Bodybuilding Guide to weight lifting - Types of exercises

Muscular tonus refers to a state of continuous contraction through which the muscle is immediately active. Contraction takes place in the case when the insertion ends being drawn near follows the increase in strain of the muscular fibre. This is one of the most common situations to be encountered during sporting activities. Isometric contraction occurs when the insertion ends of the muscle maintain the same distance even after the increase in tension of the muscular fibre.

Excitability: designates the capacity of the muscle to enter a state of excitability when stimulated. Elasticity: designates the capacity of the muscle to restore to the original shape after contraction. Conductibility: designates the capacity of the muscle to propagate the excitation through the muscular fibre at a certain speed. Contractibility: designates the capacity of the muscle to change in shape while under the action of a stimulus.

Muscles contain both organic and anorganic substances. The major proteinic substances are myoglobin, the myosine and the myogen. The role of the myoglobin is to be identified at the level of the muscle tissue oxygenation. Myosine is encountered in two forms: myosine proper and actomyosine. The role of myogen is important into the process of glucids metabolism that takes place in the muscle. Besides the substances mentioned above, the creatinephosphoric acid and adenosinetriphosphoric acid are also to be found into the muscles. Fats: lecitin, glycerides and cholesterol play an important role in producing the muscular energy. Nitrogenous substances: uric acid, creatine, creatinine, and urea. Hydrocarbonated substances: are to be found into the muscle in the form of glucose and glycogen.

Fatigue has not actually been defined yet. However, there have been many theories concerning this subject. One states that the nerv is the first to weary, followed by the neuromuscular synapse. M. Secenov demonstrated that a muscle recovers faster should other muscles be active while it rests. Due to fatigue the contraction time prolongues, the strain is weaker, the excitability drops and so on.

Proper training leads to the increase of the muscle in size, due to its growth in breadth. Once the muscle grows, the conjunctive tissue and the sarcolemma develop. In order to develop the muscles, the amount of weight to be lifted has to be increased. A significant role in the muscle development is played by the blood flow, which is 30 times higher during training than its value when the body is resting. Because of this phenomenon the cells are nourished and the toxins are eliminated.