Triathlon swimming technique: 9 common mistakes

Triathlon swimming coach Annie Oberlin-Harris explains 9 common mistakes triathletes make in the swim and advice on how to correct them


1 Poor push offs leading to poor swimming posture


Many athletes don’t realise the importance of getting a good push off the wall in the pool, for not only is one of the advantages is it can carry you through the water about 5m, or 20% off a standard 25m pool, but can also set you up with the right posture for the rest of the swim (see below).

 A great swimming technique is founded with getting a good stretch through the core, and particularly the layer of fascia passing over the muscles. When activated, this fibrous body of webbing keeps all your body tissues, organs and muscles much more connected. These myofascial lines of connection transmit strain and rebound, which facilitate movement, while providing stability. Essentially getting a good stretch gives you free energy in the water for a lot less effort, similarly to the way it does in running and cycling.

Another advantage of getting a good push off the wall is setting up the correct body position. In the picture below Matt’s head looks forward, his hips are low and legs even lower, leading to sinking leg syndrome. It’s very hard to recover from this if you don’t have a very effective leg kick (not typical for triathletes!). So getting your body streamlined reduces drag and makes it a lot less effort to get to the end of the pool.

You also reduce the likelihood of other stroke faults creeping in when swimming with a good posture, such as arm crossovers in front of the head, which can lead to snaking through the water. This lateral movement means you’re wasting energy going side to side rather than pushing water backwards efficiently to make you go forwards in the water.  

So how should you push off the wall?

Use this mantra to help you remember the order of movements:

Hands together – Head down – Bum up – Feet Up – Push

Put your hands one on top of the other, straighten your arms and squeeze your elbows together above your head. This will give you a nice upper back stretch too, which if you struggle with upper back flexibility as many modern day desk workers do, will help loosen you off, particularly with 60-120 odd repetitions in a standard swim set!

When practicing, see how long you can hold the glide for until you come to a stop. Notice your core muscles activating to hold you in a straight line. It’s these muscles we want to switch on in tandem with keeping good posture. When swimming, you’re looking to hold your body tort and stretched until the point that you decelerate when you should start your stroke. Then you’re guaranteed to maintain a good posture for the rest of the length.

You can find out more about Annie Oberlin-Harris and her training at

2 Not so smooth: Trying to train a high elbow arm recovery

You’ve probably heard about, seen or tried the ‘zip up’ drill, which aims to help you get a very high elbow arm recovery, keeping the hand close to the body. If you do have a very tight upper back and shoulders you’ll find this drill virtually impossible.

Ask yourself, is this suitable to the environment I want to swim in? What do elite open water swimmers and triathletes do? If you’re racing in open water, swimming that way will make clearing a swimmers’ wakes in front of you or waves in the sea very difficult. You may even catch your hand on the water on the way through, pushing it the wrong way. You might have experienced shoulder strain while wearing a wetsuit trying to get your elbow high.

If you naturally swim with a high elbow that’s fine, either way just open it out to more of the Swinger arm recovery, both in training and racing. 

3 Not seeing fins as useful tool to improve technique

Many Swim Smooth drills use fins, such as Kick on Side, 6-1-6, 6-3-6 etc. Kicking is very energy sapping; hence we use the longer style fin to enhance propulsion, whilst allowing you to focus on another element of the stroke, such as alignment or rotation. This reduces the need for you to kick really hard and exhaust yourself after one length. This particular design of fin also improves your ankle flexibility in the long term, helping you to achieve a better hip rather than knee driven kick technique. Its win win!

Swimming with fins: what’s the difference between long and short fins?

Swim fin workouts: Dave Scott explains how they help your training, and key sessions


Contrary to popular belief, as a triathlete you do need a good kick technique. You need to kick sufficiently hard that your legs stay high in the water to maintain a streamlined body position with minimal drag, allowing the good work your arms are doing to propel you forwards. The same goes for wetsuit swimming, yes in your 3:5 you’ll have a lifted rear, but a poor kick technique will still cause drag and slow you down.



Do leg-kick swim drills matter to triathletes?

4 Panicked breath holding

Getting your breathing right is so fundamental to your performance in triathlon. Since the swim comes first it makes sense to master it in the water first. Many swimmers hold their breath in the water.

This leads to storage of carbon dioxide, sending a panic bell off in your brain. Often you’ll interpret this as lack of oxygen. But if you think about it you’ve just had a breath in about one or two seconds ago and we’re not at the top of Everest; the oxygen content of your air was perfectly good! Storing CO2 elevates your blood lactate level leading to you reach your lactate threshold very quickly. Ever get to 75m and wonder why you’ve got to stop to ‘catch your breath’ or had to resort to breastoke in your triathlons? Get your exhalation right and say good-bye to this performance hump.

How do I breathe out properly in front crawl?

Ensure you let go of the air with a relaxed face; let your jaw drop (like when you smell your own bad breath!). Try standing face down in the deep end just simply blowing bubbles. Move to the deep end and start letting your body sink down as you learn to squeeze your diaphragm and let the air go right down to your belly.


