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Watts Per Kilo is a Cruel Witch...

I have been reading a lot of books on cycling lately.  Some "how to" and some biographical.  They are all good, some really good, but they all talk about the same thing with reverence.  Watts Per Kilo.  The holly Grail.  It seems like not only an important number, but it seems to be THE number.  And, what a devilish little number it is.

It's so black and white.  It's so simple.  Its sooo fooking hard!

The amount of power you can make divided by your body weight in kilos produces a value so clear, so cut and dry.  2.4; 2.8; 3.1; 3.6.  Amazingly simple.  I have been familiar with this little ratio for a long while, but I never really stewed on it.  I never sat down and said let me look at the formula and run some scenarios…  Until today.

Here is where I am today:

Not bad for a 40 year old former couch potato, but not where I want to be.  Not the magic age group line of FOUR.  I am not even sure why FOUR is the number except that it is a round number, its an even number and it seems to just roll off the tongue - FOUR.  I guess FOUR is the number that separates one group from another.

So, how do I get to FOUR?  Three choices - Make a lot more power, lose a ton of weight or do both.  I think the best I could ever HOPE to manage is do a lot of both.

Here is what I think FOUR could look like for me:

Tough, eh?  I gotta lose 9 kilos and gain 32 watts?  For real?  Shoot!  That seems right hard, but it also seems like a real noble goal.

165 is probably the most doable, but it's a tall order.  This Summer, before CDA, I weighed 173.  That means I gotta shave 8 pounds off that weight and be lower than I have weighed since middle school.

The watts piece seems wild as well.  My best test ever was 275.  Currently, I can do 20 minute power of about 286.  300 is gonna be crazy.

So while I am at, I start thinking about the big boys.  Michele Ferrari, yes, that Dr. Michele Ferrari, said that Watts Per Kilo is the MOST important number.  He said that to win THE TOUR, a rider would need to have a watts per kilo number of 6.7. 

6.7 watts per kilo!  That's what Ferrari said it would take to slay the contenders in the mountains.  Less then 6.7 watts per kilo and you couldn't crush your rivals in the Alps.  Fortunately for some, Michele had the rocket fuel required to jack you up!  With EPO and a rider that had a body that responded well to it, he could jack your power number up and ensure you wouldn't fade in the final week of a three week grand tour.  But, the weight was still a challenge.  Everything I read talks about the Pro Peloton being obsessed with their weight.

So what would I look like in Tour Contender shape - 6.7 watts per kilo:

Yup, lost 30 more pounds from my super skinny 165 goal and added a few watts.  Just 111 watts more than my ambitious 300 watt goal.  That's right, get your fat ass down to 135 while cranking 411 watts and you too can spank fools while flying up the side of Mt Ventoux in the big ring.

I gotta go chew some ice cubes for dinner while doing spinnervals…..

Comments

  • Cyclist know these numbers very intimately. 300 watts and/or 4.0 and above is rarified air for most cyclist. I doubt there are very few tri folks that push these numbers. Ironically as you loose weight you will likely loose power because you aren't towing around as much. Some guys I know that can crank big power numbers are also huge guys. Great power for short distance but die say on any climb. I posted a chart similar to the one below a couple weeks ago- interesting stuff. Personally I can break 1 hour for a 40ktt consistently but seem to be stuck at 297 watts and 3.76 w/k. I agree with you it is tough. What is remarkable is to see the 135 pound guys cranking power numbers that you think they couldn't possibly do with their skinny builds! Sorry the chart is not formatted well it doesn't want to paste correctly.

