Recovery Process

Excess post exercise oxygen consumption (EPOC) The total volume of oxygen that is consumed during recovery above that which would have been consumed at rest during the same period. It enables the body to fully recover, and return it to its pre exercise state. Used to be O2 Debt Made up of….?

EPOC/Oxygen Debt When we start to exercise, not enough oxygen is distributed to the tissues for all energy production to be met aerobically. Anaerobic systems need to supply energy.. This accrues an oxygen deficit-This is the amount oxygen the subject was short of during the exercise EPOC (Oxygen debt) is used to compensate for the oxygen deficit. As oxygen is not available for 3 minutes, a deficit will always build up.

Oxygen debt does not always equal oxygen deficit because it also has to do the following…. Supply oxygen to help restore the oxy haemoglobin link Supply energy for the increased respiratory and cardiac rates

Two stages of the oxygen debt Alactacid (Fast Replenishment) Mainly to restore phosphocreatine 2-3 mins, 2-3 litres of O2 50% restored in 30 seconds Restore oxy myoglobin link (role of myoglobin?) Lactacid (Slow Replenishment) Removal of lactic acid Helped by a cool down Replenishment of glycogen

Removal of Lactic Acid through buffering The removal of LA relies on the buffering capacity of the blood. Quite good at this as hydrogen carbonate ions are produced by the kidneys- which absorbs hydrogen ions from the lactic acid -to form carbonic acid and eventually carbon dioxide. Breathed out!

The fate of lactic acid Conversion into carbon dioxide and water 65% Conversion into glycogen 20% Conversion into protein 10% Conversion into glucose 5%

Removal of Lactic Acid Lactate is removed quicker with an active cool down. Oxygen is needed to remove it.

Removal of Lactic Acid Some athletes try to improve their buffering capacity by ‘soda loading’ Training with small amount of lactic acid in the system may also improve resistance and buffering capacity of the body.

Effect of lactic acid accumulation Blood will always contain a bit of lactic acid 1-2 millimole/litre of blood at rest 30 millimole/litres of blood 400m run ? What are the effects on the performer?

Muscle fatigue occurs at a pH of 6.4 This affects muscle function Inhibits the cross bridge Inhibits the enzyme activity, and energy production by glycolysis stops. High acidity may also impair neural transmission between muscles.

OBLA Onset of Blood Lactate Accumulation Point at which lactate begins to accumulate in the blood, usually taken as when it reaches 4mmol/litre of blood. Used to predict endurance capabilities/ potentials As longer an athlete can delay build up of blood lactate the longer they can keep going.

OBLA Lactate Threshold- point at which lactate is being produced quicker than the body can get rid of it. Exercise is anaerobic

Usually measured by a test that gets progressively harder. i. e Usually measured by a test that gets progressively harder. i.e. treadmill

Person takes place in progressively harder task i. e Person takes place in progressively harder task i.e. bleep test, a point is reached where energy can no longer be sustained completely by aerobic means. If intensity increases further the deficits in energy must be met by the anaerobic metabolism. By doing so, blood lactate concentration rises until a point where it causes muscle fatigue. The point at which lactic acid begins to accumulate in the muscles is the OBLA and is measured as a percentage of VO2max reached.

VO2 max Maximum volume of oxygen that can be taken and utilised or consumed by the working muscles per minute Mathew Pinsent 8.5 litres/min High VO2max = great endurance performances

OBLA and V02 Lactate threshold (OBLA) is a percentage of your VO2max The higher your VO2max, the more the delay in lactic acid build up So delaying OBLA/ lactate threshold

VO2max and Training As fitness increases (training) you delay OBLA (lactate threshold). This is why trained athletes can exercise for a longer period/ train at a higher intensity for longer. They can utilise much more of their Vo2max

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Exam Questions Outline the relationship between ‘VO2 max’ and ‘lactate threshold’. (3 marks)

Answer VO2 max – the maximum amount of oxygen utilised/equiv per unit of time/per minute Lactate threshold – the point at which lactic acid starts to accumulate in the blood/OBLA Lactate threshold is a percentage of VO2max The higher the VO2 max, the more the delay in lactic acid build-up/as VO2max increases, so does lactate threshold Trained athletes can exercise for longer periods at the same/higher intensity compared to an untrained athlete/lactate threshold a much higher percentage of VO2 max Has to be utilised, not just taken in Alternative words for utilised are uptake, used, consumed OBLA must be written in full initially

During a game, performers may suffer fatigue because they have a low lactate threshold(OBLA). What do you understand by the term lactate threshold and how is this related to VO2 max? (3 marks)

Answer Levels at which lactate/lactic acid accumulates in blood; Exercise has become anaerobic/without oxygen; Lactate threshold is some proportion/percentage of VO2 max; Proportion/percentage of lactate threshold increases as fitness increases/delayed lactate threshold/OBLA. 3 marks

Exam Questions In terms of recovery, explain the relationship between lactate threshold and the functions of Excess Post-exercise Oxygen Consumption (EPOC). (5 marks)

Answer Lactate removed during EPOC Slow/ lactacid component Oxygen used/needed for aerobic energy/ATP production formation Lactate mainly converted back into pyruvate Mitochondria/Kreb’s cycle/to CO2 and H2O In inactive muscles/other organs (liver) Some lactate converted to glucose/glycogen/protein Some excreted in urine and sweat

Measurement of lactic acid Lactate and lactic acid are interchangeable terms but not same thing Lactate is a product of lactic acid that splits to give a lactate molecule and hydrogen ions Blood lactate measurement is easier than taking muscle biopsies this is the most common method used.

Why measure? Can determine and assess training intensities to ensure athlete is working at suitable level and is producing energy by the most effective energy system Provides information current work capacity and fitness Assesses effectiveness of current training regime Main use is to establish anaerobic threshold or point of ‘onset blood lactate accumulation’ which gives an indication of endurance capacities.

Fatigue This is when we can no longer sustain a level of work. Muscle fatigue- inability of a muscle to maintain contractile force as a result of repeated contractions

What causes fatigue when we exercise?

Causes of Fatigue Build up of lactic acid /accumulation of hydrogen ions/OBLA Glycogen depletion/needed for glycolysis Dehydration/reduces blood flow/loss of electrolytes/increase body temperature Lack of PC stores

Competitive swimmers will often compete in several events and suffer from fatigue due to limited recovery time. Explain the possible causes of fatigue during a race. (3 marks)

Delayed onset of muscle soreness DOMS Tender, painful muscle soreness usually 48 hrs after intense or unaccustomed exercise. Soreness is a result of damage to muscle fibres and connective tissue and increased tissue fluids. Usually goes in couple days and muscles repair themselves. In the meantime it has a negative effect in the amount of force the muscle is able to generate.

Most likely to occur following eccentric contractions Weight training, walking done steep slopes and plyometrics Reducing the effect Warm up, cool down In a training session you progress from low intensity to high intensity exercise. Avoid eccentric contractions early on in session Ice baths Massage

Other factors affecting recovery Restoring muscle glycogen stores During exercise glycogen has been depleted. Repletion of muscle glycogen is a long process and takes up to 48 hours. Re fuelling with a high carb meal within one hour of exercise will speed up the process.

Other factors affecting recovery Restoring oxymyoglobin link The saturation of myoglobin so that oxygen can again be transported to the mitochondria. During exercise oxygen is dissociated from myoglobin to enable aerobic gylcolosis and energy to be supplied aerobically. During recovery oxygen must be re associated with myoglobin. To ensure a continuous supply of oxygen this happens very quickly in the first minute and is part of the alactacid debt.