Forum home Road cycling forum Training, fitness and health

climbing, force/power required

reacherreacher Posts: 416
Just looking for further information on this as i have seen it on forums quite a lot saying that you only need the strength to raise yourself from an armchair or climb a set of stairs, i understand the principle so i'm not saying its wrong, i just need this information to tailor my training
Going up a climb you can do several things to maintain speed, faster cadence, smaller gears but ultimately theirs a limit to cadence especially for me, basically i run out of puff, so my speed drops or alternatively stay in the same gear but lower cadence try and maintain speed , my question is on this principle of force as i stay in the same gear lower cadence it seems to me that the force goes up proportionate to the incline but i'm able to go faster than faster cadence lower gear ? is this force meant to be constant but only by using smaller gears or increasing strength/power ?
quote
Or you could just do the maths:
e.g. 300 watts on 175mm cranks at 90rpm would require an average effective pedal force from both legs of 182 Newtons, or the equivalent force of 18.6kg with Earth's gravity.

Over a long ride I'm guessing not many people here will be averaging 300W, so let's say 200W (still a pretty darn solid long ride for most) - meaning you need to apply an average effective pedal force of ~ 12.5kg from both legs
«1345678

Posts

  • frisbeefrisbee Posts: 691
    edited November 2016
    Having recently started using a trainer with power, I find that I don't perceive a huge difference between different power levels at normal cadence. The pain sort of sneaks up on you.

    So I think you can actually be putting down a surprising amount of power when you are spinning up a climb.

    10mph up a 10% incline at 90rpm is about 400W in a 39x28.
  • reacherreacher Posts: 416
    So if we half the example then to say 250 watts would that be hard to do, it seems to me that would require a fair bit of power and thats where i'm getting lost on this if it only requires a pedal force of between 12 and 18 kilos
  • imposter2.0imposter2.0 Posts: 11,729
    Power is the rate at which work is done - not the sum of the pedal forces.
  • reacherreacher Posts: 416
    Ok I'm getting it a bit more, so is this correct, anyone can put out the power but not the rate it's done ?
    That's that bit, what i'm not quite getting my head around is, can I potentially put out 250 watts but what i can't do, is do it for very long ?
  • imposter2.0imposter2.0 Posts: 11,729
    reacher wrote:
    Ok I'm getting it a bit more, so is this correct, anyone can put out the power but not the rate it's done ?
    That's that bit, what i'm not quite getting my head around is, can I potentially put out 250 watts but what i can't do, is do it for very long ?

    Well yes, the more fitness you have, the longer you will be able to sustain it. Simplistically.
  • mamba80mamba80 Posts: 5,032
    Where did you get the 12 to 18kg figure from?

    they seem very low.
  • cyclecliniccycleclinic Posts: 6,865
    The force at the pedals can be rurned into a toque. The torque applied over 2 pi radians is the work done per revolution. That can be used to calculate power. Of course force at the pedals varies with position.

    If you cant knock out 250w for long, train.

    Max Power out ploted against 1/ time should be a line straight. That means take you max average power for 5 secs, 10 secs, 20 secs, 30secs 1 min, 2 mins 3 mjns 5 mins, 10, mins 20 mins, 30 mins, 60 mins, 120 mins e.t.c plot agajnst 1/time in sec^ -1 and you will see a straight line.

    I am still not sure what this thread is about.
    http://www.thecycleclinic.co.uk -wheel building and other stuff.
  • reacherreacher Posts: 416
    It's about me trying to understand something I thought I had made that clear in the start, anyway I'm getting their, this last part I don't understand , if I'm doing 85rpm climbing and a pro is doing the same 85rpm and I'm doing 250 watts and he is putting out 450 watts where is that difference coming from if it only requires such a low amount of force because for me to do the same if we both keep the same rpm then I need a much bigger gear and I know that if I shifted into a bigger gear then the problem would be instantly that it would be very hard to turn even a few times
  • Garry HGarry H Posts: 6,639
    reacher wrote:
    It's about me trying to understand something I thought I had made that clear in the start, anyway I'm getting their, this last part I don't understand , if I'm doing 85rpm climbing and a pro is doing the same 85rpm and I'm doing 250 watts and he is putting out 450 watts where is that difference coming from if it only requires such a low amount of force because for me to do the same if we both keep the same rpm then I need a much bigger gear and I know that if I shifted into a bigger gear then the problem would be instantly that it would be very hard to turn even a few times

    Then he must be turning a higher gear than you?

