What is the definition of fitness? It is strong fundamental movement coupled with a disease free cardiovascular system. That’s it.
Strong Fundamental Movement
The body does basically five things: you can squat, hinge, push, pull, and rotate. Bending could be a sixth, but I’m going to ignore that for this post. The important thing to understand is that in the western world, most people do not do any of those five things particularly well. One of the main reasons is all the time spent sitting at a desk which, bear in mind, is not just the office. It starts in school at age five or six.
Poor movement leads to weakness, injury, and ultimately further reductions in movement. This is the downward spiral which ultimately ends in the lack of strength, mobility, and the onset of frailty as we age. So, to summarize, to be fit you must be able to perform fundamental movements well.
A Cardiovascular System That Is Free From Disease
Who is more fit, someone who runs marathons, someone who runs three mile road races, or someone who walks to work every day? You might be tempted to say the marathoner, because they can go the farthest and longest – so what? Completing a marathon, as we well know, is not a pre-requisite to making it into old age. What we need here is a common frame of reference.
I would put forward that being free from disease is the definition of a fit cardiovascular system. That means that your blood measurements such as cholesterol, glucose, and triglycerides are within normal range, your blood pressure and heart rate are normal, you do not experience shortness of breath or chest pains when moving, and whatever other measurements your doctor may choose to monitor. The key here is having a measurement that can tell us something meaningful about health.
Why Define Fitness?
In our society we do not have a good definition of fitness and as such, we chase fitness goals like weight loss, muscle gain, or cardiovascular performance without any framework to operate in. Someone who has large muscles might die of a heart atttack, while someone who runs regularly may struggle with arthritis. Someone who is perfectly healthy may spend their whole life feeling like they need to lose weight, and someone as thin as a rail may be nutritent deficient. This is why we need to define what we mean by the word fitness so that we can work to achieve that definition.