Collected Fitness Info

Thursday, August 07, 2003
I have been putting on muscle for about 7 months now. I have added a very significant amount of muscle, but also quite a bit of bodyfat. I have started running to try to bring my waistline down a bit. I have heard that running lowers the body's testoterone levels, and raises cortisol levels, making it difficult to continue to add muscle. I'm not done building muscle, and would like to increase and further balance out my muscle development. Should I stop running, and just wear elastic waists for now? Ric, we want to commend you on your progress to this point. With regard to incorporating cardiovascular work to your program consider the following. Aerobics whether it be aerobic endurance training or some form of cardiovascular work on a treadmill, stepper, or running as in your case, has numerous benefits, from fat burning to cardiovascular health to improved recovery abilities. Many ahtletes like yourself, typically stay away from cardiovascular work, fearing that it will result in muscle loss. This muscle loss is usually a direct result of an inadequate supply of calories to sustain the aerobic work rather than the aerobics itself. An individual who loses muscle during a period of aerobic training is not eating enough to compensate for the calories expended. Calorie consumption versus calorie expenditure is an important factor in keeping your muscle while dropping bodyfat. Aerobics forces oxygen through your body, increasing the number and size of your blood vessels. Blood vessels transport oxygen and nutrients to muscles and carry waste products away for muscular growth, repair and recovery. Without aerobics in your training program your body can not create any new supply routes for your newly developed muscles.

The common goal for all bodybuilders is to train for muscle size. Bodybuilding unlike strength training, which is characterized by high-resistance, near maximal contractions with high intensity and low overall volume, involves using lighter loads, with higher repetitions. This higher overall training volume coupled with a moderate relative intensity optimizes increases in muscle girth. Many bodybuilders’ training routines will be similar to this. Studies have revealed a percentage of Type II muscle fibers in bodybuilders lower than that found in other anaerobic athletes and a larger number and size of Type I fibers. (1) These same characteristics are similar to those found in endurance athletes. (2,3,4). Aerobics development of Type I fiber can account for this similarity.

Type I fibers are said to possess an oxidative capacity greater than that of Type II fibers both before and after training. Whereas strength and hypertrophy training produce somewhat similar muscular adaptations, aerobic training adaptations are different. There may be a gradual conversion of Type IIb fibers to Type IIa fibers (5). This type of adaptation is significant because Type IIa or fast oxidative glycolitic fibers possess as greater oxidative capacity than Type IIb fast glycolitic fibers, as well as being more similar characteristically to Type I fibers. The result is a greater number of muscle fibers that can contribute to endurance performance.

If you train consistently like this then some important metabolic changes take place inside the body. First at the cellular level, aerobic exercise adaptations include an increase in the size and number of mitochondria and a greater myoglobin content. Mitochondria (cellular furnaces where fat and other nutrients are burned) are the organelles in cells that are responsible for aerobically producing ATP via oxidation of glycogen. When the larger and more prevalent mitochondria are combined with an increase in the quantity of oxygen that can be delivered to the mitochondria through higher levels of myoglobin the aerobic capacity of the muscle tissue is enhanced. Second, aerobic exercise appears to increase levels of myoglobin. Myoglobin is a protein that transports oxygen from the bloodstream into the muscle fibers. Finally, this adaptation increases the level and activity of the enzymes involved in the aerobic metabolism of glucose.

Larger mitochondria in greater numbers, increased levels of aerobic enzymes, coupled with increased blood flow all boosts the fat burning capabilities of the muscle fibers. Aerobics can lead to more routes for blood to reach working muscles and more oxygen, which is needed for oxidation of nutrients within the mitochondria. The more massive a bodybuilder becomes the more routes in the form of blood vessels are needed to supply these working muscles. From fat burning to improved cardiovascular health to improved recovery abilities, aerobic work should be an integral part of all training programs. I hope this helps. Take care and have a great day.