Mean Maximal Power: A Unique Comparison

It's been a while since I posted. Just too busy for the most part so my apologies.  I'll do an update at some stage!

I had a long break from training due to a prosthetic leg changeover in June (had a few transition problems with that) and a lot of travel in August and September. I've been back on the bike for a few weeks now (the hardest part sometimes).  I sure have some fitness to catch up on.

For some personal motivation, I thought I'd post up a couple of charts comparing my performance before and after the leg amputation (I get asked about it occasionally, and my data is being analysed for a science write up at the moment).

So I thought I would summarise it in a neat chart known as a Mean Maximal Power (MMP) chart.

MMP charts show your best power ouput for all durations from very short periods (seconds) through to very long periods (hours). Because the horizontal axis represents durations from second to minutes to hours, we turn that into a logarithmic scale, so we can inspect best power outputs for durations covering a wide time spectrum.  Power is represented on the vertical axis.

As you would expect, one can produce higher power for short periods (seconds), and somewhat lower power over longer periods (hours), so the chart trends downwards as you move to the longer durations on the right.

By using WKO+ software, I made a comparison of my all time personal best power for the time before my accident and amputation and since then.

Two versions plotting mean maximal power to weight ratios, one for Average Power and one for Normalised Power. The blue line is before amputation, the red line is since then.

Click on the chart to see a full sized version:

The chart above shows my best W/kg for all durations.

What is very clear from that chart is the wide performance gap for very short durations but the closeness in performance over durations longer than a minute or so.  This suggests my sustainable aerobic power and my anaerobic work capacity hasn't been significantly hampered by riding with a prosthetic, however my neuromuscular power (used for sprinting and short duration hard accelerations and efforts) has been significantly compromised.

What about Normalised Power?

When plotting NP data, WKO+ restricts the output to a minimum of 5-minutes.  For most analysis and application, we really don't read too much into NP for durations shorter than about 20- to 30-minutes.  But nonetheless, the chart shows an interesting change in my power profile when viewed through the lens of Normalised Power.

NP appears to amplify the difference in performance over a wider part of the primarily aerobic duration spectrum (> 5-minutes) when compared with the Average Power chart

A reduction in my ability to perform those short high power bursts (up to ~ 30 seconds or so) definitely comes though in the NP for durations from 5- minutes to about 30-minutes.

For longer durations than half an hour though, I have been able to equal or somewhat exceed my best pre-amputation NP outputs.

This I think is reflective of the type of racing I do - which is lots of track and crit racing, some road races and only occasional time trials.  So for an apples to apples comparison, I certainly think this NP chart is pretty telling.

I no longer have that weapon of short high end power, but have instead found other ways to make up for it.

Of course this is just one way to use MMP charts. Once can plot one season over another and make comparisons as to their overall progress. Or any time periods they care to compare.

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Point scoring

Let's race! Say, a State Points race championship - masters 45-49.


All you need are one to two dozen hard men. Toss in one current masters world champ, one former world champ, and bike bling as far as the eye can see. Carbon wheels and frames galore. One carbon leg. I'll be screwed if they ever bring in a carbon tax.

80 laps, sprint every 10 (2.5km).

Go hard. Sprint. Blow. Recover. Cover. Grovel. Sprint again. and so on. Watch your position, keep tabs on the score for yourself and others.

Finish 4th.

These races are a whole 'nuther world of pain.

Not really much of a race report because, well, I can't remember all that much they are so effing hard!

I made a very early attack and it was on for (not so) young and old for rest of the race. 18 listed starters, I think a couple of DNS. We were nudging 60km/h for most of the eight sprints. Field too good to allow a break despite many attempts.

You are on your limit, recovering from one sprint, covering counter attacks, grovelling to stay in at times, planning the set up for next sprint and having to do the maths along the way to work out who's got what points and what wheels you need to attack/cover.

Here's another pic to show off my leg and the sexy new Turbo Studio team race kit.


Peak power: 1184W
NP: 299W (it felt harder than that though)
About 25-26 minutes of purgatory.

Damn that was fun.

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Ground Control to Major Tom

A few of you that follow this little blog will have noticed my steady progress in fitness and form.

