• Introduction
  • The basics of interval training
  • Fartlek training
  • High-intensity interval training (HIIT)
  • Tabata training
  • AMRAP training
  • Sprint interval training
  • Benefits of interval training
  • Interval training sample routines
  • Suitability for developing athletes and physical education
  • Final thoughts
  • Sources

Introduction

Interval training refers to workouts that alternate between short bursts of intense exercise with short recovery periods in between. It comes in many different forms depending on the intensity and style of the overall workout. The most common interval training methods are high-intensity interval training (HIIT), fartlek training, sprint interval training (SIT), and aerobic interval training. 

Interval training challenges both your aerobic (with oxygen) and anaerobic (without oxygen) energy systems. This means that during intense exercises, the anaerobic system uses muscle glycogen (energy stored in the muscles) as its main energy source. Because anaerobic metabolism doesn’t require oxygen, it also produces lactic acid as a byproduct. This hinders the mechanical properties of the muscle, causing lowered performance and fatigue.

Due to the oxygen debt caused by lactic acid buildup, your heart and lungs must work harder to stop further oxygen deficit and break down lactic acid. This also means that your aerobic system is using oxygen to convert stored carbohydrates into energy.

Studies state that training above the anaerobic threshold (highest possible intensity without significant lactate buildup) adapts your body to tolerate and buffer lactic acid during high-intensity exercise. Thus, you’ll be able to maintain a higher level of performance for a longer time – and without the feeling of fatigue. 

The basics of interval training

There are a million different ways to create a suitable interval training workout. Designing the perfect routine for yourself depends on four components:

  • The intensity of the workout
  • Duration of each exercise
  • Number of repetitions of each exercise
  • Duration of the recovery period

In simple terms, the longer each repetition is, the shorter the recovery periods are, or the more intense the exercise is, the more challenging the workout will be. So, if you are new to interval training, slowly increase the intensity and the number of repetitions in each set. For beginners, 30s of exercise per set with a 60s recovery is a good place to start.

Interval training can also be used for athletic performance in mind. The main difference between the two is that fitness-related intervals are performed at a lower intensity and shorter duration, whereas athletes often have a sophisticated and well-periodized training program for optimal athletic progression. Sometimes athletes may even use laboratory tests to measure the amount of lactic acid to calculate the optimal workload for individual sessions. However, to prevent overtraining, you should allow up to 48-72h of recovery between high-intensity sessions.

Interval Training


High-intensity interval training (HIIT)Sprint Interval Training (SIT)AMRAP TrainingTabata TrainingFartlek Training

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Fartlek training

Fartlek training, or “speed play”, refers to longer exercises that alternate between slow pace and faster intervals. This means that the slower phases can be used as a warmup or recovery between more intense phases of the exercise. Although this method is usually associated with running, fartleks can be used for other activities like cycling, cross-country skiing, rowing, and even swimming. 

The benefit of fartlek training is that it maintains a relatively high heart rate throughout the exercise and adapts you to perform at various speeds. Thus, it can improve your technique and improve your speed over longer distances. It also offers the same health and performance benefits as other interval training and HIIT methods. 

Fartlek training is also incredibly flexible. In fact, the same principles can be used by athletes and others alike regardless of their level of fitness. The intensity and interval duration are determined by how you feel during the exercise and what kind of terrain you are facing. Fartleks are also a great way to add some variety to your usual running routine and prevent boredom. However, we still advise you to decide on a specific workout beforehand. 

High-intensity interval training (HIIT)

High-intensity interval training, also known as HIIT or anaerobic interval training, refers to very intense exercises that raise your heart rate up to 80-95% of your maximum. In most situations, these exercises consist of a wide variety of bodyweight exercises (squats, lunges, pushups, burpees, etc.) or sprints that are performed against time. 

The duration and intensity of each exercise, as well as the length of the recovery period, determine how challenging each HIIT session is. A good rule of thumb for high-intensity interval training is to remember the 1:2 ratio – one part exercise, two parts recovery. For example, 60s of intense effort, followed by a two-minute recovery. The amount of sets also varies from 2-10 depending on your level of fitness. 

Note that not all HIIT methods follow the same guidelines for recovery and exercise. For example, Tabata training uses a 2:1 ratio (20s exercise, 10s rest) for an exercise that only lasts for four minutes, yet still challenges your endurance. On the other hand, AMRAP (as many rounds as possible) exercises do not have specific high and low-intensity intervals, yet they are considered very high-intensity workouts that often require some recovery time. Even CrossFit is sometimes considered a type of high-intensity interval training, granted it has evolved into its own respective style of training. 

Tabata training

Tabata training is a type of high-intensity interval training that consists of 20s of maximal effort, followed by 10s of rest, and repeated for a total of four minutes. It was originally a stationary bike exercise designed for elite-level speed skaters as a way to improve speed endurance. The method was proven to be incredibly effective in increasing the anaerobic capacity (total amount of energy produced without oxygen) of the Japanese Olympic skaters. 

