A Crafty Bugger

When Schooner Mark II arrives (due sometime in the next week or so), then I not only have the challenge of learning to walk on the new leg (which shouldn't take too long) but of also rigging up and adjusting a new cycling leg.

As mentioned before, the new prosthetic leg has been designed to enable a fluid pedalling motion by allowing sufficient freedom of movement around the knee joint (especially behind the knee). It is that very freedom which means I will take a little time to re-adapt to walking on it - my knees, hips and all the associated muscles, tendons etc need to have the ability to cope with the new level of freedom. That will mostly be sorted out simply through using it and maybe a few supplemental exercises.

The prosthetic is also designed so that my walking foot extension can be readily removed from the leg socket and a cycling leg extension attached. Undo/redo a couple of allen bolts to drop one out and put the other in.

Getting it right requires a few planets to align, with one of them just being put into the right orbit today.



At the moment the problem is being tackled from each end of the prosthetic - firstly the end where the remainder of my left leg attaches (fits into) to the prosthetic socket. That's been the job of my prosthetics specialist, George. I'm going to write more about that when I get the new leg.

The other end is the interface with the bicycle pedal. I still want to be able to use the standard clipless pedal system for all the normal advantages that provides (for the non-cyclists amongst you - that's a pedal system whereby a cleat on the bottom of your cycling shoe enables you to "click" into a pedal, which then holds your foot securely onto the pedal, similar to how a ski boot is secured onto a ski).

I also did some research which indicated that riders using prosthetic legs have had two main approaches to using pedals. One has been to use their normal prothetic foot (or a proxy prosthetic foot) and wear a cycling shoe on that. This has some inherent problems, as there no longer exists much of the lower leg required to stablise the foot section and the lever it creates puts non-radial forces through your leg to socket interface. The other approach is simply to place a cleat directly under the end of the pipe section that extends down from the leg socket.

This latter arrangement is effectively like pedalling with a cleat attached under your heel. That means that forces are applied in a line that goes directly down through your prosthetic socket, straight down the pipe section and into the pedal. This is radial alignment is also the strongest arrangement, and since I have no foot on that leg, there are no toes to overlap the front wheel (which is why you could not position a cleat as such with a normal foot).

But hang on - isn't that going to do some weird things with my pedalling action and balance considering my other foot will use the standard shoe/cleat and pedal position?

Well of course it will, but not as bad as one might at first think. The one advantage of a prosthetic leg is that I can make it as long or short as I want. It can be made to extend out at any angle I desire. The cleat can be moved fore/aft, side to side and rotated in its own plane, so there are significant types of adjustment should it be required. Indeed there are also shims that would enable the cleat to be slightly rotated perpendicular to its plane if that were necessary.

OK, so how about shifting that planet's orbit to make it happen?

In steps my good buddy Peter Barnard and all his crafty machining and cycling nouse on how to design and manufacture a solution for me.

The challenge was to fashion an adapter so that a cycling cleat with a standard 3-hole fit like this slightly worn Campag cleat:



could be attached to a standard attachment block used for prosthetic legs:



Here are some pics of the solution. This is the adapter plate Pete fashioned up:




Note the overall shape and how it is designed to be flat on one side for the prosthetic attachment block and curved on the other to match the curve of the cycling cleat. Also the attachment of the prosthetic block requires four screws in a square arrangement and the cycling cleat requires three screws in a triangular arrangement.

The way the design is made is so that two of the prosthetic block screw holes were able to be lined up with two of the cleat attachment holes (which was simply fortuitous), so that enables all three to be securely fitted together with two nuts and bolts and reduces the overall number of screws needed by two.

So, attaching the prosthetic block on one side:



and attaching the cleat to the other side:



and it all looks like this when together. From side on:



and head on:



So that's either end of the planetary orbits being sorted out. Now I need to work on some of the middle planets. There are quite a few, not least of which is the limited flexion of my knee joint at the moment!

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Prototype

Today was the day I was going in to to get my new leg. Or so I thought. As it turns out, I hadn't anticipated or realised (or asked or was told) that there was another intermediate step to the process.

This involved testing out a prototype of the leg with a socket made from a transparent plastic of some kind. Clearly it makes a lot of sense to test out the fitting with a prototype and not the finished product, so I feel like a bit of a dill to have not realised this.

It meant that the socket could be fine tuned to suit all of the individual characteristics of my stump/knee/tendons etc. It is very interesting to note how many elements go into getting the socket to be sized and shaped precisely to meet your individual needs, and then for the pipe section and foot attached below to be adjusted so that your gait is strong and as fluid and natural as possible.

My hips have weakened and so I need to do a little strength work on them, but apart from that I seemed to be able to use the new low-cut style socket quite well. I will likely need to use a crutch or walking stick as an aid in the first days/week as I develop the natural strength and motor control skills required.

So while I am disappointed that I don't have my new leg just yet, what I do know from the session today is that the use of the new system (distal cup and liner with the pin and socket arrangement) is significantly more secure and comfortable than what I currently use. This is good news since over the last week I was becoming a little anxious about today's session. My main concern has been whether the discomfort and pain that I have been experiencing over the last two months would go away with the new leg. That would appear to be the case.

It should be about another two weeks for George to complete the new socket. So the saga continues....

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The seven deadly sins

This will be old hat to anyone that's been around the world of training with power meters for some time. However, having monitored the cycle training forums lately, it seems the question about how to estimate a rider's Functional Threshold Power (FTP) is something that comes up quite regularly.

So I thought I'd write a post about it in the hope that it will at least help clarify one or two things for people.

Before I go into the various methods used, it's probably worthwhile quickly revisiting what FTP is and why it is important to know.

FTP is a practical and readily measurable indicator of a rider's aerobic fitness. It was introduced to the world by Dr Andrew Coggan and for all intents and purposes it removes the confusion that exists over the term "threshold" and all of the various terms associated with it.

It is important to know FTP for a number of reasons:

-- threshold power is the single most important physiological determinant of endurance cycling performance (covering events from individual pursuits of 2 km long, up to stage racing lasting several weeks). Hence improving FTP needs to be the primary focus of our training, and measuring FTP on a regular basis is an excellent means of tracking fitness changes through the course of a season.

-- it enables a rider to define and measure intensities of riding (or power levels) relative to their own current level of fitness, expressed in a manner that relates to the primary physiological adaptation that occurs at each intensity (power) level. This is very useful for guiding training and making sure that the mix of intensity and duration during a workout or training cycle is appropriate for gaining the specific fitness required for a rider's target events.

-- it is a key input into other metrics which enable a rider/coach to monitor overall training stresses, both long term training loads and recent fatigue levels.

-- it also provides an excellent guide to how a rider should most effectively pace themselves, especially in races such as time trials (or during a breakaway in a road race or criterium)

Of course you need to have an on-bike power meter or a stationary ergometer that measures power in order to measure or estimate FTP.

