What Is Interval Training?
A swim set—also known as interval training—is defined by several distinct and easily identifiable factors. These elements determine the specific goals and structure of the set.
The Key Factors of a Swim Set
- Number of repetitions
- Distance
- Stroke
- Rest time or send-off time, and recovery type
- Target intensity
And, in some cases, the number of times the full set is repeated
This article builds on a recent post on the OpenSwim blog, where we broke down the structure of a swim set in the app. For more background on swim pacing, check out our detailed article on time and intervals in swimming.
Concrete Examples
Let’s take the example of a swimmer who swims 1:00 for 100 m freestyle and 4:25 for 400 m freestyle, with the following set:
12 X 100 Freestyle send-off every 2:00 at 80% of MAS
Each factor can be adjusted, and every adjustment changes the intended purpose of the set. By modifying one or two factors, you completely shift the energy system being targeted. The example above primarily develops aerobic endurance (or what’s often called the first ventilatory threshold – VT1).
Now, if the set becomes: 6 X 100 Freestyle send-off every 4:00 at 110% of MAS ; then the focus moves to lactic power work.
You can also adjust the recovery type—active or passive—which further changes the goal of the set.
For example: 12 X 100 Freestyle send-off every 4:00 at 100% of MAS
is not the same as
12 X 100 Freestyle + 50 easy swim send-off every 4:00 at 100% of MAS
The intensity of each 100 m is identical, but active recovery helps the swimmer flush out lactate and reduces fatigue, altering the outcome of the session.
An interval training set is always structured around the five components listed above. Swimmers should clearly understand the goal of the set and the energy system they intend to train. Even changing a single variable can completely transform the physiological focus and the purpose of the workout.