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Hi,

I was just wondering, how this is measured.

Is this the power @ lactic threshold or is it some other measure like MP8 or MP30?


psi_co
 

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Usually, when the watts/kg discussion comes up, it's in the context of long climbs. That's the primary circumstance under which this is a key measure. In that situation, it's the power you can deliver at your maximum sustainable speed - typically the last 20 minutes of a 30 minute time trial.
 

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Yes

It can be given at any level you want but generally it is power in watts at LT per kg. The other typical measure is max power per kg.

I'm sure somebody has the link for the average ratios for the different Categories. Tour de France climbers are at least 7:1 power to weight.
 

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Kerry Irons said:
Usually, when the watts/kg discussion comes up, it's in the context of long climbs. That's the primary circumstance under which this is a key measure. In that situation, it's the power you can deliver at your maximum sustainable speed - typically the last 20 minutes of a 30 minute time trial.
Kerry hits the nail on the head.

But you could always look at power weight in different time periods. It depends on the outcome you are trying to predict. If you want to predict tour de france winners, it will be over this longer time period. If you are trying to predict the winner of Fleche Wallone, a race which ends on a very steep but short hill, it may be more relevant to see who has the highest power to weight over a minute.

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SilasCL said:
If you are trying to predict the winner of Fleche Wallone, a race which ends on a very steep but short hill, it may be more relevant to see who has the highest power to weight over a minute.

Silas
More like the highest w/kg at that fatigue level of the riders left. Functional threshold/longer duration power will get you to the end with less fatigue. Which is why it is the "primary determinant of endurance cycling performance" to quote Andy Coggan.
 

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whoawhoa said:
More like the highest w/kg at that fatigue level of the riders left. Functional threshold/longer duration power will get you to the end with less fatigue. Which is why it is the "primary determinant of endurance cycling performance" to quote Andy Coggan.
Correct. I always have some disagreement though, as your functional threshold is what keeps you in the race the longest, but your short duration power is what then wins you that race. I don't quite know how one can be more primary than the other. But I understand what you're getting at.

Silas
 

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SilasCL said:
Correct. I always have some disagreement though, as your functional threshold is what keeps you in the race the longest, but your short duration power is what then wins you that race. I don't quite know how one can be more primary than the other. But I understand what you're getting at.

Silas
Well, if you are strong enough aerobically you can get away and never even have to spint for the finish. Unfortunately, my pattern is to get away, get reeled in, then lose the sprint because i am exhausted from attacking all day, but sometimes it works.
 

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SilasCL said:
Correct. I always have some disagreement though, as your functional threshold is what keeps you in the race the longest, but your short duration power is what then wins you that race. I don't quite know how one can be more primary than the other. But I understand what you're getting at.

Silas
The other thing to remember is that in flatter races (i.e. the spring classics) without really long climbs, that power to weight needs to be balanced against power to drag. Big dudes like Maggy don't win Paris-Roubaix because of their high W/k.
 

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shawndoggy said:
The other thing to remember is that in flatter races (i.e. the spring classics) without really long climbs, that power to weight needs to be balanced against power to drag. Big dudes like Maggy don't win Paris-Roubaix because of their high W/k.

Heavier people, in general tend to have higher power to drag ratio,s as someone who is twice as heavy is no-where near twice as hard to push through the air, as even small people have to push a bike through the air and the frontal area of a 50kg climber is only slightly smaller than a 80 kg monster. In general, a bigger person with the same power to weight will be faster in all circumstances. If there was a mythical rider that was 100 kg and had a LT power to weight anywhere near Pantani or Armstrong they would beat anyone on earth in a flattish TT by several minutes. That is why people use other figures to assess performance like power squared divided by weight, which is a much better indicater of performance on flattish terrain. In any case, all of this can be modelled on the anylytic cycling website.
 

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Kieran said:
If there was a mythical rider that was 100 kg and had a LT power to weight anywhere near Pantani or Armstrong they would beat anyone on earth in a flattish TT by several minutes.
The interesting question is how come there aren't "big" 100 kg riders with LT power anywhere near Pantani or Armstrong? Maybe there are but it's awful suspicious that they never end up as elite cyclist. Pretty much only track sprinters can be that size and reach the elite ranks which suggests at some point muscle size becomes limiting to endurance performance. Backstedt is about the only pro rider even in the ballpark and it appears that being any bigger than about 170-180 lbs becomes limiting in some way beyond just limiting your ability to go uphill.
 

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There's always hills or corners

Dwayne Barry said:
The interesting question is how come there aren't "big" 100 kg riders with LT power anywhere near Pantani or Armstrong? Maybe there are but it's awful suspicious that they never end up as elite cyclist. Pretty much only track sprinters can be that size and reach the elite ranks which suggests at some point muscle size becomes limiting to endurance performance. Backstedt is about the only pro rider even in the ballpark and it appears that being any bigger than about 170-180 lbs becomes limiting in some way beyond just limiting your ability to go uphill.
The reality is that there are hardly any flat races, and those that are flat involve accelerations out of every corner. Having a low power:weight ratio is no good in either case. As you say, on the track you can be huge (Nothstein was 225 IIRC) because it's all about explosive power. I think points racers, where there are a lot of accelerations, tend to be smaller.
 

