Anaerobic Glycolysis Energy System

Alternative Name: Lactic acid, Lactacid Type of ActivitiesSustained sprints/power Event Examples:200m, 400m, Sprint cycling, 200m swimming Predominant: 6-30 secs (approx.) Main Advantage:Rapid supply of energy (fast rate) Main Disadvantage:Lasts for relatively short amount of time Limiting Factor:Accumulation of metabolic by products (Hydrogen ions) Fuels Used:Glycogen (from muscles and liver)

Anaerobic Glycolysis Energy System Byproducts:Hydrogen ions (H+) Lactate Number of ATP made:2 (low yield) Located where:Cytoplasm of muscle (in organelle called cytosol) Used when: High intensity, submaximal efforts Repeated maximal efforts (when not enough time to replenish PC stores) Exercising at levels greater than VO2 maximum

Incomplete Breakdown Of Glucose The Anaerobic Glycolysis system uses muscle and liver glycogen (converted to glucose) to synthesize (make) ATP. The breakdown of glucose is incomplete and this is the reason why it does not produce as many ATP as when glucose is broken down in the Aerobic energy system.

Byproducts The chemical reaction produces pyruvic acid and hydrogen ions and because oxygen is not used, is converted into lactic acid. The lactic acid splits into lactate and hydrogen ions. The build up of hydrogen ions interferes with muscular contractions. Lactate is in itself ‘good’ because it is the result of a fast rate of energy production. In fact the aerobic system converts some of the lactate back into pyruvic acid before it leaves the muscles then creates more ATP for the body to use (oxidisation).

Lactate Inflection Point (LIP) “Reflects the balance between lactate entry into and removal from the blood (it is the absolute final point before concentration in the blood increases) At exercise intensities beyond LIP, blood lactate concentration and fatigue increases Measured in: –millimol/litre (mM/l or mmol/l). or sometimes mg/ml

How Lactic Acid Interfere With Muscular Contractions It inhibits enzymes that break down glucose (an enzyme accelerates a chemical reaction) It inhibits calcium ions (calcium ions enable myosin cross bridges to attach to the actin)

How Hydrogen (H+) Ions Interfere With Muscular Contractions Makes muscles acidic –pH levels in cytoplasm decrease which decreases enzyme activity that break down glucose therefore slower rate of ATP production Also increases the irritation of the central nervous system therefore slows rate of messages sent and slows ATP production

Lactate Accumulation Lactate is localised in that it accumulates in high concentrations in the working muscles –(eg legs of 400m runner and arms/shoulders of 100m freestyle swimmer) The net accumulation of blood lactate depends on –the ratio of lactate producing muscle fibres relative to muscle fibres able to oxidise lactic acid and –the blood flow distribution to lactate removal sites.

Best Recovery Method from Metabolic By Product Accumulation (Active) An active recovery (light jogging, swimming, cycling, rowing etc) removes lactate fastest. Twice as fast as a passive recovery. –Active recovery: 50% LA removed in 15 minutes –Passive recovery: 50% removed in 30 minutes An active recovery fastest because it… Increases the Oxygen inhaled (more breaths) –to increase oxidation of lactate in mitochondria Increases the speed of blood flow –to disperse lactate to lactate removal sites of the body (heart, kidney, non exercising muscles and in liver Cori cycle converts small amount of LA back to glycogen)

Benefits Of an Active Recovery Fastest method for removal of metabolic by product Prevents venous pooling Decreases the severity of Delayed Onset Muscle Soreness (DOMS)