The importance of crank length to the cyclist.

[FrankDay]

but the 'pumping' effect of the muscle would be smaller with a smaller range of motions surely?

No. Once the internal pressure of the muscle exceeds the arterial pressure the muscle is emptied of all its blood and no more can come in. Doesn't matter how far it contracts. All that matters then for the "pumping effect" is how much blood is in the muscle and that depends upon how many capillaries are open and that depends upon how hard the muscle is working.

 

[FrankDay]

yes, I was thinking the same when I wrote that bit but what was in my head was more around the way that when someone does something with a restricted range of motion they start to crave the ability to step out of that position and stretch etc. I guess that a higher cadence (however, an 80 cadence is low!) would help with this. For me though, an 80 cadence is very low. I ride at around 95-110 so a shortening of cranks would likely (I guess?) end up in me riding up to 120 on average....

My max cadence on a 172.5 crank is upwards of 195rpm usually (varies based upon fatigue etc)

When I first made these short changes I brought my cadence up but then, as I got used to them, it came back down at least some. when I used to ride 175's I tried to keep my cadence around 65. I now, at 105, try to keep it around 85. Even at this higher cadence I think my pedal speed is lower, making "easier" for me to apply higher force to the pedal (necessary to accommodate to keep the power up).

My sense is, if you were to try this you also would raise your cadence some but then come back closer to where you are now as you got used to it. If you were to also take a serious look at cycling economy I would predict you would lower your cadence even more.

I am by no means as an accomplished cyclist as yourself and on very short cranks I can get my cadence now over 200. If you were to come down to 145 or so I am sure you would have no trouble getting the cadence above 210 to 220 as you accommodated to the new length. If you were to also put yourself on the unnamed product you could probably go even higher. Had one track cyclist report that in 6 years he took his max cadence from 175 to 240 - and this was without going shorter.

 

[blutto]

Question: Wouldn't restricting a muscle to a smaller range of contraction ultimately result in a larger risk of problems on longer sessions or over many sessions?

Describing it the way you just did I immediately started to wonder whether the muscle would be more likely to cramp etc than a muscle that is worked through a larger range of motion. Have you had any thoughts on that Frank? Is it a reasonable idea or have you discounted it?

I know personally from my rockclimbing days that I have had huge problems when movements have been restricted such that muscles were working in small ranges (such as long sections of smearing on steep faces). I would experience the 'sewing machine' in my calves and eventually cramp.

...if power production is the most important performance parameter in cycling the shorter movement will yield significant more power...

...drawing from power lifting ( which is probably as relevant rock climbing???) a quarter squat will typically have at least twice the yield of a full squat...and drawing on advice from my orthopod after my knee surgery the longer movement is much more likely to produce problems over the long run ( though to be completely honest this information is not backed by any peer reviewed scientific papers that I am aware of but than to my knowledge I have also never seen a peer reviewed scientific like paper that absolutely proves that the sun rises in the east and sets in the west either )....

Cheers

blutto

 

[Alex Simmons/RST]

...if power production is the most important performance parameter in cycling the shorter movement will yield significant more power...

...drawing from power lifting ( which is probably as relevant rock climbing???) a quarter squat will typically have at least twice the yield of a full squat...and drawing on advice from my orthopod after my knee surgery the longer movement is much more likely to produce problems over the long run ( though to be completely honest this information is not backed by any peer reviewed scientific papers that I am aware of but than to my knowledge I have also never seen a peer reviewed scientific like paper that absolutely proves that the sun rises in the east and sets in the west either )....

Cheers

blutto

Are you confusing force production with power?

 

[sciguy]

Frank,

Do you know what crank length Courtney O. will be riding in Hawaii next Saturday and what do you think his chances are of cracking top ten?

Thanks for the info.

Hugh

 

[FrankDay]

Frank,

Do you know what crank length Courtney O. will be riding in Hawaii next Saturday and what do you think his chances are of cracking top ten?

