The Chung Method is No Joke

I did TT tests yesterday at my Brookhollow course. When messing with the data last night, I came to the conclusion that my test hill must be four feet higher than the 83.1 vertical feet it was designed and staked out to be. Increasing the vertical drop by 4 feet was the only way I could get everything to work out with reasonable Crr and CdA numbers.

I couldn't stand the suspense, so I took a survey instrument (my trusty Topcon GPT-3000 W, shown at left) out there this morning to check it out. Guess what? The contractor built the road with 3.51' more vertical drop than it was supposed to have according to my design (I guess he wanted to save some cash on fill dirt).

The Chung Method is definitely no joke if you use it right. I don't know what Garmin Slipstream pays for tunnel time, but I think I have a comparable tool now for free.

I moved each of my aerobars inward by 3/8" yesterday, and apparently I was able to discern the difference in CdAs from that tiny change (which, by the way, would mean 11 seconds in a 40k TT). If I can see that type of change, this process is going to be fun (and fruitful).

More details to come.

Chung Spreadsheet - Better Acceleration Calculation

The CdAs I calculated for my road bike seemed a little lower than what I would have expected. After reading 106 miles on my Power Tap odometer yesterday for a Claxton Century course that was advertised as 104 miles, I figured the problem might be my PT odometer. I did a very accurate 3-revolution, weighted calibration of my PT wheel this morning and found the circumference to be dead on 2100 mm. I had had the PT programmed to 2098 mm. That means I'm going 2100/2098=1.00095 times as fast/far as I'd thought. Not only is that probably insignificant, it would LOWER my CdA calculations, not raise them. (A quick check revealed that my fastest CdA - when I was in the drops - was lowered by 0.001 m^2 by accounting for the PT circumference change). So I can scratch that as a significant source of error, although the fact that I picked up any change in CdA at all from a 0.095% change in speed is surprising - this method really does provide incredible data resolution).

Then I read Dr. Chung's comment on my last post: He noticed that I had used a simple approximation of acceleration in my Chung Method spreadsheet. To calculate acceleration, I used: change in velocity from T1 to T2 divided by the time interval a = (t2-t1)/dt.

That seemed correct to me. But he suggested I use a more robust approximation suggested by Adam Haile: a = (t2^2-t1^2)/(2*t2*(t2-t1))

As you can see in the highlighted columns in this screen shot of my spreadsheet, the two methods result in very similar, but differing, values of a.















It turns out those differences are enough to change my CdA calculations significantly. My road bike CdAs for hoods, horns, and drops changed from 0.310, 0.245, and 0.240 to 0.338, 0.258, and 0.255, respectively. Those numbers seem more realistic, although they are still lower than I would have guessed.

My Crr changed from 0.0054 to 0.0055 (a difference that is probably not within the resolution of the method).

I think I have everything ready now to do some baseline TT bike tests. Then I'll begin to tinker with my position and see what happens.

Chung Method Aerodynamic Testing

I've always wanted my own wind tunnel. Now I sort of have one.

A couple of years ago I read Robert Chung's presentation, "Estimating CdA with a Power Meter," on aerodynamic testing using nothing more than a known road profile, internet weather info, a bathroom scale, and a power meter.

I remember finding it interesting at the time; but I didn't follow up because I didn't have a power meter on my TT bike. And I didn't really care what my CdA was on my road bike.

A few weeks ago, I read about Colin Griffiths's recent Chung testing in the UK. I now have a Power Tap wheel that I can easily move to my Cervelo TT bike, so re-enter Chung testing.

Basically, Robert Chung took the equation for all the forces acting on a rider: power, air drag (CdA), rolling resistance (Crr), and gravity:

w = wrr + wPE + wKE + waero
w = Crr m v g + s m v g + a m v + CdA ρ vair 2v / 2

and he solved the equation for slope:

s = w/(m g v) – Crr – a/g – (ρ CdA v2)/(2 m g)

Then he used slope and known horizontal position at each time interval to build a virtual profile (using a spreadsheet). By adjusting values of CdA and Crr until the virtual profile matches the real world profile, you are able to solve for both.

Lucky for me, I'm an engineer and a surveyor (lucky in this example, anyway - most of the time I'd rather be a rocket scientist or the base player for the Stones). And lucky for me, a few years ago I designed and staked out a new subdivision street about a mile from my house, so I know the EXACT profile of the road. And lucky for me, the developer has barely sold a single lot in the subdivision, so there is ZERO traffic. And lucky for me, the profile is a perfect U shape with cul-de-sacs at each end so that I can turn around at both ends without touching the brakes. And lastly, the road is very well protected by tall pines, reducing any minor breezes that might interfere with my results.

