How to improve your SpinScan

29 12 2008

For those who know the Computrainer, it is a very good tool to analyze your pedaling. Two key measurements are:

  • SpinScan: The SpinScan number is defined as: Average Torque divided by Maximum Torque multiplied by 100. In essence, the SpinScan numbers represent efficiency of the muscle groups in the legs to produce power evenly through the stroke. The more efficiently you use the muscles in your legs to “pedal in circles”, the higher the SpinScan values will become and the flatter (bargraph) or rounder (polar) the SpinScan Torque Profile will become. If your legs could produce power like an electric motor, the graphs would be perfectly flat (or round) and the SpinScan values would be 100, as in 100% efficient.*
  • ATA (Average Torque Angle): displays the average point in degrees that represent efficient crank arm length usage.*

One of the main reasons I bought the computrainer was to be able to measure my technique so that I could improve my pedaling efficiency. The first problem though, was to understand what good looks like. The manual does mention:

What is an Optimum SpinScan?

As a general rule, higher numbers are better than lower numbers. It has been our observation that roadies produce numbers in the 70’s to mid 80’s range, while mountain bikers may see much lower values because they spend more time standing on the pedals. Clearly, staying in the seat as long as you can while increasing the grade and eventually you will produce higher SpinScan numbers.*

OK, but what is a real good realistic SpinScan number? Moreover, what is a good ATA? The manual never mentioned anything about a good ATA…

When I started to play with the computrainer, I didn’t have a clue if I had a good or bad technique. So I jumped on the bike and did my best. Let me tell you, I wasn’t thrilled. Fortunately, a few days later, Caca came to my place and tried it out… Bruno came here last weekend and tried it out too.


Nice 8, but not what one would like to see!

One thing was pretty common among us, our SpinScan was pretty mediocre and we had no clue what the ATA was supposed to look like:

  • Hans: SpinScan 63, ATA around 105
  • Caca: SpinScan 58, ATA around 106
  • Bruno: SpinScan 61, ATA around 108

Well, misery likes company! I wasn’t sure if we were all just bad riders, or if SpinScan of 70’s was just hard to achieve. But, I started to really concentrate on my technique, trying different ways of getting the number up and eventually I got to an average of low 70’s. I started to concentrate on the end of the cycle, when I was pulling just when feet hit the bottom of the cycle, but it didn’t really feel right. So I started with the best improvement tool around: google!

I found a great video on youtube that explained what good looks like (i.e. SpinScan of 80 is pretty good and 85 is awesome!) and it also explains that a good ATA is 90 degrees (up to 100 is OK)! Moreover, the author (Coach Mark Evans) tells you how to improve your technique by concentration on your pedaling when your feet are between 11 and 3’clock. It didn’t really make sense to me initially, but… What happened?

I just jumped back on my bike and tried it again, you tell me:


Even I was impressed. I averaged of 80 after 30 minutes!!!

You know what, that makes me think if I shouldn’t be looking for a coach. I wish I had something like this for my running technique.

* Definitions from the Computrainer CS manual


Polar Precision Performance vs. Computrainer

28 12 2008

The last few days I spent playing with the data from the computrainer, trying to figure out how to best use it. Lets face it, the Computrainer Coaching Software isn’t the best user friendly tool.

I started researching a software that could import and analyze the data from the computrainer and I found TrainingPeaks WKO+, which is a pretty neat application. It can not only import data from Computrainer (i.e. .3dp files) but also Polar files (.hrm). It keeps a log of your training and provides you a LOT of graphics. I tried the software until the trial expired, and I was tempted to buy it, but I already spent a lot of cash on all my toys… plus, it is a bit hard to use. A few cons were:

  1. It does not have HR zones per sport. For example, my AT biking is 155 bpm, running is 165 bpm. Having said that, you can use Power Zones for biking and HR zones for running.
  2. I found it kind of useless for swimming. When I use Polar Precision Performance 4 (PPP4) I can either use the laps with distances (i.e. I time every set and then add the distance for the lap) or I can simple add an exercise with total time and distance. On WKO+, there is no option (at least I didn’t find it) to enter a manual workout with duration and distance.
  3. To import all my data from PPP4, I would have to go one by one, setting the sport. It imports one default sport, so you can’t use the sport information from Polar… which is quite some work when you are importing 2 years of data!
  4. Perhaps because it has a lot of options, WKO+ is pretty confusing to use. I used to be a software developer, so I consider myself a fairly savvy user, but it took me quite a bit to get used to the user interface. There are a lot of different graphics, views, options. I found it hard to find the simple things, like:
    1. the distance of a specific workout
    2. a graph summarizing the total time (or distance) per week at a given interval
    3. changing the units to metric (you have to change it for each graph!)