While the modern version of Tabata training has evolved from a simple bike exercise to an intense bodyweight exercise, it still follows its original 2:1 exercise-to-rest ratio. 

Although the method has proven to be a very effective way to train, most athletic professionals recommend performing four rounds of Tabata training for the most benefit. This will keep your heart rate up longer, resulting in more health benefits. 

AMRAP training

AMRAP workouts are a form of high-intensity interval training where you must perform as many repetitions/rounds as possible in a given timeframe. In fact, the name AMRAP stands for ”as many rounds as possible”. Although AMRAP training does not have specific high and low-intensity intervals, it is considered a very high-intensity workout that often requires some recovery time.

To create your own AMRAP training routine, you should these five tips:

  • Select one or more exercises
  • Set the time
  • Perform as many repetitions as possible 
  • Always maintain good form and proper technique
  • Rest when needed 

For example, set a 7-minute time limit and perform 20 squats, 20 push-ups, and 20 kettlebell swings back-to-back as many times as possible. The biggest benefits of these types of exercises are that they take little time and they burn lots of calories. Just like any other HIIT method, it also offers improved cardiovascular fitness and better muscular endurance. 

Sprint interval training

Sprint interval training (SIT) is a type of HIIT workout that consists of short intervals of maximum intensity sprints. Due to its intensity, SIT exercises are also significantly shorter, with longer recovery periods when compared to traditional high-intensity interval training. Thus, sprint interval training often has a lower work-to-rest ratio (unless you’re specifically trying to challenge your lactate tolerance). 

For example, a sprint interval workout could comprise of five sets of 40m sprints, with a two-minute recovery between each sprint. These types of exercises are especially effective in sports that require repeated sprint ability.

Although sprint intervals often considered an advanced training method only used for athletic development, it can be an incredibly effective way to improve your fitness for average Joes/Joannas alike. According to studies, sprint interval training is much more time-efficient than traditional continuous exercises. Not to mention the beneficial effect they could have on your running technique, maximum speed, speed endurance, and anaerobic performance. 

Sprint interval training is often used for developing speed endurance.

Benefits of interval training

Interval training is considered to be very effective in improving both overall health and athletic performance. Consistent high-intensity training causes physiological adaptations such as better aerobic (VO₂max) and anaerobic capacity, as well as improved injury prevention. Interval training has also proven to burn more calories and boost metabolism, which promotes a healthy body composition.

Aerobic capacity, also known as maximum oxygen uptake (VO₂max), refers to the highest amount of oxygen consumed during exercise. This also means that it is one of the biggest contributors to endurance capability as well as a strong indicator of cardiovascular fitness. Regular interval training improves increases stroke volume (amount of blood pumped by a single heartbeat), the amount of hemoglobin and capillaries, as well as improves venous return (blood’s return to the heart). These effects result in better oxygen delivery in the body, which results in better health and athletic performance.

Anaerobic capacity describes the highest amount of energy produced without oxygen. This energy system is used when the aerobic energy system is unable to produce enough energy during intense exercises. Once the heart rate climbs over the lactate threshold, your body starts producing lactic acid, causing fatigue and nausea. Due to its intense nature, interval training is significantly better in improving anaerobic capacity and lactate tolerance than regular endurance exercises. 

Interval training boosts metabolism. Multiple studies have found that intense exercise burns more calories and also keeps your metabolism elevated for a long time after the workout. This increased energy expenditure also helps maintain healthy body composition.

Injury prevention is another reason to incorporate interval training into your workout routine. According to most studies, interval training can help prevent overuse injuries and burnout by offering a much-needed change from your regular training. 

High-intensity interval training can significantly improve cardiovascular fitness and athletic performance.

Interval training sample routines

Looking to include some interval training into your sporty lifestyle? Well, look no further. We’ve created a few samples of each interval training style for you to try out. You can also find more exercises from their own dedicated articles.

5 Fartlek training samples

45-minute Fartlek

  • Jog at a regular pace
  • Increase running speed for 60s every 7 minutes

Fartlek run for music

  • 35min jog at a comfortable pace
  • Increase your speed during every chorus

Pyramid Fartlek

  • 1min at 60% of maximum
  • 2mins at 65% of maximum
  • 4mins at 70% of maximum
  • 5mins at 75% of maximum
  • 4mins at 70% of maximum
  • 2mins at 65% of maximum
  • 1min at 60% of maximum

This can also be reversed and started with higher intensity.

