The Powermeter Thread

[Retro Trev]

The Garmin head unit does not measure force vectors (yes how ironic) from the pedals yet. The only meters that do are the Pioneer and the Rotor models. One would expect they would measure the force on the upstroke.

Why do you think there is an imbalance and under what conditions does it approach 60 / 40?

And going off topic why do you think measuring force vectors around the pedal revolution will offer a solution other than spending time trying to achieve 50 / 50?

The imbalance was found when i tested Look Keo power pedals. I did not believe it but Wattbike showed the same imbalance and subsequently Vector showed the same.

The imbalance is less at higher powers and higher cadences but always there even when i consciously try to put more effort into the weaker leg. The weaker leg also seems to show more of the imbalance as fatigue sets in.

I don't worry about it as I find my limit to performance is my breathing rather than my legs and at or around FTP provided the cadence is higher the imbalance is only a few percent.

I'm interested because the weak leg is in fact the leg i would say is stronger as it is the leg i would kick a ball with but I have had serious injuries to the knee and hip - I think perhaps i subconsciously hold back with the leg as some sort of protective measure.

I'm just interested in finding out why my injured leg has less power particularly at higher forces lower cadence. Is it just pushing less hard or is it slow or late and pushing for less time each stroke - no idea?

 

[Retro Trev]

waa waa waa and calling the person who calls out the action of a troll a troll is in my opinion acting like a troll.

Frank has continually put up strawman arguments against power meters the whole way through the argument. He has been warned about doing this and was banned for a week. He is clearly a troll. My 1% of noise in pointing people towards the correct course of action should be balanced against the 99% of on topic discussion about riding and racing with a power meter.

Truce? I know nothing about Frank's posting history so point taken.

 

[CoachFergie]

Truce accepted. If you ever need a giggle google Frank Day and you can see how low an intelligent man will sink to promote his agenda.

The imbalance was found when i tested Look Keo power pedals. I did not believe it but Wattbike showed the same imbalance and subsequently Vector showed the same.

So pretty conclusive that there is an imbalance.

The imbalance is less at higher powers and higher cadences but always there even when i consciously try to put more effort into the weaker leg. The weaker leg also seems to show more of the imbalance as fatigue sets in.

Sound fairly typical.

I don't worry about it as I find my limit to performance is my breathing rather than my legs and at or around FTP provided the cadence is higher the imbalance is only a few percent.

Again typical, and very familiar

I'm interested because the weak leg is in fact the leg i would say is stronger as it is the leg i would kick a ball with but I have had serious injuries to the knee and hip - I think perhaps i subconsciously hold back with the leg as some sort of protective measure.

Again fairly typical. Had a rider crash and another rider go over his knee causing a fair bit of damage. Our Cycling Federation put him back into competition in Europe a little too quickly and an imbalance turned into a major imbalance and even started affecting his lower back as one side tried to deliver power from every joint bar the knee. Two physios just tried to make him strong and rebuild the muscle mass. This was achieved but didn't stop the pain.

Physio number 3 worked on his position on the bike and he did a lot of one leg pedalling with a counter weight on the other side and slowly building up the time overworking the weaker leg was the stimulus for a return to competitive cycling. Point being we once we stopped just trying to build strength and size and focused on specific fitness and technique we started making progress.

I'm just interested in finding out why my injured leg has less power particularly at higher forces lower cadence. Is it just pushing less hard or is it slow or late and pushing for less time each stroke - no idea?

I expect because your body isn't keen on more pain. May mean altering the gears on your bike to keep the cadence up, building more fitness with good technique on the flat before you venture on to the hills.

 

[Retro Trev]

Truce accepted. If you ever need a giggle google Frank Day and you can see how low an intelligent man will sink to promote his agenda.



So pretty conclusive that there is an imbalance.



Sound fairly typical.



Again typical, and very familiar



Again fairly typical. Had a rider crash and another rider go over his knee causing a fair bit of damage. Our Cycling Federation put him back into competition in Europe a little too quickly and an imbalance turned into a major imbalance and even started affecting his lower back as one side tried to deliver power from every joint bar the knee. Two physios just tried to make him strong and rebuild the muscle mass. This was achieved but didn't stop the pain.

Physio number 3 worked on his position on the bike and he did a lot of one leg pedalling with a counter weight on the other side and slowly building up the time overworking the weaker leg was the stimulus for a return to competitive cycling. Point being we once we stopped just trying to build strength and size and focused on specific fitness and technique we started making progress.