FTP is simply defined as follows:

"FTP is the highest power that a rider can maintain in a quasi-steady state without fatiguing for approximately 1 hour.

When power exceeds FTP, fatigue will occur much sooner, whereas power just below FTP can be maintained considerably longer".

Okay, so that's easy. If you want to know your FTP, just go out and ride your bike as hard as you can for an hour and see what the average power was. In essence this is the gold standard measure of a rider's FTP. Unfortunately it is not always possible nor practical for everyone to do a one hour time trial like test. And not all such tests are well paced. A poorly paced effort may result in a lower average power than a well paced effort.

So what are all the alternatives available to us to estimate FTP?

Well, Dr Coggan kindly made a list of these, titled "the seven deadly sins" and posted them to the wattage forum in June 2004. Here is the original post reproduced:

"the seven deadly sins....

...er, ways of determining your functional threshold power (roughly in order of increasing certainty):

1) from inspection of a ride file.
2) from power distribution profile from multiple rides.
3) from blood lactate measurements (better or worse, depending on how it is done).
4) based on normalized power from a hard ~1 h race.
5) using critical power testing and analysis.
6) from the power that you can routinely generate during long intervals done in training.
7) from the average power during a ~1 h TT (the best predictor of performance is performance itself).

Note the key words "hard", "routinely", and "average" in methods 4, 6 and 7..."


Okay, so #7 is obviously the "Gold Standard". What about the others?

Inspection of Ride File / Power Distribution Profile
#1 and #2 require you to inspect data using power meter data analysis software. The method is described in more detail in the book "Training and Racing with a Power Meter" by Allen and Coggan. In general these two methods are more useful as a means to check whether a rider's FTP may have changed, than for estimating FTP itself. With #2, it is important that the selection of ride files chosen contain efforts such as races or very hard training.

Blood Lactate Measurements
#3, done properly, usually requires you to visit a sports science laboratory or a well set up cycling coach's facility. Even then, interpretation of the blood lactate data may not result in practical information for the rider. If you have a power meter, there really is no need to have a blood lactate test performed.

Normalised Power (from a Hard ~1hr Race)
#4 is pretty handy, particularly as an indicator of when a rider's FTP may have changed. Frequently riders who do not do time trials, but do other races such as shorter road races or criteriums of approximately 1 hour duration, can use this as a crosscheck of their current FTP. Assuming the race was hard (that is, you were pretty much on the limit for most of the race), and you were not overly fatigued beforehand, then the 60 minute maximal Normalised Power should be at least at your FTP if not a little higher (up to about 5% higher). If your 60 minute Normalised Power is reported as more than 5% above your FTP, then that is a strong sign that your FTP needs re-setting (upwards).

Critical Power
#5 is also a very useful means of estimating FTP. It explores the relationship between work performed (kJ) and duration (seconds). Essentially all you need is at least two (or more) maximal efforts of at least three minutes and less than 30 minutes duration, say one of five minutes and another of 20 minutes, although the choice is arbitrary and up to the individual. You then enter the average power and durations ridden into the Critical Power model. The model will calculate what is called "Critical Power", which is essentially equivalent to FTP (or at least a very good estimation of FTP).

A couple of notes: the "test" rides chosen should have been performed within a reasonably close timeframe (say within the same week), and should not be cherry picked from other rides. They need to be stand-alone maximal efforts. It is also preferable to have two very good data points rather than three or more unreliable data points. I recommend reading about it here (this links to a pdf document by Eddie Monnier) and downloading the spreadsheet as well. It also helps to use the same (or very similar) durations for all future Critical Power test inputs.

Interval Training
#6 is great for riders that regularly do hard aerobic interval work, especially indoors. The intervals need to be of sufficient duration, I would say at least two efforts of 20 minutes (with a short break between) at time trial power/pace. When done on an indoor trainer, then it is common for longer maximal effort intervals of 30 to 40 minutes be nearly equivalent to FTP. As training progresses over the weeks and months, then changes in sustainable power during these intervals is a great guide to changes in FTP.


I'd suggest the Seven Deadly Sins also include the following methods:

MAP Testing
5a) by conducting a Maximal Aerobic Power (MAP) test, using the test protocol on Ric Stern's website . FTP typically falls within the range of 72%-77% of MAP.
An example of a MAP test can be viewed here.

Shorter Time Trials
5b) by conducting a time trial effort of sufficient duration (say at least 20-min), with FTP typically falling into a range of percentages for TTs of this duration e.g.:
- FTP = 93% +/- 3% of 20-minute maximal average power
- FTP = 94% +/- 3% of 16km (10-mile) TT avg power
Of course everyone is different and some may fall outside of these ranges.

There really is no reason to nail it down to the nearest watt. Setting FTP to the nearest 5 watts is sufficient. I only change the FTP setting if there is hard evidence of a change of at least 5-10W.

Of course, getting the number right does depend on ensuring that a rider's power meter is correctly calibrated and any zero offsets needed are done. Strange numbers are usually strange for a good reason.

Remember, these are all just ways of estimating FTP and some are better than others at nailing down the number (and for many, some are more practical to perform than others). The final two methods for example, would typically get you to within a few percent either side and can then be cross referenced with another method.

It all depends on a rider's circumstances. Not everyone is in the position to do a ~1 hour time trial with sufficient regularity.

What do I use?
For the purposes of tracking aerobic fitness changes, and the setting of training levels, then performing a Maximal Aerobic Power test, combined with one of the other tests for FTP (usually a 16km or 40km time trial), is the method that I typically use with my coaching clients. Having this combination is particularly useful when assessing the training priorities for an athlete.

Of course, you can always track fitness and base training levels on a mean maximal power for a duration of less than 1 hour (e.g. a 20-minute test, or as has been suggested, 2 x 8-minute test efforts). However, by doing so you start to introduce the influence of anaerobic energy production into the test result, which means you may not be entirely sure which component of your fitness is changing, and hence be uncertain as to what type of training is needed in order to progress further.

So which sin will you choose?


This isn't the end of it of course. There are still a multitude of factors to consider, such as the impact of the following on FTP:
- Environmental effects
- Point of training cycle
- Chronic Training Loads
- Training Stress Balance
- Altitude
- Hills vs Flat terrain
- Different trainer types
- Different bikes and rider positions
- Motivation

I'll save that for another post.....

References:
1. Coggan, A. Ph.D, Allen, H. Training & Racing with a Power Meter, Velopress 2006.
2. Monnier, E. Using the Critical Power Model to Predict Various Points Along the Power-duration Curve. http://velo-fit.com/articles.htm, 2004
3. Stern, R. What is MAP?, http://www.cyclecoach.com/pageID-news-Test_yourself.htm, 1999

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Hurry up and wait

So, what's new in the world of Alex?

