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Winter Training: Calculate Your Jens Factor

Posted on 4 January 2010 by cosmo

No one disputes the importance of base training, and the truly serious make careful note of time, distance, and wattage in their pre-season rides. But when it comes to outdoor training—at least at my latitude—that doesn’t really capture the whole story.


[click-through for larger sizes]

Jens Factor, as defined by this chart, is just that—an integer value you can factor into your training data to properly reflect the increased benefits of staring down winter weather. Jens Voigt, a veteran roleur known to take particular glee in miserable conditions, is its obvious namesake.

It’s worth noting that Jens Factor makes no provision for precipitation, because the various types present such wide-ranging levels of difficulty depending on other conditions. It’s also worth noting that the Creative Commons license under which I released this image contains provisions for free re-use…

Oh, also—you can now buy the design on a wall poster or some t-shirts.

thoughts on “Winter Training: Calculate Your Jens Factor”

  1. Frances says:
    4 January 2010 at 11:56 am

    This is awesome.

    Reply
  2. kidpurple says:
    4 January 2010 at 1:14 pm

    -22F in Minnesota this weekend – I guess I was at Jens Factor HC.

    Reply
  3. Mike says:
    4 January 2010 at 2:16 pm

    Nice! Version 2.0 should incorporate precipitation. Driving rain is known to increase Jens Factor.

    Reply
  4. Scott says:
    4 January 2010 at 3:38 pm

    I think we need a new scale. Several in Omaha are biking the daily commute with temps as low as -16F.

    And I think we’re in for a cold snap coming up this week. 😉

    Reply
  5. Chris says:
    4 January 2010 at 5:38 pm

    No fair! It’s not my fault that the temps in Seattle don’t get beyond Jens Factor 1.

    Reply
  6. Richard says:
    4 January 2010 at 6:58 pm

    number of offspring should also be added as a variable. I think Jens has 16 children.

    Reply
  7. Anonymous says:
    4 January 2010 at 7:50 pm

    Jens factor 3 here in ontario

    Reply
  8. Debamundo says:
    4 January 2010 at 9:12 pm

    This is the coolest thing I have ever seen!

    Reply
  9. James Jordan says:
    4 January 2010 at 9:34 pm

    I think we need to not only add precipitation but also temperature on the opposite end of the scale. Having ridden in Adelaide during January at the Tour Down Under where the daily max can reach the 40C level (with overnight minimums still in the 30C’s) you need to have some ‘Jen’s Factor’ in you as well.

    Reply
  10. spice says:
    5 January 2010 at 8:18 am

    the ironic thing is, Jens probably goes south for the winter

    Reply
  11. Andromeda says:
    5 January 2010 at 9:13 am

    I sent this to my friend Mike — the only guy I know who loves Jens as much as I do — and he thought it was cool, and then I get an IM saying hey, had I seen the little photo credit at the bottom…?

    Even cooler now.

    Reply
  12. mrcranky says:
    5 January 2010 at 11:41 am

    I gave up work commuting in Edmonton when it exceeded Jens factor 4 on November 18. Definitely not up for factor HC.

    Reply
  13. jeff says:
    5 January 2010 at 12:11 pm

    Jens Factor HC made me laugh so hard I spew java through my nostrils onto my keyboard. This is one of the most killer charts I’ve ever seen. Chapeau, Cosmo.

    Reply
  14. al b says:
    5 January 2010 at 5:40 pm

    wow. when i went out on sunday, i was pretty smug… come to find out it was only a JF3. guess there is only one Jens.

    Reply
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  16. Mike says:
    6 January 2010 at 7:45 am

    Hey, thanks for the image credit! Much appreciated.

    You’re neglecting the other scale of weather-hardiness, though – the Hushovd Index, used to tally which nationalities of rider are going to be wrapped in leg-warmers, jackets and long gloves while others ride along cheerfully in shorts:

    HI1: Only the Spanish are in legwarmers
    HI2: Italians are starting to look a bit chilly
    HI3: French riders start to wrap up
    HI4: The Belgians and Germans start to feel the cold
    HI5: Even the Danes and Norwegians are starting to suffer a bit
    HI6: Thor Hushovd puts on a light jacket.

    Reply
  17. Dave says:
    6 January 2010 at 12:02 pm

    Great job, but you forget that a Jens factor 5 is the equivalent of a Boasson Hagen factor 2.

    Reply
  18. rainbow says:
    7 January 2010 at 7:14 pm

    You guys need to harden the …. https://www.youtube.com/watch?v=XY3TfjOeuhM …….up. Our domestic racing season is in our winter! I was 40 before I realized that Cyclocross photos in foreign media publications was as a separate class of cycle sport. It just looked like ‘racing’ here in New Zealand, only shorter, “why only an hour long? Why aren’t you doing the full 100 km standard club race?”
    Jens is not a fair control, we have already read on this blog that he is not human, any self flagellation in comparison is shallow braggadocio, I’m a Jens .01 pass me another beer its 20 C and the racing season is 5 still months away, thought’s of tapering for the TDF on TV haven’t even entered into the training plan yet.

    Reply
  19. Joe Steele says:
    8 January 2010 at 12:50 pm

    Jens Voigt once challenged Lance Armstrong to a “Who has the most testicles” contest. Jens won, by FIVE! And, whenever you have a problem in life, just ask yourself, WWJD? “What would Jens do”? Jens ROCKS!

    Reply
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  26. Guy says:
    29 March 2011 at 4:20 pm

    Cosmo – check out part 7 of the interview. I think you just got the ultimate compliment for your efforts.

    https://www.bicycles.net.au/Road-Cycling-News-and-Articles.62.0.html?&cHash=881a6e7bb3&tx_cmarticle_pi1%5BsingleID%5D=1060

    Reply
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  28. cna training says:
    5 May 2011 at 2:11 pm

    cna training
    Great post and informative post.

    Reply
  29. Jan says:
    5 May 2011 at 3:08 pm

    @ Guy, @ Cosmo

    Just flicked through the current edition of the German “Tour-Magazin”, in which they had a feature about Jens. He tells them about the “Calculate your Jens Factor”-thing, too. Seems like you really impressed him with that, Cosmo…

    Reply
  30. Anthony says:
    5 July 2011 at 7:28 am

    What would be the Jens Factor for 35deg Celcius and 80% Humidity! That’s my planet in summer.. Yeeeouch. Not fun.. and literally, not cool!

    Reply
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  33. cheap cycling clothing says:
    5 September 2011 at 8:58 am

    i just think we need to not only add precipitation but also temperature on the opposite end of the scale.

    any way,good job here!

    Reply
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  35. Liam H says:
    14 September 2011 at 2:05 pm

    This is fantastic. I’m planning on integrating this into our team training over the winter.

    Reply
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About the Author

a headshot of Cosmo Catalano

Best known for his How The Race Was Won® video series, Cosmo Catalano began blogging about pro cycling from a bike shop in 2005. Between then and now, he's designed cycling infographics, built cycling web apps, and supplied cycling content to print and broadcast media, all in the name of backing up his near-endless criticism with proof that it can be done better. He complains about cycling on Twitter at @Cyclocosm.

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