I expect because your body isn't keen on more pain. May mean altering the gears on your bike to keep the cadence up, building more fitness with good technique on the flat before you venture on to the hills.

Thanks for you input here.

I did the knee in 1974 and the hip in 1985.

Funny thing happened the other day.

Did an all out 20 minutes test. No problems although I was aware towards the end the stronger left leg was doing more than it's fair share.

About an hour later when sitting I got pain in the knee and hip which was at the sort of level I had when still recovering from the injuries some 39 and 28 years ago. Pain lasted for a few hours but after a good nights sleep no problems. Almost as if the leg were saying, "do that to me again you old ******* and this is what you are going to get". Really weird.

 

[FrankDay]

Can Vector tell me if I am applying any reverse force on the upstroke?

Vector should have that capability but it is not very well implemented right now, as I understand it. They will give you a pedaling effectiveness score, which I believe is simply the percentage of time you are applying reverse torque around the circle. The problem with such an approach is you don't know where the reverse torque is actually applied nor its size. If I misunderstand this someone will correct me, I am sure.

My pedalling technique has no pull up, no pushing over the top, or scraping back but I have a feeling one of my legs may be lazy or slow and applies some counterforce on the upstroke - is there a way of measuring this?

Yes, or at least there will soon be. This is how it should be done IMHO http://icranks.com/tech-information/torque-analysis-development-demo-video/ The two videos are labeled good technique and bad technique. I would think they should be labeled "lots of issues" and "fewer issues". Try guessing which rider is the pro.

 

[FrankDay]

Did an all out 20 minutes test. No problems although I was aware towards the end the stronger left leg was doing more than it's fair share.

It is almost impossible to tell which leg is stronger and weaker from how they feel riding. I have had more than a few people hop onto the PowerCranks at an expo and be surprised at which leg is found to be weaker (PowerCranks find these weaknesses because the cranks are independent and the strong leg cannot help the weak one). They will say they thought the X leg was the strong one because the Y leg was the one that always got tired. It turns out that the Y leg was getting tired because it was doing all the work. The only way to know what is going on for sure is to isolate the legs or to measure them independently. In my previous post you will see that the "bad technique" rider has substantial imbalances and that these imbalances are all around the stroke although much more obvious on the backstroke. I would bet real money this rider has had some sort of injury that led to this imbalance, just as you have. The trick is in getting him to look more like the "good technique" rider. How to do that efficiently?

 

[Retro Trev]

It's all very interesting. When I first saw the imbalance testing the Keo power pedals I was certain they had crossed the signal, as i said it was only when confirmed on other systems I accepted the right leg was the weaker leg.

 

[CoachFergie]

It's a fairly typical situation for an injured rider. I would expect regular testing on a Watt Bike will help you to determine if you are making progress. I wouldn't suggest one buy a power meter just for the L:R measuring option. Reports from early adopters of the Vector suggest riders see some imbalance with different types of riding and over different durations. I would suggest the pursuit of a 50:50 split in every situation would not lead to huge increases in performance.

 

[Retro Trev]

It's a fairly typical situation for an injured rider. I would expect regular testing on a Watt Bike will help you to determine if you are making progress. I wouldn't suggest one buy a power meter just for the L:R measuring option. Reports from early adopters of the Vector suggest riders see some imbalance with different types of riding and over different durations. I would suggest the pursuit of a 50:50 split in every situation would not lead to huge increases in performance.

I doubt there is much i can do about it as the injuries are so old. It is just something that is interesting.

 

[CoachFergie]

Do you still experience pain while riding?

If not then in theory you can learn to correct the imbalance. Whether the effort is worth is another matter, when the chips are down riding hard you tend to revert to what is familiar.

Same have imbalance imposed on them. Unless regular poster Alex Simmons's lower leg grows back his L:R will never be 50:50 but this hasn't stopped him from setting new power PBs.

 

[Retro Trev]

Do you still experience pain while riding?

If not then in theory you can learn to correct the imbalance. Whether the effort is worth is another matter, when the chips are down riding hard you tend to revert to what is familiar.

Same have imbalance imposed on them. Unless regular poster Alex Simmons's lower leg grows back his L:R will never be 50:50 but this hasn't stopped him from setting new power PBs.

The knee pain is something that is always there in the background, sometimes is annoying but not the sort of pain which would ever stop me riding. I have found that using old fashioned toe clips & straps or flat pedals allows me to vary foot position which relieves the knee pain. The hip is only a problem if I ride in an extreme TT position.


The pain in knee and hip are more of a problem after rides than they are during. And as i get older it seems to get worse.