    Not sure I understand what you're getting at there though.
  • cyclecliniccycleclinic Posts: 6,865
    edited November 2016
    Its torque. I do a lot of low cadance hill climbing down to 35 rpm at ftpish so i can produce the torque. A pro pushing out 400w for a half hour climb will no doubt be able to produce more pedal force. That means more torque and more power. They have the fitness to sustain it. Mention strength training on here and folks get there knickers in a twist. It really is pedal force training and is related to fittness but also how many muscle fibres you can co opt into working for you.

    What low cadance hill climbing does stress the muscles to work more muscle fibres and therefore promotes muscle development. You also spinny intervals and in time you find you can turn a higher gear at given cadance i.e more power. You will also be fitter in that your heart and lungs can deliver enough oxygen to your muscles for you to sustain it. What to do is find a hill up to 10% i get into 53/14 and climb seated pushing as hard as i can. It is like doing squats but on a bike. Now watch all the spinners say this is nonsense. I find it particularly useful as i ride a single speed mtb and point it at very steep hills for fun. Gearing on this is 61.5" so perfect for low cadance intervals and spinny intervals. The upshot of this kind of work is i rarely climb out of the saddle and even sprinting is done seated.
    http://www.thecycleclinic.co.uk -wheel building and other stuff.
  • Garry HGarry H Posts: 6,639
    Its torque. I do a lot of low cadance hill climbing down to 35 rpm at ftpish so i can produce the torque. Mention strength training on here and folks get there knickers in a twist. It really is torque training and is related to fittness but also how much pedal force you can generate.

    What low cadance hill climbing does stress the muscles to work more muscle fibres and therefore promotes muscle development. You also spinny intervals and in time you find you can turn a higher gear at higher cadance i.e more power. What to do is find a hill up to 10% i get into 53/14 and climb seated pushing as hard as i can. It is like doing squats but on a bike. Now watch all the spinners say this is nonsense. If it was nonsence then why does it work. I find it particularly useful as i ride a single speed mtb and point it at very steep hills for fun. Gearing on this is 61.5" so perfect for low cadance intervals and spinny intervals. The upshot of this kind of work is i rarely climb out of the saddle and even sprinting is done seated.

    But how many races do you win?
  • if I'm doing 85rpm climbing and a pro is doing the same 85rpm and I'm doing 250 watts and he is putting out 450 watts where is that difference coming from

    Forgive me if I am misreading you but it seems as though you are placing an emphasis on pedal force and suggesting that if the pedal forces at play are low why can't you turn the same gear at the same RPM as a pro, i.e. what other factors are at play? It's far more complex than this, but essentially better fitness and a supremely well developed ability within their muscles to extract oxygen and metabolise energy.

    As others have said, an ability to generate a specific power output over a set period, 250w for a 30 minute climb for example, is not really about force, it's about whether or not you are fit enough in terms of your CV system and your muscular endurance and ability to process energy to sustain the effort.

    Put simply, get fitter and you will climb better, don't waste time trying to work out cadences, gearing etc as your ability to ride to those figures will be determined by your fitness anyway.
  • cyclecliniccycleclinic Posts: 6,865
    edited November 2016
    What winning races got to do with anything. That has more to do with your vo2max. If you can get alot of oxygen into blood and use it then with little training you can produce hideous power. I think chris froomes vo2max 88 mL/(kg.min) mine is 52. People who win races generally have a higher vo2 than i do. If the op is finding it hard to turn a higher gear on a hill then train that to fix that if it bothers him. Otherwise just ride more and do intervals it is the only way to develop power output you can sustain.
    http://www.thecycleclinic.co.uk -wheel building and other stuff.
  • imposter2.0imposter2.0 Posts: 11,729
    Its torque. I do a lot of low cadance hill climbing down to 35 rpm at ftpish so i can produce the torque. A pro pushing out 400w for a half hour climb will no doubt be able to produce more pedal force. That means more torque and more power. They have the fitness to sustain it. Mention strength training on here and folks get there knickers in a twist. It really is pedal force training and is related to fittness but also how many muscle fibres you can co opt into working for you.

    What low cadance hill climbing does stress the muscles to work more muscle fibres and therefore promotes muscle development. You also spinny intervals and in time you find you can turn a higher gear at given cadance i.e more power. You will also be fitter in that your heart and lungs can deliver enough oxygen to your muscles for you to sustain it. What to do is find a hill up to 10% i get into 53/14 and climb seated pushing as hard as i can. It is like doing squats but on a bike. Now watch all the spinners say this is nonsense. I find it particularly useful as i ride a single speed mtb and point it at very steep hills for fun. Gearing on this is 61.5" so perfect for low cadance intervals and spinny intervals. The upshot of this kind of work is i rarely climb out of the saddle and even sprinting is done seated.