After all the fun and games of my bad back, trips to the hospital and a false start at work, I was finally upright again and able to do a few things. While I gradually gained confidence in walking around again, it was very clear that my ill fitting prosthetic, otherwise known as "Schooner", was causing some difficulty, discomfort and frequent pain. Anything more than a short walk was too much.

This frustrating period when I am able to do less than I could several months ago, is actually a sign of progress. While my stump has shrunk and it no longer fits my existing prosthetic, it simply means that I need a new and more permanent leg.

I visited my prosthetics specialist George last week, and we've decided on what equipment we will use for my new leg. It was quite interesting actually to listen to George explain all the various components, types of fittings and which would be best suited for the application that I'm interested in, especially something suitable for cycling.

George then took that away to prepare a quote which I received the other day. It will cost me nearly $5,000. Ouch! Still, it's a necessity and its value is far beyond its price. I visit the clinic again next week, where a cast will be taken of my stump and other key measurements made.

I really can't wait as it will be so much more comfortable and functional, and I will be able to make forward progress instead of being in limbo as I am now.

My Dad visited this weekend. He had a good time, and we took the opportunity to have a good catch up.

I went out to Dunc Gray Velodrome last week to watch the Masters national track championships and provide some support for my buddies that were racing in the individual pursuit. There were some great performances, and it was good to see my buddies do well. Congratulations to all on a successful championships. My leg was very sore after that.

See you next time!

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bon anniversaire

11 April 2008.

Exactly one year since my accident.

Not that I'm being overly reflective about it all but I thought I'd at least mark the date with a post. It's been a hell of a ride since then but I have much to be grateful for and so much good stuff in life out in front of me. Roll on 2008.

So what else is new (or old)?

Well last week I had a little set back (pun intended - you'll see). On Monday afternoon before last, doing nothing more than leaning forward a little, I had the most hideous back spasm in my lower left back. Not having suffered anything like it before I wasn't quite sure what was going on. All I knew was that it took my breath away, was intensely painful and I needed to lie down, which in itself was a challenge just getting the few metres to my bedroom.

I experienced the spasm another five times that afternoon and evening and each one was more painful than the last and the pain lasted longer afterwards. I was stuck! Fortunately my good neighbour Cisco was about when I called and he came over to help out, as did my friend Tanya. Some OTC pain relief and inflammation drugs were purchased for me. Thanks guys!

The next morning I spoke with my GP and he insisted on a trip to the hospital, so later that morning the ambulance guys came to collect me (I was stuck in bed and was scared to move) and they took me up to RPA (yep the same hospital that features in the famous Aussie real life TV show).

They were very busy so by the time I was checked out by a Doctor it was late afternoon. They administered an analgesic and a muscle relaxant and decided to keep me in overnight given the pain levels. I thought I'd done my time in hospital but it seems I had one more night in me. Jay visited to keep me company for a while and bought me a nice sandwich and piece of chocolate cake (which fixes everything - well almost - Jay's chocolate chip cookies fix everything).

I was in the EMU* for the night and shared the ward with the usual assortment I suppose. The alcoholic who'd had a particularly bad binge drinking session, the 92 year old who was sedentary and talked in his sleep all night repeating the same phrase over and over ad naeseum, something in Italian but I couldn't make out what it meant, the paraplegic who looked like a bit of a druggie, had some serious attention issues and was probably coming down off something, the guy with the slipped disk in his back who sat up to take a pee in the middle of the night, fainted and fell heavily on the floor which caused all sorts of excitement amongst the staff (as you can imagine) and a poor woman who was suffering from a bad gastric problem.

The breakfast the next morning was good. I was checked by another Doctor and found I was able to stand and walk (albeit gingerly) and was discharged with some analgesics and given a lift home by another friend of mine that happens to work at RPA. Thanks Frankie!

Assessment: muscle spasms, no spinal or nerve problems. So an acute problem only.

Two days lying down and resting and several vigourous massages from super soigneur John now has me back up and about with only a bit of residual pain.

My theory is that my still relatively weak back and core muscles have struggled, especially as my prosthetic has become no longer functionally viable, or in other words - it doesn't fit properly anymore and the large number of socks I have to use to pad it out has actually made my left leg a centimetre or so (about half an inch) longer than my right leg. So all that lop-sided walking and standing took its toll and my back went on strike! I must chat with that union boss, Workchoices has been revoked I thought!!

The irony of course was my appointment to start the process of getting my new leg was last week and I couldn't make it, so it's been delayed by two weeks. I am sure looking forward to getting a functional and comfortable leg to stand on and eventually, ride on.

Yibbida yibbida, that's all folks!
Catch you next time.


* - the Emergency Medical Unit and not the bird featured on that century old stamp shown at the top of this post

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Dr Smith

Anyone who recalls the 1960's TV show "Lost in Space" will also remember the character Dr Smith, who had a favourite saying: "Oh the pain... the pain!"

Usually it was a metaphorical reference to the unusual circumstances that Dr Smith and the crew of the Jupiter 2 space craft found themselves in on their jouneys, either on a strange planet or lost in space travel.

Well I can certainly attest to the sentiment lately but in my case the pain is more real than metaphorical.

I mentioned earlier about all those socks I have to use now the leg has changed size and form since starting out. Simply put it means that my leg stump is not held securely inside the socket of my prosthetic leg (Schooner) and the platform on which I bear my weight is unstable. It's a bit like having someone perform a Chinese burn on your leg each time you take a step. After a few hours you get fed up with it and take the leg off.

This has not helped with plans to pedal away on the home cycle trainer. Getting up in the morning and putting on a prosthetic only to be sore before you start the day is not conducive to any attempt to exercise and so my motivation to train has waned somewhat.

Last week it was particularly ordinary, even leaving Schooner off for a couple of days and getting about on the crutches again just so my leg could get a rest.

Now this won't last thankfully! It will be solved when my new leg is ready. Fortunately the funding approval from NSW Department of Health has come through and so next week I am going in to see my prosthetics specialist George to get measured up for the new leg. It will use a different and superior mechanism for supporting the leg, which should result in significantly greater comfort. Let's hope so!

Otherwise I'll need to get my hands on the robot!

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Pithy Power Proverbs

OK - I know there's a bit of tautology in the title but it sounded good, OK?

I was trying to recall all the pithy power training statements that have emerged over the years on power training forums. Last month I started a thread on the Wattage Forum with the aim of collating all those pithy little sayings.

