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.

Stroke Thoughts

The swimming stroke is not unlike a golf swing: a complicated, interconnected series of fine and gross muscular movements. For the few who do it well, it appears fluid, natural, unified, and effortless. For most, the movements of swimming and golf can feel unnatural, difficult to integrate, and frustratingly unamenable to brute force.

Even those who have mastered the swimming stroke/golf swing can develop subtle technique flaws, of which they may not even be aware. One must maintain constant vigilance against these creeping flaws, ideally through a combination of mindful practice, well-selected drills, coaching, and video analysis.

One method I find useful in maintaining proper form and guarding against creeping flaws is: stroke thoughts. I didn’t invent this phrase or idea, but I define it as: simple, succinct technique pointers repeated subvocally (internally) while swimming.

In practice, I use stroke thoughts most often at the beginning of a session (while warming up), or when I feel myself lapsing (mentally or physically) in the middle of a workout or race. I repeat each thought by itself for a few stroke cycles, focusing on just that single part of my stroke, before moving to the next thought. Basically, I’m “checking in” with each part of my stroke.

I use seven specific stroke thoughts, starting with the hand entry and proceeding through the catch, pull, hip drive, and kick.

1. “middle finger first”

I have a slight tendency for a thumb-first entry, especially on my right/breathing side. So, I focus on keeping my hand in a neutral position as it enters, fingertips parallel to the surface of the water, with the middle/longest finger entering first.

2. “reach”

When I get fatigued and/or cold, I have a slight tendency to shorten my stroke too much and rush the catch. So, I focus on reaching forward before I initiate the pull. Notice I did not say glide. I don’t pause at the front of my stroke, like catch-up drill. I’m simply trying to reach forward a bit more. The reaching motion comes from body rotation, which in turn comes from hip drive. (Everything is interconnected!)

3. “fingers down”

When I finish reaching forward, I tilt my wrist slightly and point my fingers toward the bottom of the pool. I try to keep them pointed toward the bottom (not angled to the side, not horizontal) all the way through my pull.

4. “elbows high”

I sometimes drop my left elbow slightly as I breathe to the right, especially with fatigue. This is not only less efficient, but can also irritate my left shoulder. So, I focus on keeping that elbow high, “grabbing” the water with my lats, all the way through the pull.

5. “pull straight back”

No “S”-stroke. Straight back. Like a big paddle.

6. “tight kick”

I sometimes do a slight scissor-kick as I breathe. This is an unconscious compensation for the slight “unbalancing” caused by my breathing motion. However, it greatly increases drag. So, I focus on keeping my kick tight, kneecaps close together and toes pointed inward. This has the follow-on benefit of forcing me to take a more efficient and balanced breathing motion. (Everything is interconnected!)

7. “drive the hips”

With fatigue, I also tend to rotate less, increasing the burden on my shoulders. Ironically, this causes me to become even more fatigued. So, I focus on driving my rotation from my hips, less from my arms and shoulders.

After I cycle through my seven stroke thoughts, I turn my brain off and focus on the overall rhythm and “feel” of my stroke. If something still doesn’t feel quite right, I cycle through the stroke thoughts again and try to identify where things are breaking down.

Notice I’ve said almost nothing about the recovery phase of the stroke (except perhaps “middle finger first” –> the very end of the recovery). I don’t think much about my recovery because frankly, it doesn’t much matter. It doesn’t contribute to either propulsion or drag reduction, because it’s happening above the water.

What matters is what happens under the water. That’s why elite swimmers display a wide variation of recovery styles, but are comparatively similar under water. Think Janet Evans vs. Sun Yang.

Important note: Stroke thoughts are intended as a temporary “check-in” or tune-up. Like with the golf swing, over-thinking can lead to paralysis. In the middle of a long swim or tough interval set, I’m mostly trying to focus on rhythm, flow, and feel.

Here’s a video of me swimming 100 yards at the recent Swim Smooth coaching clinic in Livermore. Which stroke thoughts should I be focusing on?

Swim Smooth stroke filming from Evan Morrison on Vimeo.

Dave Scott on open-water swimming technique

After his victory at MIMS, Paul Newsome and his Swim Smooth business partner Adam Young embarked on a cross-continental road trip to experience America via swimming.

Along the way, they stopped in Boulder, Colorado and met up with 6-time Ironman world champion Dave Scott. Paul did an interesting video interview with Dave on the topic of open-water swimming technique. It’s worth your time to watch all 7 minutes, 46 seconds of this video. Here’s the money quote from Dave:

“I’m not concerned about distance per stroke. I like an effective front-end of the stroke, on the catch.”

How to get an effective workout at public lap swim

This post is part of a collaborative project with Donal at LoneSwimmer, delving into basic issues of training and technique in swimming. Donal also published a post today, check it out here.

