Energy for Muscle Contractions
Adenosine Triphosphate (ATP) is the immediate source of energy for muscle contraction.
Some ATP is stored in the muscle fibers, but it gets used up very quickly.
After this, other pathways must be utilized to produce enough ATP to sustain muscle contractions.
There are 3 ways to generate new ATP after the original supply is used up:
Some ATP is stored in the muscle fibers, but it gets used up very quickly.
After this, other pathways must be utilized to produce enough ATP to sustain muscle contractions.
There are 3 ways to generate new ATP after the original supply is used up:
- Direct Phosphorylation of ADP by creatine phosphate
- Aerobic Respiration
- Anaerobic Glycolysis and lactic acid formation
Direct Phosphorylation uses the Creatine Phosphate stored in muscles to reattach a phosphate group to the ADP left behind after ATP gets used for energy. This storage supply lasts less than 15 seconds and only creates 1 new ATP per molecule. It is not very efficient.
Aerobic Respiration breaks down glucose to carbon dioxide and water, releasing energy (about 32 ATP). This all takes place in the mitochondria of the muscle cells. This is a slower reaction than Direct Phosphorylation, and it requires continuous oxygen.
Anaerobic Glycolysis breaks down glucose without oxygen. It produces only 2 ATPs and has a waste product of lactic acid. This reaction is less efficient, but much faster. Large amounts of glucose are needed.
If muscle activity is strenuous and prolonged fatigue occurs for 3 different reasons:
- ionic imbalances
- lactic acid accumulation in the muscle
- decrease in supply of ATP
Ionic Imbalances
Certain minerals and electrolytes are necessary for proper muscle function. If you often experience unexpected muscle fatigue and cramps, you may be deficient in certain key minerals such as potassium, magnesium and calcium. These minerals are vital for muscle function.
Lactic Acid accumulation
When the oxygen supply is plentiful, aerobic respiration takes place. When oxygen is not available, cells respire anaerobically, and lactic acid is produced. Lactic acid is a waste product which causes muscle pain and fatigue. If you have been exercising and are out of breath or hyperventilating, this will lead to anaerobic respiration and therefore lactic acid-induced muscle fatigue.
Decrease in ATP supply
Adenosine triphosphate is the fuel needed for all muscle contractions. Your body has 3 ways of creating that fuel it needs. However, putting demands higher than your body is conditioned and prepared will deplete your small storage of ATP rapidly and put stress on your other pathways for creating the ATP needed for muscle contraction.
Certain minerals and electrolytes are necessary for proper muscle function. If you often experience unexpected muscle fatigue and cramps, you may be deficient in certain key minerals such as potassium, magnesium and calcium. These minerals are vital for muscle function.
Lactic Acid accumulation
When the oxygen supply is plentiful, aerobic respiration takes place. When oxygen is not available, cells respire anaerobically, and lactic acid is produced. Lactic acid is a waste product which causes muscle pain and fatigue. If you have been exercising and are out of breath or hyperventilating, this will lead to anaerobic respiration and therefore lactic acid-induced muscle fatigue.
Decrease in ATP supply
Adenosine triphosphate is the fuel needed for all muscle contractions. Your body has 3 ways of creating that fuel it needs. However, putting demands higher than your body is conditioned and prepared will deplete your small storage of ATP rapidly and put stress on your other pathways for creating the ATP needed for muscle contraction.
After exercise, the oxygen debt is "repaid" by rapid, deep breathing.
Structure & Function Muscle Movements Roles of Muscles Microscopic Structure Contractions Nerve Supply Energy Tone
Myology: Head Myology: Anterior Torso Myology: Posterior Torso Myology: Upper Extremity Myology: Lower Extremity
Injuries & Pathologies
MUSCULAR SYSTEM
Myology: Head Myology: Anterior Torso Myology: Posterior Torso Myology: Upper Extremity Myology: Lower Extremity
Injuries & Pathologies
MUSCULAR SYSTEM