When the body's major muscle groups are regularly caused to work against a form of resistance, the muscles can become stronger and larger. This kind of exercise is known as strength training, resistance training, or weight training. Generally, it involves the use of free weights, weight machines, or various isometric devices. In order to build muscle in a safe and effective manner, it's usually recommended that each muscle group be trained at least two days per week. Typically, each major muscle is used individually during each session: including the arms, chest, shoulders, abdomen, back, quadriceps (KWAD-ri-seps), hamstrings, and calves. To achieve toning, growth and strength improvement, it's usually recommended that each muscle category carry out eight to 12 repetitions of a specific exercise, at an intensity that results in near fatigue. There are a number of benefits associated with this kind of workout. It may increase not only muscular power, but also the strength of the attached tendons, ligaments and bones. Over time, resistance training often improves flexibility, reduces body fat, increases lean body mass, and may even decrease cholesterol and resting blood pressure. Since lean body mass requires more calories at rest than fatty tissue does, increasing the overall amount of body muscle can help raise basal metabolic rate (BAY-sul met-ah-BALL-ik rayt) or B.M.R. (B-M-R). In turn, a higher BMR can help the body burn more calories per hour, so it's easier to maintain a healthy weight. It's also not uncommon for weight training to help the body manage glucose and insulin in a more balanced manner. Finally, weight training may even benefit older adults by adding strength, improving balance, and increasing functional ability. If you're interested in learning more about strength training, or have questions about how to begin such an exercise program, contact a healthcare provider.