Training for marathon swims: Pool vs. open water

Training for marathon swims: Pool vs. open water


Newbie marathon swimmers often wonder how they should allocate their training time between the pool and open water. There’s no simple answer: It depends on a variety of factors unique to the individual. A few questions to ask yourself:

What’s the target swim? Distance, water temp, conditions, etc. The further outside neutral conditions your target swim is, the more open water you’ll want to incorporate into your training. (To train for cold water… swim in cold water.)

Are you training to finish (regardless of time), or are you training to race? The more speed matters in your target swim, the more high-quality interval training in the pool you’ll probably want to do.

What’s most convenient? If you live next to a safe body of open water, but far away from the nearest pool, this may tip the balance towards OWS. In my experience, convenience promotes consistency — and consistency promotes results.

What do you inherently enjoy? If you have access to a high-quality Masters pool squad with good coaching and fun lanemates, this may tip the balance towards the pool. If you get blissed out by open water, this may tip the balance towards OWS. Enjoyment promotes consistency, and consistency promotes results.

Consistency is the main thing, and I’d say whatever formula helps you swim consistently is fine.


For the sake of argument, though, let’s say convenience and enjoyment don’t pose obstacles for you. All else being equal, what’s the ideal combination of pool & open water training?

My personal beliefs are, you can’t beat the pool for improving speed and stroke technique; and you can’t beat open water for acclimating to cold water and rough conditions.

Perhaps that’s just common sense. But there are some less-obvious corollaries:

In my opinion, for many mainstream marathon swims it’s perfectly OK to do most of your training in the pool. When I did the 24-mile Tampa Bay Marathon Swim in April 2011, I hadn’t been in open water since the previous October.  I won by 42 minutes.

I don’t mean to say open-water training isn’t valuable or important; but I do think sometimes marathon swimmers underestimate the value of pool training.

In that vein, I was struck by this recent tweet from Swim Smooth founder and 2013 MIMS champion Paul Newsome:

Like me, Paul comes from a pool-swimming background, but as an adult competes primarily in long-distance open water swims. Like me, he does most of his training in the pool, even for moderately “cold” swims such as MIMS 2013 (61F).

Among elite professional open water swimmers, the ratio of pool to open-water training approaches 100%. In the case of my old friend Mark, who competed in the Beijing Olympic 10K, his pool training didn’t “approach” 100% – it was 100%. Aside from organized races, he did literally zero open water training in preparation for the Olympics.

What are the exceptions to this rule? You probably already know the answer: very long, very cold swims. You must acclimate. The colder and longer the swim, the more longcold water training you should be doing. For me, anything below about 18C (64.4F) for marathon distance, and I’d aim to be doing at least some of my training outside the warm pool, in cold water. At 15C for the target swim, I’d spend proportionally more time in open water. At 12C, even more. Body fat will also be a factor here.

But still, even for long, cold swims — I probably wouldn’t let my ratio of pool-to-OW training go below 50%. The pool is just so, so much better for developing (and maintaining) speed and fitness. The extra speed (resulting in faster times) and extra fitness (resulting in the ability to maintain higher energy output for longer), more than make up for the opportunity costs in cold-water acclimation.

Taking liberty with a well-known proverb:

All OWS and no pool makes Jack a slow swimmer-boy.

10 Responses to “Training for marathon swims: Pool vs. open water”

  1. IronMike

    2013-10-18T20:16:59+00:00

    Nice. Need more from your extensive experience.

    Reply
  2. Sully

    2013-10-21T05:52:53+00:00

    There was one season where I got up to Alum at least one weekday morning a week. I really enjoyed setting my Garmin to vibrate every X meters. It was a good way to mix it up and do intervals in open water.

    Reply
    • Evan

      2013-10-23T10:38:37+00:00

      OW intervals are a good idea. For whatever reason I find it tougher to pull off than in a pool.

      Reply
  3. Sarah

    2013-10-23T07:37:44+00:00

    I agree with you 100%…. but I’d much rather be in the open water. I think you have to find a balance between the daily grind of necessary pool training and the joyful, fun open water training. I’d MUCH rather have cool tan lines than chlorine burn. :-)

    Reply
    • Evan

      2013-10-23T10:39:58+00:00

      Yes, I agree completely… and that balance will be different for each individual. Thanks for the comment!

      Reply
    • Writingprincess

      2013-10-23T11:21:16+00:00

      I love OW swimming but for speed it just doesn’t cut it. I never really keep track of my time when I’m in OW I’m way too busy enjoying the experience. I liken it to doing an indoor computrainer session vs a century ride. I focus better when I’m doing the indoor training in the pool. I’m doing a long race in Norway so I’ll need to acclimate to the cold weather. Luckily I live a block away from Lake Michigan and can swim all fall and as long as I can stand it this winter. :)

      Reply
      • Evan

        2013-10-23T11:40:06+00:00

        I used to live a block from Lake Michigan too! Do you swim at the Point?

        Reply
  4. Sully

    2013-10-23T17:54:50+00:00

    I just read “Grayson” cover to cover in one sitting. Any argument for pool training over open water is officially mute in my mind. haha

    Reply
    • Evan

      2013-10-30T11:53:34+00:00

      I actually haven’t read that yet. You recommend it?

      Reply

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