Thanks for the info.

Hugh

Last I heard he was on 130 but had also been injured. I was a little surprised when he took the spot because he was DNS in several late races due to the injury. But, maybe the fact he got in without needing to race more will allow him to recover. If injury isn't hampering him I would think he might have a chance to get into top 10. He felt the aero advantages he was seeing would allow him to have one of the very top bike splits so top 10 would depend upon how he ran. Anyhow, we will see.

 

[CoachFergie]

From Coutney's site...

INJURY UPDATE
It would seem that I don’t have Patella Tendonitis, but more like a Patello-Femoral Syndrome, where the pain is felt underneath the the patella. The mechanism, I am told, is the result of some knee instability, due to a combination of poor hip mobility and poor hamstring function.

Hmmmm, independent crank user and recent convert to short cranks develops a knee injury.

Hmmmm, CO lists http://www.powercranks.com as a supporter. So there is a commercial bias to any evidence provided associated with CO.

Coach Ferg would prescribe training with a fixed crank to improve cycling performance (no commercial interest). As used by current Tour de France champion Cadel Evans, current World Road Champion Mark Cavendish and many former greats of cycling like Eddy Merckx, Greg LeMond and Miguel Indurain.

 

[Tapeworm]

I totally endorse fixie cranks. By using these 3 times a week I increased my power by over 10% in just 3 months. (that's right, 3 months of training shows improvement!)

I am also 10% faster too! (pay no attention to the professional fitting I had done which improved position and aerodynamics).

Because of training with fixie cranks i have a more fluid pedal stroke and feel like I have more power on climbs and sprints (pay no attention to the sprint and climbing specific training I did with them.)

Thanks fixie cranks!

But tell me Hamish, can I get fixie cranks in 100mm length (or my money back)?

 

[CoachFergie]

I totally endorse fixie cranks. By using these 3 times a week I increased my power by over 10% in just 3 months. (that's right, 3 months of training shows improvement!)

I am also 10% faster too! (pay no attention to the professional fitting I had done which improved position and aerodynamics).

Because of training with fixie cranks i have a more fluid pedal stroke and feel like I have more power on climbs and sprints (pay no attention to the sprint and climbing specific training I did with them.)

Thanks fixie cranks!

But tell me Hamish, can I get fixie cranks in 100mm length (or my money back)?

I saw an improvement in max aerobic power from 295 watts to 360 watts in a 3 week period of Fixxiecrank training. Who would have thought that 3 days a week of 10 x 1min efforts would lead to such dramatic gains.

I did a 16km time trial on a Freewheel crank at 280 watts and a week later at the same wattage went 90 seconds faster on Fixxiecranks. Same performance but amazing improvement in results.

A potential confounder to these gains was my road bike runs 170mm cranks and my track bike runs 165mm so potentially .0001% of the gains could be attributable to that.

Ahhh now Mr Worm it's not about the money back guarantee it's about the time investment one makes and what gains they expect to see. The current research on crank length would indicate no advantage in going to a shorter crank (or a longer crank for that matter) and such a change would also require dramatic (and potentially expensive) changes to the position on the bike.

 

[Martin318is]

Tapeworm and CoachFergie,
you've had your fun. Please treat the remainder of this thread with respect.

The discussion of crank length is independant of the discussion of powercranks (even though powercranks offer length changes as an option, they are merely a product to facilitate the change).

The remainder of this thread should be discussing length ONLY - independant of crank brand.

Thanks,
Martin

 

[CoachFergie]

Tapeworm and CoachFergie,
you've had your fun. Please treat the remainder of this thread with respect.

The discussion of crank length is independant of the discussion of powercranks (even though powercranks offer length changes as an option, they are merely a product to facilitate the change).

The remainder of this thread should be discussing length ONLY - independant of crank brand.

Thanks,
Martin

I have suggested that a change from 170mm to 165mm cranks may have altered my performance by .0001%.

