# strength to push 400 watts



## plx

How much strength is required to push 400w+ plus?


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## MR_GRUMPY

For 15 seconds?
For 15 minutes?
For 15 hours???
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## asgelle

plx said:


> How much strength is required to push 400w+ plus?


In what gear? At 90 rpm, it takes an average force of about 67 lbs. So if your leg strength is 70 lbs, you can ride at 400 W. Time has nothing to do with it.


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## 32and3cross

asgelle said:


> In what gear? At 90 rpm, it takes an average force of about 67 lbs. So if your leg strength is 70 lbs, you can ride at 400 W. Time has nothing to do with it.


And yet it has everything to do with it. My wide weighs 118lbs she can make 400 watts for a limited time. I weigh 179lbs and can make the same watts for a lot longer. The upshot is they most of can make 400 watts but for how long vs your weight is what matters.


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## Wookiebiker

32and3cross said:


> And yet it has everything to do with it. My *wide* weighs 118lbs she can make 400 watts for a limited time. I weigh 179lbs and can make the same watts for a lot longer. The upshot is they most of can make 400 watts but for how long vs your weight is what matters.


I'm assuming you are talking about your "Wife" ... if so, you may not want her to see what you wrote


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## asgelle

32and3cross said:


> And yet it has everything to do with it. My wide weighs 118lbs she can make 400 watts for a limited time. I weigh 179lbs and can make the same watts for a lot longer. The upshot is they most of can make 400 watts but for how long vs your weight is what matters.


Please explain how the force required to produce 400 W is a function of duration. Do you think the force required by your wife to produce that power increases faster than the force for you to produce 400 W? Take a look at the definition of power.


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## 32and3cross

asgelle said:


> Please explain how the force required to produce 400 W is a function of duration. Do you think the force required by your wife to produce that power increases faster than the force for you to produce 400 W? Take a look at the definition of power.


Bla bla bla enjoy talking to yourself and passing on useless information


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## MR_GRUMPY

Hardly useless.
As I reread the original question, I may have misunderstood what he meant. 
A 12 year old can push 400W for a short time, so the amount of strength can't be very high.
It's like curling a 25 pound weight. Not much strength needed, but difficult a keep doing it for 30 minutes.
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## cxwrench

32and3cross said:


> Bla bla bla enjoy talking to yourself and passing on useless information


you just basically said that one of the most intelligent people on this forum is not so smart. and, managed to sound pretty lame while doing it. if you're nice, maybe you'll get an explanation from him and then you'll be that much smarter. if not...blah blah blah


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## Ric_Stern/RST

@asgelle how do u get 67 lb? using 170mm cranks @ 90 revs i get 249.7 newtons which i think works out to be 56 lb (but i'm used to working in kg not lb)


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## asgelle

Ric_Stern/RST said:


> @asgelle how do u get 67 lb? using 170mm cranks @ 90 revs i get 249.7 newtons which i think works out to be 56 lb (but i'm used to working in kg not lb)


Honestly, I wasn't very careful. I went to Andy's strength endurance article and extrapolated his data for 250 W @ 45 rpm to 400 W @ 90. The value I got was very approximate. I don't doubt yours is much better.


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## Ric_Stern/RST

i use the same formula as Andy, which gives ~56 lb. Of course that 56 lb is the average between *both* legs, which is about 28 lb for each leg. A higher cadence or longer cranks would reduce the force requirement!


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## Jay Strongbow

32and3cross said:


> And yet it has everything to do with it. My wide weighs 118lbs she can make 400 watts for a limited time. I weigh 179lbs and can make the same watts for a lot longer. The upshot is they most of can make 400 watts but for how long vs your weight is what matters.


Yes it's what matters but it doesn't have anything to do with the question in the OP.

Anyway, regarding the point I think you're trying to make comparing you and your wife. Do you think an NFL lineman could keep up as high watts over a given period as scrawney pro cyclist?
To be honest I don't know the answer to that for sure but I'm guessing it's 'no' despite the NFL lineman having much greater strength.


