Types of Fatigue
What is the definition of fatigue in sport?
A reversible, exercise-induced decline in performance.
What energy system is mainly used in high-intensity activities like weightlifting?
ATP-PC system or anaerobic glycolysis.
Is fatigue more likely to occur quickly in sprinting or marathon running? Why?
Sprinting – due to rapid energy system use and accumulation of metabolic by-products.
What does EPOC stand for?
Excess Post-exercise Oxygen Consumption.
Name the two main types of fatigue and where they originate.
Central fatigue (originates in the central nervous system) and peripheral fatigue (originates in the muscles).
Name two metabolic by-products that accumulate during anaerobic exercise and contribute to fatigue.
Lactate and hydrogen ions (H⁺).
What is the primary energy source depleted during endurance activities?
Muscle and liver glycogen stores.
Name two physiological processes that occur during EPOC.
Replenishment of ATP and creatine phosphate; removal of lactic acid.
What causes peripheral fatigue during a 400m sprint?
Accumulation of hydrogen ions and lactate interferes with muscle contraction, causing a burning sensation.
How does a decrease in calcium ions (Ca²⁺) cause fatigue at the muscular level?
Reduced calcium availability limits actin-myosin binding and weakens muscle contraction.
Explain how high-intensity and endurance activities differ in their fatigue mechanisms.
High-intensity: rapid fatigue from lactic acid buildup; endurance: slower fatigue from glycogen depletion and dehydration.
How long does it typically take to replenish creatine phosphate stores after high-intensity exercise?
30 seconds to 5 minutes.
Explain how central fatigue affects performance in endurance events.
Central fatigue reduces neural drive from the brain, affecting motor unit recruitment and decision-making.
Explain the physiological link between dehydration and fatigue.
Dehydration reduces blood volume, impairs oxygen transport, increases core temperature, and leads to cardiovascular strain.
Describe how fast-twitch and slow-twitch muscle fibers contribute differently to fatigue.
Fast-twitch fibers fatigue quickly and are used in high-intensity activity; slow-twitch are fatigue-resistant and used in endurance.
Why is active recovery more effective than passive recovery for clearing lactic acid?
Active recovery maintains circulation, enhancing lactate clearance and accelerating pH normalisation.
Central fatigue stems from impaired neurotransmitters and mental exhaustion; recovery includes sleep and nutrition. Peripheral fatigue results from metabolite accumulation or energy depletion in muscles; recovery involves hydration and active recovery.
Compare central and peripheral fatigue in terms of causes and recovery strategies.
Describe three mechanisms by which central nervous system function is impaired during prolonged exercise.
Impaired neurotransmitter function (e.g., low dopamine), hypoxia (low oxygen to brain), and electrolyte imbalance disrupting nerve signal transmission.
Discuss how fatigue is influenced by fitness level, age, and activity type. Provide examples.
Fitter and younger individuals typically resist fatigue longer. For example, a trained cyclist has better aerobic capacity and electrolyte control than a novice, delaying fatigue onset.
Outline the different recovery needs and estimated recovery times for sprinting, team sports, and endurance events.
Sprinting/HIIT: CP restoration in 3–5 min; lactate cleared in 30 min–2 hrs. Team sports: 24–48 hrs for glycogen and neuromuscular recovery. Endurance events: 24–72 hrs for glycogen and muscle repair.