WoW #1 – Peddie Aquatics What Does Aerobic Mean Anyways?

Thank you Greg Wriede of Peddie Aquatics for contributing the following workout (click on workout to view full size):


Coach Overview

The swimmers were into the first few days of a three-week “big block” and Greg ran 4 different groups through 3 different workouts.

Age/Standard: High school. The 4 groups span a large range of levels from State cuts through to Olympic Trials cuts.

Distance group: 500 specialists and those who needed a longer set
IM group: Mostly younger kids who do not yet specialize
Speed/MiddleDistance groups: Older swimmers focussing on 50 and 100 with some extending up to 200

Clive Commentary

Given there’s a lot going on with 3 different workouts for 4 different groups, let’s focus in on the Distance group’s main set. Notice the intensity level with the highest yardage… 6,400 out of the total 8,400 yards are “aerobic”.  Therefore, let’s dissect what aerobic means for this week’s WoW.


There are 3 intensity levels that are predominately aerobic: EN1, EN2, and Anaerobic Threshold (AT). However, the EN1 intensity serves a different purpose in developing the muscle to that developed by EN2 and AT:

EN1: changes the muscle’s ability to store energy. It changes its capacity.

EN2 and AT: changes the muscle’s ability to use energy. They change the power, or what Bob Bowman neatly calls utilization – the ability to use power.

So the Distance sets designed in Greg’s workout could have two significantly different developmental effects depending on how fast you ask your swimmers to perform. But how fast is fast, and how do you measure it?


The main methods used to help determine aerobic intensity level are stroke rate (more accurate) and heart rate (more convenient).

Stroke rates

Aerobic freestyle tends to sit at stroke rates (SR) between 28 (very low level “base” or recovery swims) and 33 (bordering on anaerobic threshold) cycles per minute (cpm). If your habit is timing three cycles that’s 6.4 (28 cpm) to 5.5 seconds (33 cpm), and if you are one of the rare breed that time 10 arms (yes, they do exist), then it’s 10.7 to 9.1 seconds.

These ranges cover three different combinations of muscle fiber recruitment (note: different strokes have different frequencies associated with each level – we’re only talking freestyle here):

  • 2831 cpm: expected range for slow twitch fiber use only – EN1
  • 31-33 cpm: ramps up and recruits the fast twitch “a” fibers (FTa) to help the cause – EN2
  • 33-35 cpm: where anaerobic threshold (AT) starts to raise its head because the fast twitch “b” fibers (FTb) have to kick in so that the swimmer can hold the increased pace

Swimmers start to use all three fiber-types at around 33 cpm but around the 35 cpm frequency the muscles move into the fourth intensity zone called lactate clearance or SP1. SP1 has a SR range of between 35 and 45 cpm, which is when the muscles’ energy supply methods change from aerobic glycolytic conversion (with oxygen-based methods) to anaerobic glycolytic conversion (without oxygen).

Heart rates

The comparable heart rate expectations for aerobic work is as follows:

  • 125140 beats per minute (bpm): slow twitch fiber – EN1
  • 140160 bpm: FTa – EN2
  • 160-165 bpm: FTb – AT

If you coach very young kids who have not yet reached full puberty their heart rate response is elevated compared to those who are more mature physically. Pre-pubescent swimmers would tend to be 130-150, 150-170, and 170-175 for the same intensity levels (but because they are younger it would not be as extensive an effect).

Coaches can control the specific effect of aerobic distance sets by prescribing specific heart rate ranges but coaches should also do periodic stroke rate checks from the poolside. SRs help (a) ensure that the swimmer is in the correct zone (HRs float around somewhat and are very sensitive to a ‘big’ last 25), and (b) make sure the swimmer is counting and reporting their HR accurately.


As mentioned earlier, the Distance workout Greg designed could either be used to develop capacity (EN1) or develop power (EN2 and AT), depending on what stroke rate or heart rate you have your swimmers hold.

If you are planning your season then the principle is capacity must be developed before power. It’s a first principle of periodization and it makes sense because it’s difficult to empty a container of energy if the container hasn’t been developed in the first place. So-called ‘reverse periodization’ is a strange animal, which we’ll no doubt encounter at some other time, but suffice it to say it won’t work with distance swimmers.

If the same Distance workout was given to your swimmers later in the season you should expect them to swim the same speed with less effort at the lower end of the SR scale (28-31), indicating improved aerobic capacity; to swim faster with the same effort in the mid ranges (31-33), indicating increased aerobic power; and to simply swim faster on the final 1,650, which would also indicate increased aerobic power (even though it involves quite a large amount of anaerobic contribution).

And finally…GREG’s WoW FACTOR

That last swim of the Distance workout: “1,650 on 20:00 aerobic for time”. The phrase “aerobic for time” suggests that the swimmers were asked to put in a full-blown effort to finish this terrific workout. Very good. This twisting of the knife in the ribs is what sets apart those who train swimmers and those who prepare them for races.


There you have it for Commit’s first Workout of the Week! Looking forward to sharing a new workout next week and learning more from Clive Rushton.

If you’re a coach that would like to contribute to this series, please email with your request. Thanks!

5 thoughts on “WoW #1 – Peddie Aquatics What Does Aerobic Mean Anyways?

    1. Hi Todd, this is Nico, one of the founders of Commit Swimming. Coach Wriede is using a workout manager that my co-founders and I built over the summer and launched 2 months ago. You can learn more about it on Thanks!

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