Trickle breathing versus explosive breathing out in front crawl


Most of your oxygen and carbon dioxide exchange happens in the lower part of your lungs. Think of it in thirds, rather than breathe in three thirds and let go of one, breathe in one third and breathe out three. You’ll notice as you let more and more go the increased internal pressure will allow the air to almost fall back into your lungs every time you turn your head to breathe in, without you needing to over inflate and force it in. Try it and see how much more relaxed you are swimming continuously. 


 Improve your swim breathing in triathlon training

How important is bilateral breathing for beginner swimmers?

 Believing you’re not ‘strong’ enough to swim in the arms and back muscles

Once you can feel the water well with a good catch technique, get a good body position and can sustain a good level of effort in the water then you’re onto a winner. Have you seen the size of elite triathletes? Swimming freestyle over a long distance at a good pace is about finesse not power.

What muscles do you use in front crawl?


It doesn’t matter what you can bench press if your legs are dragging along the floor and you blow up after 50m. Muscling it might come more naturally, but scrap the gym and use your precious training time more effectively by just getting in the water and swimming more often. If you are the typical Arnie Swim Type, try and control your natural inclination to muscle it in the water. Stretch more, switch on your feeling and try to work with the water not against it. This really is the only way and will help you stop seeing the water as the enemy!

6 Obsessing over technique: Learning skills slowly and not doing hard enough training sets

Technique is only one part of the triad in improving your swimming (the others being training and open water skills). It’s very important to make sure your technique is efficient, but are your training methods? Some swimmers actively try and slow the skill down in an effort to improve their learning. You’d never run in slow-mo to learn proper form would you?

Technique training is generally swum in your lower aerobic zone, or an effort level of 3-4 out of 10. You don’t race at this intensity, so once you’ve got the hang of the drills up the ante and put some more effort into it. We’re not looking for steam to come out your ears, but get that heart rate elevated to stop denying yourself an opportunity to boost the training effect of this session.

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7 Swimming short sets with long rests, neglecting aerobic and threshold work

Other triathletes get hung up on speed. A set of 10 x 100 with 30 seconds rest is very good at making you swim 100m fast, but not so good at helping you improve on your 750, 1500, 1900 or 3800 PB. The fastest guy out the water is not the one with the fastest sprint speed; it’s the one with the highest AVERAGE speed which they can sustain. You wouldn’t just do 400m track laps to get good at a 10k would you? Be realistic, is your training matching your event?

How do I train smarter?

It’s important to get the balance right. If you train three times a week in the pool stick to just one technique focussed session a week. Use your second and third sessions a week for threshold and endurance work, not speed.

By threshold we mean an intensity of about 70%, or your CSS pace (the average pace you can sustain for 1500m. Training at this speed and up to 2 seconds per 100 below it will create the necessary overload for your physiological systems to adapt. Any lower and you’re in the VO2max zone and it’s unsustainable. A good threshold set would be 4-6 x 400 at CSS -2 secs with 1 beep recovery between. The first one might feel easy, but you’ll start to feel you’re working at threshold in the later reps. Remember we’re not looking for it to be too hard, just hard enough that you can sustain it for 300+ when the body kicks into aerobic metabolism.

Endurance sets are ironically the most avoided set out there, but there’s definitely a case for just getting your head down and swimming long. You’re looking to swim about 6/10 effort. If you’re familiar with CSS pace then set your tempo trainer to CSS + 4-6 secs /100. This helps you get the pacing right so you don’t set off too fast and blow up later in the rep. A good endurance set would be 2-3 x 1000 with 2-3 beeps recovery between, or even a time trial over your race distance once a month to gage how you’re improving over time. 

 8 & 9)


How to increase your swim speed

Sub-1hr swim session: Threshold beater

8  Watch attachments and obsessing over the numbers

There’s definitely a place for analysis in swimming performance. But what do the numbers really tell you? You swam 3k today with an average speed of XX  taking X many strokes per length. So what? Unless you’re doing a time trial and need to analyse your pacing take the watch off. Follow a structured set and manually enter the distance if you’re so conscientious that you need to measure and record the distance of every training session on the current training log software.

Good swimmers just know when they’re swimming is better. But over-relying on the numbers all the time prevents this feeling from ever developing. Not least because of the size and weight you’re wearing on your wrist reducing your proprioception of the water. You’ll see your performance improve once you build this finesse, you’ll notice you’re swimming faster, which is ultimately what you want right? Leave it at home!

9 Spending money on kit rather than coaching

How much did you spend on your bike last year? And on trainers or your wetsuit? It all adds up. Then work out how much you paid on top quality coaching…. How many pounds per hour of training does that equate to? Do yourself a favour and change your tact a bit this year. Sacrifice some of your equipment budget and spend it on a great coach instead. Look for one that will offer a bespoke training plan rather than wasting your money on a generic one which will leave you in the 50% of triathletes who’ll get injured this year. Ask yourself what is the most worthwhile investment, which will nurture your individual talents and care about your performance? 


Dave Scott’s five tips for improving your swim technique for triathlon

How to reduce the chances of getting a strain when swimming

Open-water swim technique: 11 common mistakes triathletes make


For more swim technique and training tips head to our swim training section or for the latest swim gear reviews click here


Annie is a Certified Swim Smooth swimming, open water & triathlon coach, specialising in: video analysis and freestyle technique correction; endurance swimming training and Triathlon & SwimRun Training Plans for all distances and abilities. Find out more at