It has been going great and I continued with my progress in 2x20-min threshold tolerance interval efforts, culminating in an average of ~ 320W in 2x20-min efforts week before last (an all time PB), followed up with a couple of efforts over 300W a few days later.

Then I headed off to Adelaide for a week and a bit for a Cycling Australia coaching course. I had expected that week to be a light one from a training perspective and after a couple of busy days and some very ordinary weather on arrival (gale force winds and rain!) I got out for a ride on one afternoon after the course was finished for the day. Legs not too bad but still carrying a little fatigue. Nevertheless able to crank it out just fine.

But then something happened to my leg/stump that night. I have no real idea why but it decided to swell. A lot. When it does that then simply putting my prosthetic on is a struggle and very painful. Houston, we have a problem....

Indeed it took me about 10-minutes the next morning to gradually ease my leg into the prosthetic and stand up. It's really painful when that happens. I nearly didn't go to the course that day but I persisted, doing as little time on my feet as humanly possible. Over the next few days I had to repeat the process, gradually getting the leg in there in the morning.

The swelling gradually subsided over the following days but it remained painful. Suffice to say that any ride plans went out the window, even an invite to a local race which I was looking forward to had to be canned.

The real PITA is not knowing why it does this. It's not common but it's really crap when it does this.

So today, eight days after my last ride I tried a light ride to see how it was.

Not flash. Knee was very sore, putting any sort of effort down was not very agreeable, getting out of saddle was not an option and after 10-min the sore spot on the inside of my knee was starting hurt as well. So I pulled the plug after 15-min lest I create more problems. Try again tomorrow. Amazing how quickly the amputation side loses its form.

Hopefully it just needed a bit of a spin to get it moving again and will be better next time. Fitness should return pretty quickly provide the soreness goes. I'm sure gunna need it!


Other things:

Cycling NSW have still not advised on the selection policy for Track Nationals. It's now less than eight weeks to go and I have no idea whether/how selection will happen. At present, the draft selection policy suggests that no NSW para cycling rider will be selected. This is in stark contrast to all other states that are actively promoting as many riders as possible to compete.

It simply sucks and is quite demotivating, certainly not something you want overlayed when you are dealing with injury as well.


In the coming weeks I expect to spend a fair bit of time at the track, trialling a few things from a position/aero perspective as well as start the track specific phase of training. So let's hope this leg gets better quickly!

And on Friday I will be dropping my cycling prosthetic in to George at the ALS to have the outer carbon fibre shell completed. Hopefully that won't take too long. Then I'll be able to show off the flashiest bike leg in the country!

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Surface Area

I haven't posted about my own training bits 'n' pieces lately. So a brief update.

All is going well. My training is now a regular 5 days/week routine, sometimes a 6th day recovery spin if I feel like it/have the time. Riding consists of a longer ride on Sundays, a solid tempo effort on Saturdays (now doing 1.5hrs of tempo ~ 85-90% of FTP), specific threshold development intervals midweek (your typical 2 x 20-min intervals at near TT effort ~ 95+% of FTP) and core endurance level riding otherwise, with the occasional race thrown in for a bit of fun.

The long rides have been ~ 2.5hrs so far and most other rides are typically about 1.5hrs. An interval session on Thunderbird 7 might be a little shorter.

Here's the latest chart showing how the training loads have been growing at a steady rate.



In terms of power output, well I can't say I've noticed great leaps in performance over the past month or so but that's not unusual as the training loads have been progressively increasing and so the legs are mildly fatigued. Also fitness gains can kind of creep up on you. The only problems I've had have been with some exceptionally hot days, when I struggled to hit desired training levels, so on those few days you just accept it won't happen and move on. Indeed, there have been days I trained indoors because it was too hot outside!

Certainly this morning I did my 2x20s OK, with the first completed at an average of 262 watts and the next one I let it rip a bit more, ending with an average of 274 watts (which was 264W 1st half and 284W 2nd half). My current FTP is estimated at 275W.


Australia Day Race

On Australia day I raced the, er, Australia Day Race, one I've raced several times before and reported on a couple of years back in this post. Apart from being the usual blast around Heffron Park, it's also a fund raiser for the Children's cancer foundation.

