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Why Interval Training Is The Secret To Great Fitness

Written by: Nick Jack
Category: 2014
on 20 May 2014
Hits: 8232

One of the biggest hurdles people face in maintaining an exercise program is simply finding the time to do it. People are still under the impression that you must devote hours and hours of endless cardio sessions to get fit! This does not have to be the case if you have the right knowledge and plan as you can cut your workout time significantly and reap even better benefits. How? By using Interval training, which also goes by other terms such as anaerobic, burst, or High Intensity Interval Training (HIIT). When you break your exercise session into short segments that alternate high intensity with a rest period in-between, it can dramatically improve your cardiovascular fitness and fat-burning capabilities in a fraction of the time. The big mistake with activities like running, cycling, swimming etc  is when you burn fat. Once you pass the 15 to 20 minute mark, you start burning fat during exercise. This may sound like a good thing, but what this tells your body is that you need fat to burn as fuel during exercise. As a result, your body will make and store more fat to prepare for your next run or aerobic workout -- a never-ending cycle making it difficult to get rid of that stubborn fat that never seems to go away.

Burn MORE Fat and Get BETTER Results


Interval training is not a new thing to elite athletes and the fact it burns more fat than long slow cardio sessions is also old news to people in sports. Several studies have confirmed that exercising in shorter bursts with rest periods in between burns more fat than exercising continuously for an entire session. This has been shown to hold true even when the session is not done at an extremely high intensity.

For example, in one such study, those who cycled for 40 minutes, alternating four-minute bursts at 90 % effort with two minutes of rest, improved their cardiovascular fitness by 13 %, and were able to burn 36 % more fat during a later hour-long moderate cycling session. Another study went one step further proving  you can burn more fat exercising for 20 minutes than for 40 minutes!

In their trial, women either exercised for 20 minutes, alternating 8 seconds of sprinting on a bike with 12 seconds of exercising lightly, or exercised at a regular pace for 40 minutes. After exercising three times a week for 15 weeks, those who did the 20-minute, alternating routine lost three times as much fat as the other women! The researchers believe this type of exercise works because it produces a unique metabolic response. Intermittent sprinting produces high levels of chemical compounds called catecholamines, which allow more fat to be burned from under your skin and within your muscles.

The resulting increase in fat oxidation is thought to drive the increased weight loss. Again, one of the best parts of this shorter but harder training is that it cuts down on the amount of time you need to exercise, which is great if you don’t have time for hour-long cardio workouts. 

In combination with Functional Strength Training and a good Nutrition plan, you can make significant inroads into your weight loss. Remember training alone is not enough, your food must be right if you want to lose weight.

What About Fitness & Improving Performance?

What about if you are not worried about losing weight but want to run faster, cycle faster or maybe improve sporting performance?

Well Interval training is by far the most powerful training technique to improve your racing performances. Unfortunately it is either completely avoided by most gym junkies and recreational runners because it’s considered too hard and for elite runners only. Or it is abused and really overdone as in some Crossfit type programs.

People at all levels should be able to use this style of training and receive significant improvements in their racing times, regardless of where they finish in their chosen event. You just need to understand that you must build up to this type of training by building a good base first. Training hard is great but if your body is not ready for it you will cause more damage. I encourage you to get a copy of our Little Black Book Of Training Secrets below as I show you how to go about interval training correctly, whether you are a beginner or a professional athlete.

I provide all of the strength workouts and there is specific running, cycling and sports specific programs to develop your fitness to a new level.


Anyone who has participated in our running group before will know just how much we use interval training in ALL of our sessions and also just how effective they can be.

To give you an idea as to how fast this type of training can work if done correctly I will show you my personal improvement in times from running races back in 2005. My goal was to run under 20 minutes for 5km. My first few races I applied a training approach of 4-5 runs per week of approximately 30-40minutes at the same speed ( pretty much flat out ). At first I got some improvement but eventually I levelled out and I could not get my time below 20 minutes. Then I got smart and adopted interval training and a much more strategic plan. It consisted of only 3-4 runs per week. One slow long run of 6-8km and three interval runs of 5-10 reps x 90-180 second bursts. A total workout time of only 20-25 minutes. I was able to get my 5km time down to 18:35 at one point using this type of training along with a better strength workout etc. As time went on I got much faster and was even able to run a 10km in 39 minutes and 2 half marathons under 90 minutes!

