What is the FITT Principle?

Frequency, Intensity, Time, Type… and how they relate to stretching and injury prevention.

by Brad Walker | First Published September 24, 2003 | Updated January 29, 2019
The FITT Principle (or formula) is a great way of monitoring your exercise program. The acronym FITT outlines the key components, or training guidelines, for an effective exercise program, and the initials F, I, T, T, stand for: Frequency, Intensity, Time and Type.

  • Frequency: refers to the frequency of exercise undertaken or how often you exercise.
  • Intensity: refers to the intensity of exercise undertaken or how hard you exercise.
  • Time: refers to the time you spend exercising or how long you exercise for.
  • Type: refers to the type of exercise undertaken or what kind of exercise you do.

Let’s take a look at each of the components in a little more detail.

The FITT Principle - Frequency, Intensity, Time, Type

Frequency

Frequency is a key component of the FITT Principle. Remember that it’s important to know why you’re exercising and what you want to achieve before rushing into any exercise program.

Adjust the number of times you exercise per week to reflect your current fitness level, the time you realistically have available, your other commitments like family and work, and the goals you’ve set for yourself.

Intensity

This is an extremely important aspect of the FITT Principle and is probably the hardest factor to monitor. The best way to gauge the intensity of your exercise is to monitor your heart rate.

There are a couple of ways to monitor your heart rate but the best way by far is to purchase an exercise heart rate monitor. These can be purchased at most good sports stores and retail from $50 to $400. They consist of an elastic belt that fits around your chest and a wrist watch that displays your exercise heart rate in beats per minute.

If you don’t want to spend the money on a heart rate monitor, simply count your heart rate over a 15 second period. All you need is a wrist watch that has a “seconds” display. Feel for your heart beat by either placing your hand over your heart or by feeling for your pulse in your neck or on your wrist. Count the beats over a 15 second period and then multiply by 4. This will give you your exercise heart rate in beats per minute.

Time

The time you spend exercising is also an important part of the FITT Principle. The time dedicated to exercise usually depends on the type of exercise undertaken.

For example, it’s recommended that to improve cardio-vascular fitness you’ll need at least 20 to 30 minutes of non stop exercise. For weight loss, more time is required; at least 40 minutes of moderate weight bearing exercise. However, when talking about the time required for muscular strength improvements, time is often measured as a number of “sets” and “reps.” A typical recommendation would be 3 sets of 8 reps.

Type

Like time, the type of exercise you choose will have a big effect on the results you achieve. That’s why it’s important to know what you want to gain from your efforts.

For example, if you’re looking to improve your cardio-vascular fitness, then exercises like walking, jogging, swimming, bike riding, stair climbing, aerobics and rowing are very effective. For weight loss, any exercise that using a majority of your large muscle groups will be effective. To improve muscular strength the best exercises include the use of free weights, machine weights and body weight exercises like push-ups, chin-ups and dips.

What are some mainstream recommendation?

The FITT Principle is most commonly used in the weight loss industry, although it’s also commonly used as part of strength training recommendations. The standard recommendation for weigh loss is as follows.

  • Frequency – 5 to 6 times per week
  • Intensity – Moderate
  • Time – Anywhere from 15 to 60 minutes
  • Type – Just about any old exercise

FITT for stretching

Let’s take a look at how the FITT Principle can be applied to stretching as it relates to improving flexibility and range of motion. Remember, stretching can be used for other activities like warming up and cooling down, but for the purpose of this article let’s stick with stretching for improving flexibility.

The FITT Principle for stretching would look like the following.

