Strength is defined as "the quality or state of being strong: capacity for exertion or endurance." Humans possess different kinds of strength. There is physical strength, but there is also moral strength and intellectual strength. All of these forms of strength have something in common: In some way, they show a capacity for exertion or endurance. Also, each type of strength can only be developed through effort and discipline.
The word "strong" is used first and foremost to refer to someone who has ability in the physical realm. A person is considered "strong" when he can lift heavy things or apply a great amount of physical force to accomplish something difficult. For example, if a man is able to exert enough force to move a parked car, he is physically strong. Physical strength is often associated with noticeably large muscles, but someone doesn't have to have big muscles in order to have muscular strength. Physical strength, like any kind of strength, is increased through exercise. The exertion of muscles increases their strength over time. It takes discipline and work for a person to increase his physical strength.
In his essay "Metaphor, Morality and Politics," George Lakoff addresses moral strength. In this sense, using the metaphor of "strength" is really a comparison to the physical realm. A person who exercises his moral muscles has an internal ability to do right. A person is said to have "moral strength" when he shows himself to be successful in doing good things rather than bad things. Moral strength is primarily seen as self-control and begins in the person internally. When a person perceives something as evil -- overindulging in food or sex, stealing, wanting something that belongs to someone else -- moral strength is having the self-control to resist that temptation. A person who is able to control himself and resist his urges, instead of giving in to a temptation to something that he or his society views as wrong, is said to possess moral strength.
Strength on an intellectual level is developed by learning new things and thinking. A person who is learning new things and is able to apply them to his life is intellectually strong. Ability in math, art, science or any area of study is referred to as intellectual strength. In order to build intellectual strength, a person needs to do things that use his brain. Taking an art course, doing art or creative work of any kind, building something, reading, learning a new language or writing are all ways to increase your intellectual strength.
Physical, moral and intellectual strength are all developed through discipline and exercise. A person who runs and lifts weights develops a measure of physical strength. A woman who practices self-control each time she is tempted to get angry with her children grows in moral strength. A student who pores over history books, joins a debate team and takes photography classes develops intellectual strength. Each type of strength is built by different disciplines. Overall, however, attention to the care of the body results in strength in all areas. A person who gets adequate sleep, eats nutritiously, and exercises will be physically well, and will thus be able to develop strength in many parts of his life.