I have no financial interest in any brand of crank or do not have anything to gain monetarily from advocating any crank length.

I look forward to the presentation of any data (power, efficiency or aerodynamic drag) that shows a significant improvement in performance from a change in crank length.

My contention based on the available research is that there is no "importance" of crank length with regards to power, efficiency and that in terms of aerodynamic drag there are cheaper options to trial first before making dramatic changes to the bike set up.

 

[blutto]

Are you confusing force production with power?

...was not meaning to draw a very tight comparison was just trying to use a rough analogy with something with which I was somewhat familiar with to make a point ( and I guess the point making wasn't clear enough or maybe the point I was trying to make was way off base...sorry...)

...so yes force production and power are different but I would also say they are not absolutely different...as in, they have some commonalities that could useful to examine as they apply to force production and power ...

Cheers

blutto

 

[lostintime]

I'm trying out some 152mm Sugino XD cranks as we speak. It only took a few days to adjust my gearing, but so far I'm quite happy with the much less leg fatigue and other aches. I'm 73.5 inches tall, with a 36" pubic bone height, and size 15 feet, and use a mid foot position over the pedal...for reference. I'm a recreational rider only these days, and the bike I'm testing them on is a fat tire road/mountain bike, a Rivendell Bombadil frame.

I had been using 185's of recent, then decided to go back to 175's... then even 170. I thought about going shorter, but i wanted to keep it simple and stick with the same model of crank for now, so the 152mm option seemed good to start. Frankly, it's fun as heck being able to spin so smoothly and not have my knees flailing around at high speed, and it feels great. You don't have to buy $$$ cranks to try shorter cranks out. There's a ton of short 110 BCD square taper cranks to try for $50-100 USD from Origin8, Sinz, AC etc.

I'm as unscientific as they come, but wanted to share my experience so far as one doesn't need to justify trying shorter cranks for performance reasons, you can try them for comfort and just plain fun. If I'm not having fun ... why bother?

 

[Boeing]

for those of you just joining us allow me to sum-up page 2-62

Is so

is no

yes it is

no its not

uuhuh

nnutuhh

wana bet

sure because I know

no you dont

yes I do

well you dont have any proof

neither do you

uhugh


nutugh

no you dont

yest I do

this doenst work

yest it does how?

you tell me first

no way you just want my answers

no I dont

yes you do

nutugh

uhugh

.......................................................zzzzzzzzzzzzzzzzzzzzzzzzzzzz

 

[onetrack]

Now after nearly 5 months at 145mm, and seeing the best cycling performance of my life, I am ready to go even shorter. I had additional pedal holes put in at 125, 105, and 85mm.

 

[blutto]

Now after nearly 5 months at 145mm, and seeing the best cycling performance of my life, I am ready to go even shorter. I had additional pedal holes put in at 125, 105, and 85mm.

...really interesting information, but be aware that because it was not presented in a peer reviewed scientific type journal thingee, it, for all intents and purposes, does not exist...

...and furthermore, if your existance has not been verified by a peer reviewed scientific journal thingee, you, for all intents and purposes don't exist either...

...so sorry to be the bearer of bad news but rules are rules after-all and they are there for a very good reason...

Cheers

blutto

 

[CoachFergie]

While discussing the importance of any aspect it is important to make a distinction between improved results and improved performances.

WRT crank length I coach a young girl who has gone from 170mm cranks to 172.5mm and since I started coaching her has gone from placing mid field last year to 2nd fastest overall time at a South Island (of NZ) schools championship time trial and went from mid field in the road race to winning her age group solo by 30 seconds. At the South Island schools tour she went from mid field to age group champion. At the NZ schools champs she went from 4th in her age group to NZ champion.