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## campyc40

Power is Torque times angular velocity. Torque is Force times crank length, angular velocity is in radians and is (Cadence (rpm) / 60) * 2 * PI. Putting it all together, P = F * l * Cad * 2 * PI / 60.
Given a certain power output of 400 W, a Cadence of 90 and a cranklength (m) of 17.0cm or 0.17m, you can calculate the force (N/m).
For a 100lb person it is typically much harder to push 400W than for a 200lb person. To compare power outputs, you typically divide power by weight; that's when the mine-s-bigger-than-yours discussion really starts


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## Mr. Jones

Ric_Stern/RST said:


> i use the same formula as Andy, which gives ~56 lb. Of course that 56 lb is the average between *both* legs, which is about 28 lb for each leg.


Sure, but that seems to be looking at it the wrong way. I'd imagine that at any point in time, one leg is generating the vast majority of the force. (This is of course assuming 90 rpm. I could see a more even distribution of force at very low cadences).


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## iliveonnitro

Mr. Jones said:


> Sure, but that seems to be looking at it the wrong way. I'd imagine that at any point in time, one leg is generating the vast majority of the force. (This is of course assuming 90 rpm. I could see a more even distribution of force at very low cadences).


This is correct. 28lbs is the average force for each leg during one full pedal rotation. Peak force is higher and that depends on what the person's style is at that moment. If it's a standing 400w sprint, the peak power is higher than if it was someone TTing and using more of their pedal cycle to hit that number.

In general, it's 2-4x higher instantaneous force than average 360 degree force. Assume it's 3x higher, and you have ~85lbs. Remember, though, this is for fractions of a second, so it's probably just better to average it. Most people think of force as what they can lift (squats, dead lift, a box), which takes several seconds, anyway.


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## iliveonnitro

campyc40 said:


> Power is Torque times angular velocity. Torque is Force times crank length, angular velocity is in radians and is (Cadence (rpm) / 60) * 2 * PI. Putting it all together, P = F * l * Cad * 2 * PI / 60.
> Given a certain power output of 400 W, a Cadence of 90 and a cranklength (m) of 17.0cm or 0.17m, you can calculate the force (N/m).
> For a 100lb person it is typically much harder to push 400W than for a 200lb person. To compare power outputs, you typically divide power by weight; that's when the mine-s-bigger-than-yours discussion really starts



"Much harder" is a subjective term that should not be used in this discussion. 400W is 400W, regardless of who is doing it. If someone can hit 400w for a few seconds, then they are plenty strong to maintain 400w for several minutes. For someone who cannot hold 400w for several minutes, it's an aerobic capacity problem, not a strength problem.


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## campyc40

I don't think you should use "plenty strong" either, coach.


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## Ric_Stern/RST

peak force is ~2x average force


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## Dwayne Barry

iliveonnitro said:


> "Much harder" is a subjective term that should not be used in this discussion. 400W is 400W, regardless of who is doing it. If someone can hit 400w for a few seconds, then they are plenty strong to maintain 400w for several minutes. For someone who cannot hold 400w for several minutes, it's an aerobic capacity problem, not a strength problem.


Or another way to put it is that fatigue rather than strength is the limitation.

That is why many professional cyclists with small, skinny legs can maintain 400 watts for many minutes but most weight lifters with legs like tree trunks (and probably much higher peak powers capacities) couldn't come anywhere close to similar performances.


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## Dwayne Barry

32and3cross said:


> And yet it has everything to do with it. My wide weighs 118lbs she can make 400 watts for a limited time. I weigh 179lbs and can make the same watts for a lot longer. The upshot is they most of can make 400 watts but for how long vs your weight is what matters.


If your wife was Geneviève Jeanson, who probably didn't even weigh 118lbs when she was competing I'd put a lot of money on her being able to maintain 400 watts longer than you and having muscles that are quite a bit weaker than yours. 

I think if you're talking about power output beyond a minute or two, it's about aerobic energy production which isn't nearly as muscle size dependent as peak power production or power production over a relatively short period of time (e.g. 10s of seconds).

Or another way to put it is the duration your wife can maintain 400 watts would likely improve more by more endurance training and/or drugs like EPO than it would by her going to the gym and lifting weights to make her legs stronger and/or taking anabolic steroids.


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## Cyclin Dan

Ric_Stern/RST said:


> peak force is ~2x average force


??? I don't understand how that can be true. In a sprint, I can hold ~1,300 watts for 5 second, with a "max power" of ~1,500. That would be my peak force, right? 

