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How Fast Do You Need to Be??

February 16, 2014

Masters athletes, and new to swim athletes in specific, often think about what kind of paces they can hold in training in terms of sets of 100s, sets of 200s, etc, with the goal to improve their time for swims that are greater than or equal to a mile in length.  When seeking greater speeds in those sets they tend to ask what technical improvements they can make, and seek to make those improvements in the course of their workouts – doing 100s, 200s, etc. while “thinking about their stroke”.  But as you practice some new technique, your body is inevitably weak in terms of repeating that technique because it has not practiced it much.  The technique will therefore tend to degrade as one swims 25, 50, 75+ yards continuously.  In my experience, this degradation is so pronounced that much of the technique change that is desired disappears after roughly 50 yards, and the “new” stroke becomes unrecognizable after 100.

If we accept this as a truism for many athletes, shouldn’t we instead try to focus on how fast they can swim 25 yards at a pop?  And to make us “stronger”, focus on how fast we can do 25 yards, and how many 25 yard repeats we can do?  For some context, I wanted to look at just how fast one needs to be in an all out 25 in order to reach a given speed in a mile.  The two current American record holders in the 1,650 yard freestyle are as follows:

  • Womens 1650 record holder – Katie Ledecky, 15:15, averaging 55.5 / 100, or 13.9 seconds per 25.
  • Mens 1650 record holder – Martin Grodzki, 14:24, averaging 52.4 / 100, or 13.1 seconds per 25.

Let’s estimate that Katie Ledecky can swim a  25 in 11.0 seconds.  Estimate that Grodzki can go a  10.0 for his 25 sprint.  If we take these as reasonable estimates of their top speed capabilities (if someone has exact knowledge, feel free to share), then for their record swims, they averaged approximately 3 seconds per 25 slower than their all out speed.  3 seconds per 25 at these speeds means that their endurance time per 25 is about 130% of their sprint lap time.  Let’s say they can average an additional 1 second per 25 slower for a 2+ mile swim, which would equate to a lap time of ~ 140% of their all out sprint.

So… if you are physiologically suited for the a 15-20 minute event, and trained to the limit of your endurance capabilities, then you should be able to average approximately 130% per 25 of your all out 25 sprint time, and you can do 140% per 25 in a multi-mile swim.  What does this mean in terms of performance in an open water endurance race?  Based on the paces outlined here one needs to be capable of averaging about 1:13 per 100 in a threshold pool set to break 1 hour in a non-wetsuit ironman swim.  So. take this 1:13 per 100, which is 18.25 seconds per 25 as your goal speed.  18.25 is 140% of 13 seconds, so, to break an hour in an Ironman non-wetsuit we need a sprint speed of 13 seconds in a 25.  Other benchmark speeds are as follows:

  • If you can go 16 seconds in a sprint 25, then your max endurance rate would be 1.4 * 16 = 22.4 / 25 which translates to an ironman swim of about 1 hour 11 minutes.
  • If you can go 18 seconds in a 25, then your max endurance rate would be 1.4 * 18 = 25.2 / 25 which translates to an ironman swim of about 1 hour 21 minutes.

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