So as a test run, today I Chung-tested my Tarmac, and I got perfect results. Here's the procedure:

Get on the web and get the temperature, pressure, and humidity for the test location.

Dress for riding and weigh yourself with your bike, bottles, everything.

Ride a known profile (really all you need to know is the elevations of the high points and low points).

Keep EXACTLY the same position on the bike for the duration of the test.

Do not ever touch the brakes - the formula can't account for deceleration due to braking).

Record several runs over/through the known profile.

Return home and record weight and weather data again and average start/finish numbers.

Set up a spreadsheet to plot a virtual profile of your course using the Chung Method.

Adjust the CdA and Crr until you get a constant amplitude and crest height.

Here's a screen shot of the spreadsheet I created to do all of this. Download it from my eSnips account if you want a copy.

It worked like a charm. I did three runs of the course in each of three different positions: 1 - on the hoods; 2 - on the "horns" (hands wrapped around the tops of my Shimano shifters and elbows sort of low; and 3 - in the drops.

I did a trial-and-error adjustment the CdAs for all three positions to get an almost perfect and consistent profile. What little profile variation I saw was likely due to a very light breeze or hitting a rock in the road. A little tweaking of the Crr (rolling resistance coefficient) got the amplitudes right.

Here's what it looked like when I was done. Remember, this is a VIRTUAL profile. It's not measured elevations, it's calculated elevations assuming all the different forces on the rider. It looks to be so accurate and precise that I could literally use it to perform asbuilt surveys on finished roadways (Causey will find that idea intriguing, I think).

The fact that it worked is cool enough. But now comes the fun part: using the new technique to play around with different positions and equipment on my TT bike.

I also learned something very interesting and useful that I will use while training and racing on the road bike. I've always wondered how much more aerodynamic it was to ride in the drops as compared to on the horns. On the horns is so much more comfortable and seems more powerful, too. I turns out that my CdA on the horns is a LOT lower than on the hoods (somewhat expected), and only very slightly less aero than riding in the drops (I was surprised the difference was so little).

So there will be no more training or riding in the drops for me. The almost immeasurable benefit isn't worth the more aggressive, less comfortable position. I'll just ride on the horns. I guess I'll only use the drops for standing and sprinting.

Trainer vs. Road

Ok - this is a work in progress. I don't have as much data as I'd like to have, but the general trend is clear. The problem with collecting additional data is that my aerobic system is improving, which makes establishing a true best-fit line a little like trying to hit a moving target. But you'll get the gist of it. The magenta line is a best fit for trainer data. The red line is a best fit for road data.


The not-so-surprising result: it's harder to ride the trainer than to ride on the road at the same power (all the power data was collected using my Power Tap). For now I'll target my training zones on the trainer using a target heartrate along with the trainer curve to get a target power range. Later I'll do a CP30 test on the trainer, set up power zones from that and see how they compare to the first method. I find it interesting that the difference in NP vs AHR is lower close to threshold than at lower efforts. I would have expected the opposite effect.


Gotta do something to keep the trainer workouts interesting, right? But I have discovered a new indoor toy for indoor rides: I downloaded the new Computrainer scenery pack. Now I can ride cyclocross trails through downtown Atlanta scenery. That's different.

2010 Annual Training Plan

Here's my plan for 2010. Those of you familiar with various popular training approaches will recognize this training philosophy and structure as Joe Friel's. I used a Friel plan in 2006, but that doesn't really count because I didn't start training for cycling exclusively until April 2006. So this will be my first full year on an Friel-based structure.

The most significant changes from my 2008 and 2009 plans are:

• A greater emphasis on macroperiodization -- base1, base2, et cetera as shown below.


• An increase from 425 training hours per year to 505 training hours per year.


• A greater emphasis on weekly microperiodization (rest weeks following work weeks).


• Re-introduction of strength training. I lifted for 10 weeks in winter 2007/2008.


• Strength maintenance work throughout the season.
  

By May I'll know once and for all if Friel's philosophy works.

New Title Sponsor

I'm pleased to announce that Georgia Cycling, Inc., formerly racing as Security Bank Cycling Team, will race in 2010 as Walthall Oil Company Cycling Team. We are excited about our new sponsor and can't wait to see how the new kits turn out.

The Peach Peloton

It will be good to get back home to my fourth year of the Peach Peloton.

Macon Cyclocross Race

I bought a Redline Conquest Pro cross bike last fall to use for winter dirt road training. We have a million miles of dirt roads in Jasper County. It's a size too big, but with a short stem it works quite well for winter training. But I havent' raced the bike until this past weekend in Macon.

The race was every bit as fun as I had been told to expect. The racing was crit-like intensity with a laid-back atmosphere. I loved it.