Unfortunately my trial expired before I could find out more about WKO+, but considering that it costs US$99 and I have PPP4 for free… I went down a different avenue: How to import the data from Computrainer to PPP4?


Comp CS Export Options

Comp CS Export Options

Computrainer CS has a feature to export data and you can chose the fields. The problem is that my Polar  (S625X) is set to store data every 5 seconds and the data provided by Computrainer is every few milliseconds! Moreover, it is not the same interval every time. I suppose it must be proportional to the speed or cadence? I don’t know. I know that when I set TOS to 15 (on the export option of CS) it gives me each reading every ~700 ms (690 to 720 ms range). Therefore I had to create a formula that would get the closest reading to 5 seconds. 


To make a long story short, I used the grade and distance of each reading to calculate the altitude (I’ve assumed I started at zero meters). Using basic trigonometry, that gave me the Profile of the ride! I also imported Heart Rate, Power, speed, cadence, Left and Right balance (i.e. Left Balance from CS) and even Pedaling Index (SpinScan). Most importantly, it takes me around 1 minute to import the data. 😉

It is a bit too busy when you look at all data at the same time, but here is a screenshot of the PPP4 workout graphic:


I know, it is busy, but depending what I want to analyze, I will chose what data to show on the graphic. If you are familiarized to PP4, you know what I mean.

Power Distribuition

Power Distribution

Above you can see the Power Distribution for the exercise, which had an average of 175 Watts, although I spend a lot of time between 170 and 220 Watts. (Note: the unit on the graph for watts is Watts/10)

To import the actual data, I used an old hrm file and changed the following fields:

  • SMode=111111100 (this sets what data is available, like speed, cadence, power, etc)
  • Date=20081225 (date of the exercise)
  • StartTime=20:01:55.0 (time of the exercise)

Then I pasted the data I calculated on a excel spreadsheet (where I copied the CS data) to the HR Data in the HRM file:

  • [HRData]
  • 76 225 46 0 138 17460
  • 85 264 57 0 170 17970
  • 92 270 58 1 178 18225 (by the way, this is only 15 seconds of data)

Just out of curiosity, the last number 18255 is the Pedaling Index x 256 + Left Right Balance… took me a while to figure that out!

Well, two “copy and paste” and I have the data from Computrainer in PPP4! Plus I didn’t need to export and import all my existing data from PPP4 to a new software!

If anyone is interested, I can provide a copy of the spreadsheet too, it is not that complex.

Training with Power

19 12 2008

Training  with a Power Meter is a new concept, to me obviously. Since I started training with my CompuTrainer, I have this new data: Output Power.

The big question is, what do I do if it? What does it mean? I’ll be honest, I don’t know the answer yet, but I think what I have published previously on “How to use CompuTrainer in my day to day routine“, does make sense. My intend was to use Ergometer mode and increase the power (watts) during the intervals. I guess it makes more sense than I first thought, specially in a controlled environment (i.e. indoors). 

Doing a little research on the subject, I found a great page (Cycling Mathematics) where the author stated: “A completely inexperienced rider, for long periods of time, can output 50 or 100 watts of leg power; whereas a Tour de France racer is said to be able to generate 500 watts or more of continuous power—still not up to a horse, but mighty impressive, none the less!“. There is also a citation at wikipedia, where they mention “The average ‘in-shape’ person can produce about 3 watts/kg for more than an hour“… anyhow, so far my best average over one hour was 2.7 Watts/kg. Now, mind you, I was NOT pushing as hard as possible. This was during my regular off-season Foundation Ride. Anyhow, I guess I’m not as fit as I once thought.

What I find interesting though is that my Average Power Output is anywhere between 135 to 200 Watts over one hour. Why does it change this much? Until recently I have only trained using Heart Rate (HR). In my mind it makes a lot of sense to train with a Heart Rate Monitor (HRM) specially for running, but when it comes to the bike… not sure yet. I know, a bunch of people will jump on me now, but lets just think for a minute. When we are out there on the road, on a hot day burning day or just about to get sick, you can’t really follow the Power you’re producing. Isn’t that a result, a consequence? Yea, maybe my average power output is 200 Watts on a good day, but if I didn’t sleep the night before, that will probably not happen.

The only thing I want to say is that I’m still not convinced that a power meter is the best device for a race. I would guess it makes sense to train with a Power Meter, but I still makes more sense to listen to your body (with a HR or just feeling) during a race. Specially in long races, if you burn your energy to keep a certain power, you might not finish an Ironman!

I will use the CompuTrainer to keep track and to train based on power, as I will do at least 2 workouts indoors even in the summer. I’ll still trust the HRM when going outside. Why? First, I don’t want to spend the money on a power meter, but secondly because I really think that, specially in the races I should listen to my body not my power meter.

