What Is the FITT Principle? Experts Explain the Basics of Exercise Programming

The FITT principle is a foundational concept in exercise programming. It’s straightforward and accounts for all of the necessary variables in a structured fitness plan: frequency, intensity, type, and time. 

It’s a principle that personal trainers and performance coaches across all sports use to develop effective training programs for athletes and casual gymgoers alike. In this guide, you’ll learn about each element of the FITT principle and hear from certified functional strength coach and United Endurance Sports Coaching Academy (UESCA)-certified endurance coach Melissa Kendter on how to make it work for you.

Key Takeaways

• The FITT principle stands for Frequency, Intensity, Time, and Type and is a way to structure your workout routine to create clear and achievable steps that support your long-term fitness goals.
• Benefits of using the FITT principle include reduced burnout, injury, and exercise plateaus.
• Many personal trainers and health experts use FITT as the basis for custom workout plans for people at all fitness levels. 
• The FITT principle is a great way to stay motivated when reaching fitness goals, with nearly 40% of people pinpointing lack of motivation as the reason they stop working out. 

What Is the FITT Principle?

The FITT acronym stands for: 

• Frequency (how often)
• Intensity (how hard)
• Time (how long)
• Type (what activity)

These four elements make up the basics of any fitness program and can be used for any activity or sport. Personal trainers and coaches can individually manipulate any of these variables to help their clients or athletes reach specific goals. 

Ultimately, the goal behind the FITT principle is to safely and effectively progress from your current fitness level. More specifically, trainers alter FITT variables to: 

• Improve aerobic conditioning and cardiorespiratory fitness 
• Improve an athlete’s performance
• Develop strength in specific muscle groups 
• Maximize muscle hypertrophy 
• Get stronger in a specific lift, like the deadlift or bench press

FITT can also be used in a healthcare and rehabilitation context. Providers can prescribe exercise protocols to help people overcome chronic diseases, such as high blood pressure, or recover from a musculoskeletal injury such as an ACL tear. 

“When creating a program, two key factors must be considered: the specific adaptation desired and the current level of fitness and/or training age of the athlete,” says Kendter. “The great thing about these principles is that they can be used by anyone, whether they’re beginner, intermediate, or experienced,” she explains. 

Frequency

Whether your sport requires prioritization of aerobic exercise (for example, marathon running) or anaerobic exercise (for example, powerlifting), frequency is going to be a key factor in your training program. 

Broadly, frequency refers to how often you do something. But it can refer to more than one thing. Depending on the context and structure of your training plan, it could mean:

• How often you train overall (typically defined in terms of per week)
• How often you do a specific kind of exercise (like running)
• How often you train a specific stimulus for a type of exercise (such as threshold run if you are a runner) 
• How often you perform a specific lift (like squat, bench, or deadlift)
• How often you do resistance training for a particular muscle group (such as quadriceps or deltoids) 
• How often you train a particular movement pattern (like push or pull) 

Kendter points out that beginners should focus on overall frequency (how often you train per week) before thinking about any other frequency variables. “Start with one or two days of structured training, and as you get into a habit of training consistently, you can add additional sessions and get more specific,” she says. “Consistency and forming habits around our training is key first.”

Frequency for Strength Training

If you primarily engage in strength training, frequency—for you—will refer to: 

• Your total number of training sessions per week 
• How many times you work the major muscle groups (for bodybuilding programs)
• How many times you perform specific lifts (for powerlifting and Olympic lifting plans) 

Frequency is the easiest variable to manipulate (add or remove training sessions), but it also has the greatest limits: You can’t train more than seven days per week. Rest days are an important part of progression. 

Frequency for Cardio

For most people, cardio frequency is simply a measure of how many times they do cardio exercise each week. Manipulating this variable is as simple as doing more or fewer cardio sessions per week. 

