Developing stronger muscles provides you with a more toned, defined and healthy body. The type of training you do will dictate the type of muscle growth that your body will experience. Depending on the activity that you choose, you will develop specific muscle fibers that enable you to achieve your fitness goals
What is Muscle?
In simple terms, every muscle is composed of long fibers that are bundled together to form the muscle tissue. Muscle tissue is not all the same. In fact, there are many different fiber types, but the most predominant are the Type I and Type II fibers. Type I fibers, or slow twitch, are fatigue-resistant fibers primarily used in aerobic endurance activities such as jogging or walking. Type II, fast twitch, fibers fatigue quickly but can produce high amounts of force and are used in activities like sprinting or Olympic-weightlifting activities. The bulk of muscle tissue is made up of these two types of fibers. Genetics determines how much of either type of fiber your body will have and how your body will respond to training.
Resistance Training
Resistance training causes muscle tissue to increase in mass. According to the National Strength and Conditioning Association, NSCA, hypertrophy results "by enlargement of muscle fibers, not by an increase in their number." Under the proper training procedures, Type II fast-twitch fibers generally experience greater amounts of hypertrophy as compared to Type I fibers. Resistance training results in the body using less muscle to lift or move a load.
Aerobic Endurance Training
Unlike resistance training, aerobic conditioning does not result in any increase in muscle mass. Rather, aerobic conditioning trains the muscles to use oxygen more efficiently during activity. Aerobic conditioning primarily targets Type I fibers, with Type II fibers experiencing minimal changes. Type II fibers are recruited by the body during high-intensity activities such as sprinting. Aerobic conditioning trains muscle fibers to increase their aerobic capacity and causes an adaptation known as gylcogen sparing. Glycogen sparing means that less gylcogen, the primarily fuel for cells, is used during activity and results in improved performance. The NSCA cautions people to remember that aerobic endurance training cannot increase muscle strength or size. According to the NSCA, "Intense aerobic endurance training can actually compromise the benefits of resistance training."
Benefits of Building Muscle
Building muscle has many benefits for everyone. Athletes can develop increased strength and improve their overall aerobic endurance. That can be important in events such as running or cycling that require a sprint to the finish. Adults, seniors and women also enjoy many benefits from strength training. Activities of daily living, such as carrying groceries, walking stairs, or moving items become much easier because of strength training. The Aerobics and Fitness Association of America says, "As we go about our daily activities, it's muscular endurance that plays a crucial role in how well our physical bodies meet a variety of demands and resist injury."
Women and Building Muscle
Women in particular can benefit from a muscle building program. Load-bearing activities such as strength training increase bone density, prevent osteoporosis, and strengthen the ligaments and tendons throughout the body. A common misconception by women is that strength training will result in a "bulky" or muscular appearance. Although women experience an increase in muscle fiber from strength training, the simple fact that is the musculature of females cannot develop to the same point as a man's because of a lack of hormones, primarily testosterone, that contribute to muscular development.
References
- "Essentials of Strength Training and Conditioning"; Thomas Baechle and Roger Earle; 2000
- "Fitness Theory and Practice"; Laura Gladwin, editor; 2002
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