You will receive some very different answers depending upon who you ask.
To a person with a medical condition, physical fitness may be a day without pain or a day where they have the energy to walk down to the corner store. To the weekend warrior, it is being able to compete with his friends and still be able to go to work on Monday.
To an Olympic calibre gymnast, physical fitness is performing an Iron Cross. The flexibility of an accomplished yoga practitioner is a display of physical fitness. As is the endurance of a triathelete. Or the power of an Olympic style weightlifter. Or the speed of a sprinter. Or the agility of a badminton player…
They are all right and they are all wrong.
For their particular needs, there is an appropriate level of adequate fitness. The weekend warrior has no need to perform an Iron Cross. Or a gymnast to run a marathon.
The decathalete / heptahalete is supposed to represent the ultimate of physical fitness. While the other athletes are specialists, these multi-sports athletes train to develop the ultimate combination of the different components that make up physical fitness.
So that is where we will go. By breaking down physical fitness into it’s components, we will arrive at a better understanding of physical fitness.
This component of physical fitness deals specifically with the performance of the body’s skeletal muscles.
Your skeletal muscles contract and stretch in order to produce movement. Simple.
How they produce that movement is less simple. Your body’s muscles are highly adaptable. They will react to the stresses that you place upon them. Sit on the couch and they will atrophy. Try and run fast and they adapt to produce faster contractions. Lift heavy objects and they will increase their ability to produce maximum strength.
One way to organize these different types of strength is in relation to time.
Maximum muscular strength is the ability to produce the most amount of force regardless of time. That big guy at your gym that is ALWAYS bench pressing may have a high level of maximum strength. He can produce a large amount of force (to move that heavy barbell) but he does it relatively SLOOOWWWLY.
Maximum muscular endurance is the ability to produce a smaller amount of force, but do it for a long time. A marathon runner has a high level of muscular endurance. His bodyweight requires less force to move than a heavy barbell, but he is able to move that weight for 2+ hours non-stop.
Maximum muscular speed is the ability to produce muscular movement very quickly. A hummingbird’s wings are the epitome of speed.
Muscular power is a combination of maximum strength and speed. An Olympic weightlifter is a great example of power. So are high jumpers and sprinters. Another way of looking at power would be to use our weightlifter friend from the gym.
If he bench presses 300 lbs but takes 3 seconds to perform the lift, his power output is 100 lbs. per second. However, if he drops the weight to 200 lbs and performs the lift in 1 second, his power output shoots up to 200 lbs. per second.
If that wasn’t confusing enough, different types of muscular strength rely on the development of the 4 other components of physical fitness.