Swimming is often overlooked in Ironman as it’s seen as a short warm up before the main event. This thinking has led to swim training being overlooked or the bare minimum of work being done so athletes can complete the swim distance come race day.

I have heard many athletes gleaning to be pure endurance athletes as it takes them so long to warm up onto the bike in Ironman events. But looking over their training the truth is, more often than not it takes them so long to recover from the swim before they can start to even access their bike fitness.

Same goes for great runners wondering why despite being in amazing run shape they can never access this fitness in an Ironman, they will often blame nutrition when the real culprit is the energy cost of the swim and the debt accumulated recovering from this at the start of the bike.

So many athletes fall into the easy trap of blaming nutrition for things going wrong and not performing to expectations but I have seen time and time again the athletes who come to the races well trained and balanced fitness through consistent training really don’t seem to have these nutritional issues!!

In Ironman we want to swim well but more importantly we want to get out of the water as fresh as possible so we are not taking a debt into the remainder of the race. One big element in this is of course pacing the race correctly to your current fitness but this point is for another article. In this article I want to look at swim fitness specific for Ironman.

First and foremost, the Ironman swim is a long way, you need to be able to not only complete the distance but complete it comfortably – of all the 3 sports the swim is the only one I would recommend regularly going over distance on in training.

When looking at the swim in Ironman I would class it as a strength endurance test, it’s quite simple to demonstrate this if you happen to have both a 25m and 50m pool available for training, simply spend a few weeks training in a 25m pool which is great for fitness and technique development and then take that fitness to a 50m pool a do a time trial swim of race distance, you will end up very frustrated as despite feeling very fit you will just feel drained and slow very early on, breathing will be well under control as you simply will not be able to go hard enough to put a stress on your cardio system as the strength system will have been maxed out.

The reason for this is the short rest you get in a 25m pool on every turn is doubled in a 50m pool and this has a huge effect on the build up of fatigue. We can tell the fatigue is muscular as you will find breathing is very controlled and just no way to push harder in order to stress the cardio system. Now if this effect is seen from a jump to 50m you can imagine it will be multiplied many times in a 3.8k swim with no breaks.

Taking this into account, the most important part of any swim program has to be a long strength based endurance swim. To make a swim strength based we can do several things depending on what your circumstances are.

Using a pull buoy is the first step in incorporating strength into any swim session; the pull buoy takes the legs out of the stroke and forces all momentum to come from the arms so isolating muscles. A further addition to the pull buoy to make your arms work even harder is a band tied around your ankles – this prevents you from kicking and will really emphasize any lack of symmetry in your stroke and make forward progress really hard work!!

When using a band ignore the clock as it will really slow you down and can leave you very frustrated – when using a band perceived effort is your guide and just use the clock for calculating recovery between intervals!

Finding a comfortable band is hard and my tip is to find an old wetsuit and cut off a section of the leg about 2-3 inches thick and use this for your band. This proves perfect tightness and comfort so you will have no excuses for not doing your band work.

Paddles are a great tool for building strength and also promote good technique as a bonus. Adding paddles to the second half of a hard swim session will really work on strength and you are forcing already fatigued muscles to work even harder.

So an example strength endurance swim using the above may look something like

20×100 pull bouy moderate + 15s rest


5×200 pull buoy / band  @ 1 easy / 1 hard + 30s rest


2×400 pull / band / paddles @ 1 moderate / 1 hard + 30s rest

Having a swim like this as part of your weekly training will have you strong enough to cope with the demands of the Ironman swim come race day and allow you to get onto the bike fresher and ready to go from the first meters.

Now that you are strong enough to get through the swim, we need to look at what is likely to occur in the swim and the demands it will place on the body. Open water swims will involve swimming around markers and these present another fitness challenge. When swimming in a group, the dynamic of the group will always change from steady swimming into the turn to accelerating around the turn, just as in bike racing those athletes at the back of the group will have to slow right down as they approach the turn due to congestion and then accelerate hard out of the turn in order to catch back up to the group. The demands of these accelerations are high and if you don’t train them you will quickly become tired and no longer be able to stay with the group you were swimming with.

After a warm up perform the following set twice, second time through add paddles for more of a strength challenge.


100m all out + 1min rest

4×50 hard + 10s rest

3×100 moderate + 10s rest

50 all out + 10s rest

2×100 moderate + 10s rest

150m easy + 1min rest


When swimming this set expect breathing to really be out of control the first time, focus has to be on maintaining consistent pace for each effort level through the whole set.

These 2 sessions will form the backbone of a good Ironman swim program and ensure you are ready to go on race day. Some pools and regulations can prevent the use of paddles and bands so we need to find a way to simulate the same challenge without the tools, some tips on doing this


Paddles not allowed

  • Use drag shorts to increase resistance or even better board shorts
  • Turn 2-3m before the wall and then you have to accelerate back to speed without a push off

Bands not allowed

  • Cross your legs to prevent any kick – just remember to alternate legs each length

Moving forward work hard on your swim with the above focus in order to not only improve your Ironman swim but to unlock your true potential on the bike and run!!


Enjoy your training


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By Alun “Woody” Woodward


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