swinging right arm, it was a neat feature to have.

Anyway, a few times that I tried Forerunner 225 on my treadmill running I knew I had to measure my treadmill running better.

So when I got Polar V800, I was disappointed to find that the watch did not track running cadence. Although there was a mention of cadence tracking feature coming out soon (Polar V800 has built-in accelerometer), as of now V800 does not track cadence yet. And because it doesn’t track cadence, it does not estimate the distance. Ugh.

Considering it tracks steps as part of daily activity tracker features, I know the hardware is capable. I guess the V800 product managers thought that they needed to make the watch more appealing to casual users. But that meant V800 in treadmill running mode only captured heart rate with chest-strapped heart rate monitor. What a waste of hardware.

That’s missing the entire side of equation. Without distance, I wouldn’t be able to track the weekly mileage, and see how many miles I can cover on my weekend long run. Given that I cover 3 to 4 miles per each workout, and I do about 3 workouts a week, that’s about 10 miles that is missing from my weekly mileage. Cadence would be useful to measure also to see whether I’m moving my feet fast enough.

Once I realized that I was missing lots of data, I started to look into stride sensor. Stride sensor is a stand-alone accelerometer that clips on to your shoe lace, and measures the number of steps and step length. Based on the two measurements, a running watch calculates the speed and distance covered.

Thankfully Polar had its own stride sensor that is compatible with V800: Polar Stride Sensor. It supported auto-calibration with V800, which meant that I could just pair Polar Stride Sensor with V800, and V800 would automatically adjust the multiplication factor based on the GPS distance that was measured by the watch.


So I started to monitor Polar Stride Sensor price. Normally it was sold for around $55. For some reason it is more expensive on Amazon at around $67 as of now, but when I saw the price dropping below $50 on Amazon, I pulled the trigger.

Now I do all my in-door treadmill runs with my stride sensor. It pairs well with V800, and tracks my speed, distance, and cadence.


Oh No! My Marathon Partner Got Injured

I just got a message from my marathon running partner. He just got a confirmation that he has meniscus tear on his knee, and won’t be running the Napa Valley Marathon with me.

This reminded me of the three pieces of advice that I got from a running YouTube video.

There are three ways to get better at running

  1. Run more
  2. Run faster
  3. Don’t get injured while doing it

(Here is the full video if you are interested in watching:

I am now starting to read what to do to avoid getting injury. It seems like the street wisdom says

Don’t ramp up the weekly mileage too fast

Vary the training style

Rotate running shoes

I should pay more attention to these as I increase my long-run mileage.


17-Mile Run

Today was my long run day. I typically do my long runs on Saturdays, but because I will be out of town for the next few days I decided to do my long run today.

It was a great day for a morning run. I rolled out of my bed, and suited up in my long running pants, hydration belt, GPS watch, and a pair of gloves that I picked up at a Marshalls the other day. I drank two cups of water, and headed out.

A bit on colder side (37 F) than usual, and I could see white frosts on the cars parked along the street. Gray hays by the running trail was just shaking off their white glistening blankets. As I was running, I was not sure how many miles that I was going to cover. I just knew I wanted to get a good long run.

Starting pace was good. I was doing about 8:20 minute miles. I felt a bit more relaxed than usual, and felt as though paying attention to my stride length was showing on my pace. It was a good feeling.

My usual long run route is Iron Horse Regional Trail. I don’t know where exactly the trail starts, but I have been told that it goes all the way up to Walnut Creek and beyond. It has paved surface with gradual climb at about 130 foot elevation gain over 3 miles or so. Not any significant hill to speak of.

It takes about 3 miles to get to the trail from my place. By the time I start seeing the trail, I’m well warmed up, and ready to find my zone. I set my pace to be around 8:15 minute miles.

My usual route on Iron Horse Regional Trail. It's a good, flat trail for runners.
My usual route on Iron Horse Regional Trail.
It’s a good, flat trail for runners.

It was looking good until I ran out of my first water bottle. My hydration belt has 3 bottle holders. I usually carry two, but today I carried all three. I figured that if I decide to add an extra mile or two, it would not hurt to have an extra bottle of water.

Trouble was that when I ran out of water from my first water bottle, I used that as an excuse to slowdown and walked for a minute or so. I switched the water bottles so that I can grab the full bottle with my right hand. It was just before the 8 mile mark, and I think that little break in my concentration set the tone for the rest of the run.

Coming back was hard. It’s always hard to stay focused in the second half when the legs are heavy and tired. I found that when I stop and think about the heavy legs, they get even heavier and heavier. They start sending distress signals out to my brain, and I have to slowdown even more. Slowing down was a mistake.