This year the race format was different - a handicap criterium with 3 grades. Not entirely sure where to ride, I just put myself in the limit bunch and figured I'd see how it would go.

Before the race I rode to Heffron Park and did a couple of laps of the circuit. Mind you I've been around it a gazillion times, so it was more a sense of assessing how the wind is as that helps me make some tactical choices about what to do at which points of the circuit.

Anyway, I might have been better in middle chase bunch as limit wasn't very hard and most of them couldn't corner all that well or go that hard to drive a break so I just rode like a good warm up waiting for the catch to happen. When we were caught by the chasing bunch, I immediately inserted myself into the faster group and then just maintained position working my way to front 5-6 riders with a lap to go. But rather than continue the drive and good speed, the front 4-5 riders shut it off (what were you thinking guys?!) - and of course that was enough for the scratch bunch to bridge the gap.

Cruising with the limit bunch. Still a few kgs to lose!!

So with 1km to go I ended up on the front of a 50 rider bunch keeping a good tempo and looking for an attacker (there's always someone who can't help themselves). Right on cue John Sunde came through hard on my left and I instantly got his wheel, and we had a gap with 500m to go but he shut down once we hit the main finishing straight(!) which meant I had the bunch back on my tail and was staring down at a 350m sprint into the headwind LOL. I lasted maybe 3 seconds before I was swamped. All good fun. But what's the deal letting a bloke with a bit of leg missing lead the bunch inside the last km? Gotta laugh.


Riding with a Prosthetic

One of the experiences when riding with a prosthetic leg is the way the liner, which goes over my stump and connects me to my prosthetic's socket, gradually fills with fluid (sweat) and begins to loosen over time as you ride. Every day is different as to how long it takes before I need to stop, take the leg off and remove the liner, drain out the contents of Sydney Harbour, dry off my stump and liner and replace before heading off again. I carry a small hand towel with me for the job. Some days I've gone 90-minutes without a change, other days I need to stop after less than half an hour.

Over time I'm beginning to get to know handy spots to do that - all I really need is something to lean the bike against and something I can sit on. Walking is not easy with the prosthetic cycling leg attachment, so I basically need to be able to ride up to the spot. As with most things, you get creative in working out little solutions for these things.

The reason why I need to stop is that as the liner works loose, the amount of surface area contact between my stump and the prosthetic socket reduces. Since the forces are transferred to the pedals via my socket, then the greater the amount of my stump's surface area that remains in contact with the socket, the less pressure is placed on any one part of my stump and skin. I find that as the liner becomes loose, it gets harder to produce the power as well as becomming less comfortable to ride. As soon as I remove, dry and refit it, there is an immediate improvement in comfort and power.

The other issue I have is since the socket I current use for riding is my general purpose socket (which is designed for standing/walking and not bike riding) the socket shape is not ideal for the angles the knee goes through when pedalling. A large gap forms between the front of the top of my shin and the front of the socket. Currently I fill that gap with some foam and need to keep adjusting how much I use, to get the right balance between filling the gap and having a secure stump-socket connection and actually being able to get the leg properly secured into the socket.

When I finally get a dedicated cycling socket made, the socket shape will be different so that it will be more suitable for cycling. That'll happen some time this year, the timing on that needs to be agreed with my prosthetics specialist. Since I am now getting much fitter, I am losing the weight and with that comes subtle changes to my stump's size and shape, which affects the design. It's a tricky business.

Anyway, for now it's not stopping me from riding but I know a better solution exists.

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My cycling leg

This post is especially for Jason and anyone else that's interesting the the specific set up I have for cycling.

Jason commented on my previous post about his desire to tackle the Alpine challenge. Jason is a below the knee amputee as well.

The Alpine - that's awesome!! No way I could imagine doing that at this stage. I wrote about coaching a rider who did the Alpine a couple of years ago in these two posts.

You go Jason!

So, in summary, have a look at these posts which show my cycling leg set up in a little more detail:

My new leg and socket design

How my cycling leg attachment works

The cycling cleat attachment and adapter plate

The urethane adapter to provide lateral roll for out of saddle efforts

My prosthetics guy made my everyday walking leg socket with quite a shallow rear cut away with cycling in mind. The rear of the socket is such that I am able to pedal with a full length crank.