    FT FT




    6.40

    5.69



    6.31
    5.61



    6.22
    5.53



    6.13
    5.44


    World class
    6.04
    5.36


    (e.g., international pro)
    5.96
    5.28



    5.87
    5.20



    5.78
    5.12



    5.69
    5.03



    5.60
    4.95


    Exceptional
    5.51
    4.87


    (e.g., domestic pro)
    5.42
    4.79



    5.33
    4.70



    5.24
    4.62



    5.15
    4.54



    5.07
    4.46


    Excellent
    4.98
    4.38


    (e.g., cat. 1)
    4.89
    4.29



    4.80
    4.21



    4.71
    4.13



    4.62
    4.05



    4.53
    3.97


    Very good
    4.44
    3.88


    (e.g., cat. 2)
    4.35
    3.80



    4.27
    3.72



    4.18
    3.64



    4.09
    3.55



    4.00
    3.47



    3.91
    3.39


    Good
    3.82
    3.31


    (e.g., cat. 3)
    3.73
    3.23



    3.64
    3.14



    3.55
    3.06



    3.47
    2.98



    3.38
    2.90


    Moderate
    3.29
    2.82


    (e.g., cat. 4)
    3.20
    2.73



    3.11
    2.65



    3.02
    2.57



    2.93
    2.49



    2.84
    2.40


    Fair
    2.75
    2.32


    (e.g., cat. 5)
    2.66
    2.24



    2.58
    2.16



    2.49
    2.08



    2.40
    1.99



    2.31
    1.91


    Untrained
    2.22
    1.83


    (e.g., non-racer)
    2.13
    1.75



    2.04
    1.67



    1.95
    1.58



    1.86
    1.50


  • Also Dino for you to get to 300 for a 20 minute test you will need a 315 since it is 95% of your 20 minute power. Even harder. I am hoping this OS does it for me. These are the exact numbers I am shooting for in week 8! Good luck. The horse on this team that is rarified is young Stefan Reiter. BIG NUMBERS from the Austrian!!!!!!!! 
  • This is from the cycling god Andrew Coogan. It is the same table I made below but cleaner and easier to read. You are right Dino it is fun to play with this stuff.

  • Great stuff you guys....

    One thing to mention , we all know about it , but nobody every says it or talks about it..... You must factor in the weight of your bike....

    Hypothetical situation... 3 guys all with w/kg 4.0...... one at 120lbs , one at 140lbs , and one at 160lbs ..... factor in the weight of a bike (20lbs to make it easy) and now the true w/kg ratio is 3.43 for the 120lb guy , 3.5 for the 140 lb guy , and 3.55 for the 160lb guy ......

    I started EN a little over 3 years ago @ 126lbs and FTP of 175 , w/kg of 3.0...... earlier this year peaked at w/kg of 4.4 with a weight of 118 and FTP of 235..... right now I am at 3.8 w/kg 128lbs and 220FTP...... when I add 2 water bottles to my frame it drops my w/kg down by .06..... And ironically my best performances have been on flat courses .....

    Dino everyone is different but I believe most people are capable of reaching 4.0.....As you know after the 1st year FTP gains become very hard to achieve but losing weight is always easy with discipline... Having read all those cycling books you know how fanatical they all are about getting skinny... That said its nice to have FTP/weight/ w/kg targets but I think its important to just do the work get lean and let the numbers land where they do.... Just like executing your IM and let the time take care of itself...
  • I was just doing these calculations a few weeks ago and thought 3.0w/kg was possible for me this year. My peak last year was 2.71. I'm now at 2.28. Ugh. At least I know there's hope of getting back to "moderate". This is even more important for 2014 as I attempt the super hilly Quassy half this year and Placid in '15. Hauling 150lbs up those hills on a wimpy 154 FTP ain't gonna be pretty. Lol

    Time to hit the bike I'd say!

  • Posted By tim cronk on 07 Dec 2013 06:33 AM
    .... And ironically my best performances have been on flat courses...
    I think size is a factor here as well. Staying low, small, and aero on, say, AZ or FL is so important, that the ability to move less air trumps the extra watts bigger guys have.
  • Okay, I'll play... The Max FTP I ever saw on a test was 335W last yr near the end of the OS, but I got sick immediately after the test and then it was a gradual decline all yr as my weight came down and as the IM training got "longer". The lowest weight I saw last yr was ~178lb, but after taper and carb/hydration loading, I started IMLP around 182lbs. At that point, my FTP was around 310W for 3.75W/Kg.

    So my Goal for this yr is to get my FTP back up to that high point and actually keep it close to there through IM training (big stretch). If I can maintain 325W as my weight comes down and race at 178lbs, then I'll hit that magical number at 4.01W/Kg.

    There are a few bigger issues to consider... I think it's even more important what your ~5 or 6 hr power number is. Said a different way, what IF can you actually maintain for 5 or 6 hours and still run effectively off of it. There are a couple ways to have a faster IM bike leg. Getting your FTP number as high as possible always helps, but being able to maintain a higher percentage of that FTP number for longer gets you there also. And I don't mean overcooking your legs. I have underperformed with this in the past and realy want to work on that this yr as well (racing at a 0.72IF instead of a 0.67IF). We all have a power curve over time. For sprinters, 10s or 20s Max power might be more important. Most people look at 1 min or 5 min or 20 min power. Some even think out as far as 1hr power on the max curve (i.e. FTP). That's why Coggan uses those in his table. But what about 3hr max power or 6hr max power? Those are likely more important for IM racing (and nearly impossible to test).

