What’s Limiting Your Triathlon Performance?

Performance Limiters 

If you are training for your first Ironman Distance Triathlon and I was giving you a choice of swim session, would you rather do 40 x 100m with 10s Rest Intervals or would you rather do 4 x 1000m with 1 min Rest Intervals?  Maybe you’d rather do neither! The majority of athletes perhaps would opt for the former, and this might tell your coach whether you were naturally more comfortable with either endurance or shorter sessions/events.  There are other metrics of course but it might be one indication. Certainly we find that a lot of athletes train the way they like to train whereas the more successful athletes seem to train the way they need to train. Particularly when choosing sessions; so when training for a triathlon runners might default to a run and swimmers a swim etc.

So a good question to ask yourself or to ask others around you is “What is limiting your triathlon performance?”  It might be that you need to do technique work in the pool or it may be simply that you don’t swim/bike/run enough have the aerobic base required for the endurance, it may of course be power or strength-endurance. I think if you look at all the disciplines in a triathlon: swim, bike, and run and perhaps even just looking how you fare respectively when looking at results you may start to see where your performance is limited.

In the case of an athlete training for the Ironman swim of 3.8km then I’d suggest at least one session a week of endurance type work.  This doesn’t mean jumping straight into the 4 x 1000m set, it could start with a main set of 3 x 600m if that is doable and develop from there. I think in swimming we can always improve technique, but ultimately come race day they need to swim 3800m with the technique they have and do it as efficiently as possible to enable them to cycle and then run off the bike effectively.

Ironman Nutrition Guidelines

Ironman Nutrition:
Strategies for Success
Download Now

The main thing for an Ironman Triathlon is to train to swim, cycle and run efficiently and by doing so you will be nine tenths of the way to a finish.

Interestingly enough, according to Brett Sutton, if Chrissie Wellington were asked the 40 x 100m versus 4 x 1000m question she would opt for the latter.  Whether this is a like or a need I do not know – but as a 4 times Ironman World Champion she knows what works.

About The Author 

Neil is one of the most knowledgeable endurance coaches you'll ever be likely to meet, both in terms of qualifications and valuable experience. He's well into his second decade in the sport of triathlon and third decade as a competitive runner.

In recent years Neil has worked with Runners, from those looking to complete their first 5k through to Elites racing the Olympic Marathon, and Triathletes, from those looking to finish their first ever sprint event, through Age Group medallists at World Championships, Ironman Age Group winners to the Elite Squad at University of Bath.

As an accomplished Ironman triathlete, Neil races for Royal Navy Triathlon and has represented Great Britain at Age Group Level across various distances.

2013 has seen him run a sub 3hr at the Rotterdam Marathon, then complete his second 56 mile Comrades Ultra Marathon in South Africa in June; he is now making his return to racing Ironman Triathlon.

Neil is available for Triathlon & Running Coaching.



  • Interestingly as a novice triathlete who has only done 2x ‘novice’ events, I would have opted for the 4x 1000m option simply because I know I can easily swim 1000m (and even 2000m) without any break. I do it every morning (1x 1000) but feel it is only time restraints that stop me from swimming longer. The 1 min rest between 1000m sets would be a bonus.

    Having said that, in my first 2 tri’s the swims were only 150m and 300m and I actually struggled due to the open water being much much cooler than the pool I had been training in!

    Ironman? Still a long way to go!!

    • Alan, Many thanks for your comment. Within any swim routine we, like many coaches, would recommend three or four specific types of set. It looks like you have one covered and that is the long swim and that is great to see as so many people drop this on – even those going for the longer events. The other types of sessions are ones I think would benefit your training and goals and they are a technique session, an open water specific session and a session working on improving your speed. If you are swimming every morning then you could look to incorporate these sessions in your training in addition to ensuring that your overall training package, swim, bike, run, strength and conditioning, is consistent, specific to your event, progressive and lastly don’t forget fun! Happy training, Neil

  • Interesting article and comments. I am training for an Ironman and I have been mainly working on technique and speed this winter. I indeed have gained speed, but have the feeling that I am not able to maintain a proper technique when swimming longer sets. So what would be your advice, taking into account the fact that I can “only” make it twice to the swimming pool per week? Do one long swim session (around 4 km in total) and a mixed speed and technique session?

