Cadence, Train to Stregth or Weakness

Discussion in 'Power Training' started by Subliminal-SS, May 18, 2014.

  1. Subliminal-SS

    Subliminal-SS New Member

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    Hi Guys and Gals,
    Simple enough topic really.

    If your a fast Cadence rider say 110rpm on climbs.

    When doing things like 1/5/20min intervals would you train at 70-80-90-100-110? to best try to improve power at x duration?

    When I go "climbing" and the climb is not to steep for my meager power I find it most comfortable at 110rpm. Should I seek out these efforts or try with a lower cadence for better improvements in power output.


    Also is there are point where you think climbing at x cadence is pointless and you are giving the lungs a harder workout than actually pushing the legs. <-I realise there is so much wrong with this sentence but I hope you will know what I'm referring to. Or it could just be a placebo. What I'm attempting to ask is if I start to struggle as I do sometimes at the end of an effort is cranking it up to 120rpm negating from the effort as it seems easier, is it cheating, i.e. if I was weight lifting (god forbid) id imagine just smashing out the last few reps as quick as possible is a pointless exercise and is negating from the overall effect of the repetitions. In this case each pedal revolution?
     
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  2. danfoz

    danfoz Well-Known Member

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    For me, as the power requirement goes up, so does the cadence. My sprint will have the highest cadence: ~125-135, VO2 work at 90+ (but usually 95-105), followed by SST work at ~ 85-95. When I do low intensity work L1/L2 or JRA, I'm all over the map, sometimes even slogging up hills in the big ring at 75rpm.

    It's a balance between muscular endurance and aerobic efficiency, and a personal thing. Pro's who have excelled in their respective disciplines have varied from high to low and for someone to say there is an optimal cadence is just as wrong as to say cadence doesn't matter imo. Unfortunately when making comparisons to prove a point there will be the inevitable recruitement of a rider on one end of the extreme or the other who doesn't truly represent any significant population sample but themselves.

    I do believe it is easier to adapt to changes in pace more efficiently at a higher cadence though. For instance in the closing 1k it would make more sense to be spinning at 95+rpm than slogging at 80rpm.

    The climbing example you mentioned brings to mind something the old coaches used to say about "staying on top of the gear". If you are wondering if you should decrease your climbing cadence, take a look at Chris Froome. Can you imagine someone telling him he's spinning up the climb to fast? If it gets you to the top quicker do it. If there is a way to use your bodies natural abilities to cheat your way to the top, definitely do it!

    As for the weight lifting, while smashing those last few reps up might do a disservice to a bodybuilder looking to create mass, that is exactly what a power lifter would be doing (increasing the velocity of the rep) to develop power. And power, not muscle mass, is a cyclists friend ;)
     
  3. AyeYo

    AyeYo Member

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    I'm very interested in this answer too. Power in this case is a function of torque x RPM. So obviously the more RPM you can spin, the more power you get... IF the torque doesn't drop off. In an automotive application, you reach an RPM point at which the engine's torque output starts falling and it eventually starts falling so fast that the addtional RPM is insufficient to offset the torque loss and net power beings to decline. I wonder if this is true of the human body. I can't see legs being able to sustain the same force output at all possible spin speeds... or maybe they can. I'd be very intersested in seeing a power meter based dyno chart for someone on a bike. Someone could do a 0-35mph pull in a single gear for the power graph and use math to calculate the torque graph.
     
  4. Subliminal-SS

    Subliminal-SS New Member

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    I think you make some very valid points across the spectrum here however for the best part I would also tend to agree that asking Froome to Stroke like Tony Martin is only going to cause power drops for said rider, however in reference to training to optimize the time in the efforts I think its important to not approach it with if it gets you there do it.

    Personally It may be splitting hairs but when its training for me all about how I get to the top of the hill, end of the week, finish the block, complete the season. etc etc.