But remember I have the cleat directly at end of the pylon and so the knee doesn't need to bend quite as much as if the cleat was positioned further forward simulating an "under the ball of foot" position.

The socket also has some funky design at the front.

The other adaptation I haven't shown in pics is some soft foam-like material I place at the front of the stump below the knee, in-between the sock and liner, so that it fills the gap between the stump and top front of the socket when you are pedalling. Bend your knee when sitting and you can put your hand/fingers into the largish gap that forms betwen the stump and socket.

The gap isn't there when standing up of course but with the knee constantly bent on the bike, I found filling that gap really helped with power production and provides a much more secure feeling. I just got some off-cuts from a Clark Rubber store.

As my prosthetics guy says, the aim is to maximise the contact surface area between stump and socket. That will be something we look at when designing a dedicated bike leg socket.

Eventually I intend to have a dedicated socket / cycling leg made, however before that happens I need to further strengthen my hip so that the lateral offset of my "foot" can be brought a little more in line with the hip and knee.

For a permanent cycling leg, I envisage something like what Jody Cundy of Team GB paracycling squad had made. Anyone who can do a 65 second kilo sure has a leg that works!



See this item for more details:

Jody Cundy Interview

In there you'll see his new (the carbon leg) and old leg set ups. I don't expect to have my cleat positioned as far forward as Jody has his - he simply replicated what he was used to with his prior set up when wearing a cycling shoe over a prosthetic foot.

The one thing you have to consider with a direct cleat to pylon arrangement is that you can't walk on it. So logistics becomes a factor when planning on going for a ride.

Another thing I've noticed, since I have more than one bike, is that I am now much more sensitive to the different Q-factors of the cranks on my bikes - to the extent that I need to alter the angle of the prosthetic cleat attachment in order to ride a bike with different cranks. My two road bikes have 175 mm Campagnolo cranks however one is a Record crankset and the other a Chorus model and they have different Q-factors.

I never realised until now how much the ankles do the job for us, managing all the lateral roll when out of the saddle and coping with the small differences in positional set up.

What did Joni Mitchell say to us in that Big Yellow Taxi song?
Don't it always seem to go
That you dont know what you've got
Till its gone....

No parking lots here though!

If you want to drop me a line, just use:
alex A T cyclecoach D O T com

Anyway Jason, good luck with it!

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MAPpity doo dah, MAPpity day

I did my final of three power tests today to determine my Maximal Aerobic Power (MAP). If you want to know a bit more about what that is, just click the link.

Before we get to the result of my test, a little background Chronology:

11 Apr 07: My accident, admission to hospital emergency and multiple operations ensued.

16 May 07: Left below knee amputation.

15 Aug 07: Discharged from hospital

24 Oct 07: Collect interim prosthetic leg, begin to learn to walk again

04 Jun 08: Collect new prosthetic leg. Start to stand and walk again with comfort.

13 Jun 08: first ride on indoor trainer since accident. 15-min at 100 watts and using special short 100mm left crank arm (as my knee wouldn't bend sufficiently for a normal crank) and a flat bed pedal to rest my shoe and "foot" on.

28 Jun 08: first ride on special indoor ergo bike.

29 Jun 08: MAP Test - 246 watts

31 Jun 08: first ride using special prosthetic cycling leg attachment

11 Jul 08: first ride outdoors at Centennial Park for 45-minutes - now using a 155mm left crank

19 Jul 08: first race

21 Jul 08: now using a 165mm long left crank

22 Jul 08: MAP Test - 289 watts

26 Jul 08: second race

01 Aug 08: first ride on track

08 Aug 08: 500 metre time trial at Dunc Gray Velodrome

12 Aug 08: Some problems with stump - experiencing some pain and skin integrity issues. 10 days break from riding while I sorted this out.

