Clock Intervals vs Rest Intervals in Swimming: What’s the Difference & Why does it Matter?

What is this episode about?

INTRO 0-12:02

Liz broke her 5th metatarsal tripping over her own feet (shocking!).  It was two weeks before she saw a doctor (eik) but now she's in a boot and is RESTING and doing PT (with Amy!).  It’s a basic fracture but will still require a slow and careful return to running.

Rest Intervals vs Clock Intervals in Swimming

Beginner swimmers can be overwhelmed with figuring out the basics of swimming and, as such, using a clock right away is often too much to think about.  However, eventually swimmers / triathletes use a clock to track their times in the pool.

There are steps to learning to use a clock in swimming. First we learn to time how much rest we take.  Example: 8 x 50 yards on 20 seconds rest. This means we rest 20 seconds after each 50 yard swim. Next,  we learn to time the “work” or the swim efforts.  Example: It takes 1 minute to swim 50 yards.

We use these times to assign swim workouts in the pool.  When we assigning a swim workout based on how much rest an athlete should take, we call them 'rest intervals'.   In other words, each workout is based on a designated amount of rest:

Example of a set written with rest intervals;

8 x 50 on 20 seconds rest

8 x 100 on 30 seconds rest

8 x 200 on 10 seconds rest

Rest intervals are helpful but at some point an athlete may need something more challenging if they want to continue to improve. Clock intervals are a next step to increasing the level of difficulty of swim workouts and help swimmers / triathletes break through to the next level of swimming.

Example of a set written on clock intervals:

8 x 50 on 1:15 (one minute and 15 seconds)

8 x 100 on 2:30 (two minutes and 30 seconds)

8 x 200 on 5;30 (five minutes and 30 seconds)

Let’s break this down:  

8 x 50 on 1:15 it means you have 1 minute and 15 seconds to swim 50 yards. Any left over time is rest. So, if it takes you 1:00 to swim 50 yards, you get 15 seconds rest.  If it takes you 1:05 to swim a 50, you get 10 seconds rest.  How fast or slow you swim, impacts the amount of rest you get. 

This is very different from the 'rest interval' example above where you get 20 seconds of rest no matter how fast or slow you go.

It changes the intensity of a swim workout and requires an athlete to closely track both their swim times and their rest times so they can make the intervals.  It forces an athlete to work differently and often more effectively than rest intervals.  

Moving to Clock Intervals is a reasonably advanced step and is one to consider once you are comfortable enough in the pool to maintain good form and watch the clock!