    I don't know how cadence trains different systems, I'm going to look into this but as you say in the final note about power building where velocity is important it begs the question that the different systems being trained are going to also be limiters if there is insufficient training of one source of power

    Interesting idea however from what I'm reading I'm struggling to see exactly what a test like this would provide. Are you anticipating a measurement of someones optimum cadence?

    I don't know much of anything about dynotesting so I guess I'm not really qualified to make any contribution. However I have an ergometer and a power meter so if you want testing...
     
  5. danfoz

    danfoz Well-Known Member

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    You bring up an important point about different systems. I did a formal 10-12 hour/week plan this winter and Hunter Allen recommended tempo intensity workouts with portions at a lower rpm (70-85rpm one or two gears higher than what we would normally run) to help train muscular endurance. At the end of the day an increase in cadence alone wont turn us into champions (even Cat 4 or 5 champions), we actually need to be able to apply some force to the pedals.
     
  6. Subliminal-SS

    Subliminal-SS New Member

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    Lol Same plan, or at least same workouts in my Hunter Allen Plan. (V02Max)

    I like those days to be honest it really does feel like I can hold the big ring on my bike more as a first resort than last which is what it was over winter.

    I know the air is getting thinner but its helping I think. Trouble is I've noticed my average cadence for all my rides is 95+ id like to register some good 75-80rpm rides. Truth be told bopping along everywhere at ~100rpm makes my Ar*e hurt and id like to be a little more sophisticated on the bike [​IMG]


    To the topic though:

    Another thing I'm wandering though is if you are genetically pre-determined to have slow or fast twitch muscle fibers it makes me also wander if you train to a weakness as they say, you may also just not be recruiting enough fibres of your primary body composition.

    What Strikes me is hypothetically speaking you may
    A) Be improving my ability to apply force to the pedal in a more complete stroke therefore bringing my weaker "Strength" aspect in line with what I feel is strong.

    B) Doing my entire pedal stroke injustice(and training efficiency) by training a system that I am not naturally going to be able to be the strongest at. i.e. Doing Squats to get a Stronger Back. If this makes any sense. I'm not a lifter but its the best analogy I could think of.
     
  7. Alex Simmons

    Alex Simmons Member

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    Focus on power and choose an appropriate gear. The rest is noise.
     
  8. Alex Simmons

    Alex Simmons Member

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    It's a pretty simple plot if you have a power meter with reliable cadence data and sufficient temporal resolution (e.g. an SRM). Look up Quadrant Analysis.

    The nature of the plot however will vary depending on whether you are talking about a maximal sprint like effort (e.g. a track standing start) or not, and how long you make the plot for.

    When riding maximally, as in a track standing start, the relationship between average effective pedal force (i.e. average torque per crank revolution) and tangential pedal velocity (i.e. cadence) is an inverse linear one. But only for about 5-6 seconds. After that neuromuscular fatigue sets in and the relationship is no longer linear.

    But in context of riding road normally and hill climbs, that's not a relevant relationship. It's more complex and multifactoral.

    IOW, focus on power and choose an appropriate gear.
     
  9. AyeYo

    AyeYo Member

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    Just like with a car, you come out with a graph of power over speed (which could then be converted back to crank RPM). If there's a point at which power starts to drop off, you can use the graph to determine at what cadence you should be shifting.
     
  10. AyeYo

    AyeYo Member

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    So if they're inverse and linear, then power output is flat over the RPM range for a maximum effort?

    I think I'm going to throw my bike on the power trainer tonight, start in like 50x15 (or whatever gear to too high for an explosive start) and spin the gear out to at least 120rpm (or as fast a cadance as I can do) at maximum effort. I just want to see what the power curve looks like. Then I'll pick a few points to calculate a rough torque curve too. I'm just intersted to see what this looks like. I feel like power IS going to fall off at a certain RPM, because I feel like it does when sprinting on the road. Even though I can spin 120rpm+ smoothly on the road, I feel like my acceleration starts dropping at 105-110rpm. Once I shift and drop back into the high 90's, the acceleration is noticably faster again.
     
