Scientists say high cadence is inefficient

CliveyT
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Re: Scientists say high cadence is inefficient

Postby CliveyT » 15 Feb 2019, 11:26am

I've often wondered about all this. I normally commute on a singlespeed, which is currently approx 70"" gear. It used to be higher but Friday nights into a 40mph fen 'hill' with a heavy load meant my cadence was getting painfully slow, and my knees were getting more than a little upset. I'm also an ex-rugby player, and still have forwards legs, certainly much more Chris Hoy than Chris Froome.
If I compare my speed to some of the other people I regularly see then there are some people who are always faster than me and generally they do have a faster cadance than me. Most other people I'm faster going upslope (we don't have hills, but there are small lumps, railway bridges etc) and into headwinds, mostly because I can maintain my usual cadance ( know it's faster than Mrs T.s but no idea what, never measured it) against increased resistance. Equally with a tailwind a lot of them are faster than me, I simply cannot spin my heavy lumps fast enough to keep up.
Before lowering my gear, I would have kept up with them, was actually even faster going up slopes (but with a bit more O2 debt at the top) but prolonged effort was painful

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531colin
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Re: Scientists say high cadence is inefficient

Postby 531colin » 15 Feb 2019, 5:48pm

Marcus Aurelius wrote:………. and high force high Cadence pedalling forces the muscles to feed mostly from fat, so a rider with a low body fat percentage can’t afford to do high force High cadence pedalling for very long, and that’s why the skinny pros do it the way they do it.

No. The body stores fat as energy source. Even "skinny" people have enough energy stored as fat so that they can survive for days without eating.
The body stores relatively little carbohydrate, as glycogen (a polysaccharide) in muscle and liver.
The article you linked compares 2 different ways of achieving the same power output.....
High cadence/low force
Low cadence/high force.
High force requires the muscles to metabolise carbohydrate. Glycogen stored within the muscle fibre is rapidly used up, and this means more muscle fibres must be recruited to maintain force, glycogen rapidly runs out and the muscle fatigues. More glycogen can be mobilised from the liver, and the liver can synthesise carbohydrate from fatty acids (gluconeogenesis) ....but not quickly enough.
At low force, muscle can metabolise fatty acids, and the supply is virtually limitless, although the ability to mobilise fatty acids benefits from some "training"....for example, exercising before breakfast.
So high cadence is better simply because it allows the rider to develop power without using high muscle force thereby conserving the energy supply.

mnichols
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Re: Scientists say high cadence is inefficient

Postby mnichols » 15 Feb 2019, 6:32pm

531colin wrote:No. The body stores fat as energy source. Even "skinny" people have enough energy stored as fat so that they can survive for days without eating.
The body stores relatively little carbohydrate, as glycogen (a polysaccharide) in muscle and liver.
The article you linked compares 2 different ways of achieving the same power output.....
High cadence/low force
Low cadence/high force.
High force requires the muscles to metabolise carbohydrate. Glycogen stored within the muscle fibre is rapidly used up, and this means more muscle fibres must be recruited to maintain force, glycogen rapidly runs out and the muscle fatigues. More glycogen can be mobilised from the liver, and the liver can synthesise carbohydrate from fatty acids (gluconeogenesis) ....but not quickly enough.
At low force, muscle can metabolise fatty acids, and the supply is virtually limitless, although the ability to mobilise fatty acids benefits from some "training"....for example, exercising before breakfast.
So high cadence is better simply because it allows the rider to develop power without using high muscle force thereby conserving the energy supply.


That describes it as well as I ever seen it described :-)

A very useful summary / reminder

Marcus Aurelius
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Re: Scientists say high cadence is inefficient

Postby Marcus Aurelius » 15 Feb 2019, 7:11pm

531colin wrote:
Marcus Aurelius wrote:………. and high force high Cadence pedalling forces the muscles to feed mostly from fat, so a rider with a low body fat percentage can’t afford to do high force High cadence pedalling for very long, and that’s why the skinny pros do it the way they do it.