Whenever possible, I prefer swimming with other people – either with a training partner or in a coached squad workout. But occasionally my schedule dictates finding water at a public lap swim session. It’s possible to get a good workout at open lap swim, but it takes a bit of planning and training know-how.

Based on my observations at hundreds of public lap swim sessions over the years, there are some folks who come to swim laps, desire to become better swimmers, but simply don’t know how to go about the task. For those without a background in competitive swimming or similar sport, it may not be at all obvious.

For example, one of the more common approaches I see at the pool consists of: (1) Getting in the water. (2) Swimming continuously for X amount of time. (3) Getting out.

With that in mind, here are a few pointers on getting the most out of solo workouts at a public lap swim session:

Learn proper lane etiquette.

It will be less frustrating for you… and everyone around you in the pool.

Have a workout plan.

Not necessarily a full written workout with every detail, but at least a basic mental structure of a workout. What do you want to accomplish today?

A basic workout structure can be as simple as this:

  • Warm-up – mostly easy swimming.
  • Technique work & build into main set.
  • Main set.
  • Kick or pull set.
  • Cool-down.

Interval training is more efficient than continuous swimming.

Continuous low-intensity swimming is an inefficient way to build cardiovascular endurance. Interval training (repetitions of shorter distances, swum at higher intensities than one could sustain continuously) is far more effective.

Check out the Marathon Swimmers Forum for some good example interval sets:

Don’t rely on pool gear.

Fins, paddles, buoys and snorkels are swim tools, designed for specific purposes, typically strength or technique-related. When you use any swim tool for an entire workout (or majority of it), it’s no longer a tool but rather a swim aid.

If you can’t swim without fins, in my view, you can’t swim. What happens when they fall off accidentally in the ocean? If you always strap on paddles for the main set, what happens when you compete and you can’t use your paddles?

Learn flip turns – even if you only compete in open water.

If you do open turns, you’re basically coming to a complete stop between every length of the pool. Open turns are surprisingly common among triathletes, even relatively fast ones. I’ve never understood it; plus it looks goofy. Flip turns (sometimes called tumble turns) allow you to transfer much more momentum from one length to the next. It makes pool swimming much more bearable.

Learn all four strokes – even if you only compete in freestyle/front-crawl.

Different strokes work different muscle groups, and it will make you a better athlete. Backstroke can provide a nice change of pace for your shoulders after too much front-crawl.

My favorite stroke tip

Beginning with the catch, and continuing through the finish of your pull:

  • Keep your fingers pointed straight down toward the bottom of the pool,
  • palm facing directly behind you,
  • elbows high.

This is a distilled version of the “paddle stroke,” which has been taught in elite USA Swimming programs since the mid-1990s, but has only recently been widely taught in adult Masters programs.

I like this stroke tip for several reasons:

  • It’s simple and easy to understand, even for new swimmers.
  • It’s high-leverage, meaning it can produce large gains in speed.
  • It’s useful for swimmers of all abilities.


I use this “stroke thought” almost every time I swim these days. If I’m feeling fatigued or unfocused, it’s surprisingly easy to fall back on an “S” pull pattern (an unconscious but ineffective attempt to gain more purchase on the water), or to let my elbows slip.

Yet another reason I love the FINIS Agility Paddles: it is much easier to “feel” the early catch, and sustain it throughout the pull. If you start pulling through at odd angles (rather than straight back), the paddle may slip right off your hand.

fingers_down3Is that a Zoolander face?


Controlled Stroke Count Drill

In “Stroke Count Games” and “A Better SWOLF Formula” I suggested a test set of 8×100, as fast as possible, holding a specific number of strokes per length (SPL), to hone in on your most efficient combination of stroke length and tempo.

I frequently do a modified version of this set as a quick tune-up before a competition or a challenging distance workout: 12×100 short-course, aiming for the following SPL on each rep: 15, 14, 13, 12, 11, 10, 10, 11, 12, 13, 14, 15. Moderate, controlled pace on all – no more than 75%.

Obviously, the specific SPL goals will differ for each individual. For me, 15 SPL is my 400m/500yd race pace. 14 SPL is my 1-2 mile race pace. 13 SPL is my marathon pace.

The reason I like this set as a warm-up / tune-up is that the act of “depriving myself” of one stroke-per-length on each of the first 6 reps really focuses my attention on efficiency – maximizing the amount of water I’m pulling, and minimizing drag. Then, adding one SPL on the way up (11, 12, 13, 14, 15) feels increasingly luxurious and powerful.

The over-arching goal: the 13, 14, and 15 SPL reps on the way up should feel better, faster, and more efficient than the 15, 14, and 13 SPL reps on the way down.

