Skeletal Muscles
1. Discuss the relationship between distribution of muscle fiber type and performance.
How might exercise training modify or change a person’s fiber-type distribution?
Skeletal muscles contain multiple fiber types that are distinguished by their different myosin ATPase speed, and the development of their SR. The two main fiber types are type I and type II fibers. Type II fibers have a faster ATPase and a more developed SR than type I fibers. Type II fibers are also part of a larger motor unit, allowing for more fibers to contract at once and produce more force. These fibers are therefore better for anaerobic activity like lifting weights. Type I fibers are utilized for lower intensity exercise, such as aerobic endurance. These fibers do not fatigue as easily as type II fibers do (Kenney, 2011, p. 42). An endurance athlete would most likely have more type I fibers in their arms and legs due to endurance training. A bodybuilder on the other hand would have more type II fibers, since their training involves more strength exercises (Kenney, 2011, p. 46).
2. Describe the mechanisms by which muscle glycogen is broken down to glucose for use in glycolysis.
Glucose is converted to glycogen in order to be stored in the liver and muscles to use at a later time. When the body is ready to use these glycogen stores for …show more content…
Fat provides about 9.4 kcal/g, with is the most energy per gram of all the food sources. Carbohydrates on the other hand provide only 4.1 kcal/g. Therefore fat supplies the body with a higher source of energy. The body is also able to store more fat to use as energy at a later time. The fat stored within the body can supply up to 75,000 kcal of energy. Fat can be stored in adipose tissue and muscle fibers as triglycerides, which then can be broken down into free fatty acids to form ATP. Fat is best utilized as energy during long, low intensity exercise (Kenney, 2011, p.
How might exercise training modify or change a person’s fiber-type distribution?
Skeletal muscles contain multiple fiber types that are distinguished by their different myosin ATPase speed, and the development of their SR. The two main fiber types are type I and type II fibers. Type II fibers have a faster ATPase and a more developed SR than type I fibers. Type II fibers are also part of a larger motor unit, allowing for more fibers to contract at once and produce more force. These fibers are therefore better for anaerobic activity like lifting weights. Type I fibers are utilized for lower intensity exercise, such as aerobic endurance. These fibers do not fatigue as easily as type II fibers do (Kenney, 2011, p. 42). An endurance athlete would most likely have more type I fibers in their arms and legs due to endurance training. A bodybuilder on the other hand would have more type II fibers, since their training involves more strength exercises (Kenney, 2011, p. 46).
2. Describe the mechanisms by which muscle glycogen is broken down to glucose for use in glycolysis.
Glucose is converted to glycogen in order to be stored in the liver and muscles to use at a later time. When the body is ready to use these glycogen stores for …show more content…
Fat provides about 9.4 kcal/g, with is the most energy per gram of all the food sources. Carbohydrates on the other hand provide only 4.1 kcal/g. Therefore fat supplies the body with a higher source of energy. The body is also able to store more fat to use as energy at a later time. The fat stored within the body can supply up to 75,000 kcal of energy. Fat can be stored in adipose tissue and muscle fibers as triglycerides, which then can be broken down into free fatty acids to form ATP. Fat is best utilized as energy during long, low intensity exercise (Kenney, 2011, p.