In 2014 I started getting upset with the standard 2% Short Course to Long Course conversion rates mandated by Swim Ontario. As most coaches already knew, 2% was convenient but horribly inaccurate conversion rate. And it created problems for kids swimming in LC meets when they couldn’t meet their 2% converted SC time, even if they had a fantastic swim. So I looked at World and European SCM and LCM Records, as well as National Records from USA, Canada and Australia. For the US I used the faster of SC metres, or SC yards + 10%. That 2014 post can be found here.
It’s now 3 years later, and I decided to see if things have changed. The table below lists the # of events where records have been broken.
Notice that if we ignore USA SC yards, it certainly seems like nothing has really changed. And this makes sense. The biggest meets in the world almost exclusively focuses on LC, with the World SC championships being the only significant and peculiar exception. And even that meet is often not attended by many of the elite.
However, as soon as we look at USA SC Yards we see a completely different picture. Almost every official record has been broken, plus new unofficial records have been set in 50s of Back, Breast and Fly.
This raises the question as to whether this is only happening in the US, or this has also happened in other major swim countries. To address this, I repeated the 2014 analysis with 2017 data. Below is the comparison.
We can easily see that there have been virtually no significant changes in conversion rates for World, European or Australian records. There’s been a slight drop for Canada, which I’ll address later. Every other region is relatively flat.
But the big news here is the huge increase in conversion rates for the US. Not only are these much higher than any other country, but they’ve also increased by roughly 2% for women and 3% for men since 2014.
The most sensible reason for both of these observations stems from the huge emphasis in America on SC Yards in their high school and college systems. Virtually all of the top US swimmers go through these systems, and in order to do well they absolutely have to excel at turns and underwater. This massive US emphasis on SC isn’t replicated in any other country in the world, and the intensity of the competition makes the NCAA Championships one of the toughest competitions in the world. This intensity can be seen in the almost complete rewriting of their record books. This focus on SC Yards also explains the relative disinterest that Americans hold for SC metre competitions.
Now, to talk about the Canadian data. Both Canadian men and women have actually decreased their conversion rate, with the women dropping from 2.4% to 2.0%. While this could just be an anomaly in the data, it’s probably more likely that it’s due to the deliberate avoidance of Short Course championship swimming in Canada. In fact, short course championships at the provincial and national level are no longer allowed. As far as I know, this is the only significant swimming nation to establish a LC-only philosophy for championships even at the regional level.
Conversion Rates by Stroke
As with 2014, the next step was to establish conversion rates based on each stroke. It makes sense that conversion rates would be different, as each stroke has its own speed, turn time, and underwater mechanics.
In that 2014 post I developed a simple chart that indicates the relative benefits of turns based on the stroke. I’ve modified it slightly to explain the elements better.
I certainly invite discussion about the above, but this is how I see turns affecting each stroke. A flip turn has a big effect while a touch turn doesn’t. The pushoff speed, basically the same for all strokes, is of more benefit to the slower strokes. And the underwater portion is also of more benefit to the slower strokes. Distance Free is the one exception as the underwater portion is minimal. For a more complete discussion, check out the post link above.
Here’s the chart breaking down the conversion rates for each stroke, including IM. The numbers are averages of the World, European, American, Canadian and Australian conversion rates for each stroke.
As expected, backstroke has the highest conversion rates. In addition, it has also increased more than any other stroke. In fact the men’s conversion rate went from 5.8% to 6.8%. But the main reason for this increase is the massive increase in the US: 8.1%. To show how large this difference is, using the US men’s rate, a 2:00.00 SC time for 200 back converts a 2:09.72 LC time. This is a far cry from the standard 2% default conversion rate which would give a 2:02.40.
There’s another interesting point here. In every stroke and for every region, men have higher conversion rates than women, and the increases since 2014 have been higher for men. This would imply that the turn and underwater phase is strongly impacted by raw strength, as opposed to technique, lung capacity or strength-weight ratio.
And lastly, note that the Women’s Distance Free conversion rate has actually dropped significantly since 2014. I call this The Ledecky Effect. Ledecky has completely dominated distance free, and has almost exclusively focussed on international LC competitions. I have no doubt that as she hits her stride in college, those SC distance free times will start dropping to the same extent as the LC times.
Short Course – Long Course conversion rates have essentially not changed since 2014, with the notable exception of the US. Massive improvements in American SCY times have resulted in an almost complete rewriting of the record books, and has resulted in huge increases in SC-LC conversion rates.
These improvements in American records must be based on strength, as conversion rates for every stroke in every region in this analysis were much higher for men than women. This would tend to rule out improvements due to strength, lung capacity or strength-weight ratio.
Much lower emphasis on Short Course competitions in the rest of the world has left conversion rates unchanged. And a Swimming Canada national mandate to eschew Short Course championships has actually lead to a reduction in Canadian conversion rates.
Lastly, I’ll repeat my 2014 call for swimming bodies to move away from the convenient but horrendously unfair 2% conversion rate for all strokes, and institute a far more realistic rate based on each individual stroke, with freestyle split into short or long distances.