Lactic Acid SystemLactic Acid System

Anaerobic GlycolysisAnaerobic Glycolysis

OrOr

Lactacid systemLactacid system

Lactic Acid SystemLactic Acid SystemIt is Anaerobic (does not need 02).It is Anaerobic (does not need 02).

It requires more chemical reactions than It requires more chemical reactions than the ATP – PC system so is the ATP – PC system so is notnot the first the first system used.system used.

It It isis activated at the beginning of intense activated at the beginning of intense exercise.exercise.

Peak power from this system is reached at Peak power from this system is reached at between 5 - 15 seconds. It continues to between 5 - 15 seconds. It continues to provide ATP until it fatigues at about provide ATP until it fatigues at about 2 – 3 2 – 3 minmin..

400m Hurdles

Lactic Acid SystemLactic Acid System

Without this system extended High Without this system extended High intensity activity (Above 85% Max intensity activity (Above 85% Max HR) these activities would not be HR) these activities would not be possible.possible.

50m Butterfly

200m world record

Time trial work record

Point of interest……Point of interest……

Until recently we thought that ATP-Until recently we thought that ATP-PC contributed all the ATP for PC contributed all the ATP for 100m…BUT,100m…BUT,

We have since discovered that upto We have since discovered that upto 40% of this ATP is derived from the 40% of this ATP is derived from the Lactic Acid system.Lactic Acid system.

How it works.How it works.

CHO’s are broken down to glucose CHO’s are broken down to glucose and stored in the muscle and liver. and stored in the muscle and liver. (in the muscle and liver as glycogen (in the muscle and liver as glycogen and in the blood and plasma as and in the blood and plasma as glucose and in the body tissue as glucose and in the body tissue as Adipose).Adipose).

Small amounts remain in the blood Small amounts remain in the blood as plasma.as plasma.

How it works.How it works.ATP must be re-formed from ADP+Pi. This ATP must be re-formed from ADP+Pi. This required energy!required energy!The energy comes from breaking down The energy comes from breaking down Glycogen.Glycogen.Breaking down glycogen is called Breaking down glycogen is called Glycolysis.Glycolysis.The LA system does this without 02 and is The LA system does this without 02 and is therefore refereed to as therefore refereed to as anaerobic anaerobic glycolysisglycolysis..Because there is no 02 present the glycogen is Because there is no 02 present the glycogen is not totally broken down and the by-product not totally broken down and the by-product lactic acidlactic acid is formed. is formed.

Soooooo….Soooooo….

Lactic acid present in the muscle Lactic acid present in the muscle decreases muscle pH, which in turn decreases muscle pH, which in turn decreases the amount on decreases the amount on glycolytic glycolytic enzymesenzymes and the rate of ATP and the rate of ATP resynthesis, causing FATIGUE!resynthesis, causing FATIGUE!

Glycolytic enzymes are responsible Glycolytic enzymes are responsible for breaking down glycogen.for breaking down glycogen.

See page 98 “reality snap shot”See page 98 “reality snap shot”

Brainiac summaryBrainiac summary

The lactic acid system is capable of The lactic acid system is capable of releasing energy to resynthesise ATP releasing energy to resynthesise ATP without the involvement of oxygen and is without the involvement of oxygen and is called anaerobic glycolysis. Glycolysis called anaerobic glycolysis. Glycolysis (breakdown of carbohydrates) results in (breakdown of carbohydrates) results in the formation of pyruvic acid and the formation of pyruvic acid and hydrogen ions (H+). A build up of H+ will hydrogen ions (H+). A build up of H+ will make the muscle cells acidic and make the muscle cells acidic and interfere with their operation so carrier interfere with their operation so carrier molecules.molecules.

Anaerobic glycolysis.Anaerobic glycolysis.Anerobic glycolysis produces LA Anerobic glycolysis produces LA which increases H+ thus muscle pH which increases H+ thus muscle pH drops and acidity increases. This drops and acidity increases. This inhibits glycolytic enzymes and ATP inhibits glycolytic enzymes and ATP production.production.

H+ combine with pyruvate to from H+ combine with pyruvate to from lactate which is converted to lactate which is converted to glycogen for further energy release.glycogen for further energy release.

The process of lactic acid removal takes approx. The process of lactic acid removal takes approx. one hour, but this can be accelerated by one hour, but this can be accelerated by undertaking an appropriate undertaking an appropriate warm downwarm down that that ensures a rapid and continuous supply of oxygen ensures a rapid and continuous supply of oxygen to the muscles.to the muscles.The normal amount of lactic acid circulating in The normal amount of lactic acid circulating in the blood is about 1 to 2 millimoles/litre of blood. the blood is about 1 to 2 millimoles/litre of blood. The onset of blood lactate accumulation (OBLA) The onset of blood lactate accumulation (OBLA) occurs between 2 and 4 millimoles/litre of blood. occurs between 2 and 4 millimoles/litre of blood. In non athletes this point is about 50% to 60% In non athletes this point is about 50% to 60% VO2 maxVO2 max and in trained athletes around 70% to and in trained athletes around 70% to 80% VO2 max.80% VO2 max.