    So basically, you are talking about riding up hills a lot, in order to be able to ride up hills better? Whether you know it or not, you are still describing an aerobic exercise. Which is obviously going to improve aerobic fitness.
  • cyclecliniccycleclinic Posts: 6,865
    In part yes but its not just that. Otherwise riders would not do gym work would they. Doing just one kind of hill climbing work, i.e higher cadance is less effective at developing your muscles than climbing at a mix of cadances as it my understanding that muscles fibres are recruited in different ways with low amd high cadance work. Both stress your cv system so both types of climbing get you fitter.
    http://www.thecycleclinic.co.uk -wheel building and other stuff.
  • mamba80 wrote:
    Where did you get the 12 to 18kg figure from?

    they seem very low.

    Power = Avg force (N) x crank length (m) x 2 x PI x cadence (rpm) / 60 (secs/min)

    Simply flip that around to get average effective pedal force.

    Avg force (N) = Power / [crank length (m) x 2 x PI x cadence (rpm) / 60 (secs/min)]

    so 300W / (0.175m x 2 x 3.14 x 90rpm / 60) = 182 N

    Which, when equated to force exerted by a mass due to gravity = 182N / 9.8m/s^2 = 18.6kg


    People vastly overestimate the forces involved in cycling. They really are quite low, which is why it's not a strength sport.

    The limiter in endurance cycling is the ability to aerobically generate and regenerate ATP via aerobic metabolism.

    If you want to climb hills faster, you need to increase your sustainable aerobic power output and/or lose weight.
  • reacherreacher Posts: 416
    Ok thanks that's a lot clearer now, I'm starting to see where I need to train or put my emphasis on training, again thanks guys, it might sound like a stupid question but it's very easy to train in the wrong direction and waste a huge amount of time and effort when your relatively new to cycling
  • reacher wrote:
    Ok I'm getting it a bit more, so is this correct, anyone can put out the power but not the rate it's done ?
    That's that bit, what i'm not quite getting my head around is, can I potentially put out 250 watts but what i can't do, is do it for very long ?
    Power is the rate of doing work, or the rate at which energy is transferred.

    Power doesn't tell you for how long you were sustaining it, only the rate at which work is being done or rate at which energy is being transferred.

    e.g. 1,000J of work can be done by riding at 100W for 10 seconds, or at 1,000W for 1 second.

    Likewise 100W for 1 second means you did 100J of work, while 100W for 10 seconds means you did 1,000J of work.

    Our physiology set limits to the amount of power we can maximally sustain for any given duration. It's a balance between a rate limited but effectively limitless energy supply available via aerobic metabolism, and a very rapidly available but very capacity limited anaerobic energy supply.

    That's simplifying things somewhat as there are multiple metabolic energy pathways that work to supply our energy demand across the spectrum (as well as replenish short term reserves).
  • reacher wrote:
    Ok thanks that's a lot clearer now, I'm starting to see where I need to train or put my emphasis on training, again thanks guys, it might sound like a stupid question but it's very easy to train in the wrong direction and waste a huge amount of time and effort when your relatively new to cycling
    Yes, unless the climb is very short (e.g. much less than about a minute duration), then the speed at which you can climb will be directly proportional to the ratio of power you can aerobically sustain to your weight. Hence the ubiquitous reference to W/kg as a performance measure / indicator.

    IOW to climb faster one needs to work on:
    i. increasing their sustainable aerobic power (both maximal aerobic power / VO2max and their maximal lactate threshold / functional threshold power), and
    ii. lose any excess weight.
  • In part yes but its not just that. Otherwise riders would not do gym work would they. Doing just one kind of hill climbing work, i.e higher cadance is less effective at developing your muscles than climbing at a mix of cadances as it my understanding that muscles fibres are recruited in different ways with low amd high cadance work. Both stress your cv system so both types of climbing get you fitter.
    The differences would be pretty minor ones. What matters is doing the work, i.e. climbing hills and other training to improve metabolic fitness. That's orders of magnitude more important than mucking about with different gears on climbs.
  • mamba80mamba80 Posts: 5,032
    mamba80 wrote:
    Where did you get the 12 to 18kg figure from?

    they seem very low.

    Power = Avg force (N) x crank length (m) x 2 x PI x cadence (rpm) / 60 (secs/min)

    Simply flip that around to get average effective pedal force.