I thought it would be a bit of fun to collect them all. Here's the result, listed in no particular order:

"It's an aerobic sport, dammit!" - Andy Coggan

"Training is testing, testing is training." - Andy Coggan

"The best predictor of performance is performance itself." - Andy Coggan

"The more you train, the more you can train." - Andy Coggan

"FTP = how fast you can go. CTL = how long you can go fast." - Rick Murphy

"The Anaerobic Threshold is neither." - unknown

"Hmmm." - Robert Chung :)

"Alls you can do is alls you can do." - Andy Coggan

"Cadence is a red herring." - Robert Chung

"If you're on the bike and the wheels are turning, you're riding" - Andy Coggan

"Specificity, specificity, specificity . . ." - Andy Coggan

"Lydiard got it right" - Andy Coggan

"All watts are not created equal." - Dave Harris

"The body responds like a Swiss watch. You just have to figure out how to wind it." - Dave Harris

"Toss that HR monitor strap!" - Charles Howe

"Power calibrates PE, PE modulates power." - Charles Howe

"It's all about the pedal force." - Tom Anhalt

"Training with a Power Meter, does it work? No, you work!" - Hunter Allen

"waaaaah my powermeter doesn't work" - first time poster ;-)

"more is more ... until it isn't" - Rick Murphy

"The best thing about a power-meter? It tells you where you are. The worst thing about a power-meter? It tells you where you are" - Bob Tobin?

"Fitness is an integral" - Rick Murphy

"For riders of every level, power is limited but speed is precious" - John E Cobb

"The less power you have the more gearing you need" - Steve Davidson?

"In God we trust, all others bring data" - W. Edwards Demings

"The plural of 'anecdote' is not 'data.'" - Frank Kotsonis

"(The) most successful riders spend the most time at zero cadence during races." - Andy Birko

"At some point, you have to increase the power" - Andy Coggan

"If it *feels* hard, it *is* hard" - Andy Coggan

"If you're wondering whether you've underestimated your functional threshold power, you probably have." - Rick Murphy

"Train, don't strain" - Arthur Lydiard

"The PowerTap is a tool, not a bolt on motor :) " - Chris Mayhew

"The PM chart is a one picture summary of the truth, as useful and brutal as honesty can be." - Alex Simmons

"Wow, I need to train more!" - Frank Overton (after looking at his previous season's Performance Manager chart)

"The (power) training levels are descriptive, not prescriptive, guidelines." - Andy Coggan

"!!!" - Hunter Allen

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Funky things with a Power Meter #77

OK, maybe I haven't demonstrated 76 other funky things with a power meter but then I have discussed or demonstrated the following:

• Aerodynamic drag field testing with a power meter (no, that's not racing your bike while dressed up like Kylie)
• How to determine your Maximal Accumulated Oxygen Deficit (which is kind of like what we're capable of doing without breathing - like what all used to do as kids)
• What impact pacing has on an hour record attempt (i.e. what happens when you get it wrong - it's spectacular in its painfulness)
• What impact pacing has on individual pursuits (i.e. what happens when you get it wrong AND get it right)
• Pulling apart a power file from a race and analysing what we can learn from it and how it reflects what happened (i.e. a chance to brag and show off a power file when you have a win)
• What's the significance of Normalised Power vs Average Power ("crikey that was a hard race, how come my average power was so low?")
• Comparing a training stress metric vs kilojoules (what the? or how can we expect a sprinter to lose weight - ha!)
• Maximal Aerobic Power testing: how, why and what for? (IOW going to failure for a good cause)
• Time trial testing (i.e "puhleeaase let me put out more power today!!")
• Intervals - time trial power (how to suffer for extended periods)
• Intervals - VO2 Max and here (how to suffer for shorter periods)
• Intervals - Lactate tolerance (how to suffer for next to no time at all!)
• Torque readings (or "why the hell is my power meter not working right? #%$^#@$")
• What happens to us when we train "this hard" (can someone just put it on a picture so I don't have to work it out, thanks?)
• Using a season's worth of power meter data to analyse what happened and why (otherwise known as the "I really need to train more" moment) - The good and the ugly versions.
• Using a power meter and associated tools to successfully guide a comeback to cycling part I and part II (my friend had cancer and want to return after surgery to compete at the worlds)
• Using power data to predict performance (like, who's going to suffer the most in today's team time trial?)

OK, that's only 17 dots, so this will really be Funky thing # 18. I should add that most of what I've written is based on tools and analysis developed by guys far cleverer than I but is simply there to demonstrate a number of power training ideas and principles. If anything up there sparks your curiosity, then just click on link or look it up via the index at the right to find posts grouped into various categories.

So what's Funky Thing #18 all about?


The Chung Method

Well it's linked to aerodynamic field testing but using a different methodology, known as "The Chung Method", developed by a data analysis guru and regular power training forum contributor Robert Chung. It also acts as a proxy for developing an elevation profile of a loop course without the aid of an altimeter (now that's the really funky bit). It works best when you ride a course that passes the same point more than once (the more times the better). What am I on about?

From analysing the power & speed data from a power meter file for a typical ride, estimates for both the coefficient of drag-area (CdA) and coefficient of rolling resistance (Crr) can be made. These key measures indicate the degree to which air resistance and the road surface serve to retard our forward progress or how hard we have to push on the pedals to overcome these forces at any given speed.

The method works by using the equations of motion for a cyclist (well a slightly cut down version), with a few assumptions thrown in (such as a low wind day). If we know a little more data about the course and the conditions, the estimates of CdA and Crr derived and elevation profile obtained can be pretty good. Good enough that changes in rider position, equipment (or conditions) can be readily detected and that the elevation profile be correct to within a few metres.

And it does not require the usual protocol for field testing, that of doing multiple runs under highly controlled conditions. Just use ordinary power meter data from a loop course. It helps if you have a near windless day (a little wind is OK).

Now Robert's paper which discusses
this method in detail can be found here:
http://anonymous.coward.free.fr/wattage/cda/indirect-cda.pdf

So I thought I'd have a go and with the aid of a spreadsheet posted on one of the training forums I frequent, I applied it to a sample of my own data.

I picked a training file from Boxing Day 2006. Here is a pic of the training loop I rode that day, a popular local training ground - Centennial Park in Sydney. Grand Drive is a 3.8km roughly circular loop, flattish. There is also an option to climb up a hill to the Ocean Street gates, then across to the Paddington gates before descending back down to Grand Drive, which adds about 2.5km to a loop. Sydney-siders would be pretty familiar with the Park.


Here is the graph of my power and speed file for the day chosen. It was a tempo effort of 90-minutes duration where I did laps of Grand Dr with a climb up the hill to Ocean St every second lap. You can see that by and large I kept my power output within a range and let my speed vary (not that that's necessary for this method - it's just what I happened to do that day).


Using this data and the spreadsheet with the funky formulas which use the equations of motion, here is the chart produced showing the ride elevation profile of my ride in Centennial Park that day. On the chart I show the CdA and Crr estimates needed to provide a consistent elevation for the same points in the ride. Since I already knew the elevation difference from the lowest point to the highest point in the park, that helped me adjust the CdA and Crr numbers such that the profile provided an accurate representation of the course (to within a few metres).