  11. RChung

    RChung New Member

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    No. Torque and rotational speed are inversely linear, and power is the product of those two inversely linear things. The product of two things which are inversely linear isn't constant.

    Lots of people have done this. I encourage you to try it too, so you can see why it doesn't tell you what you're looking for.
     
  12. AyeYo

    AyeYo Member

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    Yea that was my mistake, it wouldn't be contast. It'd be a curve just like I was speculating. I was bored enough at work to throw this together with some arbitrary torque numbers for example's sake. Now, I find it hard to believe that everyone's pedal force vs. cadence is exactly an inverse linear relationship or that the cross in the relationship happens at the same point for anyone, and also I'm sure the torque variation is far less. However, the point still stands that everyone would seem to have an ideal range in which their cadence and pedal force yields the best power - and that range should be measurable with a power meter. Perhaps training to a higher cadence doesn't make sense if you don't have the pedal force at that speed to back it up or maybe there's no point doing it because you have very muscular legs that are better at pushing hard on the pedals slowly - or vice versa.

    X-axis is RPM, Y-axis is power.

    [​IMG]
     
  13. RChung

    RChung New Member

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    Alex said "when riding maximally, as in track standing starts." Here's a plot which shows average pedal force and pedal speed. The yellow dots are track standing starts, the green dots are seated 10x10 sec accelerations.

    http://www.aboc.com.au/site_images/site-image-repository/fig2se.jpg/image
     
  14. AyeYo

    AyeYo Member

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    That's an interesting chart, but it doesn't really tell what we need to know - what's the resulting power curve look like?
     
  15. RChung

    RChung New Member

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    The x-axis is pedal speed. The y-axis is pedal force. Their product is power, so multiply them. [Edit:] Though if you think about it for a moment, you shouldn't need to.

    As for your hypothesis about "optimal cadence" and when riders shift gears, that's been examined, too.
     
  16. AyeYo

    AyeYo Member

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    Google search just answered my own question.

    http://users.frii.com/katana/biketext.html
     
  17. Alex Simmons

    Alex Simmons Member

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    Since power is the multiple of the two factors that are inverse linearly related (up to the point of fatigue), then power v cadence will be an "upside down" parabola. Again, this is for maximal efforts, and this relationship only lasts for a handful of seconds, after which fatigue kicks in.
     
  18. Alex Simmons

    Alex Simmons Member

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    Keep in mind that to do this properly, you'll need sufficient inertial load which is not always available on many trainers, and a power meter that can reliably measure such short range high power efforts (e.g. you couldn't for instance use a Powertap or a Stages for this sort of analysis), and do so with a reasonably high recording rate. 1 second recording (e.g. from ANT+ head units) is barely fast enough. 2Hz or higher recording rate is better.

    Also, only the initial ~ 5-6 seconds of data is valid, hence if you have not attained your peak cadence by then, then the relationship no longer holds, and of course your power will fall away, because you will naturally fatigue as the immediate PCr stores are exhausted rapidly. You may need to look at starting out at a higher pedal rate first.

    Most people generate peak power at ~ 120-130rpm. But you have to hit that cadence before fatiguing in order to see it.
     
  19. Alex Simmons

    Alex Simmons Member

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    This relationship BTW was reported in this study over 30 years ago:

    Power output and fatigue of human muscle in maximal cycling exercise

    Andy Coggan also did a nice discussion of it on his blog in a series of items about muscle fibre type and force-velocity testing:
    http://www.trainingandracingwithapowermeter.com/2010/12/prediction-of-muscle-fiber-type-from_07.html
     
  20. RChung

    RChung New Member

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    Hmmm. That was written in 1999? I'm not sure how many many power meter data files the author had examined before writing that but I'm guessing it wasn't a lot.
     
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