What is Physical Fitness anyway?

So you’ve finally decided to join a gym and start a fitness routine!

First off, congratulate yourself on this first step! Rome was not built in a day…and neither were you, so expect this whole new process to take time. Don’t get discouraged if you don’t see immediate results; they will come if you put in the time and consistency. But now that you’re here, in the gym, what do you do?


The easiest thing would be to hire one of the personal training staff, as they can guide you through this new journey since they already have the knowledge and experience necessary to build bodies and improve your fitness level. But if you choose to go it alone, then you need to understand what exactly makes up a fitness routine and how you are supposed to improve your health, fitness level, and physique….that’s why you’re here, isn’t it? 

First off, what is “Physical Fitness” anyway?

Well, it’s a group of traits that measure various aspects of your body’s ability to function in the physical environment and that tend to correlate with general health. Typically, physical fitness can be grouped into five categories, or components. 

These Five Components of Physical Fitness are:

1. Cardiorespiratory Fitness
The capacity of the heart, lungs and blood carrying vessels to deliver blood (oxygen) to the working muscles in order for them to perform repeated contractions (movement).

2. Muscular Strength
The amount of force a muscle can exert while contracting. How much mass can be forcibly moved. In real world jargon, how heavy of a grocery bag can you carry, or can you push a car out of the road if it ran out of gas. 

3. Muscular Endurance
Either the length of time a muscle can sustain a sub-maximal contraction (isometric), or the number of sub-maximal repetitions performed (isotonic). Again, to put a common spin on it, have you ever tried holding something over your head? Strength is how much you can hold, endurance is how long you can hold it or how many time you can lift it. 

4. Body Composition
The ratio of lean body mass (metabolically active tissue) to fat, or adipose, (metabolically inactive tissue); lean body mass includes the muscles, bones, organs, nervous tissue and skin. Fat, or adipose, is derived from surplus calories taken in that were never converted to energy, so they were stored as fat for later use. Think of your fat as your body’s insurance policy against starvation. A high level of bodyfat is often correlated to adverse health conditions such as adult onset diabetes, heart disease, sleep apnea, etc.

5. Flexibility
The range of motion, or joint mobility, specific to an individual joint and its corresponding musculature. Flexibility is really specific per joint. Some people may have flexible hips but inflexible shoulders. It just depends what you train and what you neglect. An increased range of motion allows for easier and more fluid movement. 

Now that we understand what comprises physical fitness, let’s look at how those components are actually improved upon. 

These are the Four Principles of Exercise. In other words, in order to create a routine that functionally and measurably improves upon any of the five components of physical fitness, you must address these four governing principles.

The Four Principles of Exercise are:

The Principle of Individuality
People are not created with the same capacity to adapt to exercise. Genetics plays a major role in determining how your body will adapt to a training program. Individual differences are due to variations in cellular growth rates, metabolism, and neural and hormonal regulation. No two people will react in precisely the same way to the same exercise or nutritional stimulus. Most people are governed by the same set of physical rules, however, due to individual differences, some minor quirks and changes need to be addressed.

Just because one person sees great success with free weight squats, doesn’t mean you will too! The angle of the acetabulum (hip socket) in the pelvis, the length of the long bones of the legs, ankle mobility, length of the spinal column or personal changes in kyphosis, lordosis, or thoracic mobility, may alter how one exercise affects you as opposed to someone else. This is one reason why having a good, trained set of eyes upon you helps cut down on wasted time trying to force a round peg in a square hole! 

The Principle of Specificity
Training adaptations are highly specific to the type of activity or exercise being performed.  Strength training will not improve your aerobic capacity, but neither will jogging improve your overall strength. The training program must stress the physiological systems that are critical for performance in a given sport or activity. Basically, if you want to be good at “it”, you must do “it”! Bench pressing will not improve squats, leg pressing will not improve your butterfly stroke in the pool, nor vice versa. The best way to get better at something is to train it directly! Of course, there are supportive exercises and drills you can do to improve most tasks, but they are specifically designed to improve portions of that task that you might be lagging in. 

The Principle of Disuse
The “Use It or Lose It” Principle. Each of the five components of fitness will strive to attain a level commensurate with the demands placed upon it. If you consistently run, your cardiovascular level of endurance will rise to a point to be comfortable with that level of stress. Once you stop, the body will start finding a new level of stress to adapt to—usually much lower! The law of Entropy states that it is easier to destroy than it is to create. If you fail to continuously organize a system (we’ll call this training), then nature says that it must fall into disorder (we’ll call this getting out of shape!). 

The Principle of Progressive Overload
The body adapts to stress. In order to keep improving, the level of stress must be progressively overloaded. Overload and progressive training form the foundation of all exercise programs. As the body adapts to a certain level of strength, flexibility, or endurance, it must be pushed slightly beyond its new limits to stimulate new gains. Your body is a naturally lazy organism and will only want to divert the resources into building and organizing as much as is necessary to gain a certain level of comfort at the stress level imposed upon it. If you stop applying more stress, the body will hover at that level and no more adaptation will be required, ergo no more improvements!  

So hopefully now you have a better appreciation for what physical fitness and exercise is all about!  Hopefully, if you plan on developing your own fitness routine, you can think about some of these necessary components to help you build your program and ensure its going to work for you!  One last thing, and this is the most scientific of them all…..”if you ain’t sweatin’, you ain’t workin’!!!” 

- Gamal Castile