Tension In Muscle Contractions

Muscle contractions happen when muscle fibers are stimulated, which can cause one of many types of contractions. Isometric contractions, which means that tension happens in the muscle but there is no change in muscle length, therefore there is no movement of the muscle itself. An example of Isometric contractions would be strength training, such as holding a weight still, which happens in the biceps brachii. The biceps brachii the gets more tension, but the muscle length stays the same. As for isotonic contractions, which means that tension is in the muscle while there is a change of length, can be split into two types: Concentric contraction, in which the tension causes the muscle to shorten, and eccentric, in which the tension causes the muscle to elongate.
Fatigue is caused when glucose is broken down and oxidized to the pyruvate, and lactate is produced from the pyruvate faster than the tissues can remove it, so lactate concentration begins to rise. First, ATP breaks down creating energy for the muscular contraction. Then it binds to the myosin head and reattaches itself creating contraction. Glycogen is the storage form of glucose and is used to generate energy faster, producing lactic acid, In order for exercise to continue for any length of time, ATP must quickly and continually be reformed. This is accomplished by finding other sources of inorganic phosphate and energy so ADP can be reconverted back to ATP. The rate of lactic acid accumulation will depend upon the demand placed on ATP to release energy for muscular contraction, and the ability of creative phosphate and aerobic metabolism to meet that