Fatigue and the Recovery Process

1. Fatigue and the Recovery Process Unit 1&2 Kevin Browne

2. Depletion of energy resources • In order to exercise we must break down the energy stored in our body and turn it to ATP (This is what provides energy to our cells and working muscles) • sources of energy come from • 1)Phosphocreatine • 2)Glucose • 3)Glycogen

3. We only have enough phosphocreatine (CP) to last us 10 seconds of maximal exercise We then switch to glucose for energy production We have 15-20g of glucose in blood stream • 345gglycogen in our muscles and 110g stored in our liver

4. Glycogen to Glucose • When out blood sugar is low the liver converts its stores of glycogen into glucose/ or the skeletal muscles glycogen to glucose Overall the glycogen gets turned into Glucose These stores only last 2 hours so once these are used up the body becomes fatigued

5. Effects of waste products • Lactic acid is the main waste product of anaerobic glycolysis • Blood always contains a small amount of lactic acid, but during high intensity this increases sharply decreasing ph – 6.4 or lower means that neural messages an not be sent and prevents exercise being carried out.

6. How Neuromuscular fatigue happens • The muscle are not able to receive signals from the CNS that stimulate the muscle to contract or the muscle tissue is not able to function properly • Signals an be affected by a lack of calcium ions being release and acetylcholine which prevents the nervous stimulation of the muscle tissue/motor unit

7. Recovery Process • After any bout of Exercise, the body has to recover and return to its pre exercise state • After exercise we need to breathe in extra amounts of oxygen to return to pre exercise state. This is also know as Excess post- exercise oxygen consumption (EPOC) but is also known as oxygen debt

8. Its occurs when we have been using the aerobic system- as a result energy has been produced by the anaerobic energy system which as we know produces lactic acid • When we stop exercising out breathing rates remain high in order to get rid of the lactic acid and break it down to CO2 and H20 • Restock ATP, PC and glycogen • Pay back any O2 from haemoglobin and myoglobin

9. The 5 musts • After hard exercise five events must take place before the muscle can operate again • ATP must be replaced • PC Stores must be restocked • Lactic acid must be removed • Myoglobin must be replenished with 02 • Glycogen stores must be restocked

10. How it happens • The replacement of ATP and PC 3 mins • Removal of LA= 20mins • Myoglobin and glycogen stores = 24-48hrs • The fitter you are the faster the recovery, and the quicker the debt can be repaid • The debt is paid in 2 stages known as • Alactacid debt (fast component) • Alactacid debt (slow component)

11. Alactacid Debt • This process does not involve lactic acid • The aerobic system is used to produce ATP to restock the PC Stores and ATP Stores in the body • Around 50% occurs in 30 seconds and is fully recovered by 3 minutes • The oxygen debt needed for this is between 2-3.5l of O2 the fitter you are the greater the debt (more oxygen) because you will have more stores to replenish but it will also be quicker

12. Lactacid debt • This process takes much longer and can last minutes to hours depending on the intensity of the exercise • Oxygen is needed to break down the lactic acid back to Pyruvate. (LA +O2 = Pyruvate) • Pyruvate can then enter the aerobic system and leave as CO2 and water • Lactic acid can also be converted back into glycogen and stored in the liver or muscle • What can an active recovery do?