That's quite remarkable if you ask me. Now it was just a training run, not a time trial, so I was on my training bike, probably riding with my hands on the hoods, maybe occasionally on the bar tops going up the hill. A cool morning too, so probably a bit of extra clothing on for warmth. Hence the relatively high CdA of 0.384. A Crr of 0.005 was settled on and seems to be a reasonable estimate for the mostly decent quality hotmix/asphalt surface in the Park.

You will note some variations, particularly the opening kilometres and the final lap, where the profile varies from the consistent elevations shown from km 6 to km 40. I suspect that during this middle section of the ride I was using a consistent position on my bike.

For the final lap, since the derived elevation data doesn't match the other laps, it appears that either I rode in a different position, changed clothing, conditions changed (perhaps the wind) or I was mixed in with other riders. I'm not sure, I can't recall. But the change is very distinct with this method and is one way of assessing the impact of changes to equipment and/or rider position.

The forum thread where this sparked my interest in having a look at it myself is here:
Slowtwitch Chung Method


So what's Funky Thing #19 gunna be?

As Robert Chung would say, "Hmmm...."
:)

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Sock it to 'em

The socks I use in side my current prosthetic leg. Lots.
Thick cotton ply jobs (3-4 ply) about 12" (30cm) long.

So what's been happening lately?

Well the trainer project has moved along a bit. The frame is under construction and the flywheel will be machined down to size/weight. I calculated we needed to reduce the radius of the wheel by 45mm to get the weight down to an ideal mass. The SRM power meter is on its way and I should have that in a few days.

I also had a bit of fun with John playing with those uber strong rare earth magnets, rigging up a crude device to enable us to test the theory that they'll provide some form of controllable braking resistance for the ergo. It was a good enough test for us to consider the next step. I fashioned up a rough design as to how we could make it work (keeping in mind the functional but easy and cheap to rig up theme):An online discussion of the project can be found here.

As for my leg - well Schooner is now a 7 to 8 sock kind of guy (meaning I have around 30 ply of sock padding out the leg so it will fit snugly into Schooner's hard outer casing) and as a result he ain't all that comfy anymore. I used to use just one. See the picture above for an idea of how much sock that is. These are fatter than thick footy socks - more like Grandma's knitted bedsocks!

Accordingly, and following a review by my rehab Doctor at the amputee clinic, a script has been written to get funding for a new leg approved (via NSW Dept Health). Once that is cleared (about two weeks), then George at the Appliance and Limb Centre will give me a call to come in for a new sizing. Leg will then take another two weeks to make. So I'm about four weeks away from a new leg. That's about two months faster than normal I'm told.

I won't go for the bog standard (Schooner-like) leg that the subsidy covers but rather use the subsidy to go towards a better model of leg, which will also enable a cycling leg attachment. It'll cost more but it'll be worth it.

My knee flex hasn't improved much despite the best efforts of my physio. Not her fault, I simply haven't done enough regular work on it. For the first time in a long time I have not had the same motivation to do the work needed. It's part mental and part due to my current leg not being all that comfortable. When you start the day with a sore leg, there isn't much motivation to train on it. So I'm hoping the new leg will help me along with that. Everyone says "don't be so hard on yourself". But it's being hard on yourself that gets results, so I'm a bit frustrated with myself at the moment.

My cycle coaching is going along nicely and keeping me mentally active, with another coach asking me to coach them (I have several coaches as clients). Quite ironic in some ways but I suppose coaches really appreciate the value of coaching. My understanding of the ways of training with power has a bit to do with it as well ;)

Apart from my cycle coaching activities (I really enjoy my coaching work), the time has come to gradually venture back to the office and begin the process of re-establishing my "day job". So this week, after various consultations with my Doctor and the HR people at the office, I ventured in for some meetings with the leadership of the business, mainly to say hello and also to discuss what I'll be doing when I start back there next week. It's 11 months since my accident, so there's quite a bit to catch up on. I won't resume my previous duties but instead I'll move into a business improvement role and report directly to the CEO. The challenge of getting back to the work routine will take some adjustment but it'll be good for me. I'll start part-time and will ramp up the hours as I am able.

This getting up early and shaving is a bit rich though!! :)

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My Own Trainer Project

I've decided to have my own indoor cycling trainer built up. I'm not doing it myself but have a mate who does this sort of stuff for fun. He's done a prototype which I've looked at and it's pretty cool.

Normally I wouldn't bother but with my rehab it's likely when I do start training properly, I'll need to do quite a bit more indoors than I used to (which was bugger all). So if I'm going to have a trainer - I want one that I'll want to get on, rather than dread.

So here are the rough specs:

• free wheel
• 7 speed hub gearing (a Shimano of some sort - heavy but bullet proof)
• double reduction gearing (chainring to cog - hub gearing - to chainring to flywheel cog)
• 35kg flywheel with high quality industrial bearings (have to remove some mass from the 40kg flywheel we have available as it seems to make it too easy). Need to decide on the weight (moment of inertia I suppose).
• foils attached to flywheel for air resistance (possibly adjustable for variable resistance - but only adjustable when not moving)
• a stainless steel or alu frame that's fully adjustable in all directions (think of those specialised cycle fitter frames with square tubing) and solid as all hell but with a real bike feel
• SRM power meter with their adjustable length cranks would be ideal (ergomo is out for various reasons - but mainly due to power measured by left leg only - half of which I don't have anymore!) - the prototype unit has an ergomo
• I have considered putting a Powertap power meter in centre of the flywheel but concerned about longevity vs industrial grade bearings.
• able to be moved (infrequently) by picking up at one end and rolling along. It'll be heavy!
• covers for safety (esp. flywheel) and protection from sweat
• fine tune resistance using either a felt padded brake on flywheel or some form of electromagnetic braking
• The electromagnetic braking being considered are two types: eddy current braking by placing powerful magnets close to the flywheel or the addition of a hysteresis brake controller unit.

The large flywheel/gearing will enable full on acceleration work as well as standard aerobic and anaerobic development workouts.

A programmable ergo brake would be great but I have no idea if such a thing exists that meets my criteria:

• Needs to be solid, reliable and readily available and not that expensive. The SRM will cost significantly more than the rest of this item together! One suggestion was to use the controller from a Cateye trainer, if one could be located.

Another clever mate of mine (Peter) built a unit which was the inspiration for this project. This one has a 33kg flywheel and double reduction gearing. I had a short ride of this unit a couple of years back and it was awesome. Pete's a sprinter - note the sprinter's pedals with the toe clips and straps.


Progress so far:

• I have the SRM Pro power meter on the way. Picked one up for a really good price on ebay :)
• Just need to finalise some construction details for the trainer itself.
• Also on their way are some high power rare earth magnets from Frenergy Magnets, which I'm going to hook up a rig on the prototype to see how good they are at fine tuning resistance. These are very cheap at only a handful of dollars each.
• The manufacturer of the hysterisis brakes are investigating the right type of brake and control unit. Cost might be a problem though, expectations are around A$1,500.