13 Sep 08: now using full length cranks on all bikes (165mm on track bike, 170mm on ergo bike, 175 mm on road bikes)

21 Sep 08: trial use of poly urethane bushing under cycling cleat to aid out-of-the-saddle sprinting control

23 Sep 08: Time Trial test - 20-minute power 252 watts

25 Sep 08: MAP Test - 355 watts


What can I say, other than I am personally a little amazed. My previous best able-bodied MAP test result was 399 watts. So today I hit 89% of that. It's only 6 watts less than my MAP test from August 2006!

OK, if we want to get technical, the MAP tests this time were measured with an SRM power meter, which given it's a crank based power meter, will give ~ 2% higher reading than my Powertap, which is what my previous MAP tests were measured with (since the Powertap is a hub-based meter and drivetrain power losses are typically ~ 2%).

And for the technically minded of you, yes the SRM is calibrated and zero offsets checked and stable.

Even still, I consider it a pretty amazing result so early in my comeback.

Power chart here:

So much more work to do.....

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Kilo What?

Training is going well. I'm back on a program and so far so good. Yesterday was a solid but not super hard roll in the park - an hour at 200 watts, which clearly means my Functional Threshold Power (FTP) is now higher than 200 watts!

I'll have a better idea of that this coming week as I am scheduled to do a 16km time trial test run and also a Maximal Aerobic Power (MAP) test. That should be fun!

Today I ventured back out to the Dunc Gray Velodrome. This was the first chance I've had to test out my experimental "bushing" for my cycling cleat. I had previously mentioned how I found the bike behaves a bit strangely when doing out of the saddle accelerations, as there was no lateral ankle roll anymore on the left side since there is no ankle, just a straight pylon attached to the cleat and pedal.

So I thought about what I could do and had a few ideas but first I wanted to test the theory to see if some polyurethane under the cleat would do the trick by allowing a bit of sideways flexion.

So while looking for suppliers of polyurethane I also decided to have a closer look at one of my other ideas - to use something like a skateboard truck, which I thought would replicate the ankle flexion quite nicely. So off I go the skateboard shop to have a look...

While there and looking at the trucks on display, I told the shop assistant what I was trying to do and had brought my cycling leg attachment with me. He said, hang on - I might have something for you - and showed me this (the black thing with the H cut out of it):


It is a polyurethane spacer which goes between the skateboard truck and the board - used to provide a little vibration damping and protection for the wooden board from the metal truck. It looked about the right size and hardness, so I took a couple with me to try it out. It has a nice flex to it:


I drilled extra holes and then simply placed it between the cleat and the metal adapter plate, like so:

Not worried about cutting it down to size at this stage (since I didn't know if it was going to work or not) I decided to give it a go and see what would happen. Well today I rode it at the track and after about 30-minutes of rolling around, I decided to do some standing starts.

It worked really well. Once up to speed, the bike was giving me the ability to rock it side to side in a more natural manner without the sensation that I might pull my "foot" out of the pedal.

So after a few of those, I started to get adventurous and rolled around mid track, waiting for some others doing acceleration/speed work. As they passed under me I would get out of the saddle and accelerate down the banking, chase and pass them on the finish line if I could (which I did).

So finally, I decided it was time to get right up the banking and do a sprint effort a la the ubiquitous 200 metre flying time trial. So I rolled around the top and gave it a crack, doing a 3/4 lap effort. I had to sit in saddle a bit earlier than I would normally like but that was OK.

I hit a top speed of 55 kph. OK, so it's not that fast but 55 is OK for now (I was using an 80" gear (49x16) for those that like to know those things and had a max cadence of 142 rpm).

One other thing. On my second standing start of the day, I noticed I had a peak power of 980 watts, so I thought, hmmm, what chance of cracking the kilowatt mark today? So on my third effort I gave it a go.

1053W (5-sec MMP 1020W). :D

Mission accomplished.

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On Track

This morning I had not intended to ride as we had our club Team Time Trial training session scheduled up at Calga/Peats Ridge (which I am supervising/coaching). That went well. When I got home, well it was such a glorious winter's day, clear blue skies, light wind and about 17-18 C, so I decided to throw the bike in the car and head on down to the park for a roll. Back to that later.

