The 55 minute Ironman Swim

By Alan Cardwell of C3Triathlon

Triathletes love a logistical and physical challenge. It’s part and parcel of what we do. The question posed ‘What do I need to do to post a 55min IM swim split?’ was offered up by the Bucanneer Race team.

The simple answer is – swim lots and then swim some more. This can be difficult due to constraints on pool time, work/ family/training balance, but a few strategies and thoughts can be used to make the process more time efficient. Simply swimming lap after lap after lap won’t cut it as every swimmer has limiting factors that need addressed. In my view there are 4 pillars to swimming well and consistently and they are all important.

1. Technique flaws and efficiency

swim flaws


You can get fit in the water with significant flawes in your stroke, but your speed will plateau as it becomes impossible to produce a sufficient amount of efficient  propulsion to overcome high levels of drag. As sessions go on you will fatigue, swimming starts to feel harder and you get slower. It’s a vicious circle. As a Swim Smooth coach, the solution here is a no-brainer – get at least 1 video analysis session done and work on correcting and improving the basic flaws in your stroke. Use toys ( fins, paddles, drag belt, snorkel)  and practice breaking your stroke into component parts in order to hone each one. Bringing the parts together purposefully and then laying on different paces will allow you to develop a range of speeds in the water. You (or your coach) can then structure training to work across aerobic, tempo, threshold and Vo2 work.

2. Swim volume and frequency

Swim performance responds well to volume. Consider young club swimmers – it’s normal for them to swim 20-30k a week from an early age. This is typically achieved by swimming 5 – 8 sessions weekly. It’s way over distance, but is a tried and tested method that produces improvements. Many triathletes frequently say they are swimming once or twice and are frustrated at lack of progress – DOH! You need to be in the pool, developing  feel for the water and swim-specific fitness. So for starters it’s 3+ sessions per week.

3. Strength

It isn’t necessary to be a huge powerhouse in the water, but you do need the muscular strength endurance to conduct thousands of strokes before fatigue sets in. Swimming with paddles is one great way to do this, but it’s also worth including functional strength work using bodyweight, gym work and stretch cords in the weekly routine.

4. Flexibility

Many age group triathletes don’t come to the sport until later in life. Triathlon is achingly middle class – so most of us have spent years slouched over a laptop, steering wheel or in front of the TV. A typical athlete’s range of motion is compromised – particularly around the shoulders. Land-based flexibilty exercises, including some yoga moves, are beneficial to improve range of motion in the water. Combined strength and flexibility sessions are a good use of time.


Historically, many athletes will work mainly on technique in the winter, but this can be counterproductive as fitness is generally lost, so a year round programme, incorporating all 4 pillars is needed. The balance of work will alter through different phases of training – so simply slogging through the kilometres won’t work, but nor will becoming a technical hermit and neglecting fitness.

c32So a program featuring all these elements, with differing training intensities, needs to be worked on from the off-season, through to the key race. After video analysis, you should be able to identify how you swim – and what you need to work on to fix technically. Then it is crucial to identify your swim threshold pace. At Swim Smooth we do this by using a CSS  (Critical Swim Speed) test. Your CSS is the pace you can hold for 1500m.

More information here

So you now have a baseline to start from and a target to hit. Let’s look at some athlete’s recent results linked to their pre-race CSS:

Race Pre-race CSS/100m Race time Race Pace/100m
IM Frankfurt 2013 1:18 54 1:25
IM Switzerland 2010 1:22 57 1:30
IM Kalmar 2013 1:32 1:01 1:36
Outlaw 2013 1:35 1:02 1:38
Outlaw 2013 1:39 1:08 1:47
Challenge Barca 2012 1:46 1:16 2:00

There are variables such as tide, wind , depth of water, turns etc, but if we assume a ‘fair’ course, we can see a  rough correlation between CSS and race times. The drop off in pace from 1.5k to 3.8k is typically between 7 and 14 secs per 100m in well-trained athletes. The less well-trained (or poorer technically), the higher the dropoff in pace. We’ve seen people with 2 min CSS swim well over 90 mins on race day.

So the goal of  a sub-55  Ironman will require a CSS of around 1:22 or better. From the test and video analysis you know know where you are  now and where you want to get to.

The tricky part is then making sure you do the right work to get you there. The good news is that it’s best achieved by keeping the majority of the workload sub-CSS with some key speed sessions faster. We call this ‘pushing up from the bottom and dragging up from the top’. This actually allows you to swim hard, but with good technical focus and to top it off with some real top end work.

In summary;

  • Identify where you are – both speed and stroke-wise – and test regularly
  • Swim often, swim long and with focus
  • Pay attention to strength and flexibilty work
  • Be consistent working through a plan designed to take you from current to desired performance


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