If you are training for a triathlon swim, what kind of intervals should you be doing?

Interval Training in Swimming

At the two ends of the spectrum are tight intervals where you only get around 5 seconds of rest, and long-rest intervals where you get lots of rest. Typically, the latter swims come with the expectation of greater intensity.

But what should you be doing if you are training for a triathlon to get the most out of your swim?

Training with intensity and lots of rest will certainly help you to get faster. But this will mostly help you on sprints, such as 100- or 200-yard races. This would be training your anaerobic system. Since you have a lot more than that to deal with on a triathlon, especially when you consider the bike and run, you will help your swim a lot more by training aerobically- or on intervals where you can make with 5 seconds or so of rest.

To find out what a good “base” or “cruise” interval is for you, do a set of 8 x 100’s on a chosen interval. If you can make all of these with around 5 seconds rest, this is a good interval for you to train at. If you are getting more than 10 seconds rest, consider bringing down the interval.

Here’s an example:

Let’s say you can do 8 x 100’s on 2:00 with about 15 seconds rest on most of them. Next time, try a set of 8 x 100’s, 2:00 on the first 4, and 1:55 for the last 4. If you can make that, drop your interval to 1:55 for the entire set next time.

But whatever you do, don’t attempt to drop your interval before you are ready! You want to keep your stroke technique in tact before you work on speed or making tighter intervals.