On Friday, the planets aligned for me and so I had the opportunity to dust off the track bike (poor thing, it's been badly neglected), get down to DGV and get myself on the boards for the first time since my accident. So I circulated no problems. Saddle height needed an adjustment (I had installed slightly shorter cranks so the saddle needed to come up a bit). About 30-minutes of rolling around just reacquainting myself with the boards.

Then it was time to see if I could do the sort of stuff I'll need to do when riding on a track - namely accelerate, hard!

I rode up the banking to do an acceleration down the banking, which I did without incident.

So then I rolled slowly along the front straight and then popped out of the saddle and tried an acceleration. OK, so I wasn't going to set the world on fire but I was able to do it and that was the main thing. One more half lap effort, this time a bit harder and out of the saddle for the whole turn and down the back straight. There sure is a bit of re-wiring needed and the sensations are difficult to explain. Some stuff is the same, some I need to re-learn. Practice Alex, practice.

While I was there, Sean Eadie (2002 World Sprint Champ) was there coaching a Chinese rider. So I got Sean to time a standing 250 metre lap. 24.9 seconds. But the nice thing was simply being able to go out of the saddle for more than half a lap.

So back to today. My legs were a little sore but after a couple of laps they came good and I ended up doing a solid hour and a bit. That then gave me a 5-day block of riding and a nice little boost to my training loads. That blue line is on its way up :D



I also tried something new - putting an extra sock over my leg liner before riding, which provides addition compressesion of the leg stump inside the socket. This had the effect of maintaining a more secure fitting, not allowing the leg to sweat as much and so there was not much pooling of perspiration in the lower part of the liner creating that insecure squishy feeling. So that was pretty cool.

I'm going to sleep well tonight me thinks!

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Inspector Gadget

OK - another pictorial adventure coming up for your viewing pleasure.

I recently reported on getting a dedicated bike leg attachment made up. Some aren't exactly sure what that means, so let me show you....

First we start with the leg I have today, set up as a normal walking leg.


If we zoom in to look at the special clamp at the bottom of the socket (the large black carbon fibre part that my legs fits inside of), you can see a number of allen key bolts secure the pipe section to the socket.


These can be loosened to remove the lower pipe section which has a foot attached at the other end.


Here you can see the two parts normally hidden from view, showing the unique block style clamping system. There are four of those allen bolts, one on each side and they enable you to adjust the angles at which the pipe section fits onto the socket.


As long as I only ever undo two of these bolts (must be next to each other and not opposite) then the attachments will always clamp back on in exactly the same place each time. If I loosen three bolts, the the positioning changes. Hence I have put some loctite on the two bolts I don't intend to undo.

Here is a picture of the walking foot attachment and my cycling "foot" attachment. As you can see, there is no foot for the cycling leg. It is simply a pedal cleat attached to an adapter plate right under the end of the pipe. This enables direct force transfer down through the leg, the socket, the pipe section and onto the pedal.


Here is a picture of the cycling leg attachment connected to the socket.


On Monday I visited my good buddy, Steve Hogg at cyclefitcentre.com. Steve specialises in fitting bikes to people. So away I went and we worked on getting the bike leg attachment adjusted for length and all the multitude of angles you can adjust. Indeed it's almost as if there is too much adjustment available!

The best part was that we discovered that my knee was able to cope with using a 155mm long crank arm. At the moment I have a short 100mm crank on the bike, as I hadn't been able to bend the knee enough to use a longer crank. On my road bikes I normally use 175mm cranks and on the track I use 170mm. So my leg has improved enough so that I am not far away from using a full length crank.

That is really important as it means I will have a much greater ability to get power through to the pedals.

All I need now is a 155mm crank arm. I have a buddy looking into that for me (he made the short crank up for me), although I know there are manufacturers of cranks that small, normally designed for BMX riders, so I'm pretty sure finding one won't take long.

Then I expect to graduate to 160mm, 165mm and hopefully at least 170mm cranks.

Ultimately I would really like to have a dedicated cycling socket, so I can simply transfer from a walking leg to a cycling leg without having to bolt things on and off. Also, the design of the walking leg socket is not quite ideal for the way I pedal the bike - there are a large number of dynamic factors at play but basically the lower socket shape angles outwards when it would be better if the line between the knee, lower socket and pedal was aligned. It will certainly do for now though.

