Technical Endurance Swimming Part 2: Critical Slow Speed Swimming
Monday, January 9, 2017  By Dan Bullock67
Pacing is a big problem for many triathletes. By not swimming mechanically well enough to start at a steady effort, they struggle with keeping a sensible pace and start on the bike with unnecessary fatigue. Once you understand good swim pacing, it can be a key to further improvements in the water. When my swimmers ask me for more fitness sets, yet I can see that a 400 freestyle still exhausts them (or they can only do it using a pull buoy), I know that more technique work and pacing is exactly what they need.
If an athlete tries to hold a fast, uncontrollable pace at the start of an IRONMAN swim, say for example a 1:30 per 100yards, yet by the end they drop to a 2:20 interval, then you are simply going out too hard and you need to adjust your pacing. Fatigue sets in when you try and swim fast using only power and brute strength rather than using good technique. And it should be noted that without accurate technique at slow speeds, there will not be accurate technique at a fast speed.
Here is a technical endurance swim session with a pacing emphasis. The focus of this set is on repairing and polishing your freestyle technique during the easy 4x50’s:
Technical Endurance Session (Pacing Emphasis)

50m Free, 100m Free, 150m Free, 200m Free all at a constant pace with 15 seconds rest in between. If it takes you 45 seconds to do the 50, then plan on doing the 200 on the 3 minutes. Continue straight into 4x50m Free on the 90 seconds, as technically accurate as possible.

50m Free, 100m Free, 150m Free all at a constant pace with 15 seconds rest in between. Continue straight into 4x50m Free on the 90 seconds, as technically accurate as possible.

50m Free, 100m Free all at a constant pace with 15 seconds rest in between. Continue straight into 4x50m Free on the 90 seconds, as technically accurate as possible.

50m Free at a strong pace, rest 15 seconds then continue straight into 4X50m Free on the 90 seconds, as technically accurate as possible.
This set is a total of 1800 meters, and IRONMAN athletes can swim it in reverse for a total of 3600 meters.
Critical Slow Speed Versus Critical Swim Speed
Much has been made of working out your CSS (critical swim speed) in order to help your swim training progress. It’s important to know your approximate threshold speed, and it can be done using a variety of timed swims and simple formulas to determine a speed that you can hold for quite some time without exhaustion.
However, with most of the athletes I work with, knowing a critical slow speed can actually be of more use. Recently I held a development freestyle class and I started things off with a 400m continuous effort trying to hold an even pace with a similar stroke count. Many of the athletes found this very exhausting without even trying for a constant stroke count or pacing. If you find swimming 400m tiring, then the mechanics of your freestyle technique are not allowing you to progress effectively.
Most of my time as a coach is spent improving swimmers’ technique to the point where they swim continuously with little effort. Only at this point you’ll see that their drag has been reduced, propulsion improved and steady continuous freestyle is finally truly possible. Limiting drag in the water must come from using the smaller, more efficient swim muscles. Once drag is reduced, they can achieve a higher degree of propulsion, which leads to overall efficiency in the water.
The reverse of this holds true since swimming is generally tiring due to the larger muscle groups creating propulsion that is directionally of no benefit, and which comes at a high cost of air and energy. The common bad habit of holding a straight arm to push down in order to support a breath is an example. Swimming well comes from Efficient and Effective Propulsion (EEP,) doing the least amount of work for the most distance travelled through the water. In final preparation for an IRONMAN, I will often give novice swimmers the following set: 24x100 freestyle with approx. 15 secs rest, challenging them to swim relaxed and easy the entire time. Once they have mastered EEP, they can swim this set nice and relaxed and will see much improvement in their IRONMAN swim time and postswim fatigue as a result.
Achieving EEP
A good place to start with EEP is stroke count. Start to think of your stroke count not as a minimum to strive for but rather as an alarm bell if the count starts to rise in fitness sets, which tells you EEP is no longer being maintained. Anyone can fake a low stroke count with enough kicking and gliding, but that is not the point. If it does start to rise, then I suggest slowing down and running a quick freestyle diagnostic to check where things might be falling apart. Mentally run through a quick list:

Are your big toes brushing to a fast rhythm to reduce any splaying?

Is your kick still small and being generated from a tiny movement of the hips?

Are your shoulders properly rotating?

Is the water being pushed backward toward your feet once you are pulling?

Are the fingertips pointing downward with the back of the hand facing the pool wall you are swimming toward after your catch?
Focusing on these things should be enough to bring your stroke count back down to a comfortable and repeatable optimum.
There is nothing quite like having some goals and targets to get you motivated and into the pool frequently. This fourweek block of work is a good place to start during the offseason. Each of the following workouts begins with a choice 400m warm up, some building 25m to elevate your heart rate and a relaxed 200m freestyle with good technique:
Week 1

Swim as many freestyle 50’s (resting 10 seconds between each) for a total of 8 minutes.

Record your number of 50’s.

Swim an easy 50m to recover.

Swim as many freestyle 25’s (resting 5 seconds between each) for a total of 4 minutes.

Record your number of 25’s.
Ideally, you want the number of 50’s and 25’s to be almost the same.
Week 2

Swim as many freestyle 75’s (resting 15 seconds between each) for a total of 12mins. Try to keep a steady effort throughout.

Record your number of 50’s.

Swim an easy 50m to recover

Swim as many freestyle 50’s as possible (resting 10 seconds between each) for a total of 8 minutes.

Record your number of 50’s.

Swim as many freestyle 25’s (resting 5 seconds between each) for a total of 4 minutes.

Record your number of 25’s.
Ideally, you want similar numbers throughout the workout.
Week 3

Swim as many freestyle 75’s (resting 15 seconds between each) for a total of 12mins. Try to keep a steady effort throughout.

Record your number of 75’s

Swim an easy 50m to recover

Swim as many freestyle 50’s as possible (resting 10 seconds between each) for a total of 8 minutes.

Record your number of 50’s

Swim as many freestyle 25’s (resting 5 seconds between each) for a total of 4 minutes.

Record your number of 25’s.
Throughout this workout, try to add an additional number to each of the workout blocks.
Week 4

Swim as many freestyle 100’s (resting 20 seconds in between) for a total of 16 minutes.

Record your number of 100’s and swim a 50m recovery.

Swim as many freestyle 75’s (resting 15 seconds between each) for a total of 12mins. Try to keep a steady effort throughout.

Record your number of 75’s and swim an easy 50m recovery.

Swim as many freestyle 50’s as possible (resting 10 seconds between each) for a total of 8 minutes.

Record your number of 50’s. Swim a 50m recovery.

Swim as many freestyle 25’s (resting 5 seconds between each) for a total of 4 minutes.

Record your number of 25’s.
Your goal is to hold the same number throughout this entire last workout. This will be possible as fitness and technique both improve weekbyweek with the addition of technical endurance sessions.
Please swim a little more often in 2017, think of totals per month rather than per week. Along with focusing on technique, pacing and efficient propulsion through the water—simply putting in more pool time will be the single best thing you do. Finally, never arrive at a pool without some kind of session or plan. Arriving empty handed will ensure you swim at least 30percent less than if you had arrived with a session in mind. Work through it to the best of your ability and add some accountability to your swimming.
Read part one of our technical endurance series HERE.