    Also there is the common thought that Absolute Watts are more important on flat courses and that W/Kg is more important on hilly courses. My dudes like Coach P showed this at IMTX. But nothing is absolute as Tim Cronk also showed. I think Tim's relative strength is running well in the extreme heat, but he also shows that fast dudes are fast dudes, period. Bike position and aerodynamics are also extremely important because I'll take someone with 3.0W/Kg with great position on a tri bike in a 112mi TT any day over some 4.0W/Kg dude sitting upright on a Mtn Bike.
  • Re: 5 hour Mean Maximal Power #: about three years ago, when he was still active in EN, Chris Whyte ("Lakerfan") stated the best predictor of what your IM bike power should be was that 5hr MMP. IOW, your second race rehearsal tells the tale.
  • Damn Tim those are awesome numbers! I agree with what you all are saying. I can pound a 112 Bike and then talk about it as I walk the run!
  • Dino,

    You have the build to get under 170lb easily, IMO. And you live at the bottom of the best training venue in LA. That hill is all about motivation, caffiene, rabbit (chase on or be one) and tunes. 

    Best bike fitness I've ever had was 2010 training for Everest Challenge. 4x rides per week as 2x intervals and 2x climbing rides. No running. I got to 158lb and 315w FTP, 4.38w/kg. Sooooo glad there was no Strava back then because it would suck being stalked daily by that fookin guy and his "My Results" on every local segment. 

    4.0w/kg is just a number that means something to triathletes. That is, once you get north of 4.0, you're the guy that's putting up top 5 in your AG bike splits, etc. This is just something we've all observed over the years. 

  • I got myself to 4.0000000 last year for the briefest of moments but only for the least real situation...indoor on my road bike. It wasn't reality. :-) I'm back to just trying to be one of the faster guys in the age group by being strong, but smart, smart smart.
  • John Withrow brings out the best point here ... That is 3hr power and 5hr power for HIM's and IM's is what is important....Al confirms this..... IMO FTP is irrelevant for race day.... FTP tests , w/kg , etc are good for bragging and are necessary for setting your training zones early in the year but once we get into the long stuff I no longer care what my FTP really is and pay attention to the long stuff more and more the closer race day gets....Every year we see discussions about FTP and what percentage to ride etc etc .....If you didnt know what FTP was , and you rode your bike (hard) with a PM every weekend and collected the data...... Then looked at said data.... Wouldnt you just race your IM at proven 5-6hr power??? After 3-4 weekends you would know what is too much and what is too little..... No need to know all the acronyms and percentages etc just ride the correct capable power....

    JW Is a big guy with big numbers (probably one hell of a sprinter) and it seems he has determined his weakness to be riding longer distances at a higher percentages of his FTP... I would imagine he is going to have a good focus on those longrides at RPP this year???

    I'm the opposite of JW.... little guy with little numbers but I can hold a higher percentage for long periods of time... A diesel engine.... My weakness is once is V02 relative to FTP somewhere around 115%..... So this year I am going to do a lot of work above FTP in the OS....
  • I agree Tim but I guess I have become more of a roadie after my accident and have done more time trials and distance bike races so I am wired to the power numbers. This year if the lord is willing I am going to carry it over to IM. We will see at IMCHOO!
  • @Ray...Agreed... Definitely wired to the power numbers but in a "I know what number to ride based on my last three 5hr rides" instead of what percentage of my FTP estimate , that was derived from a 20 minute test , where I multiplied that number by .95 to get , should I ride for my 5.5 hr Ironman bike? IOW I feel any FTP test of 20min x .95 , NP of 2 x 20 , or even a full REAL ftp test of 60min just doesnt matter ..... That is why I think JW nailed the comments about sustainable 5hr power! At least for IM.....
  • I'm so happy to see the talk of 3+ hr power. I have found that I do not (yet) have the mental toughness to do a really good FTP test. I am 99% positive my FTP is higher than what the test shows. I want to cry on FTP intervals, but somewhat easily can hold Z3 for a long time. I'm thinking the 4.0 W/kg is not just a representation of fitness, which is most certainly is, but the mental toughness and pain tolerance requirements to be at that pointy end of the stick.
  • Ah yes, love these metrics and I have the Coggan table Andrew references pinned up in my pain cave.  Honestly though, I think I need to move it to the fridge…  currently sitting at 3.5 but get down to my realistic goal weight without losing any power and I’m at 4.0.  Sheesh, sounds so easy… 

  • Agreed. W/kg is the truth.



