There’s always a lot of anxiety over races on the cusp of being wetsuit legal and IM 70.3 Muncie is no different.  It’s considered a bit of a tricky swim, so most people prefer the security of a wetsuit. I have been on the fence because I really don’t like wearing them, but in the name of sports science, I decided to do a comparison test this morning to see how it affected my time.

This was the setting.


–  Lake was smooth
–  Water temp estimated to be around 77 degrees
–  Air temperature about 69 degrees
–  Partly cloudy
–  Test distance estimated to be a 350 yard loop (roughly 1/6 of a Half Ironman)
–  I warmed up for about 900 yards
–  Swimming effort – Moderate
–  Total sleep before test, about 3 hours.

The swim skin test was first and I swam the 350 yards in roughly 5:56.

I then changed into my wetsuit and swam the identical loop in 5:31.  A twenty five second difference and I felt like it took noticeably less effort.

That’s roughly 2:30 difference over the course of a Half Ironman with, in theory, less exertion.  But heart rate and core temperature are other issues that should probably be considered.

One of the reasons I wasn’t sure I’d wear a wetsuit, even if legal, was body core temperature.  The last time I wore my wetsuit was Challenge Knoxville where the water and air temp were much cooler but I felt like I was burning up in that swim.  We’ve written about this before concerning Ironman Chattanooga, but that proved to be a different animal with the current.

How accurate these test numbers are is debatable, but what was most interesting to me was comparing a wetsuit immediately after swimming without one.  Today, the buoyancy was obvious and definitely had an impact on my confidence.

I’m glad I did this test and will be fine with or without a wetsuit in Muncie, but if it’s legal, I will definitely be wearing one.


Here’s another test by someone who did longer distances and compared multiple times.

And for those of you having trouble distinguishing between a tri suit and a wetsuit, has you covered with this insightful piece.








Wetsuit Vs. Swim Skin Ironman 70.3 Muncie