Energy Systems Flashcards
ATP - adenosine triphosphate
(ATP = energy + ADP + P)
- provides energy for muscle contractions
- chemical fuel source
- lasts roughly 4seconds
- broken down and rebuilt 24/7
- rebuilt by energy systems using fuels
Fuels
Energy required to resynthesise ATP - PC, carbohydrates, fats, protein
Chemical fuel
PC/CP
phosphocreatine/creatine phosphate
PC
- chemical fuel
- rapid break down release of energy
- rebuilds ATP very quickly
- lasts roughly 10secs
- limited storage of CP within muscle
- approx. 100% recharged after 3mins
Food fuels (3 macronutrients)
carbohydrates, fats, proteins
CHO carbohydrates
- food fuel broken down anaerobically and aerobically
- easy to break down; has fewer bonds
- broken down into glucose to produce energy
- stored as glycogen in muscles and liver
- main fuel source during exercise
Fats
- food fuel broken down aerobically
- large energy source; more complex
- stored as fatty free acids and glycerol in skin tissue
- main fuel source at rest and prolonged submaximal exercise as glycogen stores are depleted
Protein
- food fuel only used in extreme circumstances
- broken down aerobically (large amounts of oxygen)
- slowest to recharge ATP because largest
- stored as amino acids in muscle
- muscle growth and repair
- 12-15% of diet
What foods contain what food fuels?
CHO - fruit, veg, bread, pasta
Fats - oils, butter, nuts
Protein - eggs, lean meat, fish
Food fuel sources at rest
Mainly fats.
2/3 fats, 1/3 glucose.
Aerobic by-products ATP + CO2 + H2O
(anaerobic ATP + lactic acid)
Food fuel sources during maximal activity
100% CHO
aerobic breakdown = ATP + CO2 + H2O
anaerobic breakdown = ATP + Lactic acid
Food fuel sources during submaximal activity
Predominantly CHO, fats and protein in extreme circumstances.
Why are CHO our preferred exercise fuel source?
- > oxygen available for muscle contractions when using CHO vs fats.
- broken down both anaerobically and aerobically
- CHO have fewer bonds that need to be broken to release energy therefore ATP production is faster vs fats
- benefit from CHO loading for prolonged endurance events
Glycaemic Index
ranking of CHO foods on how quickly CHO in food is digested and absorbed into the blood.
HIgh GI (70+)= easier to break down
sports drinks, white bread and rice, watermelon
Low GI (<55)= sloewr to break down but last longer
multigrain bread, quinoa, sweet potato, apples, bananas
Carbohydrate loading
80% of diet is CHO to increase glycogen stores to aid endurance performance >2hrs (aerobic energy system)
(well-filled glycogen stores for endurance >90mins and high-intensity efforts (anaerobic glycolysis)
Crossover concept
Theoretical model that explains the balance between fats and CHO usgae during sustained exercise.
Crossover point is the intensity at which energy from CHO predominates over energy from fats.
Glycogen sparing
performing endurance training, results in adaptations that increase fat oxidation during mid-moderate intesnity exercise.
