The Chemistry of Skeletal Muscle Fatigue


YouTube Video

Skeletal muscle fatigue is your muscles getting feeling tired after activity. My project is about why your muscles feel this way. There are two explanations that scientists argue over to explain this. One has to do with the buildup of lactic acid and the pH of the muscle. The other explanation is the resupplying of ATP to the muscles. This subject interest me because muscles in general have always interested me. This subject is also in everyday life so it is good to know about.

Composition of ...

  • Metabolic acidosis

    • lactic acidosis

      • build of of lactic acid in tissue causing the pH to become off

  • Hydrolysis of Phosphocreatine

    • phosphocreatine

      • C4H10N3O5P

    • Water

      • H2O

    • creatine

      • C4H9N3O2

    • Pi (inorganic phosphate)

      • PO43−

Main Chemicals, Compounds, Components

  • Metabolic Acidosis

    • lactic acid

      • C3H6O3

    • build up of acids due to not process quick enough

  • Hydrolysis of Phosphocreatine

    • as the body uses ATP, it is converted to ADP and there is a need for replenishment

    • the body uses phosphocreatine (Phosphate creatine)

    • phosphocreatine transfers a high-energy phosphate in ADP

    • the products are ATP and creatine

      • C4H10N3O5P

    • ADP

      • C10H15N5O10P2

    • creatine

      • C4H9N3O2

    • ATP

      • C10H16N5O13P3

Chemistry's Role

Skeletal muscle fatigue has two major explanations that scientist are still discussing. Their predictions at the moment for the cause are Metabolic Acidosis and the Hydrolysis of Phosphocreatine. Metabolic acidosis is the occurrence of extra acid in a tissue. In this case, the tissue is muscle. As physical activity is performed, there is a release of lactic acid. The body has the ability to dispose of this acidity through the kidneys. When the body can’t keep up, this is when metabolic acidosis develops. The muscle pH becomes off and fatigue begins to set in. According to others, Hydrolysis of Phosphocreatine is the cause. This occurs as the body uses ATP. When a muscle contacts, ATP is used to power this process. After the ATP is used ADP is left over. Muscles have a limited supply of ATP so there is a need for the replenishment. The body accomplishes this through the hydrolysis of phosphocreatine. Phosphocreatine sends a high-energy phosphate to ADP to create ATP and the by-product is creatine. This process is said to cause muscle fatigue.

Background Research

The two main components of skeletal muscle fatigue are metabolic acidosis and hydrolysis of phosphate creatine or phosphocreatine. In a more understandable way the development of lactic acid through the use of ATP and the regeneration of it.


the anaerobic metabolism and muscle fatigue have a causal relationship

now it is thought that hydrolysis of phosphocreatine causes it

Causes of metabolic acidosis

Lactic acidosis

anaerobic metabolism

due to the pH of blood becoming off

process of hydrolysis of phosphocreatine



The meaning of metabolic acidosis and general information

chemicals in metabolic acidosis

hydrogen ions

exogenous acids


ethylene glycol


sodium lactate

evidence of lactate production helping reduce muscle fatigue

lactate production occurs to retard acidosis

phosphocreatine helps supply ATP

creatine phosphate transfers a high-energy phosphate to ADP

products of this are creatine and ATP (adenosine diphosphate)

About the Author
Peder Rickbeil is a junior at Senior High school. He runs cross country and track. Due to the extreme exhaustion felt during both sports, he became interested in how one becomes so tired after such outrageous amounts of exercise.