  • Raphael, holding onto your form in all three disciplines of a triathlon is not an easy thing to master but is important in order to stay efficient. In the open water of an Ironman swim ones ability to hold a “pretty” technically correct stroke for a few hundred metres is not what one requires. The calm benign nature of the pool does not replicate well the conditions you may experience and you must try and get a weekly open water session in. I will always recommend a minimum of three swim sessions a week, one endurance, one speed based and one technique based. In your case as you can only swim twice and as you have spent the off season working on your technique I would recommend one endurance swim building up to a TOTAL set distance of approx 4km (4 x 1km; 8 x 500m; 5 x 800m) and for your second swim I would recommend getting an open water session in practising deep water starts, beach starts, sighting, breathing to both sides. Let us know what Ironman you are training for and the type of course and we can be perhaps more specific. Good luck!

  • Hi Neil, thanks for your response ! I’m training for Challenge Vichy (France) end August. The swim part takes place in a lake, which is usually rather calm (no waves, no stream). Plus there is a lane on all the course, which you can follow as if you were in a pool. So orientation skills may not be as important as for other races, also taking into account that I am not very fast (it took me 1h30 for the 3.8 km last year) and can therefore just follow the mass.

    I must confess that I did only a few open water swim sessions during my preparation last year and I realize I should do more of them.

    Let’s assume I could fit a third (short – around 45 minutes) swim training session in my training schedule, what should it be? Speed or technique?

  • Hi Raphael, well if you can fit in three swims a week and if open water skills are not an issue at Challenge Vichy, couled with the fact you have completed the race previously then I would do one endurance swim, one speed session (based on your critical swim speed per 100m) and one technique session. If you post your 400m and 200m swim times I will post your critical swim speed per 100 that you should aim to hit in a speed type session.

  • Excellent site i’m intersted inside starting triathlon myself i wish to do the ironman or ironman 85. 3

  • I live in frozen Canada and open water swims are not currently an option. Any tips for preparing for an open water race in Hawaii in a few weeks? It’s only 1500m. I will have 5 training days in Hawaii before the race. This will be my first open water swim.

    • For the record, I’ve done the usual three side-by-side in a lane, tons of sighting work, and swimming lengths with my eyes closed. Any other tips for open water prep with only 5 training days having access to open water?

  • Hi Chris
    That’s a tough one not least that you are actually doing a lot of things that would be advised. However things that work well are firstly to swim with a group and preferably a large one; you could join a swim squad, or a local tri club, or just go to the pool during the busy lunch hour and swim. You are trying to replicate the chop of the open water so although the set will be frustrating it will get you used to non pool conditions. The more people in the pool generally will just make waves, and will help you alter your stroke to overcome those conditions. You are already swimming with others in the lane so try things like swimming as close as you possibly can to each other, try timing your strokes to be the same, try timing your strokes so they are not. See if you can remove lane ropes so the chop is not contained, just be inventive with getting waves in the pool.
    Hypoxic training also helps for open water swims so hold your breaths for longer than you normally do. If you normally breathe on every stroke, try breathing on every three, five or seven strokes. With our swim squad we often will swim 100s breathing every 3/5/7/3 for each 25. In the open water you often miss a breath with all the splashing going on, so it’s good to practice being uncomfortable with your breathing. This way, when race day comes you are comfortable. Get comfortable with being uncomfortable. Being able to breath to both sides is also a must as the current/waves might be coming on one side and you don’t want to be breathing to that side. There’s also the chance you may have a swimmer in close proximity to one of your sides, so you want to breathe on the other side to avoid swallowing any water the other swimmer is splashing. You are already practicing sighting but this again is a must. Pick a spot, or better yet several spots, on the opposite wall from where you are swimming or the lane clock and imagine these are buoys. Practice your sighting every few strokes during say every other length. Make sure you are swimming straight when you sight. Have a look at your stroke or have someone else look at your stroke. Generally an increased swim cadence or arm turn over speed is preferable for open water swims rather than aiming for a super smooth gliding stroke that you might use in the pool. Buy a Finis Tempo Trainer and use it to improve that cadence. Open water swimming is tough and can be exhausting. Not only are you trying to swim your own race, you are battling weather conditions like choppy waves, and conditions caused by other athletes. By having your form dialed before you get there, and being as efficient as possible in the water, you’ll be able to expend less energy during the swim than if you were just battling the water the entire time. It sounds like you have most of the bases covered already and it’s just a case of practicing those. Have a great race. Neil

  • Hi Neil, I’ve entered my first sprint distance tri, which is in eight weeks time.
    I run a lot and have no worries with that section, and also cycle quite a bit. My swimming technique is good, but how should I go about building endurance? I’d love to become a great swimmer! I’m keen not to loose time in the first section (which is indoor) Thanks

Leave a comment. Ask us a question...