The human body has three types of muscles: skeletal, smooth, and cardiac. Skeletal muscles are the type that allow you to walk, lift weights, move your fingers and hands, and smile. There are more than 600 skeletal muscles in the human body, and they are under voluntary control. This means that they move when you think about moving them and want them to move.
Cardiac muscle in the muscle in the heart. It causes the heart to beat, pumping blood with every contraction. Unlike skeletal muscles, cardiac muscles are involuntary. That is, they contract without you making a conscious effort to do so. Internal signals adjust the heart rate to meet the changing needs of oxygen for the body, and to maintain homeostasis (balance in the body). During exercise, your heart pumps more rapidly to increase the amount of oxygen that your body gets.
The third type of muscle is smooth muscle. This muscle lines the walls of your blood vessels, your intestines, your bronchial tubes, and your organs. This muscle is also involuntary, contracting and relaxing as needed to function, but without conscious control. In your blood vessels, the smooth muscle tissue contracts and relaxes to distribute blood to tissues. In your intestines, the muscle tissues contracts to push food along through the intestine. Your stomach muscles constrict and contract to digest food.
Regardless of the type of muscle, the mechanism that causes contraction is the same. Muscle tissues are made up of bundles of cells, called muscle fibers. Inside each fiber are thousands of rod-like structures called myofibrils. Each myofibril is made up of smaller structures called filaments. There are two types of filaments – thick and thin. The protein myosin makes up the thick filaments and the protein actin makes up thin filaments. In fact, thin filaments are long chains of actin. For a muscle to contract, the myosin and the actin must slide past one another. The energy that they need to perform this action comes from ATP (adenosine tri phosphate), the body’s energy molecule.
The ATP required for all of these muscle types to work is made available from the food you eat. Your body prefers to use carbohydrates as the starting point for breaking down molecules to ATP. This is particularly true of athletes, and for people who train very hard.
The proteins required to build and maintain all three types of muscle also come from your food. Consuming plenty of high quality protein will allow your body to recover from training and events, as well as to become stronger from exercise.
It is very hard in a busy day (especially a day that includes a training regimen) to eat the right balance of proteins, carbs, and fats. Thankfully there are many protein shakes available to make it much easier to give your body everything it needs so that you can meet your training and athletic goals.