What happnes to the lactate?What happnes to the lactate?As we exercise pyruvate is formed As we exercise pyruvate is formed When insufficient oxygen is available to When insufficient oxygen is available to breakdown the pyruvate then lactate is produced breakdown the pyruvate then lactate is produced Lactate enters the surrounding muscle cells, Lactate enters the surrounding muscle cells, tissue and blood tissue and blood The muscle cells and tissues receiving the lactate The muscle cells and tissues receiving the lactate either breakdown the lactate to fuel (ATP) for either breakdown the lactate to fuel (ATP) for immediate use or use it in the creation of immediate use or use it in the creation of glycogen glycogen The glycogen then remains in the cells until The glycogen then remains in the cells until energy is required energy is required 65% of lactic acid is converted to carbon dioxide 65% of lactic acid is converted to carbon dioxide and water, 20% into glycogen, 10% into protein and water, 20% into glycogen, 10% into protein and 5% into glucose.and 5% into glucose.

Lactic acid - friend or foe?Lactic acid - friend or foe?

Lactic acid (lactate) is not:Lactic acid (lactate) is not:responsible for the burn in the leg muscles responsible for the burn in the leg muscles when exercising very fast when exercising very fast responsible for the soreness you responsible for the soreness you experience in the 48 hours following a experience in the 48 hours following a hard session hard session a waste product a waste product Lactate, which is produced by the body all Lactate, which is produced by the body all day long, is resynthesized by the liver day long, is resynthesized by the liver (Cori Cycle) to form glucose that provides (Cori Cycle) to form glucose that provides you with more energy. Sounds like a friend you with more energy. Sounds like a friend to me.to me.

Hydrogen ionsHydrogen ions

The breakdown of glucose or glycogen The breakdown of glucose or glycogen produces lactate and hydrogen ions - for produces lactate and hydrogen ions - for each lactate molecule, one hydrogen ion is each lactate molecule, one hydrogen ion is formed. The presence of hydrogen ions, formed. The presence of hydrogen ions, not lactate, makes the muscle acidic that not lactate, makes the muscle acidic that will eventually halt muscle function. As will eventually halt muscle function. As hydrogen ion concentrations, increase the hydrogen ion concentrations, increase the blood and muscle become acidic. This blood and muscle become acidic. This acidic environment will slow down enzyme acidic environment will slow down enzyme activity and ultimately the breakdown of activity and ultimately the breakdown of glucose itself. Acidic muscles will glucose itself. Acidic muscles will aggravate associated nerve endings aggravate associated nerve endings causing pain and increase irritation of the causing pain and increase irritation of the central nervous system. The athlete may central nervous system. The athlete may become disorientated and feel nauseous. become disorientated and feel nauseous.

Improving your Lactate Improving your Lactate ThresholdThreshold

The aim is to saturate the muscles in lactic The aim is to saturate the muscles in lactic acid that will educate the body's buffering acid that will educate the body's buffering mechanism (alkaline) to deal with it more mechanism (alkaline) to deal with it more effectively. The accumulation of lactate in effectively. The accumulation of lactate in working skeletal muscles is associated working skeletal muscles is associated with fatigue of this system after 50 to 60 with fatigue of this system after 50 to 60 seconds of maximal effort. Sessions should seconds of maximal effort. Sessions should comprise of one to five reps (depends on comprise of one to five reps (depends on the athlete's ability) with near to full the athlete's ability) with near to full recovery.recovery.

Training continuously at Training continuously at about 85 to 90% of your about 85 to 90% of your maximum heart ratemaximum heart rate for 20 to for 20 to 25 minutes will improve your 25 minutes will improve your LT.LT.

A session should be conducted once A session should be conducted once a week and commence eight weeks a week and commence eight weeks before a major competition. This will before a major competition. This will help the muscle cells retain their help the muscle cells retain their alkaline buffering ability. Improving alkaline buffering ability. Improving your LT will also improve your your LT will also improve your duration of duration of VO2maxVO2max..

Lactate Tolerance Training Lactate Tolerance Training SessionsSessions

Distance Pace Recovery Reps

150 metres 400 metres 90 seconds 3 x 3

300 metres 800 metres 2 minutes 6

150 metres 800 metres 45 seconds 12

150 metres 800 metres 20 seconds 2 x 4

300 metres 1000 metres 90 seconds 9