Strength training uses resistance and muscular contraction in order to strengthen and build up the size and endurance of skeletal muscles. The most common forms of strength training are isometric training and resistance training, both of which use either gravity or elastic forces to get opposing muscular contractions. Strength training uses three different variants when describing exercises: intensity, volume and frequency.

Isometric training is a form of resistance training in which the joint angle and muscle length do not change during a contraction. These exercises are opposed by forces equal to the force output of the muscle, and there is not any increased movement. This form of strength training strengthens the muscle at a certain joint angle (whichever the isometric exercise that takes place), with a little increase in strength at the joint angles. Isometric exercises strengthen the muscle within the entire range of motion that the exercise uses for a particular joint.

Resistance training is where each exercise is performed against opposing forces that are generated by opposing forces that are either being pushed against, squeezed, stretched or bent. Resistance training exercises are used to develop both the strength and size of skeletal muscles. Regular use of resistance training exercises help to strengthen and tone muscles and will increase overall bone mass.

The variants that need to be considered when beginning any strength training regime are intensity, volume and frequency. Intensity refers to the amount of force that is required or the size of weights that are being lifted. Volume refers to the overall number of muscles that are being worked, the number of exercise that are being done as well as the number of sets and reps that are completed during a single session. Frequency refers to the number of training sessions that are completed each week, be it two or three or more. These variants are important because they are all conflicting, allowing the muscles worked to have time to recover after each workout session. If you increase the level of one, you have to decrease the levels of the other two, so that you do not injure yourself by over-doing it.

When strength training exercises are performed correctly, they can provide vast benefits, including the overall improvement of health and well-being. Strength training increases bone, muscle, tendon and ligament strength within the body, as well as improves overall joint function. Someone who does a lot of strength condition has a reduced potential for injury during workouts or sports. Strength training also improves cardiac function and helps to increase levels of good cholesterol.