The importance of rest intervals

Jason Tait explores the importance of rest – an often neglected but vital part of a swim training session

When coaches design a swim session, rest periods are calculated based on the workout’s goals, the type of training, and available pool time. However, swimmers often overlook rest, shortening or skipping rest periods or taking longer breaks than necessary. Both habits prevent you from gaining the full benefits of the session and limit your development as a swimmer.

What are rest periods and why are they important?

Rest periods refer to the planned time between swim efforts during a set. They allow your body to recover, helping you maintain technique and speed throughout the session. Proper rest helps pace your energy systems and avoid premature fatigue, enabling consistent performance across the workout.

Why ignoring rest intervals is suboptimal

1. Skipping or reducing stated rest periods If a session calls for 20 seconds of rest, skipping or cutting it short can lead to early fatigue, slower swimming speed, and poor pacing. In a coached group, this disrupts the lane’s flow, creating issues for other swimmers.

FIX: Stick to the planned rest intervals, even if you feel capable of pushing through without stopping.

2. Taking excessive rest: On the other hand, resting longer than recommended reduces intensity and effectiveness. Training is meant to challenge you, and too much recovery undermines the workout’s goals.

FIX: Stay on track with the stated rest, even when it feels tough. Pushing through fatigue while maintaining form is a key to improved fitness.

How coaches calculate rest periods

Rest periods aren’t random; they are designed with specific session goals in mind. Different training types require different rest durations:

1. Technique and drill sets Rest periods are typically 10-30 seconds. This allows you to focus on technique and maintaining form, without rushing between efforts, helping you mentally and physically prepare for the next swim and giving enough time to change swim training aids as needed.
2. Threshold or aerobic endurance sets: In endurance-based sessions, rest periods are shorter, usually 5-20 seconds. These short breaks help maintain your heart rate and stamina, training you to swim longer distances at a steady pace.
3. Anaerobic or sprint sets: High-intensity sprint sets or maximal effort sessions require longer rest, typically 30-60 seconds, or even 1-2 minutes for an all-out sprint set. This allows full recovery so you can hit maximum effort on the next repetition.

Different types of rest intervals

Coaches use various methods to structure rest periods. Understanding these approaches helps you maximise your training:

1. Interval-based rest
   This is common in group training. For example, a 10x100m on 2 minutes means if you finish in 1:45, you get 15 seconds of rest before starting again. If you swim faster, you get more rest; slow down and you get less. This helps maintain pacing and push your limits.

There are two main ways I use to determine these swim and rest times. The more traditional approach is to give every swimmer in the lane the same swim and rest time, based on an assessment of the average ability. This keeps the swimmers working together but faster swimmers may get more rest than they need and slower ones get less.

The alternative is to use individualised intervals based of each swimmer’s threshold pace or Critical Swim Speed (CSS). In this case, a swimmer covering each length of a 25m pool in 20s might be set a 20s rest interval, while one taking 25s per length would get 25s. These sets can be managed to fractions of a second using a Finis Tempo Trainer.

2. Fixed rest interval:

In this method, rest periods are set at an exact time. For example, take 20 seconds rest after each 100m, regardless of how fast or slow you swim. This approach ensures strict timekeeping and consistent recovery for all swimmers but can cause problems with lane dynamics.

3. LIFO (Last In, First Out): The last swimmer in a lane finishes the repetition, and the first swimmer starts the next one. This helps maintain lane organisation and encourages teamwork. A variation might be “go on third swimmer”.
4. Regroup periods (RG): Ideal to use in a coached group, generally occurring at the end of warm up or specific block of work. All swimmers stop and regroup before starting the next part of the session together. It helps keep the lane in sync and allows the coach to address the group with session or technique specific instructions.

Adjusting rest for different ability levels

Not all swimmers are at the same fitness or ability level, so rest periods must be adapted. Use the above guidelines but make adjustments for less experienced swimmers who may need more recovery or those coming back to swimming after a break.

Rest is part of the plan

Rest periods are just as important as the swimming itself. They allow you to recover, maintain form, and push your limits in a controlled way. When your coach sets rest intervals, it’s with specific goals in mind, such as enhancing technique, building endurance, or increasing speed. Skipping or extending rest changes the session’s outcome, so stick to the plan for the best results. Remember, it’s not just what you swim that matters. How you manage your rest is equally crucial!

Jason Tait is the founder and head coach of South West Swim: southwestswim.co.uk