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Optimum Cadence

derekwattsderekwatts Posts: 107
I'm sure this must have been asked a thousand times, but I am slightly confused by some of the advice that comes out in the magazines regarding the most efficient cadence.

I had previously understood that whilst high cadence / low gear and low cadence / high gear result in the same power output for the same road speed (ignoring things like frictional losses), that high cadences are more efficient for burning fat and reducing lactic acid build up. So I had been trying to always ride at 85-95 rpm on 2-3 hour training rides. However the foul weather kept me indoors on my resistance rollers today, and replicating a 2 hour ride without things like hills and traffic to interrupt, I experimented with different cadences:-

For a road speed of 16mph (not really relevant - the resistance on the rollers is higher than the equivelant on a road) for a cadence of 88rpm, my HR is around 159-160. Changing to the big ring and grinding away at a diesel like 65 rpm, my HR drops by up to 5% for the same road speed...

So what (if anything) can I deduce from this? I have been riding 'hard' for just over a year, seen huge improvements in my fitness, recovery, resting HR, lost 20lbs and have completed a century, so whilst I am by no means an athlete, it's not as if my body just isn't used to high cadences yet... It seems I am wasting a huge amount of energy spinning low gears for no reason. Is this normal? Do some individuals just have a naturally lower (or higher) cadence than others, set in the genetic muscle make up?

Thanks

Derek

Posts

  • cj504cj504 Posts: 110
    Very interesting, though sadly I don't have a clue :lol:

    I'm just about to go out into the garage for an hours turbo. I might have a play around and see if I get this happening...will try and remember to report back!
    Thresholds, 60-80%, HRM's...I'll just go for a ride
  • hazychrishazychris Posts: 202
    In ""High Performance Cycling" edited by Dr Asker Jeukendrup, a peer-reviewed and published research paper found:

    "From experimental studies, it is well known that sustainable power output is maximal for cadences in the order of 90 to 100 revolutions per minute. Surprisingly, it has been consistently found that efficiency is not optimal at his rate; at a fixed external power output, oxygen uptake has been reported to be minimal at a pedalling rate as low as 50 to 60 revolutions per minute."

    So there you go - you must be normal after all! :lol:
  • My tests have given the same result.

    However, all the 1 hour records have been set at a cadence of 100rpm.

    I think a cadence of 100 on the flat is an ideal, but you need to adjust your body to it some how. I've tried the turbo, but as soon as I'm on the road, some one will mention that I use a low cadence.

    Given up trying to change for the time being, but I'm going to try track racing next year that may make a difference.
  • MettanMettan Posts: 2,103
    I should say, I've misjudged my own (and others) cadence over the last year - thought I was typically at 70-75 approx - I'm actually at 80-95 typically - recently bought a watch and found that the "second" is actually alot longer than I thought it was....... - sounds ridiculous....... and it is - my bad :oops:
  • Hmm thanks all very interesting. The only thing I can deduce then maybe is that cos it was starting to push over my threshold it wasn't sustainable at 90 ish rpm, even though as you say, power output is 'maximal' at these higher rpm's. So maybe gaining back a bit of efficiency by using a lower cadence put me back below my threshold and then it became sustainable... :roll: Maybe I should try it again but at a lower power output well away from my threshold, and then see what happens. I am 38 but my max HR is around 190, so my threshold is around 160 bpm...
  • stevewjstevewj Posts: 235
    how did you measure your threshold - my max is 180 but threshold as found by average HR over a ten mile time trial is 166. Yours at 160 cf 190 max seems low.
  • pbt150pbt150 Posts: 338
    Whilst cadence and heart rate are linked, it has a lot more to do with muscle physiology than your heart rate. Muscle consists of 2 types - fast and slow twitch. Fast twitch is used for sprinting and tires quickly because it's not well supplied with blood and has limited ability to generate energy long-term, slow twitch works at lower intensity but is well oxygenated and can release lots of energy from stores easily so can work hard for longer.

    A high cadence helps you use your slow twitch muscle more, so pedalling at a high cadence means your working muscles can work longer without tiring. Your heart rate is more dependent on your power output than your cadence, so moving to a harder gear and a lower cadence will make your overall output more efficient for a given speed (HR drops a bit), but your legs will start to hurt sooner than if you spin the pedals quickly.
  • pbt150 wrote:
    Whilst cadence and heart rate are linked, it has a lot more to do with muscle physiology than your heart rate. Muscle consists of 2 types - fast and slow twitch. Fast twitch is used for sprinting and tires quickly because it's not well supplied with blood and has limited ability to generate energy long-term, slow twitch works at lower intensity but is well oxygenated and can release lots of energy from stores easily so can work hard for longer.

    A high cadence helps you use your slow twitch muscle more, so pedalling at a high cadence means your working muscles can work longer without tiring. Your heart rate is more dependent on your power output than your cadence, so moving to a harder gear and a lower cadence will make your overall output more efficient for a given speed (HR drops a bit), but your legs will start to hurt sooner than if you spin the pedals quickly.
    While that sounds good in theory, it's not borne out by the evidence, i.e. that riders have been shown to be able to sustain long efforts (at same % of VO2 Max/power) at low (50rpm) and higher (100 rpm) cadences. IOW:

    i - fast twitch fibres aren't being recruited at any significant level at lower cadences ridden sub-maximally since if they were, then they would not be able to sustain the effort for long

    ii. fibre type recruitment at these sub-maximal / aerobic power levels is not significantly altered by cadence.

    Higher cadences are simply less efficient than lower ones (in general). But as was quoted from the Jeukendrup book previously, that doesn't mean we are more effective at lower cadences.

    Focussing on cadence is a folly as cadence is simply an outcome of the power we are producing, the resistance forces acting against us and the gear we happen to be in.

    Focus on the power you can produce and pick a gear that feels good for you. Cadence then just comes along for the ride.
  • cadence is a funny topic.
    Most pros ride at high cadence 85-100rpm but we use less oxygen at low cadences.
    Neurological fatigue is less at cadences around 80ish
    Novice cyclists pedal at around 60 rpm
    What someone needs to do is a training study with novice cyclists who pedal at 60 rpm and then train them to pedal faster and measure neuro fatigue and efficiency.

    Why do pros al pedal within such a small range? Is it because it's easier or is it because that's what they've been coached to do?
    Bear in mind your cadence will change depending on workload. it seems to get higher and higher up until a point just before failure where it slows down and you start pulling up on the pedals.
    I don't have the answers just more quetions.
  • eheh Posts: 4,854
    I suspect Pros pedal at a high cadence not for efficiency reasons but to enable fast accelerations where needed. NB: you don't win races by being most efficient but by being first across the line.

    Also as far as I'm concered while their maybe some 'optimum' cadence for every condition, you should ensure you are comfortable pedalling over a wide range of rpm.
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