Chapter 4 Fatigue and Recovery

•Definition – ‘a reduced capacity to complete work, usually brought about by a lack of energy, lack of 02 or skeletal muscle tiredness.’

1. Glycogen depletion

 2. OBLA – onset of blood lactate

 3. Lack of muscle fibre recruitment

 4. Dehydration

 5. Psychological fatigue [Central Governor Theory]

•Glycogen is stored in muscle and the liver and is the primary source of energy – we hold a 90 minute supply •Glycogen is used up as the body rebuilds ATP – the speed of this depends on the intensity and duration of the exercise being performed. •Once stores are used up blood sugar levels are low causing fatigue •Body will then metabolise fat – this uses more 02 to rebuild ATP. •The body needs some glycogen to metabolise fat. •The performer will be forced to slow down.

• 100m- ATP/PC system. Stored ATP and stored Phosphocreatine. CP-100% in 3 minutes.
• 800m- ATP/PC and Lactic acid system. Stored muscle glycogen. CP- 100% in 3 minutes, Restore muscles glycogen- up to 2 hours.
• Marathon- Aerobic energy system. Stored muscles glycogen and body fat. Restored muscle glycogen up to 48 hours.

- OBLA – Onset of Blood Lactate – the point at which there is sufficient lactic acid in the muscles to cause a change in pH levels which effects then effects muscle function.

 - caused by a lack of 02 when glucose is being metabolised into ATP.

 - also at this intensity [above 85%] muscles are likely to suffer from micro tears which also hampers muscle function

 - Long term training above 85% intensity – mostly medium interval training – the body creates proteins which absorb and convert lactic acid. Training at this intensity also improves body system functioning which delays OBLA and speeds removal. This is called ‘buffering’.

• Water makes up 60% of body mass.

Effects on Performance:

•Loss of [electrolytes] - salt and calcium – leading to cramps and reduced muscle efficiency

•Reduced levels of plasma will cause reduced blood pressure / reduced tissue fluid formation

•Also –

• increased thirst / increased
• heart rate / retention of body heat

•Body temperature is maintained by balancing heat input with heat output. •Factors which produce heat in the body:-

 - metabolic processes

 - Exercise

 - Shivering

 - increase in HR caused by sympathetic nervous system

 - Q10 effect – point at which temperature massively increases chemical reactions and therefore heat production – Tour De France [southern stages]

•Radiation - The heat generated from within the body is given-off to the surrounding atmosphere •Conduction -The body conducts heat to whatever the skin is in direct contact with. Especially critical in water, as your body loses heat about 25 times faster in water than in air of the same temperature. • Convection - Convection is the process of air or water flowing by the skin and carrying away body heat •Evaporation - When you sweat or when your skin or clothing gets wet

• Fatigue is increased or triggered by fewer nerve impulses reaching the working muscles.

•Your brain is being told fatigue is setting in due to: - glycogen depletion / OBLA and muscle fibre recruitment reduction BUT… •CGT states that the body is sending early distressing sensations to muscles which can be ignored •Chris Hoy

• EPOC
•  - Removal of LA
•  - Glycogen refuelling
•  - Rehydrating
• - Recover from DOMS

1.Fast component [alactacid phase]

 - replacing stores of CP

This happens due to:-

 - 02 combines with energy to rebuild CP

 - Small amount of lactic acid broken down into CP

 - Some ATP used to create CP

100%  in 3 minutes

2. Slow Component [lactic acid phase]

 - high 02 intake at this stage is to get everything else to get body back to it’s pre-exercise level

 - heat dissipation / energy replenishment / rehydration / removal of waste products / muscle tissue repair and growth / reloading myoglobin

•Removal begins the moment it is formed. •50% after 15 minutes •76% after 1 hour •LA is converted into 4 things at different quantities:-

 - oxidised into C02 and water [65%]

 - converted into glycogen [20%]

- Converted into glucose [15%]

Converted into protein [10%]

- Speeded up by maintaining elevated metabolic level

 -  HR

 - breathing rate

 - dilated capillaries

 - reduce blood pooling

 - light continuous activity for up to an hour

 - stretching to maintain muscle elasticity

•Delayed Onset of Muscular Soreness -Caused by excessive mechanical forces applied to muscle and connective tissue -Usually eccentric contraction -Up to 48 hours after activity -Breakdown of muscle proteins causes fluid to shift from the plasma into the damaged muscle tissue causing inflammation and pain -Can be minimised by – warm up /gradually increasing training intensity / include aerobic activity between anaerobic drills in training to help flush out lactic acid / reduce eccentric contractions / cool down

•2 hour window •High carb’ content / Protein for muscle repair

•‘Any external influences that can positively effect physical or mental performance.’ •Can be – mechanical, pharmacological, physiological, nutritional, psychological. •Eg: •During? Compression clothing – improves muscle alignment / reduces potential muscle damage / improves circulation / increases anaerobic threshold / improve thermoregulation • After? Ice baths – increases blood flow to damaged muscle tissue / helps to reduce microscopic damage