Fartlek hill run

  • 45-minute jog at a regular pace
  • Increase speed at every hill

5 Tabata training samples

Tabata’s original workout

  • 20s of maximum intensity effort on a stationary bike
  • 10s rest
  • 8 sets

Total workout duration: 4 minutes

Bodyweight workout 1

  • 2x20s burpees (as many as possible)
  • 10s rest between sets
  • 2x20s plank punch (as many as possible)
  • 10s rest between sets
  • 2x20s squats (as many as possible)
  • 10s rest between sets
  • 2x20s push-Ups (as many as possible)
  • 10s rest between sets

Total workout duration: 4 minutes

Bodyweight workout 1

  • 2x20s burpees (as many as possible)
  • 10s rest between sets
  • 2x20s plank punch (as many as possible)
  • 10s rest between sets
  • 2x20s squats (as many as possible)
  • 10s rest between sets
  • 2x20s push-Ups (as many as possible)
  • 10s rest between sets

Total workout duration: 4 minutes

Bodyweight workout 2

  • 2x20s jump rope (as fast as possible)
  • 10s rest between sets
  • 2x20s Russian twists (as many as possible)
  • 10s rest between sets
  • 2x20s split squats (as many as possible)
  • 10s rest between sets
  • 2x20s lunges (as many as possible)
  • 10s rest between sets

Total workout duration: 4 minutes

Bodyweight workout 3

  • 2x20s jumping jacks (as many as possible)
  • 10s rest between sets
  • 2x20s push-ups (as many as possible)
  • 10s rest between sets
  • 2x20s box jumps (as many as possible)
  • 10s rest between sets
  • 2x20s split squats (as many as possible)
  • 10s rest between sets

Total workout duration: 4 minutes

Bodyweight workout 4

  • 2x20s mountain climbers (as many as possible)
  • 10s rest between sets
  • 2x20s squats (as many as possible)
  • 10s rest between sets
  • 2x20s high knees run (as fast as possible)
  • 10s rest between sets
  • 2x20s skater jumps (as many as possible)
  • 10s rest between sets

Total workout duration: 4 minutes

Aerobic interval training 1

  • 10min warmup
  • 4min running at 80% of maximum intensity
  • 3min walking (maintain the heart rate at 65% of maximum)
  • Repeat for 40 minutes in total

Sprint interval training 1

  • 30s sprint at maximum intensity
  • 3-5sets
  • 3min rest between each sprint

Total sprinting duration 90-150s.

Shuttle run sample 1

  • Set two cones 25m apart
  • Sprint to the cone and back
  • Repeat 6 times
  • 5min rest
  • 3 sets

Total sprinting distance 450m.

Beginner HIIT routine

  • 30s of maximum effort 
  • 30s rest between exercises
  • 3min rest between rounds
  • 3 rounds

Exercises:

  • Jumping jacks
  • Plank
  • Step-up on chair/bench
  • Push-ups
  • High knees
  • Left side plank
  • Right side plank

Intermediate HIIT routine

  • 45s of maximum effort 
  • 15s rest between exercises
  • 3min rest between rounds
  • 3 rounds

Exercises:

  • Jumping jacks
  • Push-ups
  • High knees
  • Mountain climbers
  • jump lunges
  • Heel touch 
  • Burpees

AMRAP training sample

  • As many rounds as possible in 12mins

Exercises:

  • 50 High knees
  • 10 Burpees
  • 20 Tuck jumps
  • 10 Push-ups
  • 20 Sit-ups

Note that we are not responsible for any injuries that may occur during these drills or practices. Always remember to train within your own limits and at the guidance of a professional instructor.

Your body needs 48-72h of recovery between high-intensity interval training sessions.

Suitability for developing athletes and physical education

Interval training is generally regarded as a safe and effective way to improve your fitness regardless of your age. This is partly due to its flexibility – it can be always be designed with the individual’s needs in mind. Interval training is also relatively easy to pick up because it requires very little equipment, which also makes it an ideal home workout. 

Here are a few things to keep in mind when creating your interval training routine/program:

  • Your current level of fitness
  • Your injury history
  • The activity you want performance benefits in
  • Your individual needs 
  • Your personal goals

With these tips in mind, you can create an interval training routine that is both fun and effective. We always recommend you start slowly and warm up well before every workout. For safety reasons, always train on an even surface and only use light resistance when you start your interval training journey. As you get stronger and your body gets used to more intense workouts, you can slowly up the ante and challenge yourself even more. If you are unsure where to start or how to proceed, feel free to consult an athletic trainer. 

Final thoughts

Interval training has long been a mainstay for people looking to improving their wellness and health. And for good reason! It is a great way to stay in shape due to its flexibility. All you need to do is to design a routine that fits your own needs and goals. As you progress and get stronger, you can also increase the duration of each interval and decrease the recovery time. This will ensure you progressively overload your body, which is the backbone of athletic improvement. 

However, before you take a deep dive into different forms of interval training, you must remember that it is not a direct substitute for strength or endurance training. Also, note that interval training should not be confused with circuit training. After all, interval training is primarily a cardio workout whereas circuit training is more of a resistance training workout. If you want to improve your fitness and stay healthy, you should challenge your body in various different ways and remember to 

Because interval training can be very strenuous for your body, you should have at least 48-72h of rest between high-intensity sessions. Therefore, interval sessions should be performed 1-3 times a week. But this doesn’t mean you can’t stay active! There are plenty of ways to challenge your body even on ”lighter” training days. Just remember to eat well and rest enough and you’re all set!

Did you learn anything new about interval training? Let us know in the comments?

Sources

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