Most Saturday Swim Sessions include three distance options, allowing you to choose a workout that matches your current fitness and available training time. This week is a little different. Instead of multiple options, I’m publishing one 5,800m endurance challenge for experienced swimmers looking to spend an extended period in the pool developing aerobic endurance, pacing and mental resilience.
Before you begin, I recommend reading my article explaining Swim Intensity, as it will help you understand how hard each part of the workout should feel and how to pace each repetition appropriately.
Today’s Goal
Develop the ability to maintain consistent pacing and efficient freestyle technique across a long endurance session. The aim is to finish the final 800m swim with the same rhythm, body position and stroke quality that you had at the beginning of the workout.
Why You’re Doing This Session
Endurance isn’t simply about swimming long distances—it’s about swimming well for a long time.
This session combines continuous swimming with broken repetitions to help you build aerobic fitness while maintaining high-quality technique. The continuous 800m efforts develop sustained endurance, while the broken 800s allow you to briefly reset before continuing. This encourages better pacing, improves consistency and reduces the tendency to fade late in long swims.
The shorter preparation sets early in the session gradually increase your heart rate and reinforce efficient technique before you move into the demanding main set.
Session Inspiration
The inspiration for this week’s session came from a YouTube video by professional triathlete Ruth Astle, titled “Endurance swim & Wednesday bike session | A week in the life on Denia camp | Day 3 with pro athletes.“ This workout is my best interpretation of the session Ruth completed in that video. While I’ve aimed to reproduce it as closely as possible, some details—such as the rest intervals—weren’t shown or discussed, so I’ve used my coaching experience to fill in those gaps where necessary. The result is a session that closely reflects the original while remaining practical and enjoyable for experienced recreational swimmers, age-group triathletes and masters athletes.
Today’s Workout (5,800m)
- 2 × 400m Warm Up (WU)
- 300m Pull Buoy
- 200m Build (50m moderate, fast, faster, fastest)
- 2 × 50m Kick
- 3 × 100m (75m Easy / 25m Sprint)
- 800m Continuous (45 sec RI)
- 2 × 400m (15 sec RI)
- 800m Continuous (45 sec RI)
- 4 × 200m (15 sec RI)
- 800m Continuous
- 100m Cool Down (CD)
What You Should Focus On
- Hold an even pace during every 800m swim.
- Swim with a long, relaxed freestyle stroke.
- Use the broken repetitions to reset your breathing and technique.
- Build speed progressively during the preparation sets.
- Finish the session with the same stroke quality you started with.
Common Mistakes To Avoid
- Starting the first 800m too quickly.
- Turning the short rest intervals into extended recoveries.
- Sacrificing technique as fatigue builds.
- Sprinting the continuous swims instead of maintaining a sustainable pace.
- Neglecting hydration during such a long session.
Tips For Completing The Workout Successfully
This is a long workout, so arrive well hydrated and as always make sure you have a drink bottle at the end of your lane. You’ll be swimming for well over an hour, you may also benefit from a sports drink or other easily digested carbohydrate during the session.
For the kick set, I recommend swimming without a kickboard wherever possible, as this promotes better body alignment and a more natural kicking action. If you’re unfamiliar with kicking without a board, this video provides an excellent explanation:
During the continuous 800m swims, focus on maintaining a relaxed rhythm rather than chasing a particular pace. A smooth, controlled effort will produce a better endurance adaptation than repeatedly surging and fading.
Workout Breakdown
For the Warm Up (WU) is two sets of 400m of mixed swimming, include a range of strokes. During the warm-up feel free to stop and stretch as needed. It doesn’t need to be a continuous swim.
Next up is a further 300m with a Pull Buoy .
The following set is 200m long and you build your pace each 50m. Start off at a moderate pace, before increasing to a fast pace. As you move into the second half of this 200m rep increase to a faster pace, before finishing the rep at your fastest pace.
Ruth then moved into a short kick set of two, 50m reps. Avoid using a kickboard for the kick (see the video above).
The next set is made up of three, 100m reps. Swim the initial 75m nice and easy before sprinting the final 25m of each rep. Take a twenty second Rest Interval after each rep.
The main set is made up of broken 800s. Start by swimming 800m continuously.
The following set is also 800m, but broken into two, 400m reps.
Then swim another 800m continuously.
The following set is also 800m, but broken into four, 200m reps.
Finish by swimming another 800m continuously.
Complete the workout with a 100m Cool Down (CD). Unlike the previous sets which have to be freestyle, the Cool Down (CD) (like the Warm Up (WU)) can be any stroke you wish to swim. You can also stop and rest after any length. I encourage you to stop and stretch during the cool-down.
After Your Swim
Take a few minutes to reflect on the session.
Ask yourself:
- Did I maintain an even pace across all three continuous 800m swims?
- How did the broken 800s compare to the continuous efforts?
- Was my technique still efficient during the final 800m?
- What would I do differently next time?
Recording these observations alongside your swim times will help you measure improvements in endurance and pacing over tim
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