Here is a pic of another trainer unit which uses these high power magnets to control resistance. The small round discs are the magnets, which are able to be moved closer to (or away from) the flywheel, enabling the resistance caused by the eddy current braking effect to be modified.


Here are some photos of the prototype with an ergomo installed on which I had a client conduct a MAP Test on last night:

The trainer frame is adjustable in all dimesions imaginable and uses standard saddle, cranks and any handlebar arrangement you want.

The double reduction gearing, with the hub gear shown, placed in the drivechain between the cranks and the flywheel. The hub gear can be moved up/down and fore/aft so the chain tension for both chains can be adjusted. The chain could use a bit of lube!

The prototype has an ergomo power meter. Not a good choice for me as it only measures left leg power. Any sort of handlebar arrangement can be fitted. The gear controller for the 7-speed hub gearing is shown on the drops at bottom right of picture.

The flywheel I will have will be a solid disc. I'll have the diameter reduced instead of cutting out sections like in this one. It'll weigh something like 35kg when finished.

I also sought comments and discussion at the Cycling Forums site which can be found here.

Finally - why the hell don't I just buy one?

As to other trainers, well the only ones I know about with power and a large flywheel are the SRM, PT 300, Velodyne & Velotron. The SRM trainer is probably the closest but hideously expensive. Velotron would be perfect but is 5 times the price. PT 300 looks interesting but I don't like the handlebar set up, the less than fine tune adjustment of power levels and it's a fixed gear. I'd like gearing to allow a greater variety of workouts. And the prices:

300PT US$1,800
Velodyne US$2,600
SRM trainer US$7,250
Velotron basic US$5,700
Velotron Dynafit US$8,000

I'll let you know how I go!

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What about me? / 100 degrees

OK, this is my blog and I'll cry if I want to....

Not really, no blubbing from this duck. So some have asked - how am I going? - I haven't heard? - are you riding yet? and so on....

So a quick update.

I'm doing fine, actually socialising quite a bit lately, which has been great. :) Part of the plan* to return to some "normality", whatever that is. Those that know me from the cycling and training forums know I'm still kicking about and occasionally being useful.

* The shorter term plan includes a return to work and a return to cycle training.

My leg is doing OK although Schooner is on his, er, last legs. Simple fact is Schooner doesn't fit very well now and I am ready for a new leg. I keep having to wear these thick cotton ply socks inside the leg liner to ensure a snug fit. I'm up to six socks now and it doesn't really do the job all that well.

So after a bit of walking I get sore. Sometimes it drags over to the next day. The other annoying thing is the patch of skin that got rubbed off ages ago just doesn't get a chance to heal. Last time I tried a pedalling session on the home trainer, I created and popped a small blister. It's still healing and that was weeks ago. I've been trying all sorts of remedies. Unfortunately, as soon as you cover it with anything, it just increases the pressure on the wound and makes things worse.

I had another 25-min trainer session but it's only very small doses at the moment. So not much pedalling for me I'm afraid. I'll try again soon but it's a risk until I have a prosthetic more suited to the cycling function.

On that front, I had a good session with my prostheticist (George). He has this funky new socket design ready for me when I upgrade to the next leg. It is pretty low cut but very clever and will enable full knee flexion without interference behind the knee. It's a carbon fibre socket and very strong. I will be able to clip on separate walking and cycling legs. Inspector Gadget look out! Only a handful are in use in Australia I’m told and not used elsewhere in the world. Must be for special people like me!!

He was pretty happy with my walking. I’m a little over 3 months in with current leg. I’ll get some photos of the new socket when I get the new leg – probably not 'til later in March I’d say. My next review with the Rehab Doc is at the end of the month.

As for managing the changes in stump volume, I am eyeing off the computer controlled vacuum pump George has on his own prosthetic leg – that looks the bees knees.

I also like the look of George's “ankle” which appears to be a multi-directional joint of some kind – great for walking on – I have most trouble walking on slopes and cambers as my prosthetic ankle is a fixed joint - no flexion at all.

I am having trouble getting motivated to exercise much I have to admit especially with the current set up not being all that comfy. I’m sure hoping the new leg will help in that regard.

I also need to keep working on the knee’s range of flexion. It straightens OK but I’m not bending as well. It has improved – my physio measured 100 degrees last week, it was 85 when I left hospital. Crap for pedalling though. She has given me some exercises/stretches for the knee and I'm having a weekly physio sessions to work on it. I guess I'd need to get to about 135 degrees.

I’m also in the process of designing/building a new home trainer, with a big flywheel and power meter. Should be a cracker. I figure I’ll be doing more indoor workouts once I’m back into the swing of things. I'll be writing a separate post on all that later. Here's a prototype:

No ergomo power meter for me though (like on this bike) - it only measures left leg power!!

A week or so back I also visited the track to watch some of the Australian National Track Championships. I met many of the Athlete with Disabilities crew (nice people) and then watched their Time Trials and Individual Pursuits. Amazing.

On the right is Michael Milton. Have a read about some of his amazing feats, including the world record for downhill speed skiing.
http://www.michaelmilton.com/

Hello to the girls from the Paralympic Committee ! It was great to say hi.

And I bought a Boule set and had my first game. I got beaten!! They'll keep :)

Enough for today.

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An Hour of Power

For a change, I thought I'd write about someone else. It's not all about me you know!

In this case it's about my club mate, Jayson Austin, who had the guts to take on a cycling challenge which is not for the faint hearted. You see Jayson wanted to break the world record distance for riding a bicycle around a velodrome in one-hour, for his age category (Mens Masters cat 2 - ages 35-39).

The current record is held by Jason Sprouse at 45.641km. Think about that - go out and ride your bike at 45 km/h. Now do it for an hour. By yourself.

Now these record attempts are done under strictly controlled conditions. They must be done on an officially certified track, so that the track distance is precise. In this case it was performed on Sydney's 250 metre Dunc Gray Velodrome, which hosted the track cycling events of the Sydney Olympic Games in 2000 and many world level events since then.

There must be World level International Cycling Union (UCI - the world governing body for the sport of cycling) officials present to officiate and sign off on the results. Electronic timing must be in place and the tape of the record showing every lap split is to be provided to the UCI for certification. Electronically controlled starting gates must be used. The bicycle must conform to UCI regulations and be checked and passed by relevant UCI official. In this case the bike is similar in set up to those used by riders who ride the Individual Pursuit.


Officals from the Australian Sports Anti-Doping Authority have to be present to conduct drug/dope testing. The velodrome has to be hired. The local cycling administration has to provide its support and so on.

And that's before you even get on a bike and ride!

Jayson was preparing well for the event, had taken on a coach (my club mate and good riding buddy - Peter Montford of mypowercoach.com.au), was using an SRM power meter to guide training and had even done a practice trial at which he unofficially beat the target riding 46.41km.

