Learn how to train properly and boost your swimming endurance with these tips from open water swimmer Adam Walker.

Learn from the experience of Adam Walker, swimmer of the 7 oceans, who explains how he built his endurance and how you can too:

Getting started

When I first began endurance swimming back in 2007, I initially just ploughed up and down in a pool with no real plan. I wanted to know how long I could swim for continuously without stopping, as I had no idea having not swam properly for a number of years and I didn’t know what my swimming fitness was like.

I managed to swim non-stop for 45 minutes on my first training session and built it up to 1 and then 2 hours. This gave me a lot of confidence to know I could keep going without stopping.


Once I felt confident in being able to swim up and down for an extended period of time, I needed to work on covering more distance and improving my speed. The first key area in order to do this, is an efficient technique, maximising power with as minimal effort as possible. This is why I created the Ocean Walker technique, to save energy and prevent injury to my shoulders.

Every stroke must have a purpose and not be wasted.
-Adam Walker

Every stroke must have a purpose and not be wasted. Every week I will do sessions specifically focusing on technique and I remain conscious of head, body and arm positions throughout my training.

Training sessions

The second part was to create structured sessions designed to build speed and stamina. I found increasing the speed and opting for 'high intensity, low volume' more beneficial rather than just swimming up and down in the pool for hours at the same speed.

As an example if I am training for an event that is 10k plus, I would set myself pool sessions of 3-4 km three to four times a week pushing at three-quarter pace with no more than 5 seconds rest between each 100/200 metre set. The speed gains were considerable and I would then test my stamina 1 day a week by doing a bigger session ranging from 8-12k in the pool in the winter with a slight drop in pace. I found I could swim further as a result of the high tempo sessions I did early in the week and that this type of training was much more beneficial than when I would put myself through 8-10k straight sessions at a steady pace.

It’s important to set yourself a clearly defined goal and train accordingly. Once you have your goal in place, write down your training sessions, laminate them and stick to them. It is important you remain disciplined and that you tailor each session depending on your goal.

My typical winter training session would be: 20 x 100m, 10 x 200m and/or ladder sets such as 50m, 100m, 200m, 300m, 400m, 500m, 500m, 400m, 300m, 200m, 100m, 50m were the most effective.  

From May I would continue the pool sessions and replace the long ones at the weekend with open water training. It was important to familiarise myself back into open water with the challenging conditions. Around 95 per cent of the time I swam front crawl with a backstroke for cool downs.


It also helps to add some gym strength training . I used 25 per cent of my time in the gym working on muscular endurance for the chest, arm and back. I used lighter weights doing 4 sets with 15-20 reps each.

I also worked hard on strengthening my core, as it powers my swim stroke so I would include varied sets of sit-ups and plank work. Having a variety of planned gym sessions kept me interested and motivated.

How often

For standard triathlons I recommend doing around 2-3 km a session in the pool. How many times a week depends on your work/family commitments.

If you have an open water challenge, then similar to me you will need to get swimming outside as soon as it is warm enough to do so and at least once or twice a week preferably for approximately 30 minutes at a time. For an Iron Man you can increase the distance to an additional 1km in the pool and build up to 1 hour sessions in open water.


Nutrition and hydration is also an important element that can often be overlooked. Make sure you take a bottle of water/isotonic drink to each pool and open water session. Depending on the distance you swim, you may want to also take some food.

I would take energy bars as I needed to replace the calories being burnt. In a pool I would burn around 800 calories and in open water (as it is colder) the body has to work harder, therefore it could be up to 1,100 calories.

Be careful also not to overdo the feeding during your training sessions. Your diet plays an important role in your fitness and endurance. Make sure you eat and drink well, not only before and after a session, but throughout the day. This can become quite a task, especially when you have other commitments, so it is good to be organised when planning and preparing your meals to work with your training goals.

Final note

Making sure you have rest days in between sessions is so important and very often overlooked. Your muscles require time to recover from your training regime and this also gives you time to recoup your energy and to be at your best for training.