While I’m buried under 2 feet of snow by winter storm Jonas, I’m dreaming of the days when I lived in Miami and got to complain about how anything under 70 was cold. I’m also really missing my outdoor pool where I swam year round, even on those frigid 60-something degree days! I haven’t done any triathlons or serious triathlon training since I moved north in August and I’m seriously missing it.  Considering the work I’ll have cut out for me to get back into the training routine, I’m most concerned about the swim. It’s my weakest event already and even though I’m still swimming here and there, nothing compares to the hard training I was doing even a year ago. The swim is the smallest portion of the entire race which is good for me, but I think the importance of swim performance is often downplayed. Yes, I can still perform very well overall although I am very middle-of-the-pack on the swim, but think about how much better I’d do if I was even in the top 25%! Lots of studies measured how cycling affects running, but not as much attention is paid to swimming.

I came across an article that reviewed how the swim affects the cycle portion of tris, and some even looked at its effects on both the bike and run legs.  Here is a summary of some of the findings. I’ve put the major points in bold if you’re a skimmer, and more details if you want the nitty-gritty. For you scientists, here’s a link to the full article here.

Swimming causes a decrease in cycling power output.

The details: Triathletes swam 800m (basically, sprint distance) in an average of 10min, 24sec. Then they cycled for 75 minutes at 70% of their maximum heart rate and compared it to a cycling only trial at the same intensity. Their power output after swimming was 17% lower, meaning that at the same relative intensity (HR) they would take longer to complete a set distance.

Longer swims affect cycling performance LESS than shorter swims.

The details: Triathletes completed a 3000m swim in an average of 52.5 minutes, followed by a 3 hour cycle. There was no significant difference in the power output, heart rate response, or blood lactate buildup when compared to those who only cycled. This may or may not be good news for longer distance triathletes since the swim distance is smack in the middle of half- and full-ironman swim distances.

Swimming increases physiological difficulty of cycling.

The details: Triathletes swam 1500m in an average of 30 minutes followed by 30 minutes of cycling, compared to cycling only. Although their performance was not shown to be affected (distance covered in a given time or power output), other variables indicated that cycling was more physiologically taxing. Heart rate, blood lactate, and oxygen consumption were all higher after swimming-all of which could negatively affect subsequent running.

Swimming at 80-95% is better than swimming at 100% for race performance.

The details: Triathletes did three different test days where they swam at all three intensities (based on a 750m time trial), cycled 20k, and ran a 5k. Cycling power output was much lower after swimming at 100% (278W compared to 298W and 305W). Run time after the 100% intensity swim was an average of 1:45 longer when compared to 80-85% intensity. No 5k time difference was given for the “moderate” intensity and I would’ve liked to know it. I like this study the best because they used real triathlon distances (why WOULDN’T you?!) and compared to both biking and running.

Improve swim performance, learn how to draft, wear a wetsuit whenever possible!

These findings show us that swimming does affect cycling, especially in short distances, and if you go balls to the wall during the swim you are likely to negatively affect your overall race performance. Improving maximal swim ability can help you improve your speed at relatively lower intensities, but as anyone who does this knows that takes FOREVER. The study includes some information about how drafting, wetsuits, and speed suits affect swimming performance but they don’t compare it cycling which is why I’m not detailing it here. They tell you what you you probably already know-that all three of these things help you swim faster without wearing yourself out more, which will help everything else.

Summary

Only one of the studies reviewed used actual triathlon distances. This is a pet peeve of mine in sports research because it makes it hard to translate the research to training when things don’t match up, but it still helps you get an idea of what’s going on. The athletes’ performance level also probably vary quite a bit. Some of the reviewed studies used absolute time, some relative intensity-so it’s hard to know exactly how you’d compare. But again, it still help you get an idea how your pacing strategy can affect your race.  Happy training!