My average is nowhere near 750 Watts...?


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## Dwayne Barry

Cyclin Dan said:


> ??? I don't understand how that can be true. In a sprint, I can hold ~1,300 watts for 5 second, with a "max power" of ~1,500. That would be my peak force, right?
> 
> My average is nowhere near 750 Watts...?


I think he is talking about peak force during a pedal stroke vs. average force throughout the entire pedal stroke?


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## Alex_Simmons/RST

Peak forces are typically around twice the average effective pedal force.


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## aclinjury

For reference, here is Sagan's recent power output charts in Stage 1 of Tour de France, in which he beat out Cancellara in the final sprint.

https://www.srm.de/index.php/us/srm-blog/tour-de-france/727

Here's the 3rd chart showing Sagan's power output for the final 200 meter.










He peaked at 1225W, and was able to maintain 1000W for about 8 seconds total. And for 18-second duration (the time it took him to sprint the final 200 meters), he averaged 970W (this is all anaerobic). And for the duration of 2 minutes 20 seconds building up to the 200-meter sprint (including the 200 sprint), he averaged 493W. For the whole stage (about 5 hrs), he averaged 206W.

Sagan is one of the strongest guys (for a short duration) on the Tour.

So it's safe to conclude that for an average weekend warrior, pushing 400W beyond 1 minute will be pretty much improbable. But who knows, I've seen some incredible wattage from the RBR peloton too. Anything is possible on the net.


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## Alex_Simmons/RST

aclinjury said:


> So it's safe to conclude that for an average weekend warrior, pushing 400W beyond 1 minute will be pretty much improbable. But who knows, I've seen some incredible wattage from the RBR peloton too. Anything is possible on the net.


Really? I've held over 400W for _4-minutes_ and I'm hardly pro level.

Mind you, that was before my leg amputation 5 years ago. My best 4-minutes since then is only 380W and I'm in my late 40s. 

My post amputation one minute power best is a sad 560W.
My post amputation 5-sec power best is 1190W with a peak of 1225W.

The power outputs of Pros at end of road races are nothing particularly spectacular. It's the fact that they can do them after 5-6 hours of hard riding that is exceptional.

Contrast with peak power outputs in excess of 2.4kW for pro track sprinters and BMX riders.


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## asgelle

aclinjury said:


> Sagan is one of the strongest guys (for a short duration) on the Tour.


It would seem you're misusing the word strength (and confusing the discussion). First, there is no time component to strength (the maximum force or tension a muscle or muscle group can produce); second, Sagan may or may not be one of the strongest, but there's no way to tell that from a power file.


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## OldZaskar

Power:Weight is a huge part of this. My peak watts (1440 for 3 seconds) is higher than a lot of TdF riders. But I weight 183 pounds. For a 145 lbs rider, that'd be 1140 watts. So, yeah... Sagan would smoke me... Oh, and there's that whole riding 100 miles thing before the sprint to consider... at 27 mph...


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## wim

asgelle said:


> It would seem you're misusingthe word strength (and confusing the discussion)..


Agree, but he's not the only one. In this thread, strength (a physiological term), force (newton), torque (newton-meter) and power (watt) is merrily interchanged and, in some cases, confused with one another by more than one poster.


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## JustTooBig

aclinjury said:


> For reference, here is Sagan's recent power output charts in Stage 1 of Tour de France, in which he beat out Cancellara in the final sprint.
> 
> Sagan is one of the strongest guys (for a short duration) on the Tour.
> 
> *So it's safe to conclude that for an average weekend warrior, pushing 400W beyond 1 minute will be pretty much improbable*. But who knows, I've seen some incredible wattage from the RBR peloton too. Anything is possible on the net.


that's a bit of a stretch; I'm a fat Cat4, and my 10-min power in a balls-out effort is right at 400w (although I couldn't do that at the end of a hard effort of several hours). I can send the power file(s) if there's some skepticism, but I'm confident there are plenty of people whose numbers eclipse mine...


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## OldZaskar

wim said:


> Agree, but he's not the only one. In this thread, strength (a physiological term), force (newton), torque (newton-meter) and power (watt) is merrily interchanged and, in some cases, confused with one another by more than one poster.


