Unit 9

Question 1

Define fatigue in sports

Answer 1

A reversible, exercise-induced decline in
performance

Question 2

Outline the different types of
fatigue

Answer 2

Peripheral fatigue:
-develops rapidly and is caused by reduced muscle cell force
- Occurs in the muscles themselves

Causes of peripheral fatigue
- Energy delivery
- Accumulation of metabolic by-products
- Failure of muscles contractile mechanism

Central (or mental) fatigue:
develops during prolonged exercise and is caused by impaired function of the central nervous system

Question 3

Distinguish between high-intensity and endurance activities

Answer 3

High intensity activities​

High-intensity exercise involves a vigorous bout of intense activity that may last for less than a second, or as long as 1–2 minutes, for example, some types of interval training, plyometrics. ​

The major sources of energy for this are derived from anaerobic processes.​

Endurance activities​

Endurance activities involve prolonged sessions of low-intensity activity that may last from several minutes to several hours, for example, leisure cycling or jogging. ​
The major sources of energy​ for endurance activities are aerobic processes.​

Question 4

Describe characteristics of high intensity activities

Answer 4

High Intensity Activities​

1 sec to 2 minutes​

70-100% Max Heart Rate​

Glucose = Energy + Lactic Acid​

Sprinting​

Plyometric Training​

Anaerobic Respiration​

Weight Lifting​

Question 5

Describe characteristics of endurance activities

Answer 5

Endurance Activities​

Minutes to hours​

50-70% Max Heart Rate​

Glucuse+O2 + Energy +H2O + CO2​

Jogging​

Continuous Training​

Aerobic Respiration​

Cycling leisurely​

Question 6

Peripheral Fatigue - Causes in different types of activities

Answer 6

The development of peripheral fatigue in high-intensity activities depends on the rate of:

Depletion of energy sources (creatine phosphate and ATP)

Increase in levels of the products of exercise such as lactate and hydrogen ions:

-Causes a decrease in pH (called blood acidosis) which inhibits enzymes required for ATP regeneration.
-Inhibits the contractile processes of the muscle cell.

The development of peripheral fatigue in endurance activities includes:

-Depletion of muscle and liver glycogen reserves.​
-No glucose (fuel)

Dehydration and electrolyte loss due to sweating.
-causes plasma loss (and CV Drift)

Overheating

Depletion of acetylcholine and reduction in calcium release:
Both of the above causes the failure to stimulate an electrical impulse to cross from the motor neuron to muscle fiber.​

Acetylcholine is the neurotransmitter produced by neurons. In the peripheral nervous system acetylcholine plays a role in skeletal muscle movement, as well as in the regulation of smooth muscle and cardiac muscle. In the central nervous system acetylcholine it is involved in learning, memory, and mood.

Question 6

Causes of fatigue explained

Answer 6

Depletion of out ATP and Creatine phosphate stores will result in fatigue. Your body needs time to recover, take on board oxygen and replenish ATP before continuing with exercise

High levels of lactic acid and hydrogen in the muscles causes an uncomfortable pain and restricts the muscles ability to contract. Oxygen is needed to break down and remove these substances​

Depletion of muscle and liver glycogen reserves reduces the energy source for ATP production. ​

Electrolytes are minerals in your body that have an electric charge. Electrolyte loss during exercise is predominantly caused by sweating, if an athlete does not replace fluids, fatigue will set in. Electrolyte loss causes decreased nerve function and can cause cramping​

Overheating causes decreased muscle function as enzymes work best at normal body temperature conditions. In hot weather, your body cools itself mainly by sweating. The evaporation of your sweat regulates your body temperature. However, when you exercise strenuously or otherwise overexert in hot, humid weather, your body is less able to cool itself efficiently​

When dehydrated, the fluid loss causes a drop in blood volume making the heart have to work harder in order to push oxygen and nutrients through the bloodstream to the brain, skin, and muscles (think about cardio vascular drift).​

Question 7

Discuss recovery from fatigue after sports

Answer 7

O2 Deficit - the amount of oxygen you actually need
O2 Debt - the amount of oxygen you need to repay
Replacement of muscle and liver
glycogen stores:

• Depends on type of exercise
  800m Sprint ⟶ may take up to 2-3 hours
  Marathon ⟶ may take several days
• Replenishment of glycogen stores is most rapid during the first few hours following
  training and can take several days to complete
• Complete restoration of glycogen stores is accelerated with a high carbohydrate diet

Excess Post-exercise Oxygen Consumption - the additional oxygen that must be taken into
the body after vigorous exercise

Low Intensity/Aerobic Exercise
Complete recovery is achieved after
several minutes (1-2)

High Intensity/Strenuous Exercise
May require 24h before re-establishing thepre-exercise oxygen uptake

Question 8

After high intensity exercise there are five things that happen:

Answer 8

After high intensity exercise there are five things that happen:
1. Replenishment of ATP
2. Removal of lactic acid
3. Replenishment of myoglobin with oxygen
4. Replenishment of glycogen
5. Replenishment of Creatine Phosphate (ATP-PC)