I’m reprinting verbatim a comment-and-reply from Olympic Champions are Terrestrial Mammals Too because the question posed is of universal interest.

Marjorie asked: How do you increase stroke length? I have the TI Self-Coached Workshop DVD and I was able to decrease from 30 to 24 spl in the last 7 months but when I get to my last laps in my 1500 my spl is 27. My goal is 20. These are in a 25 yd pool.

Marjorie’s question identifies two separate aspects of how we increase efficiency: (1) Improving Stroke Length — in her case from 24 to 20 SPL; and (2) Maintaining Stroke Length – in her case to eventually be able to swim 1500 yds @ 20 SPL.

They’re equal in importance, but accomplished in different ways.

To Improve Stroke Length You do specialized sets of relatively short repeats — seldom longer than 100m — where speed or pace is mostly besides the point. The sole goal of such sets is to swim at a lower count than usual. These sets can include either drills or whole stroke, in a wide variety of combinations. These sets usually include the following elements:
1. A primary focus on Balance and Streamline. This can be in either drills or whole-stroke, and often combinations such as 25 Drill 25 Swim, or 25 Drill 50 Swim. Whole-stroke laps will most often focus mainly on swimming with a particular Stroke Thought, and testing whether that Stroke Thought results in a lower count.
2. Using a Tempo Trainer at lower rates — most often 1.3 sec/stroke or slower.
This kind of training changes your movement pattern to reduce (1) drag and turbulence caused by how your body moves through the water or how you move arms and legs; and (2) slippage in your stroke. Your goal is to learn to move through the water, rather than move it around.

To Maintain Stroke Length, you do whole-stroke repeats, most often with a goal of patiently-and-incrementally increasing the distance you can swim without adding strokes to a high-efficiency SPL. I will often do this with sets like:
[4 x 25 + 3 x 50 + 2 x 75 + 1 x 100] in which my sole focus is to establish an efficient count/pattern on the 25s and test my ability to complete the set while minimizing any increase in count. If I see the count increase when I get to 75s, I would then drop back to the 50s until I strengthen the ‘neural circuit’ for the count I’m focused on holding.

I also do this quite often with Tempo Trainer — I.E. Do the above set with TT set at 1.30 seconds/stroke. If I can maintain my starting SPL to the longest repeat, I might repeat the set at, say, 1.28 sec/stroke. I’m focused on looking for the distance at which my efficient pattern breaks down. Once I find it I’ll do as many repeats as necessary at the level where I can – with keen focus – maintain efficiency.

In Marjorie’s case it would mean NOT swimming a 1500 if her SPL rises to 27 SPL as she goes. It could perhaps mean continuing to swim so long as SPL is 24, then rest for perhaps 10 seconds after any lap of 25 SPL. Over time, her goal would be to complete the 1500 with fewer — eventually NONE — of those 10-sec breaks.

You’d use a separate kind of set to improve that SPL to 22 — and test the new improved SPL with ‘broken’ 1500s in a similar way. However I should note that while I RACE 1500 to 3000m in open water, 90% of my training reps are 200 or less and I might swim 1500 continuous in the pool as infrequently as once or twice a year. (I do swim such distances continuously at least weekly in open water practice.)

I often combine the two types of practice. Last October, while visiting Hong Kong I practiced in the 50m pool at Univ of HK. I hadn’t been in a 50m pool in quite a few months. My plan was to start with some easy 200m repeats. Last summer I would have easily maintained 38 SPL on those repeats. This day I started at 39, then saw my SPL increase to 40, 41 and 42 on the next three laps. I tried again and the same thing happened.

So I threw out the plan for 200m repeats and dropped to 50m repeats, focused on two Stroke Thoughts: (1) Hang my head until it felt weightless; and (2) Separate water molecules and reach an inch or two farther with my extending hand. That got my SPL down to 39, then 38, then 37, within 400m of 50m repeats.

Then I did several 100m repeats to test whether I could keep them at a stroke count of 38+39. When I succeeded, I tried some 150 repeats with the same goal. When that worked, I finally resumed doing 200m repeats, and was able to keep my SPL below 40.

If I’d had a Tempo Trainer with me that day I could have substituted that for the Stroke Thoughts on the Improve Stroke Length part of this process. Most likely I’d have started at 1.2 sec/stroke and gradually slowed tempo to, say, 1.25, 1.30, 1.35 until I hit the tempo that gave me an SPL of 36 or 37, then done the increasing-distance set at that tempo.

The point is to commit to practicing efficiency and make all your choices about set design subject to that goal. It’s organic, not formulaic.

Terry and Shinji -- identical effective recoveries