    Avg force (N) = Power / [crank length (m) x 2 x PI x cadence (rpm) / 60 (secs/min)]

    so 300W / (0.175m x 2 x 3.14 x 90rpm / 60) = 182 N

    Which, when equated to force exerted by a mass due to gravity = 182N / 9.8m/s^2 = 18.6kg


    People vastly overestimate the forces involved in cycling. They really are quite low, which is why it's not a strength sport.

    The limiter in endurance cycling is the ability to aerobically generate and regenerate ATP via aerobic metabolism.

    If you want to climb hills faster, you need to increase your sustainable aerobic power output and/or lose weight.

    Yes all fine for a flat, long tempo ride.....

    But if you want to get up a typical short 8 to 12% UK climb and stay in the club ride group, you ll have to generate more than 18kg with each pedal stroke, if i were to stand, hold the bars lightly and do very little else, thats (for me) 38kg, pull up on the bars and drive down through the leg and what is the force then?
    If you want to stay with the lead group, over the top of a short climb, in a RR as the pace goes up, the forces will be even higher.
  • reacherreacher Posts: 416
    In regards to training if it was the aim to do something a year or 15 months away would doing interval training on a turbo through this winter have a short term benifet or would that work translate to improved performance overall, in other words is it better to do it closer to the time or do some this winter or continue to work on the other points mentioned or do both
  • in other words is it better to do it closer to the time or do some this winter or continue to work on the other points mentioned or do both

    Do both would be my view, it will give you the short term gains but will feed into your overall fitness as you suggest. A lot of people focus on the weeks/months before an event to build which is fine but there is nothing wrong to taking an approach where you are focused on your aerobic fitness in general and add in specific blocks of interval training all year round. Long term i.e. over a number of years this is going to make you a fitter rider.
  • imposter2.0imposter2.0 Posts: 11,729
    mamba80 wrote:
    Yes all fine for a flat, long tempo ride.....

    But if you want to get up a typical short 8 to 12% UK climb and stay in the club ride group, you ll have to generate more than 18kg with each pedal stroke, if i were to stand, hold the bars lightly and do very little else, thats (for me) 38kg, pull up on the bars and drive down through the leg and what is the force then?
    If you want to stay with the lead group, over the top of a short climb, in a RR as the pace goes up, the forces will be even higher.

    Even if the forces are double (no idea whether they are or not), generating that much force with the legs is still well within the force generation capability of almost anyone, regardless if they are a cyclist or not.
  • reacherreacher Posts: 416
    It's about me trying to understand something I thought I had made that clear in the start, anyway I'm getting their, this last part I don't understand , if I'm doing 85rpm climbing and a pro is doing the same 85rpm and I'm doing 250 watts and he is putting out 450 watts where is that difference coming from if it only requires such a low amount of force because for me to do the same if we both keep the same rpm then I need a much bigger gear and I know that if I shifted into a bigger gear then the problem would be instantly that it would be very hard to turn even a few times

    Then he must be turning a higher gear than you?

    Not sure I understand what you're getting at there though.[/quote]

    I'm not realy getting at anything I'm trying to understand the best way to train and ride i know theirs lots of information out their on how to train what I wanted was the reasons why certain things happen is all, once I understand that I'm hopeing to find it easier to direct my effort, plus seems to me that theirs quite a wealth of knowledge on here, nothing worse than bustin a gut for 12 months only to find your doing half of it wrong
  • mamba80 wrote:
    mamba80 wrote:
    Where did you get the 12 to 18kg figure from?

    they seem very low.

    Power = Avg force (N) x crank length (m) x 2 x PI x cadence (rpm) / 60 (secs/min)

    Simply flip that around to get average effective pedal force.

    Avg force (N) = Power / [crank length (m) x 2 x PI x cadence (rpm) / 60 (secs/min)]

    so 300W / (0.175m x 2 x 3.14 x 90rpm / 60) = 182 N

    Which, when equated to force exerted by a mass due to gravity = 182N / 9.8m/s^2 = 18.6kg


    People vastly overestimate the forces involved in cycling. They really are quite low, which is why it's not a strength sport.

    The limiter in endurance cycling is the ability to aerobically generate and regenerate ATP via aerobic metabolism.

    If you want to climb hills faster, you need to increase your sustainable aerobic power output and/or lose weight.

    Yes all fine for a flat, long tempo ride.....

    But if you want to get up a typical short 8 to 12% UK climb and stay in the club ride group, you ll have to generate more than 18kg with each pedal stroke, if i were to stand, hold the bars lightly and do very little else, thats (for me) 38kg, pull up on the bars and drive down through the leg and what is the force then?
    If you want to stay with the lead group, over the top of a short climb, in a RR as the pace goes up, the forces will be even higher.
    Precisely what the power output and pedal velocity say it will be. It's just simple physics, which doesn't change just because you are going up a hill.