Here's a video Dan Coy made at the first barrier in the first lap in the CX4 race. I started at the back of the 63-rider group 'cause I had no idea what to expect and didn't want to pull a rookie move and create a big pile of 4s in the first turn. So I had to soft pedal a while while it thinned out. I think I was about 30 seconds back from the front group after half a lap! I come through in the video at about 23 seconds - notice my flawless form, particularly on the re-mount. I think that needs a little work, ya think?



Unfortunately my 2010 training schedule won't allow more of these this year, but I may have to shuffle things around to accomodate at least a short cross season next fall.

2010 Georgia Road Racing Schedule (preliminary)

Here's the preliminary bike racing schedule for 2010 as discussed at the Georgia Bicycle Racing Association meeting on October 3rd:

Feb 13 - Tundra Time Trial - Rockmart
Mar 6/7 - Albany (omnium/stage?)
March 13/14 - Perry Roubaix Omnium
March 20/21 - Union City Stage Race (new TT course)
March 28 - Newton County TT
April 10/11 - Chattanooga Stage Race (hilltop finish on 1-mi climb this year)
April 17/18 - Sunny King/Cheeha(sp) RR
April 24/25 - Twilight Criterium/Roswell Crit
May 1 - Aarons 'Cross Crit
May 2 - Sandy Springs Crit
May 15/16 - Tour de Gaps Omnium - Dahlonega
May 22/23 - Elberton (omnium/stage?)
May 28-31 - Tour of Atlanta (TT and three RRs included)
June 5 - Cherokee RR
June 6 - Cycle for Parkinsons crit
June 12/13 - Rome Stage Race
July 10/11 - Gainesville Stage Race
July 31/Aug 1 - Marietta ?
August 21 - Macon Crit
August 22 - Grant Park Crit

There will also be a time trial series with 8 or 10 events not listed here.

Why didn't I think of that?

Three Years of Tuesday Worlds: AP vs NP

I've had some discussions with a teammate recently regarding Average Power (AP) vs Normalized Power (NP). Although the data shows that for most time intervals my maximum average power hasn't changed drastically, I posed to him that I believe I can repeat the hard efforts more frequently in race-type situations. He responded that "it's probably just NP busters messing up your data due to different types of interval sessions you're doing this year." I thought he might be right, so I've developed a way to check.


I wanted a way to compare apples to apples so that variations in my training plan (different types of workouts) would not affect the result. I have power data for at least a portion of each of the past three seasons of Tuesday Worlds group rides - 2007, 2008, and 2009. So I made mean maximum power (MMP) and mean maximum normalized (MMNP) power charts using only those rides for each of those years. They are shown below. As you can see, 2008 was a crappier year than I thought. But more importantly, look at the huge jump in my MMNP in 2009 relative to the jump in MMP. I've sacrificed FTP by doing more L5 intervals and fewer TT training rides, but it's definately benefited my ability to repeat hard short-term efforts in RR (or crit) type events. That's the only conclusion I can draw so far - I'll keep pondering it.


Next year the goal is to move both lines to the northeast while maintaining a good aerobic engine for TTs also.

Negative Decoupling at 175 Watts

My 225-watt test showed 8% decoupling in a 30-min test. (later determined that it wasn't really 8%, more like 3-5% if I used the correct calculation method). I wanted to see the results of a lower wattage test, so I did an 80-min decoupling test at 175 watts.

Not only did I not find any evidence at all of decoupling, the result was NEGATIVE 2%. First 37 min: 176w at 123 bpm; Second 37 min: 177w at 122 bpm. Go figure.

I'll do the 225w test again to see if I can repeat the 8% decoupling result. If I can, then the next step will be to see at what wattage the decoupling effect starts to occur. Will it be at an abrupt wattage or will it gradually decouple?

If I find that it's an abrupt point, will additional aerobic system training raise the 'decoupling point?' Will additional aerobic training lower the 8% decoupling I see at 225 watts? Lots to investigate; but that's ok - I have until Spring.

More on Friel's Decoupling

Friel has a simple summary of his decoupling thesis at: http://home.trainingpeaks.com/articles/cycling/aerobic-endurance-and-decoupling.aspx

I'll summarize it even more: He says that for serious cyclists, aerobic fitness is best developed by riding at 65% to 75% of FTP. That puts me at about 200 watts, or upper portion of L2. He says if I'm training for longer road races, my decoupling should be less than 5% for 2 to 4 hours.

Calculate it by taking NP for the 1st half of the workout and dividing by average HR for 1st half of workout to get (NP/HRave) = A. Do the same for the 2nd half of the workout to get B.

Then check the percent increase by taking [(B-A)/A] x 100. If this percent decoupling is greater than 5%, aerobic fitness is not fully developed (unless heat or improper hydration have played a role).

