First MAF Test for Big Shoulders 2.5K (04/18/2014)

For those not familiar with the Chicago open water swimming scene, the Big Shoulders 2.5K and 5K open water swim is one of the big open water swims in the Midwest.  My mentor, Terry Laughlin of Total Immersion Swimming sent me an email a week or so ago saying that he registered for the 5K. I was going to skip it this year, but I would feel a little foolish not doing it this year under the circumstances. Since I hate distance freestyle, I registered for the 2.5K event (non-wetsuit division). 

After hitting the register button, a question came to my mind:  Can I use the techniques and tools that Terry’s been talking about in his webinars to get in shape and hit a good time in the swim.  The last time I did the swim, I finished in 42 minutes and change but I did absolutely no training for the swim.  I’m setting a goal to swim the race in under 39 minutes this year.  This blog post will be about how I set my baseline for my training.

Taking the cue from Phil Maffetone, I put together a Maximum Aerobic Fitness (MAF) test to establish how fast I could swim the race distance while keeping my heart rate in an aerobic zone.  My success in open water will be based on how fast and efficiently I can swim in an aerobic zone, so I thought this was a good choice.  2.5K translates to about 2700 yards of swimming, so I did a set of 27 x 100 on 10 seconds rest after each swim.  I wore an Finis Aquapulse heart rate monitor set to call out my heart rate every 10 seconds.  Using Maffetone’s 180 – Age formula with adjustments, my maximum aerobic heart rate worked out to be 133.  Essentially, I swam each 100 at the fastest tempo and pace that I could without having my heart rate go above 133.  If my heart rate was below 133, I sped up.  If it was higher than 133, I slowed down.  To track efficiency, I counted my strokes in the middle 50 of each 100.  The 10 seconds gave me enough time to write down the strokes I took in the middle 50 of the 100 on a laminated sheet by the pool.  I wore a Finis Swim Sense Performance Monitor to track stroke rate and splits.  I realized at the end that I didn’t use it correctly, so I just took the elapsed time and subtracted 260 seconds to get the total time for swimming.  Anyhoo…

So the results of the swim were:

  • Pace:  1:35.6 per 100 yards
  • Stroke Length:  28.7 strokes per 50
  • Stroke Rate:  1.31 seconds per stroke

I am VERY out of shape right now, so I had to consistently throttle it back to keep in an aerobic zone during the swim.  Using a formula derived from a Facebook conversation with a Total Immersion colleague of mine, Stuart McDougall, that test set yields an estimated open water swim time of 47:35.  I’ve got my work cut out for me.  Given that I’m starting off from square one fitness-wise, I will probably use the heart rate monitor more in the first couple of months to make sure that I’m training in the appropriate heart rate zone as I work on focal points, stroke counts/gears, and tempo games.

I’ll have some additional blog posts coming up that give the thinking behind the test and the approach:

  • Maximum Aerobic Heart Rate Formula (180-Age)
  • Doing a MAF test on your own and still get good data
  • Using the Aquapulse Heart Rate Monitor
  • Deriving an Open Water Pace from a Pool Pace
  • Why I hate SWOLF and go the old fashioned Swimming Golf route

I’m sure I’ll come up with more as I do more swim practices. I consider my training officially begun.

If you are interested in more detail, you can see the specific practice that I did for the MAF Test and others that I will be logging on our Practice Samples page.

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