Energy System Fatigue and Recovery Mechanisms

Question 1

Fatigue

Answer 1

A reduction in the ability of the muscles to produce power or force

Fatigue mechanisms work together but have one fatiguing factor which is most dominant

Question 2

what factors cause fatigue to differ

Answer 2

It can vary for different tasks such as

• duration and intensity
• types of contractions
• type of muscle fibre used
• level of fitness
• age
• diet
• environmental conditions

Question 3

Fatigue associated with the ATP-PC energy system

Answer 3

Fuel depletion (ATP and PC)

we only have a limited store of ATP (<2sec) and PC (10sec) in our muscles, when these are depleted the body is forced to breakdown glycogen to resynthesis ATP
This results in a decrease contractile force and rate of energy production (decrease in intensity and speed of performer)

Question 4

recovery strategy (ATP-PC fuel depletion

Answer 4

Facilitated by a passive recovery (EPOC)

30sec= 70%
60sec= 75%
3min=98%
10min= 100% of PC stores

Question 5

Fatigue associated with the Anaerobic glycolysis system (Pi + recovery strategies)

Answer 5

Accumulation of metabolic by product (Pi)

slows the release of calcium ions and reduces contraction force of muscles.

recovery:
removed best during passive recovery where high levels of O2 are avaliable.

Question 6

Fatigue associated with the Anaerobic glycolysis system (ADP build up + recovery strategies)

Answer 6

Accumulates during explosive activities and reduces the power muscles can exert

recovery: removed best during passive recovery where high levels of O2 are avaliable

Question 7

Fatigue associated with the Anaerobic glycolysis system (Build of of hydrogen ions + recovery strategies)

Answer 7

H+ accumulate in high amounts when LIP is exceeded
AS they accumulate, muscle acidity increases which slows the actions of glycolytic enzymes and the rate of glycogen breakdown

Recovery:
Oxygen levels must remain elevated in conjunction with an increased blood flow for maximum removal rates

• active recovery
• massage
• contrast bathing etc

Question 8

Active recovery

Answer 8

Involves continuing to move at a lower intensity once the exercise is over, using the same muscles as throughout the activity

maintains higher oxygen levels than if the person were to simply stop moving (speeds up removal of lactate and H+)

creates a muscle pump that presses on the blood vessels to increase venous returns and increase rate of oxygen supply and waste removal

prevents venous pooling

Question 9

Fatigue associated with the aerobic energy system ( fuel depletion (glycogen) + recovery strategies)

Answer 9

Muscle glycogen is used first then liver
considered a fatiguing factor after 60min of continous exercise
“hit a wall” at 2-3hrs into an endurance event when glycogen stores are very low forcing body to rely on fat as the main fuel store for ATP replenishment

recovery:
restored through CHO intake during and post exercise (consuming high Gi foods 30min after completing exercise)
Glycogen completion can be minimised by carbohydrate loading

Question 10

Fatigue associated with the Aerobic energy system (increased body temperature)

Answer 10

When we exercise, our body begins to produce heat

to remove heat, the capillaries to the skin vasodilate, encouraging blood flow to cool in combination with sweat

while this helps to remove heat from the body, it will result in fatigue as:

• decreased oxygenated blood is being delivered to the working muscles (less removal of wastes)
• results in an increase in Q to compensate for lower oxygen delivery
• greater reliance on anaerobic glycolysis meaning a greater build up of metabolic byproducts

leads to dehydration = impaired mental function, decreased plasma volume and further increases blood temperatire (cycle)

Question 11

Recovery strategies for increased body temperature

Answer 11

Hydrating before, during and after the event
- ice baths, ice vests, fans, light-weight/light-coloured clothing, seeking shade or acclimatizing to environments prior to competitions

Question 12

Fatigue associated with the aerobic energy system (decreased firing of the CNS + recovery)

Answer 12

Decreased firing of the CNS

as brain detects fatigue- weaker signals sent to the muscles to reduce intensity (self protection)
as intensity increases, acetylcholine release slows down, resulting in less forceful contractions

recovery: passive

Question 13

Fatigue associated with the aerobic energy system (loss of electrolytes + recovery)

Answer 13

electrolytes lost due to sweat

without electrolytes, nerves cannot communicate with eachother or perform their essential functions.

e.g
impaired sodium- potassium pump function can restrict muscular contractions

Recovery - sports and electrolyte drinks can help maintain and replenish electrolyte levels.