Lifting weights, also commonly referred to as resistance or strength training, is a method of conditioning which safely and effectively stimulates physical changes within the body. Lifting weights involves the use of external resistance to progressively increase your ability to exert of resist force; which, in turn, promotes the growth of strong, healthy bones and muscles.
Bones grow and become stronger when they are subjected to stress. Stress is an event that threatens the supporting structures of the contracting musculature. Lifting weight provides that stress. By progressively placing greater-than-normal demands upon the bone, the bone responds by laying down more tissue to ensure that forces do not end up exceeding a critical level which could cause damage, according to "Essentials of Strength Training and Conditioning," written by Thomas R. Baechle and Roger W. Earle. Therefore, lifting weights promotes stronger bones, which also leads to a decreased risk for osteoporosis, as well as other bone-threatening conditions.
Similar to bone, muscle also becomes stronger when experiencing a stress. When you lift weights, you aim for a specific repetition number to cause fatigue, such as 10 to 12 repetitions. When you reach that repetition number, you have reached the threshold strength for that muscle at that specific weight you are lifting, and as you progressively increase the amount of weight you lift, that level increases, consequently increasing the strength of the muscle.
Improved Body Composition
Participating in a weight-lifting program causes increases in fat-free, or lean, body mass, according to "Designing Resistance Training Programs," written by S.J. Fleck and W.J. Kraemer. As you lift weights and experience increases in muscle size and strength, the energy demand to fuel these muscles increases, and you burn more calories. More muscle burns more calories, which results in a decrease in fat mass and, subsequently, an improvement in your body composition. However, these improvements are not necessitated by large increases in muscle size; providing consistent stimulus to the muscle is enough to facilitate an increase in caloric expenditure.
Lifting weights, power lifting and body building oftentimes get lumped in to the same category. However, they are not the same. The primary goal of lifting weights is to achieve health benefits through gains in bone and muscle strength; with power lifting, it is to develop maximal power by lifting very heavy weight as quickly as possible, while the goal of body building is to put on muscle bulk.
When you start a weight-training program, it is important to first learn the proper form and technique. Doing so minimizes your risk of injury and increases the likelihood that your training program will be successful. It is also best to increase the amount of weight you lift gradually, about 3 to 5 lbs. every two weeks, depending upon the exercise. Lift the weight at an even tempo, do not rush through the exercise, and always begin with a proper warm-up that targets the muscles you are about to use in your workout.