- Slides: 15
Anaerobic energy systems
• Anaerobic energy systems • – simplified biochemistry in the lactate anaerobic system – use in sporting situations • – lactate threshold/Onset of Blood Lactate Accumulation (OBLA) and fatigue; relationship with VO 2 max • – ATP-PC energy system – use in sporting situations.
ATP system • Fuel source: ATP • Duration: 3 Seconds • Intensity: High intensity • Oxygen? : No • Example: Shot put
Alactic energy system • Fuel source: Phosphocreatine (PCr) • Duration: Up to 10 seconds • Intensity: High • Oxygen? : No • Example: 100 m sprint • PC is broken down into P and C by the enzyme Kinase • Energy is then released for ATP re-synthesis • Aerobic energy is needed for system recovery
• Advantages – • ATP can be re-synthesised rapidly using this system • PC can be re-synthesised quickly (30 secs=50%, 3 mins=100%) • No fatiguing bi- products • Can be extended by supplementing creatine • Disadvantages – • PC is limited, only enough for 10 secs • One mole of ATP, re-synthesises one mole of PC • PC re-synthesis can take place only in the presence of O 2
Lactic acid system • Fuel source: Glycogen • Duration: 1 -3 minutes • Intensity: Medium-High • Oxygen? : No • Example: 200 m sprint • Glycolysis – glycogen is broken down into glucose (using PFK), then broken down into pyruvic acid. • Without O 2, the pyruvic acid converts to lactic acid – producing 2 moles of ATP.
90 seconds – 7 mark scheme • • • A. Anaerobic/without oxygen B. (during first few seconds) stored ATP splits C. Alactic system D. Creatine + phosphate/PC broken down; E. Energy used for ATP resynthesis F. Lasts 5 -10 seconds/limited supply G. Lactic acid system/Lactate anaerobic system H. Glycogen/glucose breakdown I. Glycolysis J. To pyruvate/pyruvic acid K. Lactate/lactic acid formed
• Advantages • ATP can be re-synthesised quickly, few reactions • With O 2, lactic acid can be converted back into liver glycogen or, used as fuel through oxidation in to CO 2 & H 2 O • Can be used at a sprint finish, provides an energy burst. • Disadvantages • Lactic acid is a bi-product • The accumulation of it denatures the enzymes and stops them increasing the rate that chemical reactions take place.
OBLA – Onset Blood Lactate Accumulation • It is your lactate threshold, which is 4 mmols. • It is measured by V 02 Max • V 02 Max – The maximum amount of oxygen that can be taken in and used in one minute • Trained athletes can withstand threshold longer, but the threshold can not go over 4 mmols.
Factors influencing the rate of lactic acid accumulation • RER – Respiratory Exchange Rate • Muscle fibres • Exercise intensity • Rate of blood lactate removal • Trained status
RER – Respiratory Exchange Rate • VC 02 expired per min/V 02 intake per min • Closer to 1 then athlete is using glycogen • Closer to 0. 7 then athlete is using fatty acids
Muscle fibres • Slow twitch produces less lactate • Fast twitch produces more lactate
Exercise intensity • Higher intensity the greater ATP demand
Rate of blood lactate removal • If the rate of lactate removal equals the rate of production then blood lactate concentration remains constant