Chapter Eight: Energy System Fatigue and Recovery Mechanisms Flashcards
What does levels of fatigue depend on?
Intermittent and continuous Fast or slow twitch fibres Concentric, eccentric or isometric contractions Intensity and duration Level of fitness
Fatigue
Causes a reduction in muscle strength and power
Power equation
Power = Force X Velocity
Central fatigue
In the central nervous system, where muscular function is decreased due to central nervous impairment
Peripheral fatigue
At the muscle, when muscle function is disrupted by internal muscle functions
Levels of fatigue
Local
General
Chronic
Local level of fatigue
Experienced in one or local group of muscles, feels heavy and cramps
When called repeatedly on during training
2-4/10
After completing a weight session
General level of fatigue
Occurs after intense training or game of sport, all muscles feel weakened
6-8/10
Full on game of netball
Chronic level of fatigue
Unhealthy breakdown of the immune system caused by overtraining has persistent muscle soreness and low immune system function
10/10
Diagnosed as chronic fatigue
Key factors contributing to fatigue
Fuel depletion
Build up of metabolic byproducts
Elevated body temp
Neuromuscular events
Fuel depletion factors
Intramuscular ATP
Phosphocreatine (PC)
Blood glucose
Muscle glycogen
Build up of metabolic byproduct factors
H+ ions in plasma/muscle
Inorganic phosphate
ADP
Calcium ions
Elevated body temp factors
High core temp Increased dehydration rate Blood redistribution Elevated blood pressure Decreased plasma levels Electrolyte loss
Neuromuscular events
Decreased firing of CNS
Intramuscular ATP
When muscles contract they use ATP but there is a very limited store of ATP within the muscles and the rates of ATP breakdown can exceed rates of resynthesis the body must then use PC stores
Phosphocreatine (PC)
When ATP is used up the muscles use PC to resynthesise ADP, however there is also limited stores of PC in the muscles, the body must then use the anaerobic system which has fatiguing byproducts
Blood glucose
When blood glucose is depleted it causes decreased carbohydrate oxidation and increased fat oxidation, causing fatigue
Muscle glycogen
When blood glucose drops, blood glycogen is used to create more ATP but when it drops it causes high fatigue and fat oxidation becomes prominent causing the body to slow its work rate
H+ ions in plasma/muscle
When the muscles break down glucose anaerobically they produce H+ ions which build up and cause decreased pH level in the muscle (acidosis), this prevents the body from converting lactate back to glucose