Energy Systems

ATP Hydrolysis

the process of ATP breaking down into ADP+P+energy+heat, and the use of creatine for ADP to form ATP

Cellular respiration

process by which the chemical energy of “food” molecules is released and partially captured in the form ATP

ATP storage

The energy system that we use first. It powers the first few seconds of activity.

ATP/CP system

The energy system that takes over dominance after 2 seconds and provides energy until the creatine runs out after about 5 seconds. 

Glycolytic Systems

In cytoplasm, glucose turns into pyruvate through glycolysis. If no O2 is present during the process, pyruvate will turn into lactic acid/ethanol+2ATP. If O2 is present, pyruvate will turn into Acetyl CoA and about 34 ATP in the mitochondrion.

inner structure mitochondria

Anaerobic Glycolysis (lactic Acid System)

If no O2 present, the body produce 2 ATP and a build-up of lactate, this is fast but short. 

Aerobic Glycolysis

If O2 is present, pyruvate enters matrix (in the mitochondria) where oxidative phosphorylation turns pyruvate into AcetylCoA. This enters the Krebs Cycle and 2 ATPs are formed plus NADH and FADH2 - high energy electrons. These then pass through the inner membrane to the cristae space where the Electron Transfer Chain produces 34 ATP. 

Triglycerides

They are stored in the adipose tissue and skeletal muscles. When glucose stores run low lipolysis catabolises lipids to glycerol and 3 fatty acids to be used for energy

Aerobic Lipolysis

The process of releasing triglycerides from the body’s stores. Glycerol is glycolyzed to pyruvate in cytoplasm. Fatty acids are beta oxidised to AcetylCoA in the matrix. They produce more high energy electrons in the Krebs cycle which results in over 100 ATPs in the Electron Transport Chain.

System	Fuel	Duration	By-product	Activities when dominant	Intensity	Amount of ATP	Speed of production
ATP-CP
Lactic Acid
Aerobic glycolysis
Lipolysis

System	Fuel	Duration	By-product	Activities when dominant	Intensity	Amount of ATP	Speed of production
ATP-CP	ATP	1-5s	N/A	Any early movement	Any	1 ATP	Immediate
Lactic Acid	Glucose	2-15s	Lactate	HIIT	High	2 ATP	Fast
Aerobic glycolysis	Glucose	1m- 2hrs	Co2+H2o	Endurance	Middle	38 ATP	Medium
Lipolysis	Lipids	30m – 3hrs	Co2+H2o	Endurance	Low-middle	100s ATP	Slow

Energy Continuum

different energy systems dominate at different times and are dependent on different demands

glycogenesis

the process of storing glucose in liver and skeletal muscles

Glycogenolysis

It occurs when you are hungry or exercising and require more glucose. Glycogen is catabolised to become glucose

Gluconeogenesis

the production of glucose from non-carbohydrate sources like proteins, lactate and glycerol to create energy.

Metabolism

all biochemical reactions in body

Anabolism

energy requiring actions that build up

Catabolism

energy creating actions that break down