I had designed a spreadsheet to manage the split timing data and provide his coach valuable feedback on Jay's pacing (relative to target) and with Jay's Mum calling the splits to me as we went - I entered the times in the laptop and could tell Peter what was going on.

Why bother with that? Don't you just go out there and ride it hard, and do what you can do? Well not quite. You see for aerobic endurance events like time trialling, good pacing is critical to attaining the best result (in this case the maximal distance in an hour).

So all was set. What happened?


He didn't make it, that's what. Missed it by 4 laps of the 250m velodrome. Arrgghh!


How come?

1. Well in fairness to Jay - he did get quite sick in the fortnight before the event. That's never good when you're about to lay it all on the line.

2. His gearing and pacing on the day were sub-optimal.

3. A fault in the timing system didn't help but was not, in my view, a primary consideration. His first attempt was aborted after 4 minutes as the electronic timing had not worked correctly. He had to stop and do a restart.


I'll talk through #2.

Here are some charts to show how it panned out. The first one shows his cumulative average speed through the hour. It also shows the distance covered at each 15 minute mark. Click on the chart to show a larger version.


It is pretty clear than Jay started too fast and faded as the hour progressed. His last 10 minutes were particularly painful.

How did that translate in power terms? Well here is a graphic showing his power output (yellow), speed (blue), cadence (green) and heart rate (red). Again,click on the chart to see a larger version.


This one tells the tale even more starkly. It's almost as if, without realling knowing it, Jay paced by Heart Rate (which is never a good guide to pacing a TT). His speed and power in the early stages were simply unsustainable and so began the long slow decay in his power output until it reached such a low level that his pace became very slow, so slow that it more than made up for Jay being over the target until the 53rd minute!

The other remarkable thing to note is Jay's average power for the hour. An amazingly low 242 watts. So despite comments from some that considered him to be less than aerodynamically positioned on the bike, Jay's Coefficient of Drag by Frontal Area (CdA - a measure of how "slippery" through the air you are) is estimated to be less than 0.21, probably close to 0.20. That is very slick for a time triallist and most testers out there would give their eye tooth for a CdA that low.

Could he have broken the record on the day? Absolutely. How? Well the data clearly shows that Jay really should have listened to his coach's pacing instructions. While I was on the laptop collecting the split data - I would yell through to Pete that he was going way too fast. Jay however, simply chose to ignore the sideline pacing instruction to ease back and instead went by feel. Remember it's not a distance Jay hasn't tried before. But I don't think Jay counted on the mental effect of race day and the extra adrenaline it produces.

He didn't want to break the record - he wanted to smash it.

However, since Jay was determined to go faster than he was capable of on the day, had he followed the pacing instructions, started more conservatively, I am pretty darn sure the record would be his.

Anyway - a few of us are having a beer this weekend to conduct the post mortem.

So that it's clear there's nothing in what I say that Jay doesn't already recognise, here is his own summary - in his own words:


“Just An Hour”-the Day

Oh so close but not to be. What happened-I blew up big time- more than anytime on the road when I had gone out as an attack rider for my team in races or when I bonked from hunger flats. This was harder than an ironman but I gave 110% & had nothing left. I experienced blurry vision and hit the pads in the last 10 mins of the event & fought hard to lift the pace when I knew it was over. I was determined I would finish but it sure was hard BIG time.

What went wrong -easy in hindsight? Being sick with a strep throat & asthma since 21 January & on antibiotics did not help especially the final track workouts which we would have used to determine the gearing. I have ridden when sick before but nothing of this intensity and relentlessness. I overruled Coach Peter on the gear-stuck with 59 x 16 believing that another gear may have been harder on my respiratory & overruled him again on the pace. I had been on target before the sickness to go, we thought in the 47kms + for the hour. & I wanted to really break the record by a big margin. Pace would be as per training I said. (On June 17, 2007 I had ridden 46.41 km in an hour with no problems or any predetermined pace.)

Saturday morning felt better than I had for a fortnight although I was already starting to feel nervous. Bike was ready and it was pouring rain but warm OK. Had an easy 20 mins on rollers & some coughing but not too badly. Started hydrating with First Endurance EFS & water & watched DVD of Chris Boardman .That got me choked up but I was feeling up to it.

At the Dunc Gray Velodrome all was ready-Kevin Young had worked hard to get me an area with access for a fan & away from some of the crowds. All was good. Warmed up well and took to the track & felt great. The new TWE chain ring was so smooth & the bike moved so nicely.

The gun goes & I felt good- cadence was a bit high 109 but would slow over the next couple of laps. Don’t look down-affect aero dynamics-helmet great-concentrate & focus-laps are coming up quickly –trying to slow as too fast –feeling very good. Coach Peter calling me to back off-found out later was hitting 51.5kph/111 cadence for over 3 mins but trying to slow was difficult, it was just rolling & the adrenaline was up.

At 4 mins Peter is waving me down & yelling to stop-what’s going on-Oh no the electronic timing didn’t start. Regroup-stay calm-heart is racing-breathing affected-asthma spray-go again –bit slower.

50 mins-Really hurting and I knew the record was gone- just had to finish-don’t fall off bike. It is over & I missed the record. Congratulation to Jason Sprouse who holds the current record it is yours for the time being. I will try again & be wiser the next time.

Went to the Handlebar Tavern for a beer and a talk with some of the team and then drove back to Terrey Hills. Had beers & pizza at Terrey Hills Tavern with my parents & then home.



Sunday- feel OK a bit upset but body, legs, back are very good. My neck is sore from holding the position. No saddle sores-the chamois in the Hot Design skin suit was fantastic-even has a saddle imprint in it.



Some Facts from the Race—restart

1 km 1.21.58___10 km 12.30.15___35 km 44.57.12

2 km 2.33.94___15 km 18.50.38___40 km 52.23.71

3 km 3.47.14___20 km 25.11.48___44.628 km 60.00.00

4 km 5.00.57___25 km 31.39.40

5 km 6.14.90___30 km 38.13.26



Hindsight

1 Should have cancelled attempt when I got sick-result definitely affected

2. Should have cancelled attempt after completing over 12 laps when electronic time keeping failed- result definitely affected

3. Should have not set the pace so high- result might have been different.

THANKS

I would like to thank my sponsors: Peter Montford-mypowercoach.com.au, Steve Hogg-cyclefitcentre.com, Austin’s Timber Flooring, First Endurance Aust/NZ and my club Bicisport Cycling. Other supporters whose help & encouragement has been invaluable were, Jim Tzakos-Proline Technology P/L, Lindsay Harvey, Warwick McAlpine, Vic Davidson from LactAway, Greg Ryan-Twe Wheels, Mike O’Reilly and training partner, Peter Verhoeven.

Cycling Australia, Cycling NSW, Bill Clinch, Kevin Young, Brian Crawford, Paul Craft, Cycle SportNews and the officials and people in attendance at the Dunc all encouraged me and I am truly grateful for your support.

