climbing, force/power required
reacher
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 ?
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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
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
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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.
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.
they seem very low.
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.
Then he must be turning a higher gear than you?
Not sure I understand what you're getting at there though.
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.
But how many races do you win?
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.
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.
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.
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).
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.
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.
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.
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.
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
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.
Selection 0.2 mi 91 ft 6.0% 52s - 851W - Cadence 88 avg - 80.5kg (rider 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.