Swim CV test | 80/20 Endurance

Swim CV test

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  • #14605

    Hello here,

    Last week, I had a very frustrating experience during a critival velocity test session. I had very good sensations while swimming both 400m and 200m blocks and I improve my time in both :). But at the end, I was disappointed to find out that my CV had not changed…

    4 weeks ago: -> CV at 1min42s
    – 400m in 6min38s
    – 200m in 3min13s
    last week: -> CV at 1min42s
    – 400m in 6min28s
    – 200m in 3min05s

    In the 80/20 resources Intensity Guidelines for Triathlon I can read :

    A mathematician will notice that the CV formula result is influenced both by the time and the delta between the two tests. Even if your total combined 400+200 time goes down from test A to test B, if the difference between the 400 and 200 times are greater in test B, your CV might actually increase. In this way, the CV test “punishes” the athlete for poor pacing.

    What does it mean ?
    Am i swmming my 400m block to slow ?
    How can I improve that ?



    Being a math geek, basically you have swam your 400m 10seconds quicker but your 200m only 8seconds quicker and is half the distance. When you look at average pace for the distances your improvement for the 400m is more than double that of the 200m. Also think about your average pace, the 200m swim pace is better than your 400m swim pace, which is to be expected but being fatigued this isnt always the case.
    I wouldn’t be too worried about this, you prob were a bit more fatigued after your 400m leading to less of an improvement in the 200m which is the pacing issue. If you pace at your true LTSP then you should be able to hold the same pace in both the 400m and 200m.
    The alternative method is warmup with 200/300m then do a 1000m time trial, this method is designed more for beginners and intermediates.
    Hope that helps

    David Warden

    nreavaille, I can’t make excuses for the drawbacks in the CV testing system. Clearly, your combined 600 meters dropped by 18 seconds. But, it’s just the nature of that test to not move the needle much.

    The 1,000 meter/yard option is a better choice for some athletes. Even if you had performed that test, let’s say you dropped 20 seconds from your 1,000 test (18 seconds over 600 = 20 seconds over 1,000 as an estimate), that would only be a 2 second difference in your threshold pace anyway. 18 seconds feels like a huge drop in time, but it’s really not over the full 600. Using either system, your zones are really close to being the same.

    But, you should celebrate the improvement anyway! That’s still a sign of improved swim fitness.



    Hi and thanks for your answers.

    I will try the 1,000 meter test next time to see if my CV is different.
    But I found this test much more difficult in term of pacing, it’s hard to find the correct good pace during 1000 meters and also mentally. Especially if we have to do it every 3 weeks.


    David Warden

    N, I actually prefer the 1,000 over the CV now. Wasn’t always that way, but you’ll learn to pace yourself on that and it may become your go-to.


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