Did you know that if you race against the CompuTrainer pacer that is ALWAYS at the same power output, you might win even with a worse Power Average? That’s right, happens all the time. Why? I think it is because it makes more difference to use the power at the right time (i.e. uphill) and save it downhill… again, what do I know?! Maybe the software is just wrong. 😉

By the way, during my research, I also came across another interesting page: Cycling Performance Tips where talks about staying seated as much as possible, which is something I always try to do… ask Bruno! He keeps bugging me because I almost never leave the seat!

France… What have I done!

16 12 2008

This morning I rode the IM France course on my CompuTrainer for the first time… lets just say, I hope my course profile is completely off. I fast forwarded to KM 35, where I started and I could barely ride for one hour, in fact after one hour I bailed and loaded another course to cool down.

IM France Bike Course Profile

IM France Bike Course Profile

How am I suppose to do this after swimming 3.8 km? And I have to run a FULL marathon afterwards? Seriously, what was I thinking??

Ok, it was hard, bloody hard! But, when I built the course, I didn’t use a feature called “Elevation Noise Smoother”. Basically when you get you GPS data (from Google, in my case), elevation data is usually pretty inaccurate, or “noisy”. Small inaccuracies in altitude can lead to some pretty poor, choppy recreations of the ride. The elevation smoother that uses signal processing to remove the measurement noise from your altitude data. The diagram below compares the real GPS altimeter data to the smoothed data. *


Elevation Smooth

Elevation Smooth

That would explain why I had a lot of 15% grade hills and a lot of small downhills in the middle of the my journey to the top, which in reality shouldn’t be there (I hope). Anyhow, I just fixed the course with the “Elevation Noise Smoother”. Next workout I hope it will be a bit better! 

Here are the numbers for my workout (excluding the cool-down):

  • Total Time: 1:01:27.27
  • Distance: 21.34 km (from km 35 to 56.34)
  • SpinScan Avg: 63
  • Power Avg: 171 Watts
  • Speed Avg: 20.8
  • RPM Avg: 71
  • Calories: 601.95 Kcal (877 according to my polar)

* From CylcingPeak Software webpage:

Note: I’m having problems with the CompuTrainer HR receiver. Racermate is going to send me some replacement parts.

CompuTrainer Report

15 12 2008

I’m starting to get use to the CompuTrainer and to CyclingPeaks Real 3d. I created a bunch of courses, such as IM France 2009 and the Suburu Milton Sprint. I find it pretty interesting that I’ve finish the Milton Sprint averaging 31.9 Km/h in the Computrainer and last year, during the race, I averaged 32.0 km/h! That is pretty cool!

Mind you, I’m on my off-season now, and Milton was my first race last season, so it is hard to say how my fitness level would compare. Having said that, not bad for a simulation!

I’m attaching the CompuTrainer report, it has quite a bit of information too. On the good side, I have a pretty good right to left power ratio, but I really need to work on my “SpinScan”, which should be at least 75:


Hans Winter Report

Date/Time: 2008-12-13 16:52:25


Rider Data



Athlete: Hans Winter


Age: 38

Weight: 98

Gender: M

HR Limits

Lower: 115

Upper: 155


Course Data


Name: Milton Sprint Canada Triathlon Loop.3dc

Distance: 30.26 KM


Units: English

Laps: 1

Lap Length: 30260.30 meters

Min Grade: -6.5%

Avg Grade: -0.0%

Max Grade: 5.8%

Min Wind: 0.0 kph

Avg Wind: 0.0 kph

Max Wind: 0.0 kph


Total Climbing Meters: 166


Total Kilometers Ridden:


Performance Statistics

Lap Avg: None

Rolling Calibration:

 11: 2.00 U

Finish Time: 00:58:03.0

Calories: 650.5









Watts Per KiloGram




Heart Rate












Overall SpinScan




Left SpinScan




Right SpinScan




Power Split Left




Power Split Right




Left ATA




Right ATA





How to use Computrainer in my day to day routine

12 12 2008

It has been 3 days since I got the Computrainer. I have to say, I’m a bit overwhelmed with the amount of options, but I think I’m starting to get the hang of it. Here is what have in mind for my training… I’ll start the Ironman Triathlon Training Plan Level 4 (from Matt Fitzgerald’s book: Essential Week-by-Week Training Guide) in January.

My plan is to use the following modes depending on the workout:

  • CFR/BRW/CTR: Ride a portion of the Ironman (3D) course for the duration of the workout
  • CSI: Ride a flat course and increase the speed during the intervals at VO2max intensity
  • CLI: Same as CSI, but intervals and recovery duration are different
  • CPI: Ergometer mode, increasing the power (watts) during the intervals (either manually or creating a file that changes the power after a certain time: “.erg file”)
  • CSH/CLH: SpinScan mode, manually increasing the grade during intervals. I have to do this manually as grade is on “.crs” files, which use Distance (not time), Grade and Wind information.