The best way to make sure that happens is to keep riding!

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Hippy Hippy Shake

On Monday I had a new prosthetic foot attached to the end of Schooner MkII (although some of my Aussie friends suggested I rename him "Middy" due to the smaller capacity of the new model).

The foot is quite a complex bit of engineering and is full of carbon fibre plates and other adjustment pieces you can't see and which replicate much of the feedback you get with a normal foot. You can actually "tune" the foot to provide different levels of feedback.

The one function that is obvious to the eye however is the fully moveable ankle joint. This special ball and socket joint replicates much of the joint motion of a normal ankle. It will move in any direction as well as rotate slightly.

This is so much better to use than the fixed ankle I did have as my foot can now move with the variations in slope and camber of surfaces I walk on. Slopes and cambers on a fixed ankle are a right pain in the butt (well back and hips to be accurate).

It also means that my walking motion is progressing even closer to a natural gait.

This is the foot in its normal upright position:


And here it is with my foot out to the side, shoe flat on the floor and leg now at an angle - just like a tennis player ready to receive a serve or a soccer goalie waiting for the penalty shot to be taken.

It is rated to cope with the forces my current oversize backside will put through it but I hope to stress it less over the coming months as my training ramps up.

These things are not cheap however. All up that's now a $12,000 leg. And I'll no doubt need a modified dedicated socket for cycling. I have the pedal attachment sorted and I go in to have all the bike fitting done this coming Monday.

More on that (and my indoor cycling ergometer project) later.

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Schooner rides again!

I have a new leg. Finally!!

So today will be lots of pictures of Schooner Mk II - the new and improved version.

I went back to see George at the Appliance and Limb Centre last Wednesday and have now picked up the final product. And what a relief. After only a few days, already the pain and discomfort of using Schooner has gone.

The new leg is very comfortable but it is also provides a far greater freedom of movement for the knee. Hence I am not super steady on it yet and I need to build up the strength required to walk with a natural gait and improve the finer balance control that we take for granted. That will come with use and exercise.

So here we go with the picture tour....



Of course this is all in fashionable black and the socket is carbon fibre. What else for a post modern cyclist?!!

Notice the shaping at the top of the socket in particular. This is a unique design, in the sense that it is completely custom made for me but also in the sense that this style of socket is only made by one person in the world. There are only six of these socket types in existence!




The big difference in this design from other sockets is how low cut it is. This is to enable a lot of freedom of motion for the knee joint (which is exacly what I'm going to need when riding).









Here is the lower section connecting the socket to the foot.













Inside the socket, of course, goes my leg. But my leg has to have two special liners "rolled" onto it first.

The first, the "Distal Cup" is not shown and is a silicone like cup shaped liner that sits over the lower part of my leg. It creates a uniform shape out of the lower part of my leg.

Then this lovely lilac liner is rolled over the top. It is like a thick compression sock, with a metal pin sticking out the bottom.



Here is a shot of the pin - see the shape - it is designed to "click" into place and the notches hold the liner and via that, my leg, securely into the socket.

I then put the leg inside the socket and the pin fits through a hole in the bottom of the socket and clicks into place. Max of seven clicks!











When I want to remove the socket from my leg, all I do is press this button in and the pin is immediately released and Schooner MkII comes off instantly! No stuffing around holding onto liners and using my other foot to pull Schooner off and wince as the socket compresses my knee joint on the way through.




And this is what it looks like when I stand in it!


Next up are two more projects:

- Finalising the cycling leg attachment, and

- Getting a funky new prosthetic foot attachment, with a ball and socket which simulates the motion of the ankle joint.

These are happening over the next few weeks.

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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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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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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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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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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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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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Pro-gressive

Have a look at this guy, Jan Boyen:



Photo from November 2007 edition of ProCycling magazine. How cool is that leg? Thank insert God or other higher being of your choice for carbon fibre technology.

I want one! It'd go real nice with my carbon Teschner Track Pro.....

Jan is a Belgian pro rider with team Jartazi Promo Fashion - yep a Pro! Nice one.

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