"Strong" is a category term - used in cycling to refer to one's fitness, e.g. "Man, that guy is a strong rider" does not necessarily mean "Man that guy sure has a greater than average ability to generate force and tension in the specific leg muscles that are required to make his bike go faster when he's on it and pedaling"


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## Cyclin Dan

aclinjury said:


> Sagan is one of the strongest guys (for a short duration) on the Tour.
> 
> So it's safe to conclude that for an average weekend warrior, pushing 400W beyond 1 minute will be pretty much improbable. But who knows, I've seen some incredible wattage from the RBR peloton too. Anything is possible on the net.


Obviously power to weight ratio is as important as ever (I outweigh Sagan big time) but to think that someone outside the pro tour can't push more than 400W for more than 60 seconds is a little shortsighted.

I'll grab a screenshot later of my WKO+, but my max 5 second power is about 1,250 watts, with my 20 second power being just over 1,000.

My 20 minute power is around 340 watts.

Like I said, I outweigh Sagan big time so I'm sure he kills me in power to weight ratios...I'll grab a screenshot and post the file to eliminate the undoubted skepticism.

All that, and I don't even race. I do a few road races every year, but just because they're rides I want to do that also happen to be races.


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## asgelle

OldZaskar said:


> "Strong" is a category term - used in cycling to refer to one's fitness, e.g. "Man, that guy is a strong rider" does not necessarily mean "Man that guy sure has a greater than average ability to generate force and tension in the specific leg muscles that are required to make his bike go faster when he's on it and pedaling"


First of all, strength has a precise definition and when used correctly leads to clear communication; that people misuse it and confuse a discussion is unfortunate. Second, in the context of the original question, "how much strength does it take to push 400 W," your first usage doesn't make any sense.


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## wim

OldZaskar said:


> "Strong" is a category term - used in cycling to refer to one's fitness, e.g. "Man, that guy is a strong rider" does not necessarily mean "Man that guy sure has a greater than average ability to generate force and tension in the specific leg muscles that are required to make his bike go faster when he's on it and pedaling"


Yes. But the OP specifically asked about _strength_. I didn't think he was confusing strength with fitness.


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## aclinjury

I'd like to see some charts of power vs. speed from the guys pushing monster wattage.


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## Alex_Simmons/RST

aclinjury said:


> I'd like to see some charts of power vs. speed from the guys pushing monster wattage.


Under what conditions? 

Speed - power relationship is a function of many variables aside from power. e.g.: wind, air density, aerodynamics, gradient, mass, rolling resistance, drive train efficiency etc.


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## wim

aclinjury said:


> I'd like to see some charts of power vs. speed from the guys pushing monster wattage.


The web has many of these charts. But as said by Alex, there can't be such a chart that is universally true.

Getting back to the original question: here is a slightly modified chart from an older Cavanagh / Sanderson study you can still find in more serious cycling literature. I added the pound-force notation next to the force numbers. The plot line represents resultant force on the pedal, meaning the force that results from vectoring other force components acting on the pedal.

The data are about 40 years old, but I think they're still good as an illustration of how much "strength" is needed to generate a certain amount of power at a certain cadence in a certain gear. I can't find the gear notation right now, but I know it was a customary track pursuit gear of the time, like a 48 x 14 or close to that. At any rate, the low pound-force numbers in the chart clearly show that cycling is not a strength sport. It really is all about sustainable power, not force.


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## Cyclin Dan

oldzaskar said:


> power:weight is a huge part of this. My peak watts (1440 for 3 seconds) is higher than a lot of tdf riders. But i weight 183 pounds. For a 145 lbs rider, that'd be 1140 watts. So, yeah... Sagan would smoke me... Oh, and there's that whole riding 100 miles thing before the sprint to consider... At 27 mph...


exactly!


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## Cyclin Dan

aclinjury said:


> I'd like to see some charts of power vs. speed from the guys pushing monster wattage.


Here's a screenshot I grabbed from my WKO+.

It may be hard to read, but the second highlighted in black is 20second period where I averaged 1,053 watts. The yellow line is my wattage, the red line is my heart rate, green is my cadence and blue is my speed. The others are elevation and temperature.

You can see, farther down the graph to the right, and I actually did another sprint, and achieved a higher max power, but for a shorter time. I did a few short sprint intervals during this flat ride.


