Weight training is primarily an isotonic form of exercise (that kind of exercise in which the force applied to muscle does not change while the length of muscle changes), as the force produced by the muscle to move any weight does not change. But many exercises are not isotonic, because the force on the muscles varies as the joints move through its range of motion. Weight exercises improve the fitness of body and also help to make your body very hard and strong. There are a number of weight training principles. The basic principles of weight training entail an exploitation of the number of replications (reps), sets, tempo and exercises. The basic principles of weight training also force to cause most wanted changes in weight, staying power, size or shape by overfilling of a group of muscles. The exact combinations of replications (reps), sets, exercises, struggle and force depend on the idea of the character performing the exercise.

Weight training has a number of types. The main and important kind of weight training is resistance training. Resistance training is a form of weight training in which every effort is made against an exact opposing force produced by resistance. For example, resistance to being pressed, squeezed, stretched or bent. These exercises are isotonic if a body part is moving in opposition to the power. Exercises are isometric if a body part is gripping still beside the force. Resistance exercise is used to enlarge the power and size of skinny muscles. Properly achieved resistance training can offer important functional benefits and development in overall health and well-being.