Cardio Muscle Growth

Aerobic Exercise and Muscles

• Human muscles come in two varieties: fast twitch and slow twitch. Slow-twitch fibers are long and thin, and they are generally used for endurance. Fast-twitch fibers, on the other hand, are shorter and thicker, and better capable of delivering short bursts of intense energy. This difference between endurance (fast twitch) and strength (slow twitch) is why distance runners tend to have longer, leaner physiques than a sprinter. To build muscle while including cardio, you will need to focus on exercises that target fast-twitch muscles.

Cardio for Muscle Growth

• In order to target fast-twitch fibers and get muscle growth from cardio, you will need to do high-intensity workouts to complement your weightlifting. High-intensity workouts usually take the form of interval training, in which aerobic workouts of very low intensity are punctuated with periods of very challenging exercise.

  One simple interval exercise is to jog very slowly for two to three minutes, then follow it with 90 seconds of full sprinting. Repeat five times, alternating between the jog and the sprint. This will help to build lean muscle mass without draining your body of energy.

Benefits

• There are numerous benefits to adding cardio to your workouts, not the least of them being accelerated muscle growth. Running gorges your muscles with blood and oxygen, priming them for rapid growth and recovery. Running also improves circulation throughout your body, allowing muscles to use oxygen more effectively during your workouts. On the personal health side, running improves your cardiovascular health and literally makes your heart more efficient; running regularly can keep you healthy and strong long after your bodybuilding days are over.

Misconceptions

• One of the most persistent myths surrounding weight lifting is the idea that cardiovascular exercise burns protein, or more generally that it will make your muscles smaller. In truth, if you maintain a diet that supports your level of activity and include foods that support muscle growth, aerobic exercise can help you gain muscle.

  Another fairly common misconception about cardio is that if you tire your body with running and biking, your gains from lifting will be limited. Running a marathon each week will probably drain you of energy and strength and prevent you from devoting resources to muscle building. In moderation, however, cardio can complement workouts without stressing your body too much.

Troubleshooting Muscle Loss

• If you have been exercising regularly but seeing little or negative gains, you may be experiencing muscle loss. When you begin to incorporate cardio into your workout routine, your body's metabolism will increase as well; in other words, you'll be burning more calories during both your workout and recovery. Try tracking your calories and make sure that your nutritional needs are in line with your level of activity.

  Also, you may need to increase your intake of protein to accommodate the increased strain that running puts on your body. An increased need for carbohydrates is also common as your body needs more expendable energy to fuel your workouts.