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## aclinjury

Alex_Simmons/RST said:


> Under what conditions?
> 
> Speed - power relationship is a function of many variables aside from power. e.g.: wind, air density, aerodynamics, gradient, mass, rolling resistance, drive train efficiency etc.


Yes I know, and the list of conditions can go on and on. How about just post some training graphs? your typical training. I'm not looking for a formal study.


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## aclinjury

Cyclin Dan said:


> Here's a screenshot I grabbed from my WKO+.
> 
> It may be hard to read, but the second highlighted in black is 20second period where I averaged 1,053 watts. The yellow line is my wattage, the red line is my heart rate, green is my cadence and blue is my speed. The others are elevation and temperature.
> 
> You can see, farther down the graph to the right, and I actually did another sprint, and achieved a higher max power, but for a shorter time. I did a few short sprint intervals during this flat ride.


Thanks. Looks like your typical max speed just a tad over me. I'm usually hitting 30-32 mph on these typical flat intervals. However, my peak wattage is only about 600-700W (according to Garmin 500, no power meter, so take it for what it's worth). If I ever get to 1000W, I think I'll be approaching 38-40 mph! I'm 130 lbs, typical build (actually a bit top heavy, used to do gymnastic). But my strength is not flat speed, it's in the hills. Now usually big guys will drop on the flat, but if they let me catch their wheels, then I can tag along all day long at 26-27 mph then I'll drop them come the hills. Lol they always complain about unfair advantage! Judging from your speed and wattage, you look to be a big guy, prolly outweighs me by 30-40 lbs easily.


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## woodys737

aclinjury said:


> Thanks. Looks like your typical max speed just a tad over me. I'm usually hitting 30-32 mph on these typical flat intervals. However, my peak wattage is only about 600-700W (according to Garmin 500, no power meter, so take it for what it's worth). If I ever get to 1000W, I think I'll be approaching 38-40 mph! I'm 130 lbs, typical build (actually a bit top heavy, used to do gymnastic). But my strength is not flat speed, it's in the hills. Now usually big guys will drop on the flat, but if they let me catch their wheels, then I can tag along all day long at 26-27 mph then I'll drop them come the hills. Lol they always complain about unfair advantage! Judging from your speed and wattage, you look to be a big guy, prolly outweighs me by 30-40 lbs easily.


Gawd. All this time I thought you had a PM. How are you deriving power from a Garmin 500 w/o a PM?


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## Vibe

woodys737 said:


> Gawd. All this time I thought you had a PM. How are you deriving power from a Garmin 500 w/o a PM?


Probably from whatever Strava spits out as 'power'.


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## Alex_Simmons/RST

aclinjury said:


> Yes I know, and the list of conditions can go on and on. How about just post some training graphs? your typical training. I'm not looking for a formal study.


I have ~ 30,000 power meter files to choose from.

If you want some idea of my own personal power outputs, here is some information on my mean maximal power curve:

http://alex-cycle.blogspot.com.au/2011/11/mean-maximal-power-unique-comparison.html


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## aclinjury

woodys737 said:


> Gawd. All this time I thought you had a PM. How are you deriving power from a Garmin 500 w/o a PM?


The garmin uses your heart rate and weight to estimate your power.
I'm 130 lbs. Usually when I'm cruising at 18 mph, I'd register around 130-140W. At 20 mph, it's about 160W-170W. This is me riding by myself, no drafting. But to be honest, I'm not a racer so I'm not really concerned with the wattage accuracy. As long as the data is precise (which it seems to be the case), then the data is still meaningful.


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## Local Hero

aclinjury said:


> I'm not a racer so I'm not really concerned with the wattage accuracy.


I am a racer. That's why I'm not overly concerned with watts. Just about the only race where I think watts is crucial is the time trial (or if you solo off the front and try to TT to victory). Apart from that, I think a power meter or HR monitor is a distraction in a race. 

Well, what about training? 

Yes, I think watts are an excellent training tool. But I don't use a PM. I suppose that it is mostly because I'm cheap. Well, that's not exactly true, I have expensive things, I just don't think there is a cost benefit analysis that would justify owning one. Would it help finding my 5 X 5 minutes or 3 X 20 minutes at X% of max power? Definitely. How much better is that measurement than my wrist watch and a set course or a well-known hill? (The hill is protected from the wind.) Why can't I just do repeats on a known course and ride by feel? 

