Causes of Fatigue
Glycogen Depletion - enough to last 90 minutes, when depleted body tries to metabolise fats, unable to use it on its own.
Lactic Acid Bulid Up - accumulation of Lactic Acid releases Hydrogen ions, increase in acidity of blood, inhibits enzyme action and breakdown of glucose, irritates nerve endings, causes pain.
Reduced Rate of ATP Synthesis - when ATP and PC are depleted, difficult to sustain muscular contractions.
Dehydration - Blood viscosity increases, effect on blood flow to working muscles, blood pressure reduces. Reduction in sweating to prevent water loss, increases core body temperature
Reduced levels of Calcium - needed for muscular contractions, increase in hydrogen ions decreases amount of calcium released from sarcoplasmic reticulum.
Causes of Fatigue cont.
Reduced levels of Acetylcholine - nuerotrasmitter that aids the transport of nerve impulses over the synaptic cleft and initiate muscular contraction, when low levels, muscles become fatigued.
Thermoregulation -heat is produced from muscle contraction, raise core body temperature, increases blood viscosity, decreases metabolic processes
- thermoregulatory centre in medulla oblangata controls temperature, blood vessels vaso dilate, heat lost through radiation.
- Train relevant energy system usin appropriate training method.
- Pace level of activity to conserve glycogen levels.
- Increase glycogen levels be Glycogen Loading.
- Keeping Hydrated increases blood glucose levels.
Involves returning the body back to it's original state
Excess post-exercise oxygen consumption
- Replacement of ATP and PC.
- Replenishment of myoglobin with Oxygen.
- Removal of Lactic acid.
- Replacement of Glucose.
First 3 require large amounts of Oxygen, breathing rate remains elevated
At start of exercise, there is insufficient oxygen at the working muscles, 2 anaerobic systems have to be used, amount of oxygen short of during exercise is know as the oxygen deficit. This is compensated by the oxygen debt.
Fast Replenishment Stage - Elevated rates of respiration continue to supply oxygen to provide the energy for ATP production and PC replenishment
Recovery Process cont.
Myoglobin and Replenishment of Oxygen Stores - Myoglobin has a high affinity for Oxygen, stores oxygen in the muscles and transports it from the capillaries to the mitochondria. Surplus amounts of oxygen from EPOC helps replenish these stores.
The Slow Replenishment Stage - concerened with the removal of lactic acid, can take up to an hour. Majority of Lactic Acid can be oxidised, so a cool down accelerates its removal as metabolic rate remains high
Glycogen Replenishment - important to conserve glycogen stores so lactate threshold is not crossed. Significant amounts of glycogen can be restored in less than an hour after long duration, low intensity exercise
Factors affecting Recovery
Increase in Breathing and Heart Rate - extra oxygen is required to return body to pre-exercise state. However increase in breathing and heart rate requires additional extra oxygen to provide energy for muscles of heart and respiratory system.
Increased activity of Hormones - elevated hormone levels keeps respiratory and metabolic levels high so extra oxygen can be taken in.
Increase in body temperature - high temperature means high respiratory rates, so more oxygen can be taken in. However extra oxygen is needed to fuel this increase in temperature.