Interval Training for Runners

Interval training is more than just a buzzword in the running community; it’s a proven method to improve your speed, endurance, and overall running performance. Whether you’re a beginner looking to complete your first 5K or an experienced runner aiming for a new personal best, interval training has something to offer you. In this article, we’ll delve into what interval training is, its benefits, and how you can incorporate it into your running routine.

What is Interval Training?

Interval training involves alternating between periods of high-intensity exercise and periods of lower-intensity recovery or rest. A typical interval workout might consist of running at a fast pace for one minute, followed by two minutes of walking or jogging, repeated for a set number of cycles.

Total Time at Intensity

While the duration of the intervals and rest periods are important factors, what truly matters in the design of an effective interval session is the “Total Time at Intensity.” This concept refers to the cumulative time spent at the targeted intensity level during the workout. The advantage of using intervals is that they allow you to accumulate a significantly greater amount of time at the desired intensity compared to maintaining that level continuously.

The Science Behind Interval Training

Interval training is a versatile approach that can be either anaerobic or aerobic, depending on the intensity and duration of the intervals. While it’s true that some forms of interval training push your body into the anaerobic zone, many interval workouts operate at the high end of the aerobic level.

Targeting Primary Systems

Interval sessions are designed to work primary systems such as the cardiopulmonary system, central nervous system (CNS), and metabolic system. The “dose” of interval training—meaning the intensity and duration of the high-effort periods—is specific to the primary system being targeted.

  • Cardiopulmonary System: All intervals will lead to an improvement in cardiopulmonary function.
  • Metabolic System: Intervals done at or near lactate threshold are designed to “dose” the metabolic system, as are efforts up to and slightly beyond VO2Max.
  • CNS and Musculoskeletal Control: Efforts above VO2Max target the CNS and aspects of muscle and skeletal control.

Dose and Response

Understanding the principle of dose and response is crucial when prescribing intervals. The “dose” refers to the intensity and duration of the high-effort periods, while the “response” is the physiological adaptation that occurs as a result. Tailoring the dose to target specific physiological adaptation helps in meeting individual training goals and optimizing performance.

Monitoring Progress: The Role of Modern Running Watches and Power Metrics

Equally important to understanding the dose required to elicit the desired response is having a reliable way to monitor progress. Modern running watches and tracking technologies offer various metrics such as heart rate, pace, and VO2Max, providing invaluable data to assess the effectiveness of your interval sessions.

The Power of the Critical Power Curve

One advanced metric that has gained prominence is power, with almost all high end running watches now incorporating power as a metric. Power allows for the modeling of the Critical Power curve. This curve provides deep insights into how an athlete is responding to different training doses. By using modelled data, coaches and athletes can make more informed decisions about where to focus their training efforts.

For instance, the Critical Power curve can help determine when pursuing further gains in lactate threshold (LT) would yield diminishing returns. There are commonly used standards when using a power duration curve that can point to an athlete having temporarily maxed out the gains in a particular physiological area. This enables us to identify the optimal time to transition to the next phase of training, or to pinpoint areas where an athlete stands to achieve the most significant gains.

Benefits of Interval Training for Runners

  • Improved Speed and Endurance: By pushing your limits, you train your body to sustain higher speeds for longer periods.
  • Enhanced Aerobic and Anaerobic Capacity: Interval training improves your body’s ability to use oxygen and produce energy.
  • Mental Resilience: The challenging nature of interval workouts can help build mental toughness, a crucial asset for any runner.

Types of Interval Workouts

  • High-Intensity Interval Training (HIIT): Short bursts of maximum effort followed by brief recovery periods.
  • Fartlek: A Swedish term meaning “speed play,” this involves varying your pace throughout a run.
  • Tabata: A specific type of HIIT involving 20 seconds of intense activity followed by 10 seconds of rest.
  • Pyramid Intervals: Increasing and then decreasing the length and intensity of intervals in a structured pattern.

How to Incorporate Interval Training into Your Running Routine

For Beginners:

  • Start Small: If you’re new to interval training, begin with shorter intervals and longer rest periods. For example, try running at a higher intensity for 30 seconds, followed by a 90-second walk or jog.
  • Frequency: Aim to include one interval session per week to start, gradually increasing as you become more comfortable.
  • Progressive Overload: As you adapt, gradually increase the duration of the high-intensity intervals or decrease the rest periods to continue challenging your body.

For Intermediate Runners:

  • Mix It Up: Don’t stick to just one type of interval workout. Incorporate various forms like HIIT, Fartlek, and Tabata to target different systems and keep your training engaging.
  • Quality Over Quantity: Focus on the quality of each high-intensity interval. It’s better to complete fewer intervals with good form and intensity than to push through more intervals with declining quality.
  • Recovery: Ensure you have adequate recovery days or lower-intensity workouts between interval sessions to prevent overtraining and reduce the risk of injury.

For Experienced Runners:

  • Advanced Metrics: Utilize modern running watches to track advanced metrics like power and Critical Power curve. Use this data to tailor your interval sessions more precisely.
  • Periodization: Consider incorporating interval training into a periodized training plan, where the focus shifts from building a base, to lactate threshold improvement, and finally to VO2Max and speed work as you approach your goal race.
  • Periodization Flexibility: The traditional approach to periodization may not always apply, especially for ultra races. In such cases, you might start with VO2Max and speed work early in the training cycle to build a strong aerobic engine. As race day approaches, the focus could shift to lactate threshold improvement and endurance work to prepare for the sustained effort required in ultra events.
  • Listen to Your Body: This aspect takes on heightened importance during a period of interval-based training. The goal is to arrive at each interval session well-rested and ready to execute the workout properly. Being in tune with your body’s signals allows you to maximize the “dose” of each session, thereby optimizing your training gains. If you’re feeling fatigued or notice signs of overtraining, consider adjusting your training plan to include more recovery or lower-intensity days.

General Tips:

  • Warm-Up and Cool Down: Always include a proper warm-up before starting your interval session and a cool-down afterward to help your body transition in and out of high-intensity work.
  • Nutrition and Hydration: Pay attention to your pre- and post-workout nutrition to fuel your body adequately for the demands of interval training.
  • Consult a Coach: For a more personalized approach, consider consulting a running coach who can design an interval training program tailored to your specific needs and goals.

The Role of Plyometrics in Warm-Up

Before diving into your interval session, consider incorporating plyometric exercises into your warm-up routine. Plyometrics, which involve quick, explosive movements, can serve as an excellent primer for the high-intensity work to come. Not only do these exercises help to activate the muscles you’ll be using during your intervals, but they also prepare your central nervous system for the rapid contractions and force production required in high-intensity running.

Examples of plyometric exercises suitable for a warm-up include:

  • A-Skips
  • B-Skips
  • High Knees
  • Butt Kicks
  • Quick Feet

By including plyometrics in your warm-up, you’re setting the stage for a more effective and dynamic interval session.


Interval training is a versatile and effective way to elevate your running performance. With benefits ranging from improved speed to mental resilience, it’s a training method worth exploring. We encourage you to incorporate interval training into your routine and experience the difference it can make. For personalized coaching and more in-depth guidance, feel free to reach out to us at Mindful Runner.

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