I'm derailing the thread here but I'll say one more thing, and this is probably germane to the commented I just quoted. 

If the powermeter says I'm pushing 280 watts for 20 minutes and I know that's a good 3 X 20 workout for me, what difference does it make if the powermeter is off by 10% or even 20%? As long as the thing is consistent, the calibration isn't very important, save for bragging rights.


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## tom_h

aclinjury said:


> The garmin uses your heart rate and weight to estimate your power.
> ...As long as the data is precise (which it seems to be the case), then the data is still meaningful.


Impossible to compute power from that. HR cannot be used, varies widely between individuals. Muscle mitochondria density, blood hematocrit %, heart's stroke volume, etc etc, will influence what HR is at a given power output. 

On an uphill of 4% or steeper, Strava will give a decent estimate of power IF you use accurate values for your body weight + weight of ALL equioment (clothing, water bottles, bike, etc)


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## woodys737

aclinjury said:


> The garmin uses your heart rate and weight to estimate your power.
> I'm 130 lbs. Usually when I'm cruising at 18 mph, I'd register around 130-140W. At 20 mph, it's about 160W-170W. This is me riding by myself, no drafting. But to be honest, I'm not a racer so I'm not really concerned with the wattage accuracy. As long as the data is precise (which it seems to be the case), then the data is still meaningful.


Making assumptions based on your small sampling of Strava's estimates of power doesn't mean you should automatically say those of us that can hold X watts for X time are full of it. Especially given many of us actually use PM's. IME, most all the gents I ride and train with can hold 400W for several minute and we are nothing special. Matter of fact, 400W for a minute or two is pretty much unremarkable in the grand scheme of things. There are some amazing amateur's out there. I think once you start digging a little deeper you'll realize much the same as I.


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## JackDaniels

400wha?


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## TylerrJohnsonn

It hurts my eyes to read this. It's like another language...


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## Alex_Simmons/RST

aclinjury said:


> The garmin uses your heart rate and weight to estimate your power.


What happens when your fitness changes?



aclinjury said:


> I'm 130 lbs. Usually when I'm cruising at 18 mph, I'd register around 130-140W. At 20 mph, it's about 160W-170W. This is me riding by myself, no drafting.


OK, well that's plausible, if inaccurate.

e.g if you do say 135W at 18mph on flat terrain, then at 20mph under same conditions you'd need to be doing 177W.



aclinjury said:


> But to be honest, I'm not a racer so I'm not really concerned with the wattage accuracy. *As long as the data is precise (which it seems to be the case)*, then the data is still meaningful.


So here's a quick graph of average HR v average power for 140 or so rides. Ignoring the few outliers, how precise do you think the HR v power relationship is?


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## iliveonnitro

Ric_Stern/RST said:


> peak force is ~2x average force


Thanks, it's been awhile since I've looked at those graphs.


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## iliveonnitro

aclinjury said:


> So it's safe to conclude that for an average weekend warrior, pushing 400W beyond 1 minute will be pretty much improbable. But who knows, I've seen some incredible wattage from the RBR peloton too. Anything is possible on the net.


I'm no pro, but I wouldn't say just a weekend warrior, either. Here's my MMPC.

4min @ 450w (never actually tried to do these as an interval)
1min @ 569w
Peak 1sec in this graph is 1488w, but I've hit mid-1500s.

68kg


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## nightfend

The difference between a pro and an amateur is simple. Both can hold 400 watts for a minute. But only one can hold 400watts for over a minute AFTER a 5 hour ride.


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## durianrider

400watts? Depends on how much the person weighs.

Anything over 5watts per kg for 20 mins is SUPER fit.


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## tricycletalent

asgelle said:


> Please explain how the force required to produce 400 W is a function of duration.


You need higher max power until the force required to produce 400w is less than 20% of your 1RM according to a sports scientist I took classes with. Deduced from repetitions of weightlifting.


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## asgelle

tricycletalent said:


> You need higher max power until the force required to produce 400w is less than 20% of your 1RM according to a sports scientist I took classes with. Deduced from repetitions of weightlifting.


And what has that got to do with the question of duration? Are you saying it takes more force to generate 400 W after 20 minutes than it does after 10 (or whatever time pair you like)?


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