At about 14, I started feeling a bit of cramping on my toes. Uh-oh. I better slow down. Another excuse. Could munching on some salty snack have helped? I don’t know, but I was on a downward spiral . I didn’t want to get cramps with 3 miles to go, and it gave me another reason for me to slow down. Pace dropped to 12:20 minute mile and the next one was even worse.

The whole run came out to be 8:59 minute mile average pace. I covered 17.26 miles in 2:35:11.

My mile splits.
It was nice going until mile 8, and it fell apart at mile 16.

I should experiment with eating before my run. Maybe running on the empty stomach is not such a good idea.

Plus I should not give myself excuse to take a break. Once I take a break, starting back up and finding the zone again is hard, especially when my legs are getting tired in my second half.

Another lesson learned, and things to experiment.

Happy Thanksgiving everyone!


Signed Up for Napa Valley Marathon

I signed up for 2016 Napa Valley Marathon.

This is going to be my first marathon experience. I did a half marathon last year. But I never tried to complete a marathon course.

I didn’t think I was ready to commit. Yet when a bunch of my cycling friends and I were messaging back and forth, a veteran marathoner invited us to join. I jumped at that chance. Knowing my aversion to commitment, I’m not sure why. It must have been the right time for me.

I must have been waiting for the next challenge. When I did my half marathon, it was not because of my own initiative. It was my wife’s idea. She invited me to run together.

It was Kaiser Permanente S.F. Half Marathon.

On the race day, it started to drizzle when we headed out in the early morning Sunday. It became pouring rain when we were driving to the race course. Neither my wife nor I had adequate rain gear on us. Flimsy sweat jackets were all we had. When we got out of the car, and out of the garage, it was cold. We were not sure whether it was a good idea to run. Sky looked gray all over, and there was no sign of letting up.

But we ran. Although the rain continued through out the race, we ran. When we were down on the final few miles, the rain drops angled by blustery winds were so sharp that it was painful to endure. In spite of the cold rainy and windy weather, thankfully we finished.

It was the first time ever that I ran over 5 miles. Looking back at it, it was not as physically challenging as I originally thought. Perhaps it’s because I kept pace with my wife. What seemed more daunting before the race was the idea that I had to prepare for the race, and to break my Sunday routine to get out to the race course early Sunday morning. Both of the inconveniences now seem like small price to pay when I look back at the gain from the whole half marathon experience.

Napa Valley Marathon is going to happen on March 6th, 2016, 7am in the morning. I have exactly 14 weeks 6 days to prepare. My marathoner friend tells me that it’s likely that it will rain. I better mend my mental wet suit to prepare for the long run.

Here’s what the course looks like. If you are looking for the next challenge, I would love to see you on the course.


Bryan Krouse NVM_2015 Course Map
Napa Valley Marathon.
Thankfully it has net elevation loss. 🙂

How I Ended Up Choosing Polar V800

My V800.
Photo is a bit deceiving: It’s not a small watch.

When I finally decided that I wanted to get a GPS running watch, I didn’t know what watch I was going to get. All I wanted from a GPS watch was to measure my speed. I have been doing my fartlek for a while, and I wanted to know my pace during my run. Well, simple enough request, right?

So I started searching. I browsed Amazon for GPS watches with the best reviews, googled for the latest fitness watches that just came out, and went through pages of GPS watch reviews on fitness magazines to online communities. And I found a watch that did everything that I wanted, and plus a whole lot more. I picked up a Garmin Fenix 3.

It was around June. It had only been a couple of months since Fenix 3 came out, and I remember that there weren’t any online discounts available. Note that I consider myself a value shopper (my wife can vouch for that), and very price conscious. I hate paying the full price, if I can run some simple searches to find out deals online. But I simply couldn’t for Fenix 3. So I did a very unusual thing. I walked in to a REI store, and pick up a brand new Fenix 3 at its full price. It was $550 plus tax.

Fenix 3 was a great looking watch. It had a bright color screen without any grainy pixels, it featured GPS and GLONASS location (I heard that GLONASS is a Russian GPS that can be used as backup when GPS is not working; never got to test it myself, though), it did navigation, it showed temperature, altitude, mobile phone alerts, and heart rate using the included heart rate monitor. Oh yeah… it also had the speed.