    Strength moving the mass is just as valuable on the run as it is on the bike, too.

    As I take 2014 off from any huge race plans, my goal is to keep the crosshairs on this very point. And, though it's a long ways down the road, it's geared for Sept of 2015.


    That gives me 2 years of listening to everyone telling me that I'm sick, losing too much weight, eat a burger, etc. As long as my W is going up and I don't feel worn down, the kg's will be dropping.
  • Great thread. Thanks for starting.

    So - just to clarify:

    1) derive FTP (test)
    2) ride long rides at estimated xIF (% of FTP @ estimated IM pace).
    3) Look at 4-6 hour max power number and correlate to RPE.
    4) Ride IM to wattage of 4-6 hour sustained power number.

    If the 2 numbers (% of FTP, and 4-6 power) are congruent, I would feel confident in applying those numbers.

    However, what if they aren't? I am hearing that it is preferable to default to the long ride power number over riding to a percentage of FTP. Isn't there a risk of having this 4-6hr power number be too high for IM sustainability such that it seems possible (even likely) in training to be able to ride to a higher 4-6 hr power by not swimming before, and running after. This might falsely elevate goal watts and encourage riding the IM too hard.

    What am I missing?

    Thanks,

  • Posted By Ian Kurth on 09 Dec 2013 01:40 PM


    Great thread. Thanks for starting.



    So - just to clarify:



    1) derive FTP (test)

    2) ride long rides at estimated xIF (% of FTP @ estimated IM pace).

    3) Look at 4-6 hour max power number and correlate to RPE.

    4) Ride IM to wattage of 4-6 hour sustained power number.



    If the 2 numbers (% of FTP, and 4-6 power) are congruent, I would feel confident in applying those numbers.



    However, what if they aren't? I am hearing that it is preferable to default to the long ride power number over riding to a percentage of FTP. Isn't there a risk of having this 4-6hr power number be too high for IM sustainability such that it seems possible (even likely) in training to be able to ride to a higher 4-6 hr power by not swimming before, and running after. This might falsely elevate goal watts and encourage riding the IM too hard.



    What am I missing?



    Thanks,

    Ok, I think we're getting away from the original intent of this thread and beginning to steer towards how to race the IM with power.

    W/kg @ FTP is a good number to reference because you pretty much always know what your FTP, you know what you weigh = you can assign yourself a number today that reflects where you are, today, against your goals. You can also compare your current w/kg @ FTP to that same number pretty much anywhere in the season across a number of seasons.

    You won't start to accumulate 3-5hr power numbers until you start doing rides of that length...and then the issue of specificity comes up -- road bike vs tri bike, 5hr climbing ride vs 5hr flat ride, etc, etc. 

    In other words, looking at, tracking, and making race day pacing decisions as a function of accumulated long ride data is a Race Prep conversation and exercise. 

  • Ian I am absolutely in agreement with you versus the consensus here. I have done many 200 mile races and relied on my one hour FTP number. It has never even crossed my mind to use anything else.

     I think there are too many variables in relying on a 4 to 5 hour time. Particularly if the course is not a consistent route from an elevation standpoint or wind or heat or.......I know 70% of my FTP will be more of a predictor.

    But I must qualify my comments because I ride A LOT. Typically 10,000-12,000 miles per year.

     I will say though I am going to try what Tim is saying for the hell of it and see how close I am.

  • Coach responded while I was typing!
  • I've been looking at this also as I look to next season and aim for IM Chattanooga
    Last years peak FTP was 237, just off my best FTP of 240 in 2012. My final A race last year I was 142 lbs = 64.4kg. I'm pretty lean and 142-143 is about my normal race weight although in 2008 I was around 140.