I don't see it as a performance limiter, the old leg does cut in and do the business when the chips are down.

 

[CoachFergie]

http://www.dcrainmaker.com/2013/09/meter-depth-review.html

In depth review of the Quarq Riken. Interesting comparisons with a Stages Powermeter and a Powertap G3. Riken is a standard power meter without the bells and whistles. No L:R measurement but as Ray points out there is no consensus about the importance of training to improve this over the importance of trying to raise various thresholds, increasing measures of fitness like chronic training load while managing fatigue, and power delivery specific to ones goal event.

 

[2beeDammed]

I would suggest the pursuit of a 50:50 split in every situation would not lead to huge increases in performance.

That's a really interesting thought. I have the LOOK Keo power system, it just slotted in to the CS500 head unit that I already used. Just last week I picked up a CS600 on ebay cheap just so I could see the left/right distribution. Not sure if the watts displayed is a total of left and right readings on the CS500 ? Anyway I'll fit the CS600 today and find out.

 

[FrankDay]

I would suggest the pursuit of a 50:50 split in every situation would not lead to huge increases in performance.

Don't you think it would depend upon how one achieved that balance as to what the performance outcome would be. Bringing the weak leg up to the capability of the strong leg should result in a performance increase. Lowering the power in the strong leg should not.

Further, the one thing most sports medical professionals believe is that balancing the power should reduce the risk of future injury. That, in itself, should be worthy of pursuit. Nothing hurts performance more than an injury.

 

[CoachFergie]

One needs to differentiate between correcting an imbalance due to injury with devoting time to achieve symmetry that could be better spent trying to meet the performance demands of the goal event.

Then it depends on the type of injury. For my rider with the knee injury we only started making progress going from using generic strengthening and hypertrophy exercises to focusing on single leg pedalling with a counter weight to get the rider up to speed. Other injuries you don't bounce back from and you just have to live with the imbalance.

One could also expect to see imbalances due to the nature of the sport. Track cyclists only go anti-clockwise round the track so one could expect imbalances to occur especially if the bankings are very steep. But then no data has been presented that this contributes to any chronic injuries.

Best thing one can do to prevent an imbalance is to avoid the acute injury that causes it in the first place.

 

[FrankDay]

One needs to differentiate between correcting an imbalance due to injury with devoting time to achieve symmetry that could be better spent trying to meet the performance demands of the goal event.

Perhaps you could give us an example of a significant imbalance that isn't due to injury and wouldn't correcting imbalances due to injury be a completely separate issue to meeting the performance demands of the goal event.

Then it depends on the type of injury. For my rider with the knee injury we only started making progress going from using generic strengthening and hypertrophy exercises to focusing on single leg pedalling with a counter weight to get the rider up to speed. Other injuries you don't bounce back from and you just have to live with the imbalance.

So, to correct your riders problem, you had him pedaling in the PowerCranks fashion just one leg at a time? And, you think some imbalances simply can't be fixed? (forget the A Simmons examples and give us an example of what you mean.)

One could also expect to see imbalances due to the nature of the sport. Track cyclists only go anti-clockwise round the track so one could expect imbalances to occur especially if the bankings are very steep. But then no data has been presented that this contributes to any chronic injuries.

Could you present any data that riding on the track leads to any imbalance

Best thing one can do to prevent an imbalance is to avoid the acute injury that causes it in the first place.

Best advice ever to cyclists to avoid injury, avoid crashes!!! LOL.

 

[Alex Simmons/RST]

Best advice ever to cyclists to avoid injury, avoid crashes!!! LOL.

Proper bike fit and set up along with working on riding skills, nouse and craft go a long way to reduce the incidence of such injuries and crashes.

 

[FrankDay]

Proper bike fit and set up along with working on riding skills, nouse and craft go a long way to reduce the incidence of such injuries and crashes.

Could you explain how those things (fit, skills, etc) "go a long way to reduce" any injury incidence other than a crash injury? Any evidence to support your contention? And, just what is a "proper bike fit" anyhow?

 

[Alex Simmons/RST]

Could you explain how those things (fit, skills, etc) "go a long way to reduce" any injury incidence other than a crash injury? Any evidence to support your contention? And, just what is a "proper bike fit" anyhow?

I would have thought them self evident.

Better bike handlers and those with better skills and nouse on the bike have improved ability to anticipate and avoid danger, or to minimise the damage when a collision of some kind is inevitable. e.g. good track riders learn about the most effective ways to avoid crashes that happen ahead of them, as well as how to land to reduce injury if you do find yourself going down. Not to mention riding skills that reduce the likelyhood of crashes in the first place.

