Define the Cori Cycle?
-Also know as the lactic acid cycle-Its a pathway in CHO metabolism linking anaerobic glycolysis in muscle tissue to gluconeogenesis (formation of glucose from lactate) in the liver.
Define the Alanin glucose cycle?
-Also known as the Cahill cycle-Series of reactions in which amino groups and carbons from muscle are transported to the liver.
Cori cycle's importance during exercise
Encompasses both gluconeogenesis and glycogenesis as a method of providing energy to the body during times in which an adequate oxygen supply is not present in the body (such as periods of heavy exercise or other muscular activity).
Alanin glucose cycle importance during exercise
Alanine glucose cycle participates in glucoeogenesis and stabilises blood glucose.
Define lactic acid
Lactic acid is formed from glucose, and used by working muscles for energy.
How is lactic acid produced?
when muscle releases energy for contraction via anaerobic respiration
Why is lactic acid produced?
-As the breakdown of glucose is incomplete. Anaerobic respiration produces an O2 debt. This is the amount of oxygen needed to oxidise lactic acid to carbon dioxide and water.
What is the effect of exercise on lactate production?
During light to moderate exercise lactate production equals lactate disappearance <50% (as oxygen-consuming reactions adequately meet exercise energy demands), anything above 50% of aerobic capacity causes the production of lactate to take place.
Effect of exercise on lactate accumulation?
if pyruvate formation exceeds pyruvate oxidation.
What is the effect of exercise on lactate clearance?
Exercise increases the rate of lactate clearance
Define lactic threshold
exercise intensity when blood concentration of lactate/lactic exponentially increases.
What is the impact of aerobic training on lactic threshold
Vo2 max increases, increases aerobic capacity and ability to train at a higher intensity without the anaerobic pathway being tapped into.
What is the impact of anaerobic training on lactic threshold
Slight Vo2 increase, higher ability to clear lactate, delays the onset of lactate accumulation because the body has a better ability to metabolise the lactate, Increases the bodies capacity to metabolise lactate accumulation.
Discuss differences in recovery oxygen uptake from light, moderate, and intense exercise
-Light activity: rapid steady-rate VO2 attainment: small O2 deficit: rapid recovery VO2 -Moderate-to-intense aerobic activity requires a longer time to achieve steady rate VO2. Creating a larger O2 deficit with a longer recovery time for the VO2 to restore resting levels.
List three factors that account for excess post exercise oxygen uptake
-Thermogenic affects of hormonesRe-synthesis of ATP/PCRRestore O2 to blood/myoglobin
Outline optimal recovery procedures from steady-rate and non-steady-rate exercise
Steady state: re-synthesis of high-energy phosphates -replenishment of O2 in blood-replenish bodily fluids-replenish muscle myoglobinNon-steady state: Performing aerobic exercise for recovery accelerates blood lactate removal from liver/heart.-increases blood flow through skeletal muscles.
Discuss the rationale for intermittent exercise applied to interval training
-Produces rapid recovery and enables subsequent intense exercise to begin following a brief recovery.-Manipulating the duration of exercise and rest intervals can effectively overload an energy-transfer system of choice.
Describe the role of the citric acid cycle in energy metabolism
-pyruvate converts acetyl-COA for entry into the citric acid cycle for aerobic energy metabolism.
Explain specificity and generality as they apply to physical performance and physiologic function
-A high VO2max in one activity does not ensure a similarly high VO2max in a different activity (specificity principle).-Some individuals with a high VO2max in one activity possess above-average VO2max in another dissimilar activity illustrates the generality principle.
Describe the anaerobic-to-aerobic exercise energy transfer continuum
-Energy for physical activity from each energy transfer form progresses along a continuum.-In intense, brief exercise the intramuscular high-energy phosphates supply almost all of the energy for exercise.-The ATP-PCr and lactic acid systems supply about half the energy for intense exercise lasting 2 min with aerobic reactions supplying the remainder.-Long duration endurance exercise requires a constant aerobic energy supply with little reliance on energy transfer from anaerobic sources
Explain differences between peak VO2 and VO2max
-Vo2 max: A leveling off or peaking over in VO2 with increasing exercise intensity.-VO2peak: Highest value of oxygen consumption measured during a graded exercise test
List criteria that indicate attainment of a "true" VO2max
-Oxygen uptake follow an increase in % grade until 10% grade is achieved, when the grade is increased to 12.5% the Vo2 levels off. -The plateau in O2 uptake with an increase in work rate is the criterion for having achieved Vo2 max.
Outline three common treadmill protocols to assess VO2max
-Balke test -Harbour test-Bruce test
List factors that influence VO2max
-Genetics-Age-Gender
List assumptions to predict VO2max from exercise heart rate
-Based on linear relationships between HR and VO2 during increasing exercise intensities.-Line of best fit drawn through several sub-maximal points.
List two important functions of carbohydrate in energy metabolism
-Aerobic breakdown of CHO for energy occurs rapidly.-CHO provides energy substrate with stored energy generating ATP anaerobically.
Discuss dynamics of lactate formation and accumulation during increasing exercise intensity
Energy to converts to phosphorylate ADP during intense, short-intense exercise, it comes mainly from stored muscle glycogen breakdown via anaerobic glycolysis resulting in lactate formation. Rapid and large accumulation of blood lactate occurs during maximal exercise of 60 to 180 s
Discuss oxygen's prime role in energy metabolism
Oxygen is used in energy metabolism to convert nutrients (carbohydrates, fats, and protein) to carbon dioxide and adenosine triphosphate (ATP).
Give three examples of physical activities where each energy source predominates
Weightlifting- CHOMedium distance running- LIPMarathon runners- PRO