UNTIL NEXT TIME!!

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The Bionic Man

Someone sent me this link to an article about another champion amputee cyclist. This time Czech Champion Jiri Jezek.

Here he is competing in the Pro crit up at Sufers Paradise. Yep, that's Aussie pro star Henk Vogels on the front.


Jiri's story is on Pez Cycling News here:
Jiri Jezek on Pez

And another item sent my way - this time about the development of robotic limbs - in this case a robotic ankle. Pretty funky stuff. Move over Steve Austin, the $6 BILLION dollar man is coming your way soon!

Story is here:
http://www.technovelgy.com/ct/Science-Fiction-News.asp?NewsNum=1035

See ya!

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A Blistering Pace

Well after my effort yesterday, I thought there were no ill effects but I discovered in the evening that I had created a small blister on my shin (akin to what you get on your heel with a new pair of hard leather shoes). Presumably a bit of skin rubbing going on inside the prosthetic, which I still can't feel as the nerves on that part of my skin are pretty much non-existent. It wasn't large or anything nasty looking so I wasn't that concerned with it.

Today was a bit different. Having managed to actually turn a crank and prove to myself that it was possible (albeit in a modified way) it meant of course that I now need to keep up the effort, gradually building up my capacity to train again. But I still need to be careful and make sure I don't go like a bull at a gate. So with these conflicting emotions, I actually needed a bit of psyching up to get on the trainer today - which I eventually did during the evening news. Here's the file:


OK, this time I did 15 minutes averaging 108 watts, with a 10-minute max of 116 watts. That's 1/3rd of my all time best 10-minute power of 345 watts! (not that I've done any specific 10-min efforts mind you). So a long road ahead.

One thing that really sticks out in the file is how the leg discrepency, combined with the Powertap's aliasing effect (see link for an explanation of aliasing), shows up in the power line, which jumps contantly between appoximately 100 watts and130 watts. I'm guessing my cadence is not that fast, probably close to 80 rpm, which puts it right in worst zone for aliasing to show up.

So, session #2 completed. At the moment I doubt I'll have trouble holding myself back. Pedalling with Schooner is not the most comfortable thing in the world to do, so a constant reminder is there tempering the effort. And I took a peek at the leg afterwards and my blister had burst exposing a bit of raw skin underneath. Such is life. It'll be a while before my leg toughens up to the demands of riding.

Other news - I got my crash bike back the other day and dropped it into Hoggies for a check over and repair of relevant items. Interestingly, there is a small dent and a long white streak along the top right full length of the top tube. The front wheel is out of true so it clearly got a knock. The white streak is from the paint of the boom gate I hit but what I simply can't work out is how the bike managed to get damaged there. Weird. Anyway, we'll soon find out what the damage is.

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279 Days

Well I did it!

I managed to get on the bike and ride. OK, so it was on an indoor trainer but who cares? That's the first time I've turned a crank since 11 April 2007. That's 279 days but hey, who's counting? ;)

OK - so how did I do it? With a bit of help from my friends, that's how. I have described before how I was unable to pedal a full revolution on a bike as the range of motion in my left knee was limited (both by my knee and especially due to the nature of the prosthetic, which was designed to get me started with walking but definitely not for riding a bike). Schooner is definitely the walking type - so bike riding is a new adventure for him.

Enter the machining genius (well in my eyes anyway) of club mate Steve Dixon, who with some assistance from Peter Barnard, who fashioned up a special short crank for me. In this case a 100mm crank. My normal road bike crank is 175mm, so it's quite a bit shorter. What we were trying to do was to enable me to pedal but with a largely reduced pedal circle on the left side. Up top is a pic of the crank.

Cycling fit guru Steve Hogg helped put the crank on the bike for me today and loaned me the flat bed pedal so I could just put my left "foot" with running shoe on top of the pedal. Note how short it is! So short it doesn't even reach the cadence sensor. But who needs cadence anyway when you've got a power meter. Yeah - that's right, before I hopped on, I made sure the trusty Powertap was connected and working, even doing a torque zero just to make sure I was getting a true reading.

On with the bike shoe on the right foot, which still has the normal length crank and pedal/cleat arrangement. So on I hop and off I go. Took a little while to work out where to place my foot on the pedal, most comfortable was basically mid-foot, a bit further back on the sole than usual but it wasn't so easy if I tried to put the shoe back further (pedal further forward). Remember that there is no ankle to flex as you rotate around the pedal stroke - my "ankle" is fixed.

Anyway, it's a start. Once I have a leg more suitable for riding and the knee improves, I'll graduate back to a normal length crank.

And how did I go? - well here is the ride file:


5-sec smoothing as the data is exceptionally choppy, no doubt in part due to the leg imbalance as well as the Powertap's infamous precession "feature". All up, a little over 10 minutes at ~ 110 watts. A far cry from my 10-min all time best of 345 watts.

So, another little goal* ticked off on my journey.

Today was a good day. Most of 'em are anyway but this was worth shouting about.

See ya next time!


* which was to earn my first TSS point once out of hospital.

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A Graphical Representation of Training Levels

OK - a break from talking about my rehab progress and back to matters concerning training and racing with a power meter.

Above is a graphical representation of training levels and associated physiological adaptations to help explain the relativities between using Coggan training levels (based on FTP - Functional Threshold Power) and Ric Stern Training zones (based on MAP - Maximal Aerobic Power).

Click on the image to see a larger hi-res version.

The left hand side of the graphic shows the training levels/zones and how they relate to each other. I also show what is commonly referred to as the "Sweet Spot" for training.

I always took Sweet Spot to be upper-L2 to L4 (Coggan) although I put a limit in the graphic at FTP since the idea of sweet spot training is that it's good trade off between duration and intensity that gives Chronic Training Load (CTL/fitness) a great boost in the "bang for buck" sense. Once you go over FTP, the sustainable volume starts to decline somewhat.
The nice thing with RST zones is that there are three pre-defined (overlapping) levels that fall neatly within the sweet spot.
At the end of the day, it's the nature of the training and not what we call it that matters. But it sure helps to have a common language. I thought this might help translate between two commonly used training levels/zones.
It should be noted that the FTP:MAP ratio can vary a bit and I have taken a typical mid-point of 75% (typically 72%-77%). It wouldn't change the graphic much either way since levels/zones sort of blend into one another.

The right hand side of the graphic is my interpretation based on the Coggan table showing adaptations and number of ticks per level indicating impact of training at that level.

All I did was to represent that in shades of grey, with the darker areas indicating the relative power level where the adaptation most strongly occurs and fading out to white for power levels with little to no impact. In the same way the training zone/level colours blend into each other to show a continuum, it was an attempt to graphically demonstrate the non-discrete nature of the training impacts.

I also re-ordered the adaptations to show those primarily occuring from lower to higher relative power outputs.

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