Big improvements in results and because her Father brought her a power meter (not that she claims to care about power even though she has stopped wearing a heart rate strap) we can track her improvements in power. The question is whether she has improved because she races and trains with a power meter, uses fixed gear training, has me as a coach (at SI champs my riders placed 1-2-3 in overall best times out of 150 girls and in her National RR she broke away from a field of 30 with another girl I coach for the win), the change in cranks length, being a year older, having more experience and so on. A large variety of factors could contribute towards her improved results.

With the power meter we can measure her improvements riding the bike. But very hard to separate the reasons why she has improved. Hence the need to use research that controls for these factors like the Martin and McDaniel studies that showed no significant changes in power or efficiency from changing crank length.

 

[blutto]

While discussing the importance of any aspect it is important to make a distinction between improved results and improved performances.

WRT crank length I coach a young girl who has gone from 170mm cranks to 172.5mm and since I started coaching her has gone from placing mid field last year to 2nd fastest overall time at a South Island (of NZ) schools championship time trial and went from mid field in the road race to winning her age group solo by 30 seconds. At the South Island schools tour she went from mid field to age group champion. At the NZ schools champs she went from 4th in her age group to NZ champion.

Big improvements in results and because her Father brought her a power meter (not that she claims to care about power even though she has stopped wearing a heart rate strap) we can track her improvements in power. The question is whether she has improved because she races and trains with a power meter, uses fixed gear training, has me as a coach (at SI champs my riders placed 1-2-3 in overall best times out of 150 girls and in her National RR she broke away from a field of 30 with another girl I coach for the win), the change in cranks length, being a year older, having more experience and so on. A large variety of factors could contribute towards her improved results.

With the power meter we can measure her improvements riding the bike. But very hard to separate the reasons why she has improved. Hence the need to use research that controls for these factors like the Martin and McDaniel studies that showed no significant changes in power or efficiency from changing crank length.

....a word of caution....vigorous patting of oneself on the back can result in very serious shoulder damage...

...oh by the way see post no. 615....

Cheers

blutto

 

[onetrack]

coach,
You are absolutely right. There is no way of saying definitively what caused my improvement. Maybe I unknowingly ate tainted meat. Without a power meter, I can't scientifically prove that I even had any improvement, maybe the wind just blows in my favor now. Realize that the point of this thread is not to provide the ultimate crank length formula that every coach should put their rider on. The point of this thread is to examine the possibility that there are benefits in using crank lengths that are outside the 165-175mm range. Given that an Ironman was won at the professional level on very short cranks, there is weight to this idea, and it is worth a closer look.

everyone else,
The off season is here and those looking for an edge on the competition next year may find it in experimenting with different crank lengths. Or not, but you can't know unless you try it out. Maybe changing crank length from what you usually ride leads to some muscle confusion and you get stronger just from the adaptation alone.

This is simply my experience, take it for what it's worth, and please, share your experience in this matter if you have any. In the space of months, I was able to improve my average speed on familiar roads by 2mph. Even on days when my legs didn't feel good, I out-rode my previous bests with standard crank lengths. And I consistently ride hills much faster after the change to 145mm. I won cx races with no cx experience and no off road training. Again, I can't prove 100% that the shorter cranks made me faster. But this is the biggest gain I've ever seen in my riding ability (as well as comfort on the bike) and I attribute it to the shorter cranks and the necessary position changes.

 

[CoachFergie]

coach,
You are absolutely right. There is no way of saying definitively what caused my improvement. Maybe I unknowingly ate tainted meat. Without a power meter, I can't scientifically prove that I even had any improvement, maybe the wind just blows in my favor now. Realize that the point of this thread is not to provide the ultimate crank length formula that every coach should put their rider on. The point of this thread is to examine the possibility that there are benefits in using crank lengths that are outside the 165-175mm range. Given that an Ironman was won at the professional level on very short cranks, there is weight to this idea, and it is worth a closer look.

Given that the World Time Trial Championships was won on very long cranks I think we should avoid making decisions based on what the celebs do.

