Cruise Interval Challenge

As mentioned in a previous post (HERE), one of my 2022 running resolutions is to complete a training block with emphasis on cruise interval runs. 

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Cruise Interval Challenge
The goal for this challenge is to run at cruise interval intensity for a total 30 minutes by the end of a 6-week training block. To practice for this challenge, one run at cruise interval intensity is to take place each week, starting at 10 total minutes and gradually building to the goal of 30 total minutes.
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Background to this Challenge 
The cruise interval run is part of threshold training and is aimed at raising the runner’s lactate threshold and further improving endurance ability. Rather than a tempo run (a steady run at threshold pace) cruise intervals are also done at threshold pace but with short rest intervals added. According to running coach, Jack Daniels, threshold runs feel “comfortably hard” and are best done at a pace the runner can sustain for one hour. For example if a runner finishes a 10K race in 60 minutes then their threshold pace is 6:00/km (9:39/mile). Also the pace for cruise intervals can be calculated by adding a race or time trial result into an online running calculator (For this challenge I used a 10K race result to calculate my threshold pace with an online calculator). According to Daniels, “The great advantage of the brief recoveries is that blood-lactate levels remain fairly constant, and the runner experiences threshold effort throughout the entire training session, which can last a fair bit longer than could be accomplished with a steady tempo run at threshold pace.” (For this challenge I used one minute rest intervals.)

How to Track Cruise Interval Success
How do I know if I am improving in my ability to run cruise intervals? First of all, Daniels warns against running cruise intervals faster than one’s threshold pace. He says, “When a workout begins to feel easier, use that feeling to support the idea that you’re getting fitter. Then prove that you’re getting better in a race, not in a workout.” So, I focused on maintaining my threshold pace during cruise intervals workouts for incrementally longer periods of time and adjusting my pace when race results improved. I started with two intervals of 5 minutes each, with 1 minute rest and worked my way up to four intervals of 8 minutes each.

How Did It Go?
While not perfect, overall this cruise interval challenge was a success. I did reach my goal of 30 total minutes of threshold running (36 total minutes to be exact by running four intervals of 8 minutes each with a one minute rest interval). More importantly though, even getting a one minute rest interval left me less tired than a steady 30-minute tempo run (which I mentioned in an earlier post on my Tempo Run Challenge).

Tempo Runs or Cruise Intervals?
Due to the benefits, running coaches will add threshold training early, midpoint, or late in the runner's training year. After this run challenge I’d have to conclude I’m going to stick with cruise intervals over tempo running when threshold running is part of my training schedule. In addition, I’m going to  try to extend the total time to 40 minutes from 30 minutes set for this challenge.  Especially noticeable to me is a stronger half marathon finish after completing this cruise interval challenge. However, if I have a time-crunched schedule, a tempo run makes sense. For instance, on a day when a 60 minute run is usually scheduled, the time-crunched runner can still benefit from a 10 minute warm-up into a steady 10 minute tempo run followed by a cooldown of 10 minutes.

Other Fitness Activities 
Cruise intervals are not just the exclusive purview of runners. Walkers can use a cruise interval strategy to build fitness. Warm up by walking easily for 10 minutes. Then pick up the tempo of walking for five minutes followed by one minute of easy walking. Build up the number of times you pick up the tempo followed by easy walking. Cool off with 10 minutes of easy walking. The same strategy applies to biking by picking up the tempo of cycling followed by one minute of easy riding.
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Readers may be interested in these posts related to threshold running and this run challenge:

“Comfortably hard” running - Reconsidering Running by Feel

Two earlier posts on tempo running with additional pointers from Jack Daniels - Trying to Master the "Elusive" Tempo Run & Tempo Run Challenge

Thanks for reading! 



Experiment of One Coaching covers topics ranging from running, strength training, health & wellness, sports nutrition to travel.