No. The body stores fat as energy source. Even "skinny" people have enough energy stored as fat so that they can survive for days without eating.
The body stores relatively little carbohydrate, as glycogen (a polysaccharide) in muscle and liver.
The article you linked compares 2 different ways of achieving the same power output.....
High cadence/low force
Low cadence/high force.
High force requires the muscles to metabolise carbohydrate. Glycogen stored within the muscle fibre is rapidly used up, and this means more muscle fibres must be recruited to maintain force, glycogen rapidly runs out and the muscle fatigues. More glycogen can be mobilised from the liver, and the liver can synthesise carbohydrate from fatty acids (gluconeogenesis) ....but not quickly enough.
At low force, muscle can metabolise fatty acids, and the supply is virtually limitless, although the ability to mobilise fatty acids benefits from some "training"....for example, exercising before breakfast.
So high cadence is better simply because it allows the rider to develop power without using high muscle force thereby conserving the energy supply.


No you’re wrong there.

Read this.

https://www.active.com/cycling/articles ... =pepperjam

It explains the what and why with numbers.

Marcus Aurelius
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Re: Scientists say high cadence is inefficient

Postby Marcus Aurelius » 15 Feb 2019, 7:12pm

mnichols wrote:
531colin wrote:No. The body stores fat as energy source. Even "skinny" people have enough energy stored as fat so that they can survive for days without eating.
The body stores relatively little carbohydrate, as glycogen (a polysaccharide) in muscle and liver.
The article you linked compares 2 different ways of achieving the same power output.....
High cadence/low force
Low cadence/high force.
High force requires the muscles to metabolise carbohydrate. Glycogen stored within the muscle fibre is rapidly used up, and this means more muscle fibres must be recruited to maintain force, glycogen rapidly runs out and the muscle fatigues. More glycogen can be mobilised from the liver, and the liver can synthesise carbohydrate from fatty acids (gluconeogenesis) ....but not quickly enough.
At low force, muscle can metabolise fatty acids, and the supply is virtually limitless, although the ability to mobilise fatty acids benefits from some "training"....for example, exercising before breakfast.
So high cadence is better simply because it allows the rider to develop power without using high muscle force thereby conserving the energy supply.


That describes it as well as I ever seen it described :-)

A very useful summary / reminder


And totally wrong.

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NATURAL ANKLING
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Re: Scientists say high cadence is inefficient

Postby NATURAL ANKLING » 16 Feb 2019, 2:11am

Hi,
This is better :P
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3918546/

"Conclusion

When using our novel prolonged cycling protocol that simulated conditions that occur during competitive cycling (varied intensities and sub-maximal workloads), the selection of a higher freely chosen cadence (100 vs. 80 rpm) resulted in excess energy expenditure (~5-6 % greater) and an attenuation of subsequent maximal performance (i.e., reduced power output). In addition, gross efficiency was lower during both exercise intensities at our higher pedaling frequency. These results suggest that, in competitive cyclists, selection of a high cadence during prolonged, variable, low-moderate submaximal exercise intensities subsequently results in greater energy expenditure and reduced maximal power output when compared to a lower cadence. However, these findings must be viewed cautiously, as testing protocols did not allow conclusions to be drawn regarding effects of our prolonged exercise paradigm on subsequent sprint or time trial performance."


So don't use high cadence on your sunday burnup with the lads :mrgreen:

Edited-
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3907705/

"To conclude, low cadence training (40 rpm at 73–82% of HRmax) twice a week during 12 weeks did not increase aerobic capacity, cycling performance or leg strength in highly trained veteran cyclists. On the other hand, improvement in both aerobic capacity and cycling performance was seen after freely chosen cadence training at moderate intensity, and seems to be preferable compared to low cadence training."
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Tigerbiten
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Re: Scientists say high cadence is inefficient

Postby Tigerbiten » 16 Feb 2019, 6:58am

All but the first paper quoted are about outputting the maximum sustainable power over some time.
That's where a high cadence works best.

