Energy Systems Flashcards
Three energy systems
-ATP-PC system
-Anaerobic glycolysis system
-Aerobic system
Carbohydrates
Bodies preferred source of fuel, particularly during exercise
Fats
Bodies main source of fuel during rest and prolonged submaximal exercise
Protein
Used for growth and repair of muscles and sometimes during long endurance events
What is ATP
ATP consists of a large molecule called adenosine and three simpler components called phosphate groups. The energy released from the breakdown of ATP is used to perform biological work.
ATP stores at rest
We store 50 grams of ATP but actually require 190kg so we rapidly remake ATP as we need it
ATP-PC sysytem
Provides bulk of ATP during powerful or explosive efforts, the predominant system for all maximum intensity exercise up to 20 seconds
How the ATP-PC works
This system works by breaking down creatine phosphate to produce ATP, PC releases a free phosphate to donate to ADP creating ATP
ATP-PC system fuel source
Creatine Phosphate
ATP-PC system Rate of energy for ATP resynthesis
Explosive/instantaneous
3.6 mol/ min
ATP-PC system intenisty
Maximal intensity (95+% MHR)
ATP-PC system yield
Limited yield 0.7 ATP for every CP molecule
ATP-PC system duration
0-10 seconds
ATP-PC system by-products
Creatine, Inorganic phosphates
Resynthesis of CP
Mainly takes place when the athlete stops exercise, 30 seconds for 50%, 2-3 minutes 100%
Anaerobic Glycolysis System
Predominant system for high intensity exercise up to 60 seconds in duration, when CP runs out this is the predominant energy system
How anaerobic glycolysis system works
Glycogen is broken down in the absence of oxygen, glycogen turns into glucose and with insufficient oxygen its then broken down into pyruvic acid and further into lactic acid
Anaerobic Glycolysis System fuel source
Glycogen
Anaerobic Glycolysis System rate of energy for ATP resynthesis
Fast but not as fast as ATP-PC system
1.6 mol/ min
Anaerobic Glycolysis System Intensity
High intensity exercise (85-95% MHR)
Anaerobic Glycolysis System Yield
Small yield 2-3 ATP per glucose molecule
Anaerobic Glycolysis System duration
10-75 seconds
Anaerobic Glycolysis System by-products
Lactate, H+ ions
Onset of blood lactate
The point at which lactate levels begin to rise rapidly is known as onset of blood lactate and occurs at about 4 millimoles per litre
Lactate Inflection Point (LIP)
The exercise intensity beyond which lactate production exceeds removal, sometimes referred to as the lactate threshold
Aerobic energy system
Predominant system for long duration, sub-maximal intensity exercise
How the Aerobic energy system works
- CHO’s and triglycerides are broken down to release energy. This produces pyruvic acid.
- Pyruvic acid is further broken down producing carbon dioxide (krebs cycle)
- Further breakdown via the electron transport chain. It requires hydrogen ions and oxygen producing water and heat
Aerobic energy system fuel source
Glycogen and Triglycerides
Aerobic energy system rate of energy for ATP resynthesis
Slow
Glycogen 1.0 mol/min, triglycerides <1.0 mol/ min
Aerobic energy system intensity
Submax intensity exercise (70-85% MHR)
Resting/ low intensity exercise (<70% MHR)
Aerobic energy system yield
Large yield
38 ATP per glycogen molecule
441 ATP per triglyceride (147 per FFA)
Aerobic energy system duration
75+ seconds
Aerobic energy system by-products
CO2, H2O, heat
ATP-PC system advantages
- Simple anaerobic energy pathway
- Provides energy at an explosive rate
- Allows for maximal intensity affort
Anaerobic glycolysis system advantages
- Also an anaerobic energy pathway
- Provides energy at a fast rate
- Allows for high intensity efforts
- Provides energy in larger amounts that ATP-PC
Aerobic system advantages
- Provides an “endless” amount of energy
- Allows sustained long duration efforts
- Produces non-toxic by-products
- Ability to oxidise lactic acid
ATP-PC system disadvantages
- Limited intramuscular stores
- Very limited amount of energy produced
- Short duration of muscular effort
Anaerobic glycolysis system disadvantages
- Relatively small amounts of energy produced
- By-product of H+ ions lead to fatigue
Aerobic system disadvantages
- Delay in aerobic responses at start of exercise
- Slow rate of energy production
Fatigue
Reduction in ability of muscles to generate force or power
ATP-PC system fatigue factors
Accumulation of metabolic by-products (ADP and Pi), fuel depletion of CP
Anaerobic glycolysis system fatigue factors
Accumulation of metabolic by-products (H+ ions)
Aerobic system fatigue factors
- Fuel depletion (glycogen)
- CNS fatigue
- Thermoregulatory fatigue
- Dehydration
Metabolic by-products
Substances left over after metabolic processes
