Energy systems

kreb cycle Series of chemical reactions in the mitochondria Oxidizes acetyl CoA to produce ATP (Adenosine Triphosphate = energy molecule found in all cells) CO2 is formed in this process

anaerobic energy Muscles Fibers need energy to sustain contraction 2 main sources of stored energy ATP (Adenosine Triphosphate) PCr (Creatine Phosphate)

anerobic energy When stored energy runs low, the body must produce more ATP Carbohydrate (glycogen) stored in muscle and liver Anaerobic glycolosis By-product is lactic acid

anerobic energy Non – oxidative (without oxygen) Brief; but intense Byproduct is Lactic Acid Important at the onset of exercise Important for events of short duration Low efficiency 1 glucose = 3ATP

anaerobic power Maximal all out effort for several seconds ATP-PCr energy system Nervous system sends a message to muscle cell ATP is split to ADP to release energy PCr restores ADP to ATP, thus repeating the cycle. Anaerobic glycolysis Break-down of glycogen without oxygen. 3 ATP / 1 glucose Produces lactic aid

lactic acid By product of anaerobic metabolism Change the acid-base balance in the muscle cell Causing burning sensation in muscles, nausea physical and mental fatigue Training reduces production of Lactic acid and improves the body’s ability to remove it from the system.

aerobic energy Uses oxygen to produce energy With exercise heart rate and breathing rate increases so more oxygen is getting to the muscles. Within a few minutes the muscles are supplied with enough oxygen for aerobic respiration. Abundant energy stores Carbohydrates 4 Kcal / gram Fat is abundant and rich energy source 9 Kcal / gram

aerobic energy More efficient than anaerobic 1 glucose = 36 ATP Occurs in Mitochondria of the cell. Glucose + O2 = CO2 + H2O + energy * Protein is essential to build, maintain and repair issue, but is not a preferred energy source.

aerobic capacity The ability of the aerobic system to take in, transport and utilize oxygen. a product of the respiratory, cardiovascular and muscular systems. Measured in L/min Higher measures indicate excellence in non-weight bearing sports.

aerobic energy Aerobic energy is used for low to moderate intensity and long duration. It offers a high energy yield, allowing activity to be maintained for long periods.

aerobic energy Elite athletes may use their aerobic pathways to perform what would be high intensity to lesser athletes.

aerobic energy Aerobic system uses oxygen to break down food fuels CARBOHYDRATES & FATS High energy yield

energy supplied against time A = ATP-PC - Lactic Acid threshold. The point at which ATP-PC system is exhausted and the lactic acid system takes over. B = Lactic Acid - Aerobic threshold. The point at which the lactic acid system is exhausted and the aerobic system takes over.

energy continuum

energy continuum Considers the importance of each energy system in a particular activity. Intensity and duration will decide which energy system is used. Often there will be a combination of all three.

energy continuum e.g: Marathon ATP-PC System – Start of race. Aerobic System – Majority of race. Lactate Anaerobic System – Sprint finish.

energy continuum e.g: Midfield in football ATP-PC System – Sprinting for the ball. Lactate Anaerobic System – High intensity work, chasing ball, moving into space, dribbling with ball. Aerobic System – Less intense periods when play does not involve the player. Time to recover using aerobic system.

to do Complete theory of knowledge on page 66. The triathlon is an athletic event that involves performers undertaking a long distance swim, immediately followed by a cycle race and then finally a run of several kilometres. What would be the major energy sources used by a triathlete? Briefly explain how these energy sources are used for regeneration of ATP.

Briefly explain how these energy sources are used for regeneration of ATP.

What would be the major energy sources used by a triathlete?

O2 deficit & EPOC Oxygen deficit: temporary oxygen shortage resulting from immediate, strenuous exercise

O2 deficit & EPOC EPOC = excess post-exercise oxygen consumption during recovery from exercise, O2 utilization continues at a rate greater than need at rest Offsets anaerobic metabolism during early phase of exercise

O2 deficit & EPOC Oxygen needed in recovery for: Rebuild ATP % PCr stores Myoglobin (protein) oxygenation Cost of elevated respiration to clear out excess CO2 O2 needed to cool the body ( breathing) * See page 70, fig 3.18

to do Draw your own fig 3.19, p.71 to help understand the relationship between exercise intensity & rate of ATP demand. Test yourself page 72 Question 1 and 2. Then: explain each sport and the energy systems they use: why and when are they used/dominant. Self-study questions p.73-74