But the first paper quoted is about novices and recreational cyclists who sometimes stay in a low gear and spin quickly, even though the overall intensity of their exercise is relatively moderate.
In which case then more power is wasted by moving their legs up and quickly vs changing up a gear and spinning slightly slower.
If you normally spin along at 80-85 rpm at max sustained power output, would you still spin at that speed if you're only ticking along at 50% power or would you spin slower ??
I know I can/will spin along at 80-85 rpm if I'm working hard and aiming of maximum average speed.
But if I'm on tour and not working hard then I'm more likely to spin along at only 65-70 rpm because it takes less energy in the long run.
Then again on tour I'm aiming for the maximum distance for the minimum energy used and not the maximum distance in the minimum time.

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531colin
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Re: Scientists say high cadence is inefficient

Postby 531colin » 16 Feb 2019, 4:39pm

Here's a quote from Marcus' article...…
"....In one case the cyclists pedaled their bikes at 50 revolutions per minute (rpm) while using a high gear. In the second case, the athletes pedaled in a low gear at 100 rpm. The athletes were travelling at identical speeds in the two instances, so their leg muscle contractions were quite forceful at 50 rpm and moderate but more frequent at 100 rpm.
As it turned out, the athletes' oxygen consumption rates were nearly identical in the two cases, and heart and breathing rates, total rate of power production, and blood lactate levels were also similar.
However, athletes broke down the carbohydrate in their muscles at a greater rate when the 50 rpm strategy was used, while the 100 rpm cadence produced a greater reliance on fat.…"

(My colour)

Marcus Aurelius
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Re: Scientists say high cadence is inefficient

Postby Marcus Aurelius » 16 Feb 2019, 4:54pm

531colin wrote:Here's a quote from Marcus' article...…
"....In one case the cyclists pedaled their bikes at 50 revolutions per minute (rpm) while using a high gear. In the second case, the athletes pedaled in a low gear at 100 rpm. The athletes were travelling at identical speeds in the two instances, so their leg muscle contractions were quite forceful at 50 rpm and moderate but more frequent at 100 rpm.
As it turned out, the athletes' oxygen consumption rates were nearly identical in the two cases, and heart and breathing rates, total rate of power production, and blood lactate levels were also similar.
However, athletes broke down the carbohydrate in their muscles at a greater rate when the 50 rpm strategy was used, while the 100 rpm cadence produced a greater reliance on fat.…"

(My colour)


And that totally flies in the face of what people thought previously. There’s a whole section later on that covers a few more ‘paradoxical findings’ and what they’ve worked out as to why it happens. Interestingly the way they’ve found it is what I’ve found experimentally ( by riding ) I’ve used this study’s findings to help me avoid the dreaded ‘bonk’. The proof of the pudding is very much in the eating. I’ve used it to help on hills ( in particular ). I’ve found that grinding to start, until the carbs are gone, then switching to spin, then refilling the carbs at the top, is far preferable. This has proved the findings nicely ( for me anyway ) obviously YMMV.

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Re: Scientists say high cadence is inefficient

Postby Marcus Aurelius » 16 Feb 2019, 5:01pm

Tigerbiten wrote:All but the first paper quoted are about outputting the maximum sustainable power over some time.
That's where a high cadence works best.

But the first paper quoted is about novices and recreational cyclists who sometimes stay in a low gear and spin quickly, even though the overall intensity of their exercise is relatively moderate.
In which case then more power is wasted by moving their legs up and quickly vs changing up a gear and spinning slightly slower.
If you normally spin along at 80-85 rpm at max sustained power output, would you still spin at that speed if you're only ticking along at 50% power or would you spin slower ??
I know I can/will spin along at 80-85 rpm if I'm working hard and aiming of maximum average speed.
But if I'm on tour and not working hard then I'm more likely to spin along at only 65-70 rpm because it takes less energy in the long run.
Then again on tour I'm aiming for the maximum distance for the minimum energy used and not the maximum distance in the minimum time.