I'm going to try a longer, slightly lower power test today (maybe 200w for an hour) to see how the decoupling looks.

Decoupling

Joe Friel has written lately about decoupling. That's when you're exercising aerobically (at sub-threshold) and your heartrate is not consistent with your power output. I used to use a coupling test when I was training for triathlon. I'd hold my heartrate constant while running on a track. The further I had run after 20 minutes, the more aerobically fit I was. I was amazed at the variation throught the trainign season back then (2001).

So I decided to do a coupling test on the bike yesterday. I put on the heartrate monitor, warmed up, and did 30 minutes at tempo (225 watts for me). I felt nice and steady for the whole interval and was on Hwy 11, which is flat. Wind was minimal.

The ride felt very consistent, so I was surprised to see later that my heartrate gradually rose during the interval, starting in the low 140s and finishing around 150. My threshold HR is about 160. I sort of had a plateau in the middle, but it didn't last.

Supposedly this means that my aerobic system is not well-developed at the moment. I look forward to doing more aerobic work during the fall and winter to see if I get a more coupled 30-min tempo result. If that does happen, maybe I can use this very easy test throughout the season to monitor my aerobic fitness and do more aerobic work when I see things start to "come apart."

Unique

TTT Pacing

Below are some interesting charts related to TTT pacing. Two very similar teams (only one rider different on a 4-man squad) did the same course (at least up till mile 17.5) under very similar conditions about two months apart - both in competition. The first time we went out much too hard and had trouble at the end. The second time we might have gone out too easy - it's hard to say for sure. On the second attempt (August), we were lagging behind the first attempt (June) pace until very late in the race, when we easily caught and 'passed' ourselves.

The course was more difficult in the second half, which makes the interpretation a little more complicated.



More consistent speed in August:




Making up major time toward the end (10-20 seconds per mile):


Course was tougher in 2nd half, but not too much speed was lost in August:

Ready for the Mountains

295/65=4.54

Fall Training Plan

This'll take me through the end of the season:

Macro Periodization

If you saw me race in the Gainesville crit last weekend you'll know the obvious: I didn't get my ass handed to me, I got it thrown at me. It was very ugly. And the worst part was that my legs were fine and my power was decent. I was just outclassed by my competition in an 8-man masters field with nowhere to hide.


Anyone who's read anything about training is familiar with periodization. You work harder and harder for two or three weeks, then take an week so the body can supercompensate.


Well I guess I've sort of unintentionally done that on a macro scale. We'll call 2001 through 2005 my base period. I was a triathlete then and probably averaged about 75 to 100 miles per week on the bike - mostly at tempo. I got stronger on the bike each year, but never got very fast.


In 2006 I discovered bike racing. I'm not sure how it happened, really - I guess I'll go back and read my blog - that's why I starting writing this stuff, anyway - so I could see trends. I delved into all sorts of training literature and worked pretty hard to get better. And I did get better. I trained with structure for three years, 2006, 2007, and 2008. I could barely hang onto the back of the cat5 pack when I raced in Gainesville in spring 2006. I catted up to cat 4 for 2008, where my biggest achievements were winning the Tour of Atlanta and getting a 2nd in the Elberton road race in a 40-mile break. I think I was on the cusp of getting some real results.


Then in fall 2008 my power meter crapped out and I didn't replace it. Then 2009 started out poorly - I had a bad crash at my very first race in early March that messed me up for a while and caused a bad back that lingered for a couple more months. The end result is that I really have not 'trained' this year at all. I've ridden a decent amount, averaging about 8 hours per week since February. But I've done no intervals and had no training structure. Basically, I've taken the year off from training. So we'll call this my recovery year. Also, my Tarmac SL downtube cracked for no reason that I know of and Calfee is working to repair it (it really has been a tough year). And to make it just a little bit tougher on myself, I catted up to 3 (a move of true genius, I see now).


But through all this year's problems, I've still gotten a little stronger. A friend loaned me a SRM for the past month with a loaner frame when mine cracked. It has confirmed what I felt - that my MMP curve has moved northeastward even with no structured training (I'll post the curve later). I'm slightly stronger in almost all time intervals.


So now I guess it's time for me to start another four-year cycle. Last week I created and initiated a training plan to take me through October (I'll post that later, too). Today I ordered a Power Tap which will be here by mid-week. Since I catted up to 3, I figure I have no choice but to get stronger if I want to continue enjoying racing.


So it's time for me to get stronger.

BBQ Bass 2009

Thanks to everyone who joined us for the BBQ Bass ride on Saturday.

At Hog Wild BBQ in Hillsboro


Betty Jean lobbies for "BBQ Bass Banana Ride"


Bill explores the mysteries of his new Blackberry.