As for bike fit, well a quick glance down your local bike circuit at those riding with cleats clearly in the wrong place/angle with knees wobbling all over the joint, seats too high etc would suggest a beter fit will assist avoid injury.

 

[FrankDay]

I would have thought them self evident.

Better bike handlers and those with better skills and nouse on the bike have improved ability to anticipate and avoid danger, or to minimise the damage when a collision of some kind is inevitable. e.g. good track riders learn about the most effective ways to avoid crashes that happen ahead of them, as well as how to land to reduce injury if you do find yourself going down. Not to mention riding skills that reduce the likelyhood of crashes in the first place.

I accept that better bike handling skills would help avoid crashes and resulting injury. However, it may not be the case as better bike handlers are generally faster cyclists such that any crash that might occur would probably have a higher incidence of injury occurring. I am not aware of any statistics to support this though, just a thought.

As for bike fit, well a quick glance down your local bike circuit at those riding with cleats clearly in the wrong place/angle with knees wobbling all over the joint, seats too high etc would suggest a beter fit will assist avoid injury.

Yes, but I am not aware of any data that supports that such results in an increased injury rate. It is easy to rationalize that it might (especially if you do bike fitting) but there is no data to support that conclusion that I am aware of. Can you point to any?

 

[Alex Simmons/RST]

I accept that better bike handling skills would help avoid crashes and resulting injury. However, it may not be the case as better bike handlers are generally faster cyclists such that any crash that might occur would probably have a higher incidence of injury occurring. I am not aware of any statistics to support this though, just a thought.Yes, but I am not aware of any data that supports that such results in an increased injury rate. It is easy to rationalize that it might (especially if you do bike fitting) but there is no data to support that conclusion that I am aware of. Can you point to any?

At risk of going off topic, and I have not reviewed these to specifically look for injury rates etc:
http://www.ncbi.nlm.nih.gov/pubmed/10081053
http://www.ncbi.nlm.nih.gov/pubmed/11388717
http://www.ncbi.nlm.nih.gov/pubmed/16144585
http://www.ncbi.nlm.nih.gov/pubmed/18063715
http://www.ncbi.nlm.nih.gov/pubmed/20086406
http://www.ncbi.nlm.nih.gov/pubmed/2011683
http://www.ncbi.nlm.nih.gov/pubmed/21615188
http://www.ncbi.nlm.nih.gov/pubmed/23147089

etc etc

For further discussion if people are interested, I suggest a new thread or finding an old relevant one.

 

[Retro Trev]

One for Coach Fergie or Alex.

I know NP takes into account many critical physiological responses and tries to estimate the true physiological demands etc etc. rather than just take average watts.

But when TSS is calculated, is the fatigue from the previous day or the fatigue from an earlier session taken into account?

If I do a ride in the morning which includes 20 min at FTP then do a lunch time session which includes 2 x 20 min at FTP then an evening session which includes 20 min at FTP, do all the 20 mins segments get the same TSS score?

Then if I do a 20 minute session at FTP the following day when very fatigued does that session get the same score?

Is this build up of fatigue accounted for by the software or is this something I should take into consideration in some other way?

Thanks.

 

[CoachFergie]

I know NP takes into account many critical physiological responses and tries to estimate the true physiological demands etc etc. rather than just take average watts.

But when TSS is calculated, is the fatigue from the previous day or the fatigue from an earlier session taken into account?

No just from that ride itself. But then if one was carrying fatigue from a previous ride then you would expect the power to be lower anyway.

If I do a ride in the morning which includes 20 min at FTP then do a lunch time session which includes 2 x 20 min at FTP then an evening session which includes 20 min at FTP, do all the 20 mins segments get the same TSS score?

Again, same deal. If the AM ride was fatiguing you would expect lower power in the PM ride.

Is this build up of fatigue accounted for by the software or is this something I should take into consideration in some other way?

This is where the Performance Manager earns it's keep. Takes into account fitness and fatigue and allows you to see the affect on one's Training Stress Balance. Based on the Training Impulse model this tool has allowed me to fine tune a riders performance like no other tool or measure.

 

[Retro Trev]

You would expect lower power due to fatigue but if I push it and keep the power up I end up with the same score despite the physiological cost being greater.

I end up with a score which does not reflect the true physiological cost, fatigue is then underestimated.

 

[CoachFergie]

You would expect lower power due to fatigue but if I push it and keep the power up I end up with the same score despite the physiological cost being greater.

I end up with a score which does not reflect the true physiological cost.

Then by definition you are not fatigued.