Energy Systems and Muscle Fibres
Muscle Fibre Types
Fast Twitch Muscle Fibres:
- Ideal for short lasting activities.
- Can generate large amount of tension with
relatively low endurance levels
- Have the ability to tense and relax quickly
- More pale in color
Type 2b/x Fibres:
- Muscle fibres share lots of oxygen and sufficiently
high levels of enzymes necessary for quick contraction
requiring oxygen.
Type 2a Fibres:
- They allow for high-speed energy release as well
as glycolytic capacity
- Muscle fibres are intermediate type muscle fibres
Slow Twitch Muscle Fibres:
- Ideal for long distance activities
- They are able to maintain a lower level of
tension for long durations.
- Generate and relax tension relatively slow
- These are dark or red in color
Type 1 Fibres:
- Primarily depend on aerobic processes
- Are more fatigue-resistant
- Generate energy slowly
2 Energy Systems
Anaeobic
- Can occur in two separate metabolic pathways, one not involving the breakdown of glucose, and one involving partial breakdown of glucose
- Without the use of oxygen
Aerobic
- leads to the complete breakdown of glucose
- Requires oxygen
- Involves many enzymes and several complex
sub-pathways
Energy Sources
Glycogen Fats and, proteins
Glycogen is the stored form of glucose that's made up of many connected glucose molecules.
Fats are nutrients in food that the body uses to build cell membranes.
Protein is a nutrient your body needs to grow and repair cells, and to work properly.
Glucose
A type of sugar you get from foods you eat, and your body uses it for energy.
Creatine Phosphate
The main high-energy, phosphate-storage molecule of muscle.
Nutrients
They provide materials to build cell membranes
One of the most important sources of
energy
They supply energy, regulate cellular activity, and also build and repair tissue
Three key nutrients
Fats
Proteins
Carbohydrates
Chemical substances obtained from food
Myoglobin
- Acts as a storage unit for oxygen
- Fast twitch muscle fibres are low in myoglobin
- Slow twitch muscle fibres are high in myoglobin
- Oxygen-binding protein located primarily in muscles
- Delivers oxygen to working muscles when they need it
3 Metabolic Pathways
Cellular Respiration:
- Complete breakdown of glycose.
- Requires large amounts of oxygen
- 120 seconds and beyond
- Aerobic
- 36 molecules per molecule of glucose
- Long duration
Glycolysis (Anaerobic Lactic):
- Second energy pathway
- It allows longer bursts of energy
- It does not involve oxygen and is anaerobic
- Short bursts of energy for longer periods
- Involves the partial breakdown of glucose with lactic acid as a by product.
- 2 molecules of ATP for every molecule of glucose
ATP-PC (Anaerobic Alactic):
- Yields enough ATP for about 10-15 seconds of strenuous effort
- It is alactic
- It allows for quick, intense muscle contraction
- The first and simplest pathway.
- Does not yield lactic acid as a by product
ATP
_ There is 36 molecules of ATP, and there's three different processes that work to split ATP
- A molecule that provides energy for cellular processes in the human body
- Break down of fuel molecules, proteins, fats, and carbohydrates