  • CFR – Cycling Foundation Run (steady pace)
  • BRW – Brick Workout
  • CTR – Cycling Tempo Run
  • CSI – Cycling Speed Intervals
  • CLI – Cycling Lactate Intervals
  • CPI – Cycling Power Intervals
  • CSH – Cycling Short Hills
  • CLH – Cycling Long Hills

Note: “.erg” and “.crs” file definitions can be found at the Computrainer Coaching Software :

  • “.erg” file defintion can be found on page 29 and 30
  • “.crs” file defintion can be found on page 27 and 28

By the way, I got a very cool software, CyclingPeaks Real3D, which converts GPX files to 3D courses. However, unlike the GPS Course creator from Racermate, it maintains the turns. (From the documentation: “3D courses created using GPS data do not retain the curve information.”. With CyclingPeaks you have not only the profile, but the actual turns too.

Since this post, I’ve started to use Ergvideo for the interval training. Have a look at ErgVideo 2 – Second Impression!

Computrainer First Impressions

10 12 2008

I got the Computrainer yesterday, here are my first impressions.


First of all, the installation! In reality it is VERY simple. There are only a few wires to be connected: candace, heart rate receiver, load generator, computer serial connection and power outlet. That’s it! Having said that, if IKEA had the same quality of manuals, you would still be working on that cabinet!

There is a “Basic Hardware and Electronics Stand-Alone Users Guide”, which is a manual (paper) that comes in the box (with 2 other manuals). It has a note “READ THIS MANUAL FIRST along with INSERT ME FIRST! CD”. The problem is that when you insert the CD, it opens another manual (PDF). Guess what, both the paper copy and the soft copy have a “Quick Setup Guide”, which describe the same thing, using different words and pictures… which is really confusing. I read both and I was trying to figure out which manual to follow. I’m just glad I had downloaded and read all manuals before I go the trainer!

After one hour carefully installing the unit, I did the calibration, and started to play with the software pieces. There are two softwares that come with the trainer, plus the optional  Real Video Course that I got:

Computrainer 3D Software: basically allows you to build course profiles. It reminds me a toy that I had as a kid. I used to have this track for matchbox cars made of plastic pieces that you joined to build the course the way you wanted. This is the exact same concept. Just keep adding a piece of the track; each piece could be a turn, a straight line, up hill, down hill. It has the same problem too, which is getting at the end an managing to close the loop (you don’t have to in either case)! Anyhow, in addition to building the course, you can set parameters as wind, add a pacer to ride with you, etc. You can also load pre-recorded courses. Obviously you can ride these courses too. There are variety of sceneries that can be choose too (Seattle, Desert, etc.). One of the limitations I found was that although you have a 3D representation of the entire course profile on the screen, you can’t browse the course. In other words, you can see the entire course or zoom in to the last portion. For example, if your course has a “U” shape, your view is at the top of the “U”, you can’t zoom to the bottom of the “U”. That doesn’t really help when you load a 180 km IM Course! Anyhow, once you load or build a course, you can use this software to ride the course, which looks like a video game. I rode the IM Canada course for 30 minutes and when I stopped, the app crashed after trying to save the report… I need to investigate more. The performance data was saved though.

Computrainer Coaching Software (CS): this software allows  you to analyze your performance (from a file or realtime). It gives you the ability to create courses too (not 3d). You basically tell it how long (time or distance) you want a resistance (grade or watts) to be applied to the trainer. As you are riding, it gives you information of your speed, cadence, heart rate, calories, watts (per leg!), distance, etc. A LOT of info! The “problem” with this software is that is has clearly been written by an engineer, not a software developer. For example, to analyze a performance chart, one would think that you would go to File –> Open –> Performance File, right? No, you go to Start –> Chart, then you chose the file you want to open. After you open the file, the menu disappears, and the only way to go back to that menu is by hitting “R” on the keyboard. No, I didn’t read that in the manuals… just typed started with “q” nothing, “w” nothing, “e” nothing, “r” wow, I’m back to the menu! 🙂

Real Course Video: this is the software that provides you the ability to ride with an actual DVD recorded at the course itself. The only issue is that you can’t try to catch up with the car (or bike, etc.) that is in front of you! Guess what, even when you go faster, that car is going faster too, as you are just influencing the speed that the video is played! It is a great tool to familiarize yourself with a course that you will do, since when you get to a hill, it will adjust the resistance accordantly. I used it for 27 minutes and it froze the computer… I had to reboot. I did load some patches from but I didn’t tried it out yet.

Now, what is really cool feature available on all three softwares is the spinscan. It gives you realtime feedback on your stroke. It tells you the power split between left and right leg, and it also shows you how much power you are applying at each angle! That is really cool feature that will definitely help my technique.

Overall I find it is a pretty good product that will help me improving my technique and surviving the winter while training for IM France!