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Dirty Dozen: 12 Essential Running Workouts for Ultramarathon Success

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By Jason Koop,
Head Coach of CTS Ultrarunning

Every week when I sit down to build workouts for athletes, I have an unlimited number of combinations I can choose from. I can create intervals ranging from seconds to hours. I can manipulate the intensity of intervals, combine different interval modalities into one workout, vary the amount recovery between intervals, and more. Despite the buffet of choices available, I tend to use very few of these combinations across a wide variety of athletes. Why? Because workout architecture need not be complicated to be effective. Furthermore, because many ultrarunners determine their intensity by Rate of Perceived Exertion (vs heart rate or pace), the structure of the intervals and recovery periods will dictate the intensity and how much time is spent at that intensity. By reducing the complexity, I can derive most of the adaptations I’m looking for with the right combination of interval number, duration, and recovery period. Below are the twelve most common workout combinations I give athletes, categorized by workout type and level of athlete you are.


If there was a workout ultarunners are allergic to, it would be RunningIntervals. The lung searing intensity is seemingly incompatible with the long, slow nature of an ultramarathon. Combine that with the sheer discomfort these intervals elicit, and even the most seasoned ultrarunners avoid these like the plague. Yet, even ultra-distance athletes can reap benefits from this type of work. RunningIntervals improve your stroke volume and maximum cardiac output, and therefore your VO2max. But the benefits do not end there. Adaptations from RunningIntervals can also increase your plasma volume, giving you the ability to tolerate heat better, as well as improve muscle capillarization, which helps improve blood and oxygen deliver to working muscles.

RunningIntervals are performed at an effort coaches call ‘VO2max’ intensity. The quotes are intentional, as you are only at your true VO2max for part of the workout. More importantly, and what drives most of the adaptation, is that you are running at an effort that elicits 90% of your VO2max oxygen consumption for greater than 10 total minutes. Most of the research behind this specific time-at-intensity (10 minutes at 90% of VO2max) was done by French researcher Vérinoque Billat, who interestingly enough won the famed Sierre-Zinal race in the 1982. Now that the history lesson is over, let’s get into how to structure a workout to drive this critical time at intensity.

In order to derive the critical amount of time (>10 minutes) at the specific intensity (>90% of VO2max oxygen consumption), I target individual intervals that are 2-4 minutes in length, separated by equal recovery periods, to accumulate 12-24 minutes of total interval time. The RPE for these efforts is between 9 and 10. Although these intervals can be completed on any terrain or on a treadmill, I recommend doing them uphill if possible. The incline is helpful for increasing the workload and enabling you to reach 90% of your VO2max oxygen consumption more consistently. RunningIntervals should never be done downhill as it will be nearly impossible to achieve >90% of your VO2max oxygen consumption.


TempoRun intervals are a crucial workout for making you a faster and stronger runner. The pace and intensity for these intervals are strenuous, and you will be running slightly below or at your lactate threshold intensity. These intervals help to drive the process of increasing the size and density of mitochondria in your muscles, which improves your ability to burn fat and carbohydrate, as well as process and utilize lactate as a fuel. Like RunningIntervals, they can also increase plasma volume, giving you greater ability to manage your core temperature, and increase mitochondrial enzyme activity which helps you produce more energy faster.

Like RunningIntervals, the critical component of TempoRun intervals is the time spent at the particular intensity. So, the design of the interval structure is imperative. Too much interval volume combined with prolonged interval length and insufficient recovery, leads the intensity level to be too low to be effective. On the other end of the spectrum, too little volume with a protracted interval length and copious recovery leads the intensity to be too high. TempoRuns target an intensity that is at or slightly below your lactate threshold. For most trained runner, this in an intensity you could sustain for 40-90 minutes if you were to do an all-out time trial. That’s a big range. But, in the laboratory and in the field, we see this range play out. Less experienced runners start out with the ability to tolerate only 40-50 minutes at their lactate threshold pace. As they become more trained, they can increase this tolerance to an hour or even longer, even when adjusting for the increase in pace to accommodate the increase in fitness. In other words, training makes your lactate threshold pace faster and increases the time you can tolerate running at that faster pace.

Accordingly, the total amount of interval time for a TempoRun workout will be between 40 and 90 minutes, divided up into individual intervals of 8-15 minutes each. Recovery periods between intervals should be half the duration of the interval, meaning a 2-to-1 recovery ratio, or 6 minutes of recovery between 12-minute intervals. TempoRun intervals should be run at an RPE of 8 or 9 with the Rate of Perceived exertion gradually creeping up throughout the course of each interval and throughout the set. TempoRuns can be done on flat, uphill or slightly rolling terrain.


A SteadyStateRun workout pushes you to a challenging aerobic pace but keeps you below your lactate threshold intensity and pace. This intensity plays a very important role in developing a stronger aerobic engine because you are maintaining an effort level greater than your normal “forever” pace. SteadyState intensity is very close to you everyday EnduranceRun intensity. Most runners find that they naturally fall into this intensity when doing continuous climbs of >20 minutes. SteadyStateRun intervals should be as continuous as possible, with individual intervals ranging from 20 to 60 minutes and total time at intensity for a single workout ranging from 20 minutes to 2 hours. A typical SSR workout might be two 30-minute SSR intervals separated by 5 minutes of easy recovery. The RPE for SSR is 7-8 and it will take a bit of extra attention to be careful not to let your intensity level creep up toward TempoRun territory on climbs. SteadyStateRuns can be done on flat, uphill or slightly rolling terrain.

A Word on Recovery 

All this talk about interval RPE, duration, the number of intervals, and terrain should make you think ‘What about the recovery period?’ Don’t overcomplicate recovery pace. Do the work periods hard and the easy periods easy. This means that the recovery between intervals can be easy running or even walking. Remember, the structure behind these Dirty Dozen Workouts is specifically designed to target an amount of time at a physiological intensity which then drives certain adaptation. Running slightly harder during the recovery periods does more harm than good. Increasing the intensity of the recovery periods beyond an easy jog or walk will limit the intensity you can achieve during the actual intervals, which will limit the total time spent at the target intensity. This reduces the overall quality of the workout as well as the benefits you can reap from it.

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  5. Your discussion of the recovery periods between the intervals was VERY helpful!

    I always feel guilty not keeping a brisk pace during those periods. I shall henceforth recover and not feel guilty! 🙂

  6. How would you break this up over a week? What days and how often and for a 62YO who’s very fit. I’m about 1 month away from a 50 mile, 17,000 ft. gain/descent White Mountain Hut Traverse over brutal rocky terrain running/power hiking with the goal to finish sub 24 hours.
    To late to apply these training methods???

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