The four categories of fitness are strength,  conditioning, skill, and mobility. Any other metric of which you may think can be categorized under these primary categories. I structure the fitness framework like this for simplicity. If a person is working on and improving in these areas, he or she is getting fitter. So, again, the four categories of fitness are 


  • Strength
  • Conditioning
  • Skill
  • Mobility


This could be a highly nuanced topic that is open to plenty of argument and fine tuning, but I will lay out a basic idea behind each.




Strength is a basic ability to apply force. One-rep max is, arguably, the greatest representation of true strength. For example, the ability to squat 500 pounds for one rep is the maximum squat strength level for the person who performed the life.


The argument part lies in other expressions of strength, such as the ability to hold a handstand, complete a muscle-up, or even the ability to complete a pull-up. None of these movements have external load, and in the general perception of one reps maxes, cannot be measured as such. 


Both of these groups, each of these movement types, is an expression of strength. In that same line of thought, so are being able to complete a log press, clean and jerk, machine base movement, etc.


Any variations of strength—such as speed-strength, strength-speed, and power—can be bulked under strength.




Conditioning is the ability of the body to do work. The more work that the body can do, the more conditioned it is. For example, being able to complete multiple reps of an exercise is an improvement of conditioning, not strength. 


In that same line of thought, being able to run a mile is a form of conditioning, whereas improving from running one mile to two is an improvement in conditioning. Any time the body increases the ability to do work, the more conditioned it becomes.


Another example that is more modern in the CrossFit era, is being able to complete workouts such as metcons, circuit training, and anything that falls in line. Being able to complete a 21, 15, 9 crossfit workout is a form of conditioning, the same as being able to circuit machines at the gym for rounds is a form of conditioning.




Skill is the ability to perform technical movement. Learning to throw a ball, to squat, to run, to swim, etc is an expression of skill. Becoming better technically at these things is an improvement of skill.


This is not to be confused with increasing weight or reps. Those are improvements in strength and conditioning. Skill is solely focused on the technical aspects, though it goes hand in hand with improvements in the other areas.


Skill is an essential part of improving strength and conditioning, as well as fitness overall. Skill is and should always be the first step. For example, to squat 500 pounds, you have to learn how to squat first. You do not just load weight on a bar, get under it, and inherently know how to squat.




Mobility is the ability of the joint to move through range of motion. Having mobility is essential to every function you perform through your day, no matter how mundane. For example, if your hip cannot move through range of motion, then you will not be able to walk.


Joints moving through range of motion are primarily a matter of extension and flexion. How each joint engages in flexion and extension varies. The basic idea is that extension leads to an increase in joint angle while flexion leads to an decrease in joint angle. For example, a bend in the elbow is a flexed elbow, while a straight elbow is an extended elbow. 


Mobility matters to the other categories in that a lack of it will lead to limited ability to move. Limited ability to move may present as an inability to achieve full stride in a run, short range of motion squats, short range of motion pull-ups, etc.


How to assess fitness using these categories


When assessing fitness for myself and clients, I look at these categories. The simplest way to think about it is to assess each category for progress, then compare all four, and contrast with where you were during your last assessment period.


I will use me as an example.


For mobility, I have the most range of motion and have improved problem areas to the point where my mobility is the best it has ever been. I simply look at how much range of motion I have compared to before and how hard or easy my mobility makes it for me to get into different positions.


For skill, simply put I have more skills now than ever. This is probably the most straightforward one for me to assess. I never lose skills, I regularly add to them, and I work to improve. There is some ebb and flow depending on the focus on my workout program, but the overall trend has been an upward one for years.


Conditioning is a bit harder to assess. I do not have benchmark workouts, per se, as I rarely do repeat conditioning workouts over time. Instead, I look at how well I am able to complete conditioning type workouts, and also look at other metrics of conditioning such as how well I can stay on the rings or complete the same type of movement multiple times per week. 


For example, I can clean and deadlift every day and still muster up 80+ percent of load for every session. In that same vein, I can hang out on the rings and do routines  more than I could before. There is no conditioning workout that has been thrown at me recently that I could not complete. These are just examples.


Strength is a bit more cut and dry. Looking at one rep max allows me to assess this in a pretty straightforward manner for lifting. Some movements—such as the back squat—I do not complete anymore, so these are worse, while others—such as the bench press—I rarely complete, so these are worse. 


That said, every other long time lift—such as the clean and jerk, snatch, deadlift, and front squat—are at 80+ percent of best. Some are at best ever, such as the farmer carry and kettlebell get-up.


When we look at this, we see some areas that are not best, but looking at the overall picture of my fitness, my fitness is the best overall presentation it has ever been. Take a similar approach when assessing you fitness


And in your workout program, be sure to target these categories if you want to have the best all around fitness you can.,

And that is it. Have questions? Let me know on social media. You can click the links here, or just look up Nathan DeMetz Personal Training on Facebook and Instagram.

Demetz Personal Training About Nathan Demetz Personal Trainer

Nathan DeMetz holds degrees in Exercise Science, Business Administration, and Information Technology as well as certifications in strength and conditioning, sports nutrition, run coaching, and other areas. His credentials come from organizations such as Indiana Wesleyan University, Ivy Tech College, Utah State University, and the ISSA College of Exercise Science.

Nathan has 20 years of personal and professional experience in the health and fitness world. He works with people from across the globe, including locations such as Kuwait, Australia, and the USA.

To work with Nathan directly on your personal training goals, contact him today!