Intervals Explained – Don’t Fear the Swimmers and Their Special Way of Measuring Time

By Bruckner Chase, Swimming & Ocean Sports Editor

Indoor Swimming

Winter season for most triathletes or open water swimmers means pool time, and if improving for 2017 is a primary goal, the best thing to find in that pool is a coached masters workout. For those who are new to coached swim sessions, or even masters style workouts, the most intimidating component can be the dreaded question: “What’s your hundred interval?”

Pool SwimmingFor those interested in making the most of their aquatic conditioning at any speed, and at any time, using Intervals rather than rest times will not only get you faster, they will let you develop the mental strength and connection to the physical experience of swimming at various speeds that no wrist monitor and software system will ever be able to duplicate. Basically an “Interval” is the time you have to swim a designated distance before starting the next swim in the series or set. Once you cover the designated distance and touch the wall the time remaining in your “Interval” is your rest and recovery time. Some swims are swum at an intense level with long intervals and lots of rest, while others may be swum at a lower intensity and shorter interval to create a more aerobic focused set.

Sample Set: 

4 x 400 Meters on 5:00 Interval

Circle represents the 5:00 Interval

Yellow is the time spent swimming

Blue is the time spent resting


How interval based workouts help…Interval Board

Always knowing your time for the designated distance with the ability to immediately apply that to perceived exertion.

Improves awareness of pacing over a set distance and through a set as you fatigue.

What’s your interval?

This is going to be the first question you often here from a coach helping you determine what the best lane is going to be for you in a workout group. Typically the coach means that if you were to swim an aerobic set of 10×100 meters, what interval could you maintain that would let you finish each of the ten hundreds and have enough rest to start the next one while staying relatively comfortable throughout the set of ten.

Group Workout Courtesy – Dropping into a group workout with multiple lanes?

Typically fast lanes will have hundred based intervals such as 1:20 – 1:30 per hundred. Slow lanes will have intervals based on 2:10 – 2:30 per hundred. Often the number of repeats, distances, and intervals will be adjusted to keep all the swimmers together and able to complete a set during the designated workout session.

What does the coach mean by “Hundred Base”?

Hundreds are typically the basic building blocks of workouts. Someone who does that set of 10 x 100 on a 2:00 interval would swim an aerobic set that includes 500’s on an interval of 10:00 {5 x 2:00}.  300’s would be on 6:00.  150’s would be on 3:00.

For more information on coached adult workouts check out US Masters at for listings of pools, teams, meets and training resources.

Bruckner ChaseBruckner Chase is a triathlon and swim coach, ocean lifeguard trainer, endurance waterman and ocean advocate whose marine and community endeavors have taken him to waters around the world is places such as Australia, American Samoa, Denmark, Greece and Poland. He is a global ambassador for the Lifesaving World Championship 2018 organizing committee, and he is the Technical Director and Media Ambassador for the Red Bull Surf + Rescue Championships. Closer to his home in New Jersey he is a member of the Sea Girt Beach Patrol and the founder of the Ocean City Swim Club. He is a professional member of the US Lifeguard Association, the American College of Sports Medicine and the American Swim Coaches Association.

Bruckner’s athletic career spans the most challenging events on water and land. He competed as a professional triathlete, and he continues to be an elite level competitor in every endurance sport he takes on. On the water Bruckner has completed multiple ultra-distance swims and paddles in some of the harshest conditions imaginable: a record setting no wetsuit swim in Alaska, a 22-mile swim of Lake Tahoe and historic swims between the islands of American Samoa. Bruckner competes in professional surf lifesaving sports across multiple aquatic disciplines. He is the fifth American in history to compete in the iconic Coolangatta Gold Surf Iron Man in Australia, and in 2016 he became the only American to finish the event three times and the first to earn a spot on the winner’s podium.

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