1. Definition

A reversible, exercise-induced decline in performance.

1.1. Different types of fatigue

There are two main areas that fatigue can come under:

Peripheral fatigue: Peripheral fatigue occurs in the muscle itself. It develops

rapidly and is caused by reduced muscle cell force.

Causes of peripheral fatigue include:

- Lack Energy delivery

- excess of physical activity

- Accumulation of metabolic by-products

- Failure of the muscles contractile mechanism

Central fatigue: Develops during prolonged exercise and is caused by impaired

function of the central nervous system (brain and spinal cord).

1.2. Different types of activity

High-intensity exercise: involves intense workout which can last from a couple to seconds to 2 minutes.

The major sources of energy for this are derived from anaerobic processes (ATP-CP and Lactic Acid system)

Endurance activities: involve prolonged sessions of medium-intensity activity that have the ability to last several minutes to hours.

The major sources of energy for endurance activities are aerobic workouts.

2. Causes of fatigue

Fatigue is perceived differently by individual athletes and may depend on multiple

factors such as:

- Age

- Level of athletic ability

- The type of activity or exercise carried out

2.1. Causes of fatigue in high intensity activities

physiologically the peripheral activities depends on:

1. The rate of depletion of energy sources (Creatine Phosphate and ATP)

- CP is used in anaerobic conditions, short duration high intensity

exercise

- It maintains ATP levels in the muscle

- Depletion of CP will cause fatigue in this type of exercise

2. Increase in levels of the by-products of exercise

- Lactic acid is a by-product of anaerobic glycolysis.ñ

- Activities of a short duration and high intensity rely heavily on anaerobic

glycolysis and produce large amounts of lactate and H+ ions.

2.2. Causes of fatigue in endurance activities

The physiological causes of peripheral fatigue in endurance activities include:

1. The depletion of muscle and liver glycogen reserves

- Aerobic glycolysis relies on stored glycogen for the production of ATP

- The body stores glycogen in the muscles and liver.

- During moderate intensity, prolonged exercise glycogen concentration

decreases and is depleted after around 2 hours of activity.

2. Reduction in calcium release

- Calcium plays an important role by contracting muscle fibers

- Reduced Calcium levels will inhibit muscle contraction

3. Dehydration

- Dehydration leads to a decrease in blood plasma volume

- This causes an increase in HR in order to maintain CO

4. Overheating

- Increase in body temperatures during prolonged exercise.

- an increase in carbohydrate utilization and hasten of glycogen depletion.

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