FITT principle for stretching
  • Frequency – 5 to 7 times per week. Unlike other types of exercises, like cardio and strength training, stretching (when done properly) is very relaxing and therapeutic, and will help you recover from your other activities. So feel free to add stretching to your exercise program every day.
  • Intensity – Slow, easy and relaxed. When the goal is to improve flexibility and range of motion you should do your stretching at a low intensity. Move into the stretch position and as soon as you feel deep tension within the muscle group, stop there. If it’s hurting or painful, you’ve gone too far. On a scale of 1 to 10 aim for a tension of about 6 or 7 out of 10.
  • Time – Anywhere from 15 to 60 minutes, and hold each stretch for 40 to 60 seconds.
  • Type – Static, Passive and PNF. For improving range of motion and creating permanent changes in your flexibility the best types of stretching to use are long-hold static stretching, passive (or assisted) stretching and PNF stretching.

How does all this relate to injury prevention?

The two biggest mistakes I see people make when designing an exercise program are:

  1. Training too hard, which often results in overtraining or injury; and
  2. Not including enough variety. The problem, most commonly, is that people tend to find an exercise they like and very rarely do anything other than that exercise. This can result in long term, repetitive strain to the same muscle groups, and neglect, or weakening of other muscle groups. Leading to a very unbalanced muscular system, which again is a sure-fire recipe for overtraining or injury.

When using the FITT Principle to design your exercise program keep the following in mind.

Frequency: After you finish exercising your body goes through a process of rebuilding and repair. It’s during this process that the benefits of your exercise are forthcoming.

However, if you’re exercising every day (or at least 5 to 6 times a week) your body never has a decent chance to realise the benefits and gains from the exercise. What usually happens is that you end up getting tired or injured and just quit.

My frequency recommendation: Only perform intense or strenuous exercise 3 to 4 times a week MAXIMUM!

This may sound strange and a little hard to do at first, (because most people have been brainwashed into believing that they have to exercise “to the max” everyday) but after a while exercising like this becomes very enjoyable and something that you can look forward to. Sure beats dragging yourself out the door everyday because you feel guilty about taking a day off every now and then, or just having an easy training day.

It also dramatically reduces your likelihood of injury because you’re giving your body more time to repair and heal. Many elite level athletes have seen big improvements in performance when forced to take an extended break. Most never realize they’re training too hard, too often.

Intensity, Time & Type: The key here is variety. Don’t let yourself get stuck in an exercise rut.

In regards to intensity and time, vary your effort. Dedicate some of your workouts to long, easy sessions like long walks or light, repetitive weights. While other sessions can be made up of short, high intensity exercises like stair climbing or interval training. And remember, if you’re not feeling 100%; take the day off or schedule an easy workout.

The type of exercise you do is also very important. Like I said earlier, many people get into a routine of doing the same exercise over and over again. If you really want to lower your risk of injury, do a variety of different exercises. This will help to improve all your major muscle groups and will make you a more versatile, all round athlete. Cross training is a great way of adding variety to your workout schedule.

What else can you do?

The Big Book of Stretch RoutinesWhile the recommendations on this page are a good starting point, you'll get a lot more benefit when you include a wider variety of stretches and stretching routines.

Get over 150 of the best stretch routines to do away with injuries; increase your flexibility; improve your sporting performance; and become loose, limber and pain free.

There's a routine for every muscles group in your body, plus daily stretching routines to help prevent over 35 different injuries. Get your daily stretching routines here.

Research and References

Brad Walker - AKA The Stretch CoachAbout the Author: Brad Walker is often referred to as the "Stretch Coach" and has even been called the Stretching Guru. Magazines such as Runners World, Bicycling, Triathlete, Swimming & Fitness, and Triathlon Sports have all featured his work. Amazon (author page) has listed his books on five Best-Seller lists. Google cites over 100,000 references to him and his work on the internet. And satisfied customers from 122 countries have sent 1,000's of verified customer reviews. If you want to know about stretching, flexibility or sports injury management, Brad Walker is the go-to-guy.

Disclaimer: The health and fitness information presented on this website is intended as an educational resource and is not intended as a substitute for proper medical advice. Please consult your physician or physical therapist before performing any of the exercises described on this website, particularly if you are pregnant, elderly or have any chronic or recurring muscle or joint pain.

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