There are three kinds of fitness:
Aerobic fitness. Aerobic activities condition your
heart and lungs. Aerobic means "with oxygen." The purpose of aerobic
conditioning is to increase the amount of oxygen that is delivered to your
muscles, which allows them to work longer. Any activity that raises your heart
rate and keeps it up for an extended period of time will improve your aerobic
Muscle strengthening. Stronger muscles can mean
either more powerful muscles that can do bigger jobs (such as lifting heavier
weights) or muscles that will work longer before becoming exhausted
(endurance). Weight training (resistance training) or simple exercises such as
push-ups are two examples of ways to focus on muscle strengthening.
Flexibility. Like aerobic fitness and muscle
strengthening, flexibility is a result of physical activity. Flexibility comes
from stretching. Your muscles are repeatedly shortened when they are used,
especially when exercising. They need to be slowly and regularly stretched to
counteract the repeated shortening that happens through other
Understanding the differences between each kind of fitness will help
you set your fitness goals. Reaching a balance between the three is important,
because they affect each other and each contributes to total fitness.
Some physical activities involve more than one kind of fitness. Some
activities that are thought of as aerobic exercise, for example, also
strengthen muscles (swimming, cycling, skiing).
Fitness: Getting and Staying Active