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 the use of safer plate loaded lever gyms 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, and incorrectly, 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, increased bone density, increased metabolism, improved cardiac function, and elevated HDL (good) cholesterol. Training commonly uses the technique of progressively increasing the force output of the muscle through incremental weight increases 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, power-lifting, and strongman, which are sports rather than forms of exercise, although training for them is inherently interconnected with strength training, as it is for shotput, discus, and Highland games. Many other sports use strength training as part of their training regimen, notably football, wrestling, rugby, rowing, lacrosse, basketball, hockey, and track and field.
The basic principles of strength training involve a manipulation of the number of repetitions, sets, tempo, exercises and force to cause desired changes in strength, endurance or size 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: to gain size and strength multiple (4+) sets with fewer reps must be performed using more force. Exercise selection should be limited to the basic barbell movements such as the squat, bench press, dead-lift, overhead press and bent-over row.
Muscles should be trained in concert with surrounding muscles,(i.e. chest/shoulders/triceps) and for maximum training effect lifts should be performed with heavy (70-85%1RM, aka high intensity) weights and multiple sets with fairly long (2-5 min. depending on intensity) rest periods between sets. Typically 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. There are cases when cheating is beneficial, as is the case where weaker groups become the weak link in the chain and the target muscles are never fully exercised as a result.
The benefits of strength training include increased muscle, tendon and ligament strength, bone density, flexibility, tone, metabolic rate and postural support.
You can check out videos on strengthening exercises here.