Retesting my "CSS" Swim Pace

>> Wednesday, November 23, 2016

I first started talking about CSS swimming when Robby B mentioned it to me 2 years ago. In this post from 2014, I mentioned this:

[Robby B] turned me on to Swim Smooth and some of their ideas of swim training:

To improve your lactate threshold you want to do your quality swim sets at your current threshold pace or just below it. Many athletes make the mistake of training above lactate threshold in short sharp swim sets - that isn't nearly as effective.

Well, that's what I've been doing for the last 5 weeks: hard interval swims. So what's your "best" pace to train at? Your "CSS" pace. They go on to explain what that is:

CSS is an acronym for Critical Swim Speed. It's an approximation of your lactate threshold speed and you can find it by doing a couple of swimming tests (no blood involved - just a stopwatch!). It's not precisely the same as lactate threshold but it will be within a couple of seconds per 100m, which is plenty accurate enough to guide your training.

They say to swim an all-out 400, rest and swim easy a bit after that, and then do an all-out 200. Find the difference between your time in the 400 and 200, and then divide that by 2 to get your CSS pace / 100.

For example, in Nov of 2014, I did this: I swam my 400 in 6:10. Then I did my 200 in 3:00. The difference between those is 2 times is 3:10. Divide that by 2, and my CSS training pace should be 1:35/100.

Six weeks later, I "retested" my CSS pace and did this: 400 in 5:55, the 200 in 2:55, difference of 3:00, which means my CSS training pace should be 1:30/100.

Last week, I tested it again. I've FINALLY been able to swim enough (with my elbow/forearm and shoulder issues being kept at bay) that I felt like it was worth testing. I did the 400 in 5:54.49, the 200 in 2:54.53, difference of 3:00 (well, 2:59.96), which means my CSS training pace is STILL 1:30/100.

This was GOOD NEWS and BAD NEWS. It was good news because I'm essentially back in (similar) shape as I was before my best year of swimming. It was bad news because I've been sand-bagging my workouts a bit lately, and this tells me I CAN kick my butt into gear and work harder.

I think some of these "longer" CSS workouts are what I need now. My distance is slowly coming back (nearly 9,000 yards in Sept, 10,000 in Oct, and already over 10,000 this month - which is about half of what a GREAT month in the past was), but my endurance is still sh*t. I don't need to go nuts in the pool because I'm not planning on racing anything over a sprint tri in 2017, but I'd still like to be able to work on my endurance. So some CSS swims where I let off the gas a little, but then hold that pace for some longer sets is what I need.

Here's my post from 2 years ago with more info about CSS swimming if you're interested.


Mitch Clayton,  9:12 AM, November 23, 2016  

Just for a little clarification... Is your CSS pace supposed to be more of a "base" pace or more of an "aerobic threshold" pace?

Steve Stenzel 3:56 PM, November 23, 2016  

Mitch, it's sort of a just-below-threshold pace that's supposed to be good for training. The idea is to do your swimming at that pace even if the start of your intervals seems a little easy. Then, by the end, it will be hellish to try to keep that pace with such short rest.

Check out the link that goes back to my post from 2 years ago, and then in THAT post, there's a link to more "official" info about the idea of CSS swimming/training.

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