Unit 1 Principles of anatomy and physiology in Sport

BTEC Sport

Principles of Anatomy and Physiology in Sport


In this section of (2.2 Function of the muscular system) I will be discussing the function of the muscular system and the different fibre types. The final part of this assignment requires a more in depth analysis of the muscular system and fibre type.

I will include the structure and function of the muscular system and different fibre types and discuss with reference to the structure and function of each fibre type, why a games player needs a balance of all 3 to ensure optimal performance.


Fibre Types

Every person’s body whether they are athletes or non athletes each contain a mixture of fibre types. The fibre types vary from person to person and with each person the muscle group to muscle group also varies. “Inheritance is taken into consideration also with the Muscular Fibre types as they can be inherited through genes” (The World Of Psychology 2005 Beck et al)

Each type of fibre typed is grouped on the speed to muscular contraction. Whether they are:
Type 1: Slow Twitch.
Type 2: Fast Twitch which has Type 2a & Type 2b

“Many people believe that having more fast and slow twitch muscle fibres may determine what sports athletes excel at and how they respond to training.”
(http://sportsmedicine.about.com/od/anatomyandphysiology/a/MuscleFiberType.htm)

Each myocyte contains many myofibrils, which are strands of proteins that can grab on to each other and pull. This shortens the muscle and causes muscle contraction.

Characteristics of Type 1 Muscle Fibres

Slow Oxidative Fibre

These fibres are the ones that contract slowly with little force, because they are slow without force they are slow to fatigue and are suited to longer duration activities. The slow muscles are more efficient at using oxygen hence the name oxidative, to generate more fuel (known as ATP) for continuous, extended muscle contractions over a long time. They “twitch” more slowly than fast twitch fibres and can go for a long time before they fatigue due to storing and using less oxygen in the muscle. Therefore, slow twitch fibres are better at helping athletes run marathons and cycle.

As an athlete can’t gain any more fibres, they can train them, but training does damage them, but will make them grow back bigger and stronger. In the human skeletal system our bodies are made up of lots of fibres, when stimulated to contract help produce movement.

“They have more glycogen (carbohydrate) granules and lipid (fat) droplets than fast twitch, which allow them to exercise for longer.” (www.brianmac.co.uk)

Slow-twitch fibres have both a higher density of capillaries supplying oxygen to the muscle and high concentrations of but it's not simply a case of burning substrate to produce the energy required for movement there's a more complex way in which the fibres reacts using different bits of machinery (body system) and enzymes. For example Slow Twitch fibres are better suited to Marathon Runner and Tour De France or any long distance event, they also come into have a huge influence in super human type events such as the IRON Man contest as actions and movements are at a high rate but need the slow twitch fibres for endurance.




Characteristics of Type 2 Muscle Fibres

Type 2a – Fast Oxidative Glycolytic Fibres

Fast Oxidative Glycolytic Fibres are a mixture of Slow Twitch and Fast Glycolytic Fibres where it is fast contracting, able to contract and exert large amounts of force, but are also resistant to fatigue. These are the muscle fibres needed for medium endurance activities. Type 2a Fast Twitch fibres contain large amounts of myoglobin and many mitochondria, this makes them able to perform fast contractions with saving and using ATP efficiently just like Slow Twitch fibres, but are able to exert more force.

“They use carbon dioxide and oxygen and this type can produce energy both aerobically and anaerobically by breaking down carbohydrate to pyruvic acid, however it is far more suited to anaerobic respiration, which means it can release energy very quickly.” (Notes Taken In Class)

Fast Twitch Type2a have many blood capillaries, this means that they have high capacity for generating ATP by oxidation which are split ATP at a very rapid rate and, hence, high contraction velocity, they are also resistant to fatigue but not as much as slow oxidative fibers as high levels of force are exerted

They are needed for sports such as middle distance running and swimming, and team sports such as football and rugby as high and low intensity is required.







Type 2b – Fast Glycolytic Fibres

These fibres are another step up from Type 2a as they contract very rapidly and have the capacity to produce large amounts of force, but they do fatigue at a faster rate therefore are suited to anaerobic activities. They rely heavily on anaerobic respiration for releasing energy as they have very few mitochondria.

Type 2b fibres are white, geared to generate ATP by anaerobic metabolic processes, not able to supply skeletal muscle fibres continuously with sufficient ATP. This is why they fatigue easily as they are split ATP at a fast rate and have a fast contraction velocity.

“They adapt to high-intensity anaerobic exercise involving explosive or powerful movements, but are increasingly employed as fatigue sets during low-intensity endurance work.” (BTEC Sport Level 3, Mark Adams et al 2010)

These twitch fibre types are suited to activities short distant sprints such as 100M and 200M and activies such as gymnastics and weight lifting as they require fast jerking motions which require fast contractions.














Bibliography

BTEC Sport level 3 Adams et Al
The world of psychology, biological psychology
www.brianmac.co.uk
www.sportsmedicine.co.uk
Notes taken in class