Mile repeats are a simple enough workout: you run hard for one mile, recover for a bit, and repeat a few more times. The beauty of this workout, much like the long run, is in their simplicity: they are effective, easy to execute, and adaptable based on your ability and goals.
Mile repeats offer significant physiological benefits to runners across all distances, from the 5K to the marathon. Additionally, they can increase capillary and mitochondrial density, which in turn helps more oxygen get to your muscles. Mile repeats also recruit both your fast-twitch and your slow-twitch muscles, which help you build speed and stamina. Finally, an increase in stroke volume and the amount of red blood cells helps improve your running economy, which will benefit you no matter what distance you are racing.
Like all good workouts, mile repeats not only help you improve physically as a runner – they build mental toughness. You have to be mentally comfortable with physical discomfort during these intervals. You also learn how to pace yourself evenly, minimizing the “fly-then-die” tendencies for some runners, and how to hold a hard pace for a longer amount of time. It can be easy to crank out a bunch of 400-meter repeats at a very hard effort since you enjoy more frequent recovery intervals. The same cannot be said for longer intervals, even if the total distance of hard running is the same.
Mile repeats are a versatile workout. You can manipulate the number of repetitions, pace/perceived effort, duration of recovery intervals, and even where you are in your training season. The following workouts are some examples of how you can include mile repeats in your training.
5K-Paced Mile Repeats
5K-paced mile repeats are challenging no matter what your pace is. As a result, you want to save them for the 3-6 weeks out from a 5K or 10K race, when you are fit enough to handle the stimulus, but not so close that you leave your race in training. 5K-paced mile repeats work your aerobic system almost at your VO2max, therefore improving your running economy and optimizing your recruitment of fast-twitch muscles.
5K pace intervals come with numerous caveats. First, you have to stay controlled. If you run any pace faster than 5K race pace, long intervals become less of a workout and more than a race effort. Second, you want to avoid doing them if they will last longer than 5-6 minutes, since output near VO2max will decline and lactate will too rapidly accumulate. If you are slower than that, either scale the duration or intensity.
If you are training for a 5K race, you can use 5K-paced mile repeats to build race-specific fitness. At the beginning of the training cycle, run three one-mile repeats at your current 5K pace, with 3-4 minutes recovery in between. As your race approaches, run closer to goal race pace in the repeats and shorten the recovery intervals to 90 seconds.
For longer distances, 5K-paced mile repeats can be used throughout the training cycle – especially in the earlier weeks – as a way to build speed without compromising endurance.
1-2 mile warm up
3 x 1 mile at 5K race pace with 3 minute recovery in between
1-2 mile cool down
Threshold Pace Mile Repeats
Threshold pace is approximately the effort you could sustain for an hour if racing. This effort improves aerobic fitness by taxing your system right at your lactate threshold (when anaerobic glycolysis occurs and lactate accumulates rapidly in the blood). Mile repeats at threshold pace allow you to do a greater volume while minimizing training fatigue.
You can use threshold repeats at any point in the training. Early on, they can prepare you for bigger threshold workouts. Workouts such as 4 to 6 x 1 mile at threshold pace to prepare the body for longer workouts like 2-mile repeats or continuous tempo runs. During high mileage marathon builds, threshold pace mile repeats maximize adaptation while minimizing training fatigue. Regardless of your ability level, threshold mile repeats utilize short-rest intervals, rather than the longer recovery intervals of 5K and 10K paced mile repeats.
You can also use slightly slower half marathon pace mile repeats to add in a higher volume of training near at your goal pace without as much fatigue as a continuous tempo run. For example, you might choose to run 8 x 1 mile at goal half marathon pace about 2-4 weeks out from your race, to practice a high volume of goal pace running without the risk of leaving your race in your training. Marathoners will find that long intervals at threshold pace allow them to work at a higher volume near lactate threshold during the peak fatigue of marathon training.
1-2 mile warm-up
5-6 x 1 mile at threshold pace, with 1 minute recovery in between
1-2 mile cool down
Marathon Pace Mile Repeats
Marathon pace may feel relatively comfortable for mile repeats – and that’s exactly why you do mile repeats at marathon pace. For the first half of a marathon, marathon pace SHOULD feel relatively comfortable. You need to learn in training how to control your intensity when running at marathon pace. Mile repeats at marathon pace teach that control.
Marathon pace repeats are typically best done earlier in a cycle, before an athlete is ready for continuous marathon pace runs. For more experienced marathoners, marathon pace workouts can be folded into long runs.
1-2 mile warm-up
6-8 x 1 mile at marathon pace, with 1 mile easy run in between
1-2 mile cool down
Pacing Mile Intervals
It’s important to note that mile repeats are not meant to be run at race effort. You might set your mile PR during these workouts if you never run mile or even 5K races, but the focus should always be on proper pacing for the intention of the workout. The best way to tell you are running at an appropriate effort? You should always have a little bit left in your tank, rather than feeling completely wiped by the end of the workout.
- Pacing matters. Aim for consistent repeats, which often means holding back a bit in the first repeat and pushing slightly harder in the final repeat. Read this post for more guidance on pacing speed workouts.
- Jog or walk slow on the recovery intervals. It’s okay to walk or walk-jog if you have to. The purpose of recovery intervals is to lower your heart rate and allow your body to recover just enough to run at the same effort again.
- No track available? Any flat, uninterrupted stretch of road or trail will work.
- Always include a warm-up that includes dynamic stretches and at least 10 minutes of easy running.