Exercising Muscles

Everybody moves throughout the day, and to move, we use muscles. Dancing, snapping your fingers, waving to your neighbor outside washing your car all of these activities use muscles. However, to build strength in specific muscles, you must be sure to give them appropriate exercise. You can exercise muscles to build strength in three ways:

With isometric exercises
With isotonic or dynamic resistance exercises
With isokinetic exercises

Muscle Movement

Every time a nerve impulse stimulate a muscle, the muscle contracts. However, a contracting muscle isn't necessarily getting shorter along its whole length. A concentric contraction, also called a positive contraction, shortens the muscle and develops tension. An eccentric contraction or negative contraction develops tension while actually lengthening the muscle. In either case, the muscles are moving against external resistance. If the force of the contraction is greater than the external resistance, it's a concentric contraction. If the force of the contraction is less than the external resistance, it's an eccentric contraction.

Intensity

Exercise intensity measures the workload or how hard the heart is working.