What does it mean to be fit?
We are mostly living in comfortable environments that don’t require any fitness. It is easy to walk from the house to the car and putter around the yard without much fitness. It seems that the popular idea of fitness simply means having more muscle mass than fat.
Fitness could better be defined as: Having an elastic range that allows us exposure to a great variety of circumstances, without failure or rupture of any part of our body or mind.
I’ll digress a moment into physiology theory…

In Wolff’s Law it states that bone in a healthy person or animal will adapt to the loads under which it is placed. Bone will remodel itself over time to reflect the increased loads and become stronger in relation to those loads by changing first the internal, and then the external architecture. The inverse is also true. When load is removed from bones, they become less dense and weaker due to the lack of stimulus.
In Davis’s Law we say the same thing about soft (non-bone) tissue, “…when put under even a moderate degree of tension, if that tension is unremitting, will elongate by the addition of new material; on the contrary, when ligaments, or rather soft tissues, remain uninterruptedly in a loose or lax state, they will gradually shorten, as the effete material is removed…”
passage from Davis’s 1867 book, Conservative Surgery
Additionally Davis’s Law states that ultimate tensile strength increases or decreases in periods of use or disuse. Wikipedia tells me that in a low gravity simulation, human test subjects had a tendon strength decrease of up to 58% in only a 90 day period.
According to Wolff’s and Davis’s Laws I would do well to maintain the tensile strength of my tendons (and other soft tissue) and the density and elasticity of my bones by placing loads on them. By stressing them, but not to the point of rupture, so that they can handle exposure to a variety of circumstances. This seems more meaningful than a vague muscle to fat esthetic. This is our ability to do, or not do, the activities that give us joy.
Outside of the desire to not self-destruct I think there is something to be said for raising our threshold for incurring stress damage. Stress is stress…physical stress is easier to measure than emotional stress, so let’s say we put a sudden load on two tendons. One of these tendons undergoes loading equal to or greater than our hypothetical, sudden load on a regular basis. The other tendon regularly only experiences a maximum load of about 20% of what we’re challenging it with. So, with the same amount of stress one tendon does not experience any particular challenge and the other tendon ruptures. We would rather have the first tendon, right?
If we have lives that don’t require us to be fit, why would we put forth the effort to increase the elastic range of our bodymind? I’ll sympathize with that, a bit. I like comfort as much as the next person, and when life doesn’t require much from us it’s hard to find the place where motivation comes from. Though part of this de-motivation is actually a physically generated inhibition of activities that are perceived as noxious.
I’ve already crammed a bit into this article. So I’ll carry on with the idea of creating desire or motivation, rather than exhausting a limited supply of will power, another time.
But I’d like to end with the thought that there is something to be said for practice. Fitness, like meditation and personal development has no end point and is not static. There are useful temporary end points, like the goal to walk three miles, or run a marathon, but it’s the practice itself that contains rewards. So, how do we practice persistently?