    Last year watt/kg = 3.68

    To get to 4 watt/kg I'd have to either increase my FTP to about 260 at my current race weight.
    If i could somehow race at 135 lbs or so, I only have to get my FTP to about 245.
    I can't imagine being able to drop to 135 lbs and slightly increase my power output. Plus at 135 people might start wondering if I was sick or something.

    Mark

  • @ Dino, I have no idea of your height and BF% but Rich knows you well and says to work the weight angle so I believe him. I think to maximize watts/kg most of us can work on the kg. I hit 4.2 watts/kg last year by working the watts and am pretty certain there's not much more I can do on that front. I might be able to get another few watts of FTP but really it's getting friggin' hard. This year I might try to work the kg part of the equation more aggressively and see if I can get weight down WITHOUT LOSING POWER!! Of course working kg down helps you on the run a LOT too. But can we all do this without turning into perpetually-hungry and easily-irritable assholes to our friends and families??????

    Btw to the comments about longer power averages being critical are spot on for long-course triathlon.

  • Posted By Ray Brown on 09 Dec 2013 01:59 PM

    Ian I am absolutely in agreement with you versus the consensus here. I have done many 200 mile races and relied on my one hour FTP number. It has never even crossed my mind to use anything else.

     I think there are too many variables in relying on a 4 to 5 hour time. Particularly if the course is not a consistent route from an elevation standpoint or wind or heat or.......I know 70% of my FTP will be more of a predictor.

    But I must qualify my comments because I ride A LOT. Typically 10,000-12,000 miles per year.

     I will say though I am going to try what Tim is saying for the hell of it and see how close I am.

    For everyone: our complete Ironman execution guidance is here.

    IM pace by the math (ie, FTP x goal IF per our guidance in ^that^ doc above) is a starting point but could/should be refined through the data you see on long rides and especially on your race rehearsals. In other words:

    • Start with the math
    • Accumulate long ride data to help validate this (sorta)
    • REALLY refine and validate it with your first race rehearsal
    • Refine and validate it again with your final rehearsal.

     

  • Thanks all for the feedback and discussion. I had not considered this for Ironman other than that being a stronger lighter rider would make me a lighter, faster, stronger Ironman. I have never used W/kg for IM planning. Instead I find an FTP that works and then test multiple IF's over the coarse of IM training - meaning 4-6 hour rides - to find the magic NP that allows me to run well.

    For me the FTP number is just a bench mark to develop an IF that feels like the magic NP number. The absolute target 5 hour watt number is what I really want to define. Meaning, I could choose 300w as an FTP and then ride IM at .60 IF, or I could choose 225 as an FTP and then ride IM 0.90 IF. The number for me is what NP number over 5-6 hours leaves me running well without leaving any watts on the table "unused". That is just how I wrap my head around IM planning and then ride in 15 minute boxes targeting that sweet NP number.

    My current fascination with W/Kg is based on the Outseason riding I am doing. In the past three months since IMTahoe, I have been riding 3-4 times per week, always outside and never alone. I go out of my way to find strong riders and then try and either hang with them or slay them.  I have been riding with anything from 1-2 training partners, to 20-30 on a tri club ride to 100 roadies on a standing Saturday Tour of the San Gabriel Valley called The Montrose Ride.  Montrose is a roller coaster 2 hour suffer fest in legit peloton.


    I want more W/kg to smash intense road rides and climbs. I will do extended climbs as 1-2 hour efforts where I am either racing to stay away from or trying to catch a trainer partner(s). During the big Montrose or club ride I am either sitting in, pace lining or on the attack. That means briefer more intense efforts where I am looking for more 5 and 20 critical power numbers.



    In group rides and climbing sessions, raw power to weight is what I seeking. This is December, I just want to use my fitness to test my mettle and that of my friends 3-4 times per week. I then want to carry that into Spring with some 70.3 racing and then ultimately toe the line in Chattanooga lighter and faster with 12-14 weeks of 5-6 hour rides under my belt at a sustained power that sets up a sub-4 hour run.
  • And with that approach, you are going to shred the course at IMCHOO!!!

    (with that said, I'll race you to 4.0W/Kg)

     

  • Just my 2-cents to add here .... >4W/kg is where to big boys of all AGs play... but without having the proper "race execution" and "pacing" even a 5W/kg boy will walk it in instead of running home image
    I'm will try to reduce body weight this year as you benefit A LOT of that on the run which is the most important part.
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