Viewing 33 posts - 1 through 33 (of 33 total)
  • Cadence, power and heart rate
  • theotherjonv
    Full Member

    I’m a geeky scientist, i admit it. And i like numbers and finding stuff out as much as wanting to optimise the output of this knowledge.

    On zwift last night I did a workout (Gorby, for those that know) which is basically a warmup and then 5 repeat intervals of 5 mins at 110% FTP / 5 mins at 60% FTP.

    But in these intervals i messed around a bit with cadence to attain the power output.

    First one was at what felt the right cadence for me, which was ave 85 / HR 90% of max

    2 – C = 97, HR = 93% – but felt much harder, really blowing by the end

    3 – C = 80, HR = 90% – legs starting to burn but not breathing as hard

    4 – C = 88, HR = 93% – hurting now, but may be more related to building fatigue

    5 – C = 85, HR = 94% – but not reliable as I saved the last minute to try to ramp up so that cadence actual went from 80-110, and the HR went from 85% up to 99% – the others were much steadier around the averages.

    I was most interested by the difference between 1-3, with ‘perceived wisdom’ being that spinning faster is better (Lance <cough> but also read Jens book and he targeted / averaged 104rpm for his hour record)

    But for me trying to spin at even 95+, I felt I was working much harder than at say 80-85, even though the HR numbers don’t really show it – seems as if those extra few % put me from under to over my redline.

    Any thoughts?

    I know there will be folk that say don’t obsess, just ride at what suits you and they’re right but as i said I’m a geek and i like the science.

    Is my sweetspot 80-85, and just accept it – it’s not as if it’s ridiculously low after all?

    Or should i deliberately set out to train to spin that bit faster like LA/JV because in time it’ll make me more efficient?

    legend
    Free Member

    You can’t just jump up to a faster cadence as your muscles aren’t used to working like that, got to build up to it.

    FWIW I tend to live at 95-100RPM

    theotherjonv
    Full Member

    but is it worth trying to train up to it?

    rawka
    Free Member

    It’s a can of worms. HR will always go up for higher cadences as you are using your cardiovascular system more over muscle strength. I’ve heard of pros deliberately reducing their cadence in breaks to lower their heart rate.

    Pat Shaw said in an interview with Cycling Maven that you’ll be ok at a lower cadence on the flat you just need the higher cadences for high climbs and big efforts (I’m paraphrasing). Also the infamous GCN video about climbing cadences where they compare 75rpm to ~100rpm (I can’t remember the higher cadence exactly) showed they were quicker at 75rpm.

    I think unless you specifically trained to do 110rpm up climbs then it’s probably not going to be the most efficient for you. Everyone is different.

    thecaptain
    Free Member

    Higher cadence in the case of lance/tour riding and hour records is more to do with maintaining endurance and performance over a sustained period. Short tests in 5 min intervals probably won’t reveal this. Also, you need to practice at it anyway.

    TiRed
    Full Member

    Power is force x crank velocity (cadence). So you can mash a big gear slowly or spin a small gear quickly. How your cardiovascular system responds to mashing vs spinning may vary. I have to spin and find it very easy to do so. I ride fixed wheel a lot and have it tuned to 90-95rpm.

    In general spinning will be less fatiguing. And allows for faster changes in pace when racing.

    Of course cadence is also a function of fatigue. I can start faster but as I go on at ftp efforts, power stay the same but cadence tends to drop. I see this most in a time trial.

    legend
    Free Member

    TiRed, just for clarity, what do you consider spinning to be? One mans spin is another mans seat bouncing!