After trying it out for a couple of days, however, I realized that I really did not mean to spend $550 on my GPS watch. Let’s think about it for a minute. When was the last time I went out hiking in wilderness relying only on my GPS watch to find my way back home? Well, it has not happened yet, and I don’t see that happening anytime soon. I knew I had an impulse purchase. Thankfully, REI was gracious enough to take my return. No questions asked.

Then I was back at the drawing board. It wasn’t Fenix 3. Then what would it be? What was the right watch that I needed to measure my speed? Let’s see, I wanted to use a watch for running, primarily for running, and maybe indoor running as well. Yes, heart rate monitoring would be a must. Oh look. Garmin had the new watch that did not require a separate heart rate monitor. Let’s check it out. It was Garmin Forerunner 225.

It must have been July because I remember ordering a Forerunner 225 from Amazon, and receiving it when I returned from a couple of nights in Monterey. Unboxing it, doing a quick setup, and wearing it, it felt solid. It had a very intuitive navigation, and it was easy to use. The optical heart rate monitor was working as advertised when I clicked a button to read my heart rate on the fly.

So I gave it a real try. I took it to 24-Hour Fitness, and wore it three times on my treadmill run. But for some reason, it just couldn’t produce the accurate heart rate reading for me. I would say about 20% of time, it was showing totally off heart rates, something like 220bpm at one time, and on the other times, it was showing sharp drop of heart rate in the middle of the run. After I failed to get a consistent heart rate reading, I realized that I wanted my measurements to be accurate. As we geeks say, garbage in, garbage out.

Forerunner 225 was not meant for me either. After spending about a week of honeymoon, it was back in the box to be UPSed out to Amazon. By then, I was getting a bit desperate to find a GPS watch that would work for me. So I started widening my search, and looked for something that’s simpler, cheaper, and perhaps more reliable.

Then I found Polar M400. It was built for runner, and had all basic GPS functionalities, plus activity tracking and bluetooth message display. And to make it even more attractive, it was sold for under $200. What a bargain, I thought. I found a deal through Google Shopping site, and ordered one. Finally, I found a watch that would be just right for me. No fancy features. Just an honest GPS location tracking, speed, and heart rate monitoring. Just what I wanted. Problem solved. I just had to wait for my M400 to be delivered through ground shipping.

While my anticipation of M400 built, there were a couple of things that happened. A very bad omen, if you ask me. I found the M400 price dropped by about $40 within a few days after I ordered. Bad sign because it gave me an incentive to return and buy it again if the seller was not going to match the price for me (the seller did not agree to do that, BTW). But even worse was to find this damning report by fellrnr. He was basically saying that he couldn’t recommend M400 because its GPS accuracy was the worst out of all the watches that he tested. And test, he did. If you take a look at his report, he goes into science-journal-article level review process to vet the series of GPS watches, and concludes that M400 is not even fit to be called a GPS watch because its accuracy is so bad.


My anticipation turned into a liability of owning a lemon. In reality, I didn’t know whether M400 would be so bad that I wouldn’t be able to get my speed reliably. All I knew was that I wanted a quality device that captured good data. The thought of knowing that there were better options out there, I just couldn’t live with that hanging over me. So I did what any sensible geek would do. I returned the watch, the moment I received it.

Now, at this point a dilettante may have given up on the idea of getting a GPS watch. But hey, if I were a quitter, I wouldn’t be a runner. I had to find a watch that would work for me. So I dug in and read the fellrnr’s report closely. And to my surprise, he found that Polar V800 had the highest GPS accuracy out of a dozen or so GPS watches that he tested. I searched and found a few other articles discussing GPS accuracy, and found that V800 owners rarely complained about its GPS accuracy, while other watch owners had a few negative comments regarding their GPS accuracy.

From then on, I started to monitor V800 price, and found this great deal where it was sold for under $300 including H7 bluetooth heart rate sensor on eBay. That’s how I ended up with my V800.

How do I like V800? I like it very much. I have been wearing it on my run since I got it in late August, and GPS tracking has been superb. Looking at the GPS tracked route, I can see where I cross the street, and even how I ran off the path to avoid pedestrians. With that level of GPS accuracy, I know that my speed is pretty darn close to the real speed that I run.

What about that speed? Well, we’ll talk about that later. Let me just say that I did not regret my career choice of being a geeky product manager. 🙂


Let’s Start A Run!


Welcome to the Run Data Geek blog.

I am a runner, a bicyclist, a product manager, and a data geek. Although I have been running to stay in shape since my college days, I haven’t really challenged myself to be a better athlete. Now that I set a goal to run my first marathon, I wanted to measure my progress, and document the journey to completing my first marathon and beyond.

Let’s start.