The New Components of Fitness

Some time around 1628, The United States Department of Agriculture created a powerful icon of health and wellness: The Five Components of Physical Fitness.

These were listed as -

Muscular Strength
Muscular Endurance
Cardiovascular Endurance
Flexibility
Body Composition

However, the criteria embodied in this list was not based on sound scientific evidence, and it has not been updated to reflect major advances in our understanding of human health and performance.


In 2017, The US Department of Health and Human Services will officially retire the Five Components in favor of The Four S's of Physical Fitness. The Four S's reflect a simple yet more scientifically accurate criteria. A modern vernacular is used in order to make fitness a more appealing endeavor to the 2/3rds of the American population that is currently sedentary.

The Five Ss of Physical Fitness-

Strength - How much can you dead lift and bench press?
Speed - The ability to turn on the jets and break ankles.
Swolness - Nobody is impressed by a shredded skinny guy.
Showboating - What the individual can actually do with their swolness.

Not helpful to most athletic pursuits other than yoga

Okay, in all seriousness, the original five components could use a major overhaul. For example, everyone knows that being inflexible is a bad thing. But rarely to people appreciate that too much flexibility is also detrimental (particularly to joint health and the individuals ability to be powerful). Being able to sit and bend forward towards your toes says very little in terms of spine health and overall physical function.

Muscular strength and endurance are related.

A stronger muscle will be able to repeat any given submaximal force more times than a weaker muscle. Say that a given task demands 50 units of force. Given the task of repeatedly producing 50 units of force, a muscle that can maximally produce 60 unites will fatigue a lot sooner than a muscle that can maximally produce 100 units. So, in terms of muscle endurance, we need to better define and standardize our terms.

Lastly, current cardiovascular endurance tests highly favor lighter people of well muscled individuals, even though it is certainly possible to be well-muscled and even heavy and have a healthy cardiovascular system. Rather than running or walking, cardiovascular endurance tests should be conducted in a manner where body mass is less of a factor. For example, tests completed on a stationary bike or rowing machine may be a better indication of cardiovascular fitness since these are more independent of body mass.

Being a critic is easy. So here are my recommendation for the components of fitness:

Absolute Strength - One repetition maximum strength tests with free weights are great, but they are contraindicated in some populations. Isometric strength tests are much safer but less clinically valid. How much can you bench press, squat, or deadlift? How much force can you generate?

Relative Strength/Endurance - This would be tested by an individuals ability to repeatedly generate a given force, based off percentage of bodyweight. How many times can you bench press X% of bodyweight? How many full range of motion, strict chin-ups or push ups can you perform? How fast can you run 200 meters?

Absolute Power - This would need to be completed in a more activity- or sport specific manner. With how much force or speed can you hit or throw? How high or far can you throw a standardized medicine ball? How much force can you generate into the ground (would require a basic force platform)?


This bro would probably score very WELL on a Sit&Reach test

Relative Power - Power measures per body weight, activities that involve acceleration of the entire body mass. How high can you jump (vertical jump)? How far can you jump (standing broad jump)? How fast can you run 200 meters?

Controlled mobility - Gone is the Sit & Reach test, as we are less interested in old school passive flexibility. We now want to determine how well a person can maintain good posture and spinal stability while moving through different positions. Can you pass a functional squat test, full lunge and hip hinge, rotational stability test, and can you get up and down off the floor without using your hands?

Cardiovascular Endurance - For how long can you generate 300 watts on a stationary bike? How long does it take you to row 3000 meters?

Body Composition - This should be done away with all together. Measuring body composition is redundant, since many of the fitness components listed above involve strength, power, and controlled mobility relative to body mass. Some lean people have poor strength and cardiovascular health. Some overweight people are very powerful and otherwise fairly healthy. The accuracy of field tests to measure body composition is fairly poor.