I took some GoPro video of myself doing this set, so you can see the subtle differences in my stroke from one rep to the next. The video shows a bottom-of-the-pool view of me descending from 15 to 10 SPL; then a side-underwater view of 14 SPL; then an above-water view of 14 SPL.

(Direct link to video)

A better SWOLF formula

SWOLF (“swim golf”) is a drill that measures swimming efficiency. A SWOLF score is your time (in seconds) on one lap of the pool, added to the number of strokes you took. Lower scores = Higher efficiency. SWOLF is a fuzzy, indirect measure of efficiency, because stroke count doesn’t necessarily reflect effort. In my view, the most precise definition of SWOLF is that it identifies the most efficient stroke count for a given level of effort.

I originally wrote about SWOLF in April 2012, and the post has become – by a wide margin – the most widely-read in the history of this blog. In a subsequent post a month later – “Stroke Count Games” – I described how SWOLF doesn’t quite capture the most efficient stroke count. At least for me, using stroke cycles (number of strokes divided by two) produces better results.

I wondered if this was true for other swimmers, so I asked any interested readers to send me their own data, using a test set of 8×100. Three readers sent me their results. In short, my suspicions were confirmed: Strokes cycles produces better results than stroke count. In essence, the original SWOLF formula seems to over-weight stroke length in its measure of efficiency (and thus under-weight speed).

Reader #1 is a 6-foot 2-inch (188 cm) male in his late-20’s with an ape index of 1.07 (arm-span greater than height). He did not swim competitively at the high school or college level. His recent best times include 25:21 for the 1650-yd Freestyle and 3 hours, 18 minutes for a 10km open-water swim. His typical open-water stroke rate at marathon pace is approximately 50 strokes per minute.

Here are his results for the test set of 8×100:

SPL m:ss SWOLF SWOLF-improved
10 1:50 150 130
11 1:40 144 122
12 1:30 138 115
13 1:23 135 109
14 1:16 132 104
15 1:12 132 102
16 1:13 137 105
17 1:15 143 109
18 1:17 149 113

Reader #1 pegged his “natural” stroke count per 25 yards at 15-17. According to traditional SWOLF, he was most efficient at 14-15 SPL, followed by 13. According to SWOLF-improved, he was most efficient at 15 SPL, closely followed by 14 and 16 SPL. SWOLF-improved seems slightly more accurate in this case. In Reader #1’s own words:

15-17 feels natural.  At 14 I could already notice some laboring.  Anything at 13 or lower, inertia was a huge factor.

I think that’s why the curve is much steeper on the lower stroke side.  It might have said 13 was more efficient than 17, but no way I’d want to swim more than a 100 at 13.  17 – no problem.

Reader #2 is a 5-foot 7-inch (170 cm) female in her late 20’s with an ape index of 1.0 (arm-span equal to height). She swam competitively in both high school and college, and is a Triple Crown marathon swimmer. Her recent best times in the pool include 19:15 for the 1650-yd Freestyle. Her typical open-water stroke rate at marathon pace is 70 strokes per minute.

Reader #2 insists her data include the caveat that she did a big training swim (21km) the previous day 😉

SPL m:ss SWOLF SWOLF-improved
15 1:20 140 110
16 1:18 142 110
17 1:15 143 109
18 1:12 144 108
19 1:10 146 108
20 1:08 148 108
21 1:08 152 110
22 1:10 158 114

Reader #2 puts her “natural” stroke count per 25 yards at 18-20, depending on pace. SWOLF-improved agrees. Traditional SWOLF, on the other hand, under-estimates her most efficient stroke count.

Reader #3 is a 5-foot 6-inch female in her early 20’s. She swam competitively in both high school and college, and is a national-caliber distance swimmer. Her recent best pool times include 17:09 for the 1650-yd Freestyle. Her typical open-water stroke rate is approximately 80 strokes per minute.

SPL m:ss SWOLF SWOLF-improved
12 1:14 122 98
13 1:10 122 96
14 1:08 124 96
15 1:04.5 124.5 94.5
16 1:02 126 94
17 1:00 128 94
18 0:59.5 131.5 95.5
19 0:59 135 97

Reader #3 puts her “natural” stroke count per 25 yards at 16-17. SWOLF-improved agrees. Traditional SWOLF, once again, underestimates the most efficient stroke count.

For comparison, here are my results from the 8×100 set, as reported previously:

SPL m:ss SWOLF SWOLF-improved
9 1:20 116 98
10 1:14 114 94
11 1:10 114 92
12 1:07 115 91
13 1:05 117 91
14 1:02 118 90
15 1:00 120 90
16 1:01 121 93

In sum, you may find that using stroke cycles instead of stroke count produces more useful SWOLF results. If you own a Swimsense, then you’re golden – it already uses stroke cycles for its SWOLF calculation. I don’t own a Garmin Swim watch, but from what I’ve read online it seems to use the traditional formula.