(Photo: Chris Coduto/Getty Images)

Workout of the Week: Marathon Pace Alterations

Try elite marathoner Allie Kieffer’s marathon/10K alteration workout.

Molly Hanson

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Peppering your training with a few sustained, endurance-based efforts is a great way to prepare for any race running anywhere from a mile to a marathon. 

This workout, which comes from 2:28 elite marathon runner Allie Kieffer, alternates between longer segments at marathon pace and shorter segments of faster 10K race-pace efforts.

Workout Summary

  1. Warm up for 10–20 minutes + strides 
  2. 400–800 meters at 10k race-pace effort 
  3. 1 mile at marathon-pace effort
  4. Repeat steps 2-3 without a break until you complete the predetermined distance (3–12 miles depending on goals and fitness) 
  5. Cool down for 15–20 minutes


The workout is simple and effective because it allows you to adjust the variables depending on what race you are training for. Kieffer, who specializes in the marathon and 10K, switches between a steady effort at marathon pace and a 10K pace. 

“I especially like it because I can change the variables depending on what race I’m training for, so it fits into every season!” says Kieffer. “If I’m in a 10K phase I do less overall distance, but a larger percentage of the run at 10K pace. When I’m marathon-training, I do larger portions at marathon pace with smaller segments at 10K to teach my body to recover at marathon pace!”

For reference, Kieffer tends to aim for 6–7miles of this alteration workout when training for a 10K training, and 10–12 miles in marathon training. If you’re training for a shorter race such as a 5K, you could dial this down to 4–6 miles. 

The Workout

Kieffer competes in the 2019 Humana Rock ‘n’ Roll Arizona 1/2 Marathon in January, 2019 in Phoenix, Ariz. Photo: Ezra Shaw/Getty Images

This workout is meant to be done a few times over a training period for a specific race—or time trial—so as to increase the distance or time that you hold the faster pace. For example, when preparing for a 10K race, the first time Kieffer does this workout in a training phase she only runs 400 meters at a 10K race pace. The next time she does it she’ll run 600 meters at that pace, and the third time 800 meters. Eventually she aims to be able to hit 1200 meters at that 10K pace in the workout, still recovering with one mile at marathon pace between each 10K segment. 

“For me this has served as a great indicator workout and tells me where my fitness is at for each distance,” says Kieffer who does the workout once every three to four weeks. “The goal of my training is to extend the length of time I can hold my goal pace, and this workout effectively shows me that. It’s also nice because you can use it at any phase of training.” 


The beauty of this workout is that it’s also simple to adjust for different goal races. For example, if you’re preparing for a 5K, you could switch between marathon and a 5K race pace. 

You could also adjust the faster segments to be based on time. For example, in replacement of the 400 meters, you run about 90 seconds at the faster pace the first time you do it. The next time, you could run about 2 minutes and 30 seconds at this pace in replacement of the 600 meters. In replacement of the 800, you could run at the fast pace for a little over 3 minutes. 

Words of Wisdom 

One piece of advice Kieffer notes is to only change one variable at a time if you repeat the exercise. “I increase the distance of my goal race-pace and keep the other one the same,” she explains. “So, if I’ve started with continuous sets of 400 meters at 10K [pace] and one mile at marathon pace, the next time I do it I run 600 meters at 10K [pace] and one mile at marathon pace.” 

She also advises that you begin this workout at a current fitness level, and work up to the “goal pace.” Meaning, the first time you do this workout don’t run your 10K spurts at a pace based on the 10K time you want to run. Run the 10K spurts at a pace based on the time you can actually run a 10K at that moment. 

“It’s a very challenging workout that takes a balance of speed and endurance because you continuously cycle from fast to moderatethere is no stopping,” she warns. “So it’s much better to start off conservative and complete it well then to go out too fast and not complete it at all.” 

It is indeed a challenging workout. Kieffer, after all, is a high caliber marathoner. With that in mind, here is an easier version of this workout for mortals, with shorter race-pace segments and longer “recovery” at a steady-state marathon pace: 

  1. Warm-up for 10-20 minutes 
  2. 400 meters or 90 seconds at 10K race-pace 
  3. 1.5 miles at marathon pace
  4. Repeat 2-3 continuously for 3-5 miles 
  5. Cool-down 

Do this every 3 to 4 weeks aiming to get in 3 to 4 sessions in a training block. 

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Lead Photo: Chris Coduto/Getty Images

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