women engages in weight training on a regular basis. Types of strength training: Weight training:Weight and resistance training are popular methods of strength training which use gravity (through weight stacks, plates or dumbells) or elastic/hydraulic resistance respectively to oppose muscle contraction. Each method provides a different challenge to the muscle relating to the position where the resistance to muscle contraction peaks. Weight training provides the majority of the resistance at the initiating joint angle when the movement begins, when the muscle must overcome the inertia of the weight's mass (however, if repetitions are performed extremely slowly, inertia is never overcome and resistance remains constant). In contrast, elastic resistance provides the greatest opposition to contraction at the end of the movement when the material experiences the greatest tension while hydraulic resistance varies depending on the speed of the submerged limb, with greater resistance at higher speeds.

In addition to the equipment used, joint angles can alter the force output of the muscles due to leverage and the relative overlap of actin and myosin contractile proteins. Resistance training:Resistance training is a form of strength training in which each effort is performed against a specific opposing force generated by resistance (i.e. resistance to being pushed, squeezed, stretched or bent). Exercises are isotonic if a body part is moving against the force. Exercises are isometric if a body part is holding still against the force. Resistance exercise is used to develop the strength and size of skeletal muscles. Properly performed, resistance training can provide significant functional benefits and improvement in overall health and well-being.The goal of resistance training, according to the American Sports Medicine Institute (ASMI), is to "gradually and progressively overload the musculoskeletal system so it gets stronger." Research shows that regular resistance training will strengthen and tone muscles and increase bone mass.

Isometric training:Isometric exercise, or "isometrics", is a type of strength training in which the joint angle and muscle length do not change during contraction. Isometric exercises are opposed by a force equal to the force output of the muscle and there is no net movement. This mainly strengthens the muscle at the specific joint angle at which the isometric exercise occurs, with some increases in strength at joint angles up to 20° in either direction depending on the joint trained. In comparison, isotonic exercises strengthen the muscle throughout the entire range of motion of the exercise used. Basic principles:The basic principles of strength training involve a manipulation of the number of repetitions (reps), sets, tempo, exercises and force to cause desired changes in strength, endurance, size or shape by overloading of a group of muscles. The specific combinations of reps, sets, exercises, resistance and force depend on the purpose of the individual performing the exercise: sets with fewer reps can be performed using more force, but have a reduced impact on endurance.

Strength training also requires the use of 'good form', performing the movements with the appropriate muscle group(s), and not transferring the weight to different body parts in order to move greater weight/resistance (called 'cheating'). Failure to use good form during a training set can result in injury or an inability to meet training goals - since the desired muscle group is not challenged sufficiently, the threshold of overload is never reached and the muscle does not gain in strength.The benefits of strength training include increased muscle, tendon and ligament strength, bone density, flexibility,

Strength Training

Strength training is the use of resistance to muscular contraction to build the strength, anaerobic endurance and size of skeletal muscles. There are many different methods of strength training, the most common being the use of gravity or elastic/hydraulic forces to oppose muscle contraction. See the resistance training article for information about elastic/hydraulic training, but note that the terms "strength training" and "resistance training" are often used interchangeably.When properly performed, strength training can provide significant functional benefits and improvement in overall health and well-being including increased bone, muscle, tendon and ligament strength and toughness, improved joint function, reduced potential for injury, improved cardiac function and elevated good cholesterol. Training commonly uses the technique of progressively increasing the force output of the muscle through incremental increases of weight, elastic tension or other resistance, and uses a variety of exercises and types of equipment to target specific muscle groups.

Strength training is primarily an anaerobic activity, although some proponents have adapted it to provide the benefits of aerobic exercise through circuit training.Strength training differs from bodybuilding, weightlifting, powerlifting and strongman, which are sports rather than forms of exercise. However, participants in these and many other sports often use strength training as part of their training regimen. History: An early plate-loading barbell and kettlebellUntil the 20th century, the history of strength training was essentially a history of weight training. With the advent of modern technology, materials and knowledge, the methods that can be used for strength training have multiplied significantly.Hippocrates explained the principle behind strength training when he wrote "that which is used develops, and that which is not used wastes away", referring to muscular hypertrophy and atrophy. Progressive resistance training dates back at least to Ancient Greece, when legend has it that wrestler Milo of Croton trained by carrying a newborn calf on his back every day until it was fully grown.

Another Greek, the physician Galen, described strength training exercises using the halteres (an early form of dumbbell) in the 2nd century. Ancient Persians used the meels, which became popular during the 19th century as the Indian club, and has recently made a comeback in the form of the clubbell.The dumbbell was joined by the barbell in the latter half of the 19th century. Early barbells had hollow globes that could be filled with sand or lead shot, but by the end of the century these were replaced by the plate-loading barbell commonly used today.Strength training with isometric exercise was popularised by Charles Atlas from the 1930s onwards. The 1960s saw the gradual introduction of exercise machines into the still-rare strength training gyms of the time. Strength training became increasingly popular in the 1980s following the release of the bodybuilding movie Pumping Iron and the subsequent popularity of Arnold Schwarzenegger. Since the late 1990s increasing numbers of women have taken up strength training, influenced by programs like Body for Life; currently nearly one in five U.S.