This thread is based on a claim that after 600 or so posts has no evidence provided in support.

everyone else,
The off season is here and those looking for an edge on the competition next year may find it in experimenting with different crank lengths. Or not, but you can't know unless you try it out. Maybe changing crank length from what you usually ride leads to some muscle confusion and you get stronger just from the adaptation alone.

As a coach who likes watching his riders perform and win races (another NZ Schools Champion in U14 boys this morning) I like to experiment myself. I took a group of 30 kids down to Invercargill for 2 days of track racing on their indoor track in the middle of winter. The result? We now have an influx of riders wanting to do track, the performance standard has improved, the depth has improved and our regional selectors will have a nightmare picking teams for Nationals.

Based on the success of group sessions on the track I have tried the same approach on the road and again with great success. The biggest investment is time. I can even claim it's a evidence based approach: social facilitation theory improving performance in gross motor performance.

When choosing what of the 10,000 or so variables in cycling where time is an issue to experiment with as a coach I look for areas where there is a proven benefit. Sadly for crank length (and there are just as many people who will claim the benefits of longer cranks) the research so far says there is no significant advantage.

 

[CoachFergie]

Just looking at both Alexander and Wellington from pics at Kona and neither appear to be on short cranks. Alexander is using an SRM as are a lot of riders judging by the pics. Why would they bother carting that extra weight around if not for either pacing their bike section or as part of a long term plan. Quite a few Ossymetric (or similar) chainrings. Some really badly set up riders. Position is really low hanging fruit so perhaps some of these Ironman competitors really should experiment with that first.

 

[Martin318is]

Just looking at both Alexander and Wellington from pics at Kona and neither appear to be on short cranks. Alexander is using an SRM as are a lot of riders judging by the pics. Why would they bother carting that extra weight around if not for either pacing their bike section or as part of a long term plan. Quite a few Ossymetric (or similar) chainrings. Some really badly set up riders. Position is really low hanging fruit so perhaps some of these Ironman competitors really should experiment with that first.

Without looking at the pictures of the bad setups - I'd still just raise this thought: Its a triathlon - position on the bike can pulled away from the ideal for the bike by the other two disciplines. For instance, needing to keep muscles freed up and loose for the run may force some changes - just as back muscle issues coming off the swim may force some other changes.

The positions that Cancellara, Evans, et al use in road time trials are often very uncomfortable for aero reasons but that is all that they have to do that day.

 

[CoachFergie]

Without looking at the pictures of the bad setups - I'd still just raise this thought: Its a triathlon - position on the bike can pulled away from the ideal for the bike by the other two disciplines. For instance, needing to keep muscles freed up and loose for the run may force some changes - just as back muscle issues coming off the swim may force some other changes.

The positions that Cancellara, Evans, et al use in road time trials are often very uncomfortable for aero reasons but that is all that they have to do that day.

Duly noted.

Some of these positions looked really uncomfortable. Comfort isn't even an consideration on the track. For a Worlds or Olympic Medal they can suffer for 10-240 seconds!

I have done several bike set ups for Ironman athletes and comfort is a consideration. That being said I have got some people into some pretty aero positions (looked aero, no hard numbers).

 

[onetrack]

Sadly for crank length the research so far says there is no significant advantage.

30% reduction in drag ala cobb. I find that significant.

glad I don't need to wait around for the scientific community to come to a consensus before my coach will allow me to bolt on a 30$ crankset that may noticeably improve my power output instantly.

 

[CoachFergie]

30% reduction in drag ala cobb. I find that significant.

glad I don't need to wait around for the scientific community to come to a consensus before my coach will allow me to bolt on a 30$ crankset that may noticeably improve my power output instantly.

What John Cobb says in an interview should not be taken as Gospel till one sees the actual numbers to back it up. Quite a few big claims out there about performance improvements that have no evidence to support them.

How would you know your power has improved instantly without a power meter?