And that’s the crux of it. Low Power High cadence riding is indeed inefficient, it’s not until your making ‘sufficient’ power at that Cadence when the efficiency of the metabolic mechanisms outweigh the mechanical inefficiency of the ‘leg wanging’ Involved in low power spinning.

mnichols
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Re: Scientists say high cadence is inefficient

Postby mnichols » 16 Feb 2019, 5:44pm

I think what also needs to be considered is the rate at which you can absorb carbs versus the rate at which you burn calories

Pushing high power (anaerobic) burns carbs/glycogen at a rate faster than I can absorb them at that's not sustainable on long days - unless I stop for food and let my body catch up

I think it's estimated that people can absorb around 1 gram of carbs for every kilo of body weight, so for me that's 80 grams of carbs, which is 320 calories per hour. So If I burning carbs faster than that by pushing high power, say 500 per hour then I'm going into deficit. In this situation the body will start to consume muscle in preference to fat.

However, if I'm spinning then I'm burning fat, which is almost inexhaustible, especially in my case. If I do occasionally do need to push harder for some reason beyond my fat burning zone, then I can cover that lesser expenditure with carbs within my absorption rate

Last year I did a 9 day, 110 mile per day LEJOG. Unfortunately I had a bad crab sandwich on day 1 which meant I was unable to keep any food down for the whole trip. It was like I had a pipe connected between my mouth and bum. I actually had to eat my food sat on the toilet. I was able to complete the ride by spinning, staying in my fat burning zone and drinking electrolytes. I lost a load of weight, but managed to complete the trip.

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foxyrider
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Re: Scientists say high cadence is inefficient

Postby foxyrider » 16 Feb 2019, 6:50pm

This is all very well but what happened to just riding?
Convention? what's that then?
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mnichols
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Re: Scientists say high cadence is inefficient

Postby mnichols » 17 Feb 2019, 7:42am

foxyrider wrote:This is all very well but what happened to just riding?


Nothing. There is nothing wrong with just riding. It's what I do most of the time

But there is also nothing wrong with understanding how your body works. Sometimes it's useful to know what's happening if you want or need to go a little further. For example if a planned coffee stop is closed, and the next one is a few hours away and you're out of food, as has happened to me a few times when touring

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foxyrider
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Re: Scientists say high cadence is inefficient

Postby foxyrider » 17 Feb 2019, 9:13am

mnichols wrote:
foxyrider wrote:This is all very well but what happened to just riding?


Nothing. There is nothing wrong with just riding. It's what I do most of the time

But there is also nothing wrong with understanding how your body works. Sometimes it's useful to know what's happening if you want or need to go a little further. For example if a planned coffee stop is closed, and the next one is a few hours away and you're out of food, as has happened to me a few times when touring


Few hours away! Where are you riding? Surely you carry emergency supplies and these days almost every petrol station / supermarket sells coffee.

It's one thing to understand your body, another entirely to be paranoid about it. I like looking at my ride stats after the ride, they don't dictate what I do during the ride.

As Mssr. Merckx says, Just Ride
Convention? what's that then?
Airnimal Chameleon touring, Orbit Pro hack, Orbit Photon audax, Focus Mares AX tour, Peugeot Carbon sportive, Owen Blower vintage race - all running Tulio's finest!

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Re: Scientists say high cadence is inefficient

Postby ChrisButch » 17 Feb 2019, 12:12pm

mattsccm wrote:I believe that the article says that inexperienced/less fit cyclists are wrong to twiddle excessively. Froome etc are different.
I know we are all different but I have always maintained that spinning a very low gear fast is daft. My legs are at their best a a slower cadence.

Yes, you can frequently see this in those who set off on the flat twiddling furiously from a standing start even when stopping briefly at traffic lights etc, then move up through the gears. Presumably this is people starting to ride as adults and thinking you use the gears on the bike in the same way as you would when driving. The palpable waste of effort always make me wince.