Don't Let the Pool Cheat You!




Did you know a 1.5k open water swim can be 39% longer than a 1.5k swim in your local pool?   “Say what?” as your eyes bug open!  Follow along as I explain this phenomenon.


When swimming a pool 1.5k (1650 yards or 66 lengths in a 25-yard pool) I consistently average 18 strokes per length or 1,188 strokes overall.  I recently had the opportunity to work out in a 50 yard pool (yes 50 yards not meters) and naively thought I could swim each length in 36 strokes.  Imagine my surprise when it actually took me 43 strokes per length.  Since there was a marker at the ½ way point in the pool I decided to count the number of strokes during the first 25 yards and then during the second 25 yards.


Sure enough, I took 18 strokes to reach the ½ way marker but then needed 25 strokes to finish the length (I refer to these 25 strokes as my honest stroke count since I didn’t have the benefit of the wall push-off).  If I convert this to a 1.5k open water swim where there are no walls, I’ll swim 1,650 strokes overall (the equivalent of 25 strokes times 66 25-yard pool lengths). 


This equates to 39% more strokes in open water than in the pool to cover the exact same distance.  This is huge!  Looking at it the other way, my pool stroke count per distance is 28% less than my honest open water count.


Does this also affect my time?  You bet it does! 


In the pool, I swim 1.5k in 27:50 or 25.3 seconds per 25 yards (OK, at 58 I’m no longer as fast as I was 10 or 20 years ago).  During my session in the 50 yard pool, instead of a time of 50.6 per 50 yards (2 x 25.3), I swam each length in 55 seconds:  25.3 seconds for the first 25 yards when I pushed off the wall and 29.7 seconds for the remaining 25 yards (I refer to this as my honest swim time since I didn’t get to push off the wall).  Converting this to the open water, I swim a 1.5k in 32 minutes and 40 seconds (29.7 seconds times the equivalent of 66 25-yard lengths).  This is 17% longer than in the pool.   Looking at it the other way, my pool time is 15% faster than my honest open water time. 


So what does this have to do with you?  Well, consider the following as it pertains to your training and race preparedness.


First and most obvious from the example above, your average 3,500 yard pool work-out is probably closer to 2,500 yards (28% less) due to the sling shot effect of pushing off the wall.  Second, your swim time is 15% artificially faster.  And, if you’re like the majority of triathletes for whom the swim is the least favorite component, your pool work-out is the first to hit the cutting room floor when push comes to shove in your weekly struggle to balance family, work and training. 


Also consider that accurate sighting arguably is the least developed swimming skill of most triathletes.  The resultant inability to swim a straight line due to poor sighting can add up to 5% more to the swim distance especially if the course is poorly marked.  Finally, just to make it interesting, throw in some current, chop and / or wind and your 1.5k swim is a whole different creature than its pool counterpart.   


Bottom line on race day:  you swim a longer distance than what you undertrained for in a time far slower than you expected.


What’s a triathlete to do?  The simplest answer is to train in open water but this is not practical for those who live in winter climates; and admittedly, coached pool workouts (such as US Masters Swimming) do afford an opportunity to focus on intervals, drills and technique. 


Increase the yardage in your workouts to compensate for the yards spent torpedoing off the pool wall on your turns.  If your current workout is 3,500 yards increase it to 4,500 yards.  But make sure they’re quality yards with an emphasis on streamlining your body movement through the water: 


  • Envision swimming through the smallest hole possible in the water to minimize the drag flowing over your body (think aquatic wind tunnel),
  • Maintain a horizontal body axis (to also minimize drag),
  • Keep a hand extended and anchored in the water during as much of the stroke cycle as possible (known as front quadrant swimming) in order to maintain your forward momentum by holding the water, and
  • Flutter kick with minimal leg separation and with minimal knee bend.


Maximize your open water swimming to the extent possible so you are conditioned to swim race distances without the push-off “rest” every 25 yards and so you swim effectively without the training wheel effect of lanes and black lines.  Most swimmers in open water swim one straight long set but with a little creativity and imagination you can create and simulate a pool workout complete with a warm-up, drills, intervals and a cool-down.  


Practice drafting.  It’s a useful skill to hone since it allows you to swim faster with less energy.  This is an easy skill to practice in the pool with some of your friends.  Your best position is 6-12 inches behind the swimmer ahead of you.  You should be close enough to feel yourself in the “slip stream” but not so close you keep slapping their feet.  During the race make sure the swimmer ahead of you is swimming a straight line or you’ll negate the drafting advantage by swimming a crooked line.


Practice your sighting.  You can add distance and time to your swim with poor sighting skills.  At the pool, while warming up or cooling down, pick an object at the end of the lane:  an exit sign, a clock, a life ring, etc.  Raise your head slightly (without disrupting your horizontal body axis), locate the object and then return to your normal breathing pattern.  While pool goggles work fine in the pool, you may want to consider a pair of the larger lens goggles that give you a bigger direct and peripheral field of vision for your race. 


Learn to breathe bilaterally.  This is a companion skill to sighting.  Though very difficult to master, it’s one of the most valuable open water skills you can learn; and it has a three-fold payback.  You improve your sighting because now you’re looking to two sides.  Your neck muscles become more balanced from turning both directions.  Most importantly, if waves and choppy water are coming from one direction, simply breathe to the other.


Pool swimming does have benefits but just as you don’t train exclusively on a treadmill or stationary bike, you need to train sufficiently in open water to be at the top of your game on race day. 




Gary Emich is an ASCA and USA Triathlon-certified coach, former race director of the Alcatraz Challenge Aquathlon, co-host of the DVD, Lane Lines to Shore Lines:  Your Compete Guide to Open Water Swimming, and co-author of Open Water Swimming – Lessons from Alcatraz.  Gary has completed over 1,000 swims from Alcatraz – without wetsuit!  Visit for more information.