    Cadeance (and general form on the bike) dropping with fatigue is very true. iirc it’s a bit of a spiral of decline when you’re starting to go, better to try and keep the cadence where you know you work best.

    theotherjonv
    Full Member

    interesting comments, thanks

    I mean, it’s not as if my current sweetspot of around 80-85 is exactly ‘mashing’ as it is – and given a lot of my winter riding is off road ss it’s perhaps understandable that over the years I am more tuned to this area as opposed to 95-100 – I was just slightly surprised that adding 10rpm to this made quite a bit of difference.

    thomthumb
    Free Member

    but is it worth trying to train up to it?

    for mountain biking? probably not.

    fifeandy
    Free Member

    Already covered above, but spinning faster shifts muscular load to cardiovascular load. It keeps the legs fresher for longer so still have the raw strength left to put the power down at the business end of the race/event.

    legend
    Free Member

    I was just slightly surprised that adding 10rpm to this made quite a bit of difference.

    It’s over a 10% increase so not insignificant!

    for mountain biking? probably not.

    Would disagree with that assuming you have gearing to let you climb at a decent cadence (and we all spend a lot of time climbing)

    epicsteve
    Free Member

    I’ve had a power meter since Christmas and have started to develop some ideas about how I generate power best, although I’ve got a fair bit to learn yet. I’m not entirely sure what my FTP although I think it’s round the 250 mark somewhere, maybe a tad higher (my best average power so far was 276W for 30 minutes but I’ve not had a proper go at FTP for an hour). When trying to maintain above FTP efforts I find that much easier if my cadence is in the 90-100 range than if I’m using a lower cadence. On the climbs I find I move into that cadence range naturally however on the flat I tend to default to a lower cadence and have to use my Garmin to remind me to keep my cadence up.

    cynic-al
    Free Member

    but is it worth trying to train up to it?

    Depends – are you racing? might make a tiny difference for a lot of investment in the right circumstances. I guess you’d have to ask a coech to the pro’s.

    Klunk
    Free Member

    I was going to ask a similar question relating to single speeding, when climbing I’m pushing quite hard at a low cadence, legs are really are burning like **** breathing is quite relaxed and measured 😕

    legend
    Free Member

    cynic-al – Member
    Depends – are you racing? might make a tiny difference for a lot of investment in the right circumstances. I guess you’d have to ask a coech to the pro’s.

    Doesn’t really matter about racing, any ride (of significant distance/effort) is going to go better if you are using your energy effectively

    TiRed
    Full Member

    TiRed, just for clarity, what do you consider spinning to be?

    80 is a good target for most cyclists to maintain. For racing, my average over an hour has been up to 105, and is typically 95 on the road. My natural cadence is 90-95. When riding fixed it’s higher and I tend to max out at 140 for any prolonged effort!

    As an aside, I ride single speed off road exclusively – go figure! At least I don’t tend to spin out on the flat stuff and rely on being light and having good CV to climb the steep stuff.

    scaredypants
    Full Member

    Already covered above, but spinning faster shifts muscular load to cardiovascular load. It keeps the legs fresher for longer so still have the raw strength left to put the power down at the business end of the race/event.

    I’ve read this, though haven’t found an explanation that sounds sensible

    I’m accepting it mostly as I’ve got Lance as exemplar – he was much more of a spinner than the competition and on balance I’d suggest that in a “cardio” competition he’d always win as he was at least better organised at the EPO than them

    I think my lega are better than my cv system (I’ve a pretty low haematocrit, for example) so not sure that mega-spinning suits me. I run maybe 85-90 in zwift races

    paton
    Free Member
    scaredypants
    Full Member

    yeh, that’s the sort of thing I’ve seen before paton. No real evidence; it reads as simple opinion

    They could just as easily say that the low cadence rider has a longer recovery section of each rotation and so will recover more fully. Without soem proper evidence it’s no help (to me)

    scaredypants
    Full Member

    I say! – just been googling

    you’re not “Paton DD” by any chance ?

    (Several of the (few) abstracts I’ve just seen suggest that high cadences are inefficient, e.g. this one)

    chilled76
    Free Member

    Really interesting reading around this.

    Have you read Joe Friel’s book on hr training?