My best half marathon time I finished in the top 300 runners out of 9000. Now I am not sharing these times to brag how good I was as a runner but to show you that I really did not run that much. My training consisted mainly of weight training mixed with short high intensity interval sessions How many sessions of running per week do you think I had to do to get these times? I only ran twice a week, sometimes 3 times! Compare that to my original plan of 5 runs per week and I was also about 5 years younger then but I was considerably slower from that approach, and nowhere near as fit, as I am now at the age of nearly 40.

So my message to you is Quality over Quantity gave me a better results.

How Does This Help If You Play Sports?

If you play sports like football, basketball, netball, hockey etc etc then Interval training is paramount to your success because your game is a series of them anyway.

The aim of interval training for us is to improve the endurance of the fast twitch muscle fibres. Your training needs to be able to replicate game-changing bursts of powerful activities that you are likely to do when playing that you need at the start of the game and also in the dying minutes of the match. I like to use strength training interval circuit, that includes ALL of the Primal Patterns of Push, Pull, Bend, Lunge, Squat, Twist mixed with 8 different Bio-Motor Abilities such as Speed, Power, Strength, Agility, Balance, Endurance, Flexibility and Co-Ordination.  

I’ll often choose exercises that closely mimic the clients sport and couple several of them together.  I like this because it really challenges the neuro-muscular system in a manner that reflects team sport. For example, we might do a agility exercise for 20 seconds followed by integrated strength movements.

Check out the videos below of examples of Agility and Strength Training.


Funnily enough I like to use this type of training during the season as I keep the weights lower meaning their will not be any DOMS ( Delayed Onset Muscle Soreness) as there is not enough load or time under tension. This type of training really improves movement skills and overall fitness levels, which isn’t that exactly what you want to improve at your sport? I would however not do this more often than 2 times per week. 

What Are Some The Best Workouts To Do For Interval Training?

Unfortunately, insufficient knowledge and understanding concerning the principles on which interval training is based leads to inefficient workouts for many people who attempt to use it, and worse, it can cause injury or sickness if it’s overdone. Finding your level of performance for interval sessions is tricky, and you need to take several factors into account.

These factors can be remembered in the acronym DIRT which stands for:

  • D = Distance of each fast run or cycle etc,
  • I = Interval, or length of recovery between fast bursts,
  • R = Repetitions. How many fast intervals you complete in one session,
  • T = Time recorded for each interval.

Try to pick the right type of training for your goal. For example if you just want to lose weight then 12 secs fast with 8 secs slow for 10-15 mins is great. The speeds you do are completely irrelevant is more about your exertion. However, if you are preparing for a 10km running race then you will need to do more longer distances such as 800m to 1200m intervals. We use the 800m distance a lot in our training sessions for Triathlon, 10km races, Half Marathons as it is a distance that is not short enough to be over quickly but not long enough to be able to pace yourself at a comfortable pace. Basically they hurt! When starting out try not to do too many reps. Start with 3-4 reps and build up over the coming weeks as you get better.

Circuit training is a great way to do this using weight training as seen in the videos above. 

Varying the rest times can also make a massive difference. Sometimes we stand still for 2 minutes whereas other times we jog between sets. Decreasing the length of the recovery interval between fast bursts achieves great results because this doesn’t allow your energy sources (ATP and glucose) to completely resynthesize. Meaning you draw on the emergency back up system, the lactic acid system. Your body adapts to this by tolerating smaller amounts of lactic acid, enabling you to cruise at a “higher wattage”, or a much faster pace with less lactic acid building up. Again it just depends on the goal of the workout or what you are working towards.

Just remember you must find the find line between training too much versus not enough. Watch the video below for more detail on this.



So in conclusion Interval Training is by far the most effective method of cardio training for improving fitness and sports performance. It is also much more time efficient which is one of the biggest reasons people don’t get their exercise program completed.  So if you are not doing this type of high intensity training now, make a start, remembering to start slow and gradual and build up as you get better. And for those of us just wanting to lose a few kilos this is one of the fastest ways to lose weight. Again it doesn't need too much time to have a great effect which is even better for people who are time poor.

For more ideas and information on specific topics I may not have covered in detail be sure to check out our INDEX PAGE on the website that has over 300 of our best articles. These are all sorted into categories for quick reference so you can find what you are after more easily.

If you do need specific help with your exercise program please feel free to reach out to me for help and we can set you up with your individualised program.


About The Author

Nick Jack is owner of No Regrets Personal Training and has over 15 years’ experience as a qualified Personal Trainer, Level 2 Rehabilitation trainer, CHEK practitioner, and Level 2 Sports conditioning Coach. Based in Melbourne Australia he specialises in providing solutions to injury and health problems for people of all ages using the latest methods of assessing movement and corrective exercise.


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