    If you have the correct gearing so that cadence is not silly low and are sustaining same power output, then the forces are still not particularly high. The limiter is still your aerobic metabolic capacity.

    The forces are only going to go up a lot if you choose to push very hard (i.e. lift your power output a lot) for a few seconds, but of course that's not sustainable and hence the forces will revert back to regular levels as you settle in to a power level that you can sustain.

    Keep in mind that our peak force generation capacity is about an order of magnitude higher than the forces involved in such sustained efforts. We are not force limited but we are metabolically limited.
  • mamba80mamba80 Posts: 5,032
    mamba80 wrote:
    mamba80 wrote:
    Where did you get the 12 to 18kg figure from?

    they seem very low.

    Power = Avg force (N) x crank length (m) x 2 x PI x cadence (rpm) / 60 (secs/min)

    Simply flip that around to get average effective pedal force.

    Avg force (N) = Power / [crank length (m) x 2 x PI x cadence (rpm) / 60 (secs/min)]

    so 300W / (0.175m x 2 x 3.14 x 90rpm / 60) = 182 N

    Which, when equated to force exerted by a mass due to gravity = 182N / 9.8m/s^2 = 18.6kg


    People vastly overestimate the forces involved in cycling. They really are quite low, which is why it's not a strength sport.

    The limiter in endurance cycling is the ability to aerobically generate and regenerate ATP via aerobic metabolism.

    If you want to climb hills faster, you need to increase your sustainable aerobic power output and/or lose weight.

    Yes all fine for a flat, long tempo ride.....

    But if you want to get up a typical short 8 to 12% UK climb and stay in the club ride group, you ll have to generate more than 18kg with each pedal stroke, if i were to stand, hold the bars lightly and do very little else, thats (for me) 38kg, pull up on the bars and drive down through the leg and what is the force then?
    If you want to stay with the lead group, over the top of a short climb, in a RR as the pace goes up, the forces will be even higher.
    Precisely what the power output and pedal velocity say it will be. It's just simple physics, which doesn't change just because you are going up a hill.

    If you have the correct gearing so that cadence is not silly low and are sustaining same power output, then the forces are still not particularly high. The limiter is still your aerobic metabolic capacity.

    The forces are only going to go up a lot if you choose to push very hard (i.e. lift your power output a lot) for a few seconds, but of course that's not sustainable and hence the forces will revert back to regular levels as you settle in to a power level that you can sustain.

    Keep in mind that our peak force generation capacity is about an order of magnitude higher than the forces involved in such sustained efforts. We are not force limited but we are metabolically limited.

    yep, i can go with this, though gravity and weight, it seems, plays a big part too, or so my winter kilos tell me!

    i think though, that most RR'ers can sustain fairly high forces for more than a few seconds, but thats a moot point tbh.

    thanks for input.
  • okgookgo Posts: 4,368
    Alex, what would this be in force using your calcs? I think this is likely the sort of effort Mamba might be referring to, and I remember it feeling quite hard at the time (especially at such low cadence), but I reckon its still probably not a lot of KG force...

    Selection 0.2 mi 91 ft 6.0% 52s - 851W - Cadence 88 avg - 80.5kg (rider weight)
    Blog on my first and now second season of proper riding/racing - www.firstseasonracing.com
  • reacherreacher Posts: 416
    I'm starting to see now the difference between strength and power, it's suprisingly easy to get the two mixed up when your inexperienced and also it's relevance to training
  • Alex99Alex99 Posts: 1,407
    reacher wrote:
    Ok thanks that's a lot clearer now, I'm starting to see where I need to train or put my emphasis on training, again thanks guys, it might sound like a stupid question but it's very easy to train in the wrong direction and waste a huge amount of time and effort when your relatively new to cycling
    Yes, unless the climb is very short (e.g. much less than about a minute duration), then the speed at which you can climb will be directly proportional to the ratio of power you can aerobically sustain to your weight. Hence the ubiquitous reference to W/kg as a performance measure / indicator.

    IOW to climb faster one needs to work on:
    i. increasing their sustainable aerobic power (both maximal aerobic power / VO2max and their maximal lactate threshold / functional threshold power), and
    ii. lose any excess weight.

    Clear on that. However, does strength come into part of the strategy to increase i? IOW, does developing strength generally lift the ceiling for increasing sustainable aerobic power?

    In one of the previous threads about using weights, there was a study posted that showed strength training to be effective in endurance sport. Obviously the devil is in the detail... can't recall the cohort and study details. Interested to know your thoughts.
Sign In or Register to comment.