    What I can’t get my head around is that if for the same power you are running a higher heart rate at a cadence of about 100 vs 85 then how does this keep the legs fresher? I would have thought a higher hr means more lactate is being built up in the muscles being used?

    fifeandy
    Free Member

    High cadences are indeed inefficient, maybe not common knowledge, but as you point out, its shown in several studies.
    But it’s still worth it for the vast majority, as in most cases it’s best to preserve the muscular strength so max power is available for as long as possible.

    @chilled, lactate buildup isn’t the problem, that will be cleared by a few mins easy spinning. Muscular damage from high torque efforts on the other hand can take days to repair

    garage-dweller
    Full Member

    It’s a bit like the diesel/petrol engine thing.

    Based on my weekly solo spin bike session (not in a class) I can hit a much bigger power number more easily at 60-70 rpm (for a limited period) than I can at 110rpm but my sweet spot for a decent churn endless circles at moderate power is probably 90-95rpm. I don’t find that rhythm? tiring as it tends to be where i have a reserve of strength without whirlygig legs.

    I think I’m more of a diesel.

    TiRed
    Full Member

    https://www.ncbi.nlm.nih.gov/m/pubmed/?term=cycling+cadence+efficiency

    Plenty of academic studies. Little consensus. Although there is evidence that slower cadence can be more efficient. Doesn’t work for me though.

    tinribz
    Free Member

    If higher cadence is cardio then performance will be directly relational to fitness (which will take weeks (6?) to improve) and also related to genetics.

    For the latter reason caparison with world champs may not be wise.

    Back to the original post, as mentioned already the highest sustainable cadence is desirable for preserving glycogen, but you will need to experiment in training at different levels for weeks to determine your peak.

    scaredypants
    Full Member

    Back to the original post, as mentioned already the highest sustainable cadence is desirable for preserving glycogen

    got a link, tinribz?

    also, if true, does the level of muscle glycogen determine max sprint power? The paper I linked up there suggests that spinning reduces aerobic power so (notwithstanding the muddy water mentioned by TiRed) I guess that’s what we need to see – a lab full of cyclists doing a mock race followed by a maximal 10-20 second sprint 😀

    Flaperon
    Full Member

    TrainerRoad workouts seem to spend an awful lot of time on pedal technique for exactly this reason.

    bigrich
    Full Member

    you can tell who trains with power and cadence because they accelerate away from you on the hills.

    dpfr
    Full Member

    you can tell who trains with power and cadence because they accelerate away from you on the hills

    …now applies to me too

    tinribz
    Free Member

    got a link, tinribz?

    Here’s one: High cycling cadence reduces carbohydrate oxidation at given low intensity metabolic rate

    This CHO-saving effect of approximately 12 % disappears at an IntVO2 of approximately 70 %, which is roughly comparable to an IntP of 60 % with corresponding relCHO of 82 and 86 % (equivalent to 46 mg · kg?1 · min?1 vs. 44 mg · kg?1 · min?1 CHO oxidation) at 50 and 100 RPM, respectively, above which relCHO approaches saturation. Many endurance athletes monitor their exercise intensity via blood lactate measurements adjusted to exercise intensity domains expressed as a fraction of the peak oxygen uptake rather than mechanical power [49, 55]. kCHO50 and kCHO100 and also the cadence-effect on kCHO were independent of both Ppeak and V.O2peak suggesting that in top cyclists athletes with an up to 40 % higher V.O2peak than the present subjects combined with up to 30 hours of training per week such a cadence related CHO preserving effect may become a protective factor against glycogen depletion.

    Although not sure I completely understand it all 😕 Seems to indicate only applicable at cruising speed.

    scaredypants
    Full Member

    50 rpm? – 😆

    And total conjecture about depletion over the course of weeks

    If that’s how far they have to push it to show a difference (at low intensity, as you say), they can spin right into the **** sea*

    *you know, I sort of swore to myself that I’d never use that term 🙁

    tinribz
    Free Member

    Those poor misguided pros, they must all have it wrong then 😆

    njee20
    Free Member

    I think the inference is that 50rpm is incredibly slow, so it’s a very exaggerated example.

    “The pros do it” is a terrible defence of anything though.

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