Energy Systems Flashcards
Bioenergetics
Describes processes of various energy/macronutrient use within the body and the function of energy systems for fuel provision during exercise
Maximal muscular work lasting 1-3 seconds
ATP; vertical jump, 1RM
ATP rest period
90 seconds
Creatine phosphate
Organic compound capable of storing and providing high energy phosphate elements to fuel muscular contraction
Refuels ATP stores to deliver short, powerful bouts of work lasting 10-15 seconds
Creatine phosphate; 3RM, 100 meter sprint
CP rest period
2-5 min depending on activity and volume
Glucose
Simple sugar molecule; primary source of metabolized fuel for glycolytic energy
Glycogen
Stored form of carbohydrate; skeletal muscle (3-400g), liver (75-100g)
Glycolysis
Metabolic process breaks down glucose to provide ATP
Moderate intensity work up to 90 sec; contributes to aerobic system
Glycolytic
Lactic acid (lactate)
Used by various tissue to fuel continuous work; initial buffer to H+ during glycolysis
Pyruvate
End product of sugar metabolism during glycolysis in the presence of oxygen; broken down in Krebs cycle to aid aerobic metabolism
Ischemia
Low oxygen state caused by tissue acidity
Ischemia occurs as excess H+ builds, causing a drop in acidity which may:
Inhibit enzyme reactions
Alter calcium handling
Localized muscular fatigue
Lactate is shuttled to various tissues to aid in
Gluconeogenesis
Delayed Onset Muscle Soreness (DOMS)
Muscle soreness expedited by inflammatory response to cellular damage, ischemia and spasms; presents 24-72 hours after intense work, new exercises, heavy eccentrics and high volume
Steady state
O2 use matches demand; HR levels off no more than +/- 5 BPM
Oxygen deficit
Elevated O2 consumption after exercise to pay back anaerobic demand bringing body to homeostasis
Excess post-exercise oxygen consumption (EPOC)
Increase in O2 consumption following strenuous activity due to oxygen deficit
Metabolic Equivalent (MET)
Multiples of resting metabolic rate; one MET = oxygen uptake rate of 3.5 ml/kg/min
Aerobic System
Metabolic pathway where mitochondrion utilize substrates of fat, carbs & protein to produce ATP in presence of oxygen
Krebs Cycle
Aerobic metabolism of compounds to produce ATP; sparked by pyruvate from glycolysis; signals the body that more energy is needed
Fuels ongoing work >3 min until CHO stores are depleted
Aerobic system
Fat burning zone
Lower intensity training (<65% VO2 max) predominantly fueled by fat
FatMax (aerobic threshold)
Highest intensity of work sustained by fat as a fuel source; 60-70% VO2 max in trained individuals; 60-80% HRmax
Each energy pathway determines:
Magnitude of potential force
Sustainability of force output
Total force produced from energy system
Rest intervals
Fatigue sets in when
CHO stores are depleted, elevated metabolites in working muscles
Protein sparing is facilitated when
blood glucose and glycogen storage is adequate
The body metabolizes BCAAs to maintain glucose levels for the CNS when
Glycogen is depleted
Lack of CHO will cause significant fatigue, reduced performance and protein catabolism even when
O2 and lipid levels can meet work demand
Acute peripheral fatigue
Cells experience dysfunction due to a metabolic reduction in pH
General peripheral fatigue
Lack of energy in working tissues due to low pre-exercise stores or localized depletion; recovery period needed
Central fatigue
Systemic depletion of CHO; reduced motor unit recruitment & firing; reduction in exercise intensity until refueled/recovered
Rest periods
Period between sets; dictated by energy system use
Recovery periods
Period of time between separate exercise bouts so adaptation can occur
The only carbon-fuel nutrient that yields energy without the use of oxygen
Glucose
The end products of glycolysis include
2 ATP molecules, lactate & pyruvate
The body maintains ATP levels through metabolic processes that happen in the
Cytosol or mitochondria
Anaerobic processes can support work lasting up to
3 minutes
Cellular oxidation in aerobic metabolism refers to
Mitochondrial oxidation of fatty acids, pyruvate from glucose and deaminated amino acids
In short aerobic bouts of exercise at mild intensity, 50% of oxygen recovery will occur within
30 seconds; “fast component”
EPOC “slow component” can last up to
24 hours
In aerobic exercise, the three largest determinants of of efficiency are
Number & size of mitochondria
Concentration of enzymes
Amount of 02 rich blood delivered
