How do you compare swimming and running speeds? For example, is swimming 100m in 60s comparable to running 1 km in four minutes in terms of effort or in terms the times in races (e.g. map percentiles of finish times).
A similar question was asked here.
That question included data from the 2009 Ironman Triathlon Championship in Kona, Hawaii. As you may know, the race consists of a 2.4-mile open water swim, a 112-mile bicycle ride, and a 26.2-mile marathon. A version of the scatterplot matrix from that question is shown here.
The scatterplot matrix above plots the swim, bike, run, and overall times (in hours) for each finisher. Although not shown on the plot, the correlation between swim and run times is .588, which indicates that there is a moderately strong positive relationship between swim and run performance across individuals (though not as strong as the correlation between bike and run times). The plot shows that "good" runners can be mediocre swimmers, and vice versa.
However, if one is interested in the question "what are equivalent run and swim paces for those who both swim and run?" one way to examine the data is to ask "how does the median run pace compare to the median swim pace?" Similarly, you could ask "how does the 90th percentile run pace compare to the 90th percentile swim pace?", how does the 75th percentile run pace compare to the 75th percentile swim pace?" and so on, comparing each percentile to each percentile. This is what the plot below does. It shows a quantile-quantile comparison of run and swim paces, normalized to minutes per mile for running and minutes per 100 yards for swimming. The dotted red lines show the 2nd, 10th, 25th, median, 75th, 90th, and 98th percentile times for run and swim pace.
Note the linearity of the relationship between run and swim pacing. In fact, between about the 2nd percentile and the 98th percentile, the correlation coefficient between the two is above .99. The solid red line shows the regression of swim pace on run pace, and the equation for the regression line is given. As a reminder, this shows the quantile-quantile pacing for multisport athletes who are trying to complete an Ironman, so the pacing will be slower than for single-sport athletes in standalone events.
If you start with the world records in a 1500m swim and 10km run you get these times for 100m and 1km
approx 26min 10km --> 2:36min/km approx 14:30 1500m --> :58s/100m
:58 vs 2:36 World record level
1:04 vs 2:51* % increase in the swim time based on the European Masters Record 1500m 35-39.
1:10 vs 3:00* based on a recent swedish swimmer 35-39 time for the 1500m, and that I know several 40+ runners that run under 35. Also a % increase.
**Masters ER 1500m men's 35-39 is 16:00 (1:04). This weekend one of Swedens swimmers swam 1500m in 17:54 (1:11.6). I think these two levels are possible. Not everyone can swim at those speeds, so its not expected that everyone could run at that speed. Maybe we can call this group the amatuerelite. People who train and race for fun, but are not professional athletes.
1:33 vs 4:00 might be a big jump, but this is based on a year OW river race 3km, and a series of 10km races in Sweden. Roughly 7% of those who swim the river race manage a time under 46:30 in 2012. The 10km races had less than 2% under 40min. But this difference could be explained that swimming in 16C water is not for everyone, and in the higher number of participants in a 10km might walk parts, effecting the faster times percentages poorly.
1:55 vs 5:00 (approx 28% of race finishers in the 3km river race "Vansbro" vs 20% 10km)
2:20 vs 6:00 (approx 63% Vansbro vs approx 60% 10km)
so sure one can say it's like comparing apples to oranges, but if you scale the results from enough swimming events and running events, I am sure you will find these values to be relative close.
Open water races in warmer water will produce a higher precentage of breaststrokers that float through the race, were as warm flat races will also attrack more and more "run/walkers". so maybe one could start by removing the last 5-10% of the finishers time?!?