Increasing cardio sessions from one 60-minute session to three 60-minute sessions per week can lead to improved health outcomes in individuals with obesity and/or other chronic diseases. (1)(2)

For athletes, it’s a bit more complex. Athletes who rely on excellent cardiovascular fitness to compete track and change frequency for multiple stimuli, including:

• Low-intensity aerobic activity (building an aerobic base) 
• Threshold training (pushing anaerobic/lactate threshold) 
• Speed training 

Changing the frequency of any of these stimuli will affect an athlete’s training adaptations, thus their performance, too.

Intensity

Intensity generally refers to the level of effort output in a given session. You can measure intensity by using: 

• Heart rate (percentage of maximum heart rate)
• Rating of perceived exertion (RPE, or how hard the session feels to you) 
• Weight (for resistance training)
• Talk test (can you hold a conversation while exercising?)
• METs (metabolic equivalents)

[Read More: How to Use the RPE Scale for Effective Strength Gains]

Intensity is defined in levels:

• Very low-intensity exercise
• Low-intensity exercise
• Moderate-intensity exercise
• High-intensity exercise (vigorous intensity)
• Maximal-intensity exercise

Intensity for Strength Training

In strength training, intensity basically means “how heavy,” generally defined as a percentage of your one-rep max (1RM) for the exercise you are doing. 

For example, if you’re doing squats, performing a set of two reps at 85 percent of your 1RM would be considered high-intensity. Conversely, performing a set of 12 reps at 50 percent of your 1RM would be considered low-intensity, even if your heart rate increases and your legs burn.

[Read More: High Volume vs. Maximum Intensity: How to Choose?]

Heads up: Intensity is often mistaken for volume in strength training. The terms are frequently used interchangeably, but they are not the same thing. Volume refers to the total number of repetitions multiplied by sets multiplied by the weight lifted. (Example: three sets of 10 squats at 100 pounds equals 3,000 pounds.) 

Intensity refers to the amount of weight itself. So, to increase intensity, increase the weight.

Notably, some research shows that high-intensity training results in greater strength gains than high-volume training, at least in individuals who already have weight training experience. (3) (4)

Intensity for Cardio

For cardio exercise, intensity is usually measured as a percentage of your maximum heart rate, as follows: 

• Zone 1: 50 to 60% of HRmax (very low intensity)
• Zone 2: 60 to 70% of HRmax (low intensity) 
• Zone 3: 70 to 80% of HRmax (moderate intensity) 
• Zone 4: 80 to 90% of HRmax (vigorous intensity) 
• Zone 5: 90 to 100% of HRmax (maximal intensity)

To manage intensity levels in cardio-focused training, coaches prescribe target heart rate zones. For instance, for your weekly long run, your goal should be to stay in heart rate zones two and three. For interval training, it’s typical to reach heart rate zone five for short periods of time. A heart rate monitor, such as one on a fitness tracker, is the most practical way to monitor your heart rate while exercising. 

[Read More: Learn How to Identify Aerobic Vs. Anaerobic Exercise]

Low-to-moderate exercise results in greater aerobic adaptations (endurance), while higher-intensity exercise results in greater anaerobic adaptations (speed/stamina). (5)(6)

Time 

Time represents the duration of a given training session. There’s a saying: “You can train hard, or you can train long, but you can’t train both.” 

In other words, the tougher your training session is, the shorter it will be—or should be, to minimize the risk of overtraining. 

[Read More: Physiological Symptoms of Overreaching In Strength and Power Athletes]

“When altering duration, take into account the intensity of your activity,” Kendter says. “More time is not always better and can sometimes lead to overtraining. However, if you are training to improve endurance, moderate- or low-intensity exercise performed for a longer period of time will provide the results you want.”

Time for Strength Training

With strength training, measuring time against intensity can get tricky. If you are training at a very high intensity—say, 80 to 90 percent of your 1RM—you’ll need more rest in between sets. It’s common to rest up to five minutes in between sets to maximize performance on each set. So, you could end up in the gym for a long time, even though your actual time spent training is lower. 

The reverse is also true. If you are training at low intensities (using light weights or your body weight), you will be able to perform more reps and sets in what seems like a shorter amount of time. But the truth is that you took less rest, so your actual training time was greater.

