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Selecting swim interval distances

Updated: Mar 18, 2022

trisutto triathlon swimming swim workouts intervals ironman coaching coaches

One of the most frequent questions asked by athletes and coaches is why in swimming do we gravitate to shorter distance reps done many times?

'If an Ironman race is 3.8km, why swim 40 x 100m instead of a straight 4km to 'get the distance'?'

The answer is about technique and the ability of the individual athlete to hold the stroke.

In triathlon even our shorter swims are considered 'long' by mainstream swimming standards. For an Olympic distance race we are swimming 1500m and for an Ironman 3800m, which for the sake of simplicity let's say equates to 1500 arm strokes for the shorter distance and 3800-4000 for the longer.

This brings me to ask - what is more important? To encourage conditioning of the muscles for the good stroke, or cardiovascular conditioning to cover the distance? Using the rest intervals of the repetition can help us have both. Keeping the rest less than the length of time of the‎ interval itself is a good rule of thumb. How we break our own training down is often like this:

3 parts interval and 1 part rest.

If this is held for over 45 minutes of actual work time, you will gain a cardiovascular benefit. Keeping the intervals short will also allow you to gain more good strokes as it gives the arms a short break many times over the actual time of the set. Thus the athlete can cover a longer ti‎me duration with a better stroke, giving both arms and cardio an excellent work out.

It's important to understand that an athlete who loses their stroke after 5 minutes during a 1500m non stop swim will get an inferior workout than a person doing 60 x 25m with 10 seconds rest while keeping tempo and stroke for more of the workout.

It we are dealing with a poor swimmer, or an athlete new to swimming, I even prefer to do 4 sets of 15 x 25m with a 5 minutes rest rather than to push on when I can see the stroke is falling apart.

For international swimmers I like sets of 50m efforts over 200m or 100m efforts over 400m. Indeed some of my best distance swimmers would do a set of 200 x 25m on 25 seconds. We frequently use sets like 80-100 x 50m on with the rest as short as 10 seconds.

For even the best triathlon swimmers I rarely use 200m or 400m efforts with totally short rest. Instead we may kick down with varying rest intervals, shortening from 30 seconds to 20 to 10 to 5 then back up to 30 seconds and keep revolving them.

Or we might change the intensity with a session such as 3 x (3 x 400m) 1. Moderate 2. Medium. 3. Mad with a set interval of around 30 seconds so we still get an aerobic outcome. However, we mix it up. Short interval work combined with the above longer work and then, yes, the non-stop swim. When we do the non-stop swim we use the swim equipment. Paddles and pull buoy or pull buoy only. The very best triathlon swimmers may add a band. While we see this as power endurance training, we also do this so we can keep our stroke in place. The poorer the swimmer the less stroke mechanic mistakes are made with the swim gear. This again comes back to thinking about how many good strokes we take.

In conclusion, make a judgement on your level or your athletes level then apply the above information to your swim program. And remember it's individual!

* Nicola Spirig's most effective set is 100 x 50m

* Daniela Ryf's most effective set is 400s done with a pull buoy.

* and a Mary Beth Ellis favourite – hers, not mine, is 200 x 25m!

You too can benefit by understanding the better the mechanics over time and distance the better you will swim on race day.

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