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Kerry Irons said:
The reality is that there are hardly any flat races, and those that are flat involve accelerations out of every corner. Having a low power:weight ratio is no good in either case. As you say, on the track you can be huge (Nothstein was 225 IIRC) because it's all about explosive power. I think points racers, where there are a lot of accelerations, tend to be smaller.
Yeah but even pursuit riders who may only have to perform maximally for a handful of minutes in no way approach the muscular size of say elite bodybuilders or powerlifters' legs. I would say clearly at some point more muscle is not good even under circumstances where it isn't apparently obvious from a physics standpoint why more mass would be detrimental.
 

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Dwayne Barry said:
Yeah but even pursuit riders who may only have to perform maximally for a handful of minutes in no way approach the muscular size of say elite bodybuilders or powerlifters' legs. I would say clearly at some point more muscle is not good even under circumstances where it isn't apparently obvious from a physics standpoint why more mass would be detrimental.
What about muscle type? Fast versus slow twitch. Yes, absolutely, there is a quantity of energy required to perform a task. However, you would never have seen Marco outsprint Marty Nothstein. Marty, is built for the track. Look at his rioad racing career. His wins in that field were when it came down to a sprint or a break away caused by that sprint.

As a form,er weight junkie, mass is what I believe we are discussing. You can have freakish mass in certain muscle groups and there is zero correlation to strength and or power. At least, that was my experience. Coming into cycling, I lost weight and yes, muscle mass. However, in some respects, I am just as if not strionger than I was while in others, well, my arms are not what they were and really, dont need to be on the bike.
 

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ttug said:
What about muscle type? Fast versus slow twitch. Yes, absolutely, there is a quantity of energy required to perform a task. However, you would never have seen Marco outsprint Marty Nothstein. Marty, is built for the track. Look at his rioad racing career. His wins in that field were when it came down to a sprint or a break away caused by that sprint.

As a form,er weight junkie, mass is what I believe we are discussing. You can have freakish mass in certain muscle groups and there is zero correlation to strength and or power. At least, that was my experience. Coming into cycling, I lost weight and yes, muscle mass. However, in some respects, I am just as if not strionger than I was while in others, well, my arms are not what they were and really, dont need to be on the bike.
Well I was really talking about the fact that I think clearly at some point muscle mass becomes limiting in the case of power output over a time period of anything more than let's say 30 seconds or so. I don't think fiber type necessarily plays into that.

I think it's pretty well established that muscle size does influence strength and that there is pretty much a linear relationship. And that muscle strength (i.e maximum force producing ability) is also related to maximum power. Just look at track sprinters. If you double the size of muscle it will have the capacity to produce twice as much maximal force, power will increase as well but not linearly because velocity also affects power and making a muscle twice as big doesn't make it contract any faster. You've got to be careful comparing across muscles though as in the body there are biomechanical and neurological factors that greatly affect the force/power that can be produced by any given muscle group.

I'd be surprised that if you've lost lower body muscle mass that your legs are any stronger (i.e. than can produce a higher maximum force) than they were, but probably due to their greater endurance capacity from cycling they can sustain higher power outputs for almost any length of time beyond a few seconds or 10's of seconds.
 

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Dwayne Barry said:
Yeah but even pursuit riders who may only have to perform maximally for a handful of minutes in no way approach the muscular size of say elite bodybuilders or powerlifters' legs. I would say clearly at some point more muscle is not good even under circumstances where it isn't apparently obvious from a physics standpoint why more mass would be detrimental.
Pursuit riders are still endurance athletes. Many of the top kilo athletes race on the road all year round. The only cycling events where strength is a limiter are the sprints,kilo, 500m, etc.
 

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Just a few points of reply:

When i talked about a mythical 100kg rider with p/weight near pantani or armstrong, i meant mythical, i.e. no one exists like that. It is important to clarify i was talking about power to weight at lactic threshold, ie aerobic capability. There are two reasons IMO that larger riders tend to have lower P/W, firstly, that heavier riders tend to have higher absolute aerobic power due to having, crudely, bigger lungs and bigger hearts. But heavy riders are never really just scaled up versions of the climbers, they generally carry more muscle,(and some times lard) as a proportion of their total weight than the climbers, and have less "body". In other words, a 100 kg rider will not have lungs and a heart twice as big as a 50 kg rider. More likely, their lung capacity might be 1.5 times as big, whilst their lean muscle mass might be 2.5 times as big. In this example, MAX power to weight would be HIGHER for the 100kg rider, whilst LT power would to weight would be lower (bear with my crude generalisation that lung capacity is directly proportional to aerobic power, and muscle mass is in directt proportional to max power)

Secondly, and this is a similar point, is that larger organisms are generally more inefficient, as they need more bone and connective tissue as a proportion of total weight. This is a demonstrated trend for all organisms, metabolic potential/weight decreases as an organism gets larger.
 

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whoawhoa said:
Pursuit riders are still endurance athletes. Many of the top kilo athletes race on the road all year round. The only cycling events where strength is a limiter are the sprints,kilo, 500m, etc.
That's exactly my point. If it were possible for a pursuit rider to be more of strength athlete and less of an endurance athlete someone would have observed that by now. So even over the relatively short times of a pursuit it is still about endurance not strength.
 

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And even beyond those reasons. Let's say you have two 5'10" riders one who weighs 165 lb and the other who weighs 205 lb with all that extra 40 lbs as cycling specific muscle so potentially capable of producing more power, the CV system still has to supply all that extra muscle with the oxygen to generate that power and in all likelihood the larger size of the 205 lb guy is going to be due to larger muscle fibers which will lead to a lower capillary to fiber ratio and greater diffusion distances for the oxygen into the muscle fibers which may compromise sustainable power even if if his CV system was just as competent as the smaller guys at delivering oxygen.
 
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