Time for Cardio

For cardio exercise, the time-to-intensity relationship is much more straightforward. In heart rate zone 2, for instance, you can move for hours on end. Exercising in heart rate zone 4 or 5, on the other hand, requires rest intervals after short bursts of work. 

For general health, research shows that the minimum effective dose (that is: the least you can do and still see benefits) for aerobic exercise is one hour. However, additional benefits are seen with three hours of aerobic exercise per week. (1)

Type

Type is simple: It refers to the kind of training you do. Depending on your fitness goals, you may engage in more than one type of training. 

CrossFit athletes, for example, must perform well in multiple fitness domains to be good at their sport. They must have speed, endurance, strength, power, agility, and gymnastics skills, and their training reflects that. 

[Read More: The Best Running Workouts to Level Up Your Conditioning]

Conversely, marathon runners need to be good at one thing: running marathons. Their training protocols reflect that by prioritizing aerobic conditioning.

Type for Strength Training

In a resistance training context, type can refer to a specific sport or modality, such as: 

• Bodybuilding
• Powerlifting
• Olympic lifting
• Free weights 
• Weight machines 
• Bodyweight exercises

Changing the type of training you do will change your results. Bodybuilding training is designed to maximize muscle growth, for instance, while Olympic lifting training intends to maximize strength and power in the snatch and clean-and-jerk.

Type for Cardio

Types of cardio include: 

• Walking
• Running
• Hiking
• Biking
• Swimming 
• Step aerobics 
• Water aerobics 
• Dancing 

Depending on your goals, choosing a type of cardio can be as simple as choosing the one that sounds most fun. If you’re simply trying to improve your cardiovascular health, doing more than one type of cardio on a regular basis can keep things interesting and fun. 

For athletes, the type of cardio they do should be specific to their sport.

How to Use FITT

“Fitness isn’t just about working hard to achieve our goals, but it’s also about working smart, and that’s where the FITT principle comes into play,” Kendter says. “The FITT principle outlines key components for a structured and effective training program. Following these components to create a routine ensures the exercise you’re doing will work for you specifically.”

Here’s a quick recap on how to implement the FITT principle into your training for progressive overload: 

• Frequency: Add or remove training sessions to achieve the desired outcome.
• Intensity: Increase or decrease the intensity depending on your goal. Lift at higher intensities, for instance, to increase strength. 
• Time: Change the duration of your sessions based on goals and intensities. 
• Type: Alter the type of exercise you do to elicit specific adaptations. For example, run more to become a better runner.

Frequently Asked Questions

Editor’s Note: The content on BarBend is meant to be informative in nature, but it should not be taken as medical advice. When starting a new training regimen and/or diet, it is always a good idea to consult with a trusted medical professional. We are not a medical resource. The opinions and articles on this site are not intended for use as diagnosis, prevention, and/or treatment of health problems. They are not substitutes for consulting a qualified medical professional.

References

1. Coleman CJ, McDonough DJ, Pope ZC, Pope CA. Dose-response association of aerobic and muscle-strengthening physical activity with mortality: a national cohort study of 416 420 US adults. Br J Sports Med. 2022;8.
2. Pinckard K, Baskin KK, Stanford KI. Effects of Exercise to Improve Cardiovascular Health. Front Cardiovasc Med. 2019;6:69. 
3. Mangine GT, Hoffman JR, Gonzalez AM, et al. The effect of training volume and intensity on improvements in muscular strength and size in resistance-trained men. Physiol Rep. 2015;3(8):e12472.
4. Giessing J, Eichmann B, Steele J, Fisher J. A comparison of low volume ‘high-intensity-training’ and high volume traditional resistance training methods on muscular performance, body composition, and subjective assessments of training. Biol Sport. 2016;33(3):241-249.
5. Stöggl TL, Sperlich B. The training intensity distribution among well-trained and elite endurance athletes. Front Physiol. 2015;6:295. 
6. Festa L, Tarperi C, Skroce K, La Torre A, Schena F. Effects of Different Training Intensity Distribution in Recreational Runners. Front Sports Act Living. 2020;1:70.