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BTEC NCSport & Exercise
SciencesUnit 7 Unit 7
Anatomy for Sport & ExerciseAnatomy for Sport & Exercise
Know your Bones?Know your Bones?
To revise, try this site…To revise, try this site…http://www.medtropolis.comhttp://www.medtropolis.com
The Muscular SystemThe Muscular System
Muscles provide the forces which move our skeleton. But they have other functions too…
Muscle Tissue
Involuntary
Cardiac
Smooth
Voluntary
Skeletal
You've got around 650 muscles in your body, and they make up roughly half of your bodyweight. These muscles can be
divided into three different groups:
Skeletal Skeletal (striated)(striated) Muscle Muscle
Properties:-
• Extensibility – ability to lengthen
• Highly Elastic – return to normal length after stretch
• Contractability - forcibly shortens on nervous/hormonal stimulation
Function of Skeletal Muscle
•Movement
•Posture & Support
•Heat Production
Basic Basic MusclMuscles of es of the the HumaHuman n BodyBody
Anterior
Basic Basic MusclMuscles of es of the the HumaHuman n BodyBody
Posterior
Muscle Muscle StructurStructuree
Muscle Muscle StructurStructuree
Muscle StructureMuscle Structure Muscles are attached to bones with tendons.
• Tendons are made from collagen fibres.• There is an Origin & Insertion for each muscle.• The Origin is usually proximal. Insertion is distal.
Outer layer is EPIMYSIUM
The muscle itself is made up of many FASSICLES.• Each Fassicle contains many muscle FIBRES (or cells).• Fassicles are covered in and separated by PERIMYSIUM• Perimysium is made from collagen fibres.
Each Fibre is held together by ENDOMYSIUM.
Each Fibre consists of many MYOFIBRILS.• These are the contractile units of the muscle.
Each Myofibril contains many repeated units called SARCOMERES.
Sarcomeres contain ACTIN & MYOSIN filaments• Actin is the thin filament• Myosin is the thick filament
Troponin and Tropomyosin prevent muscle action.• They bind to Myosin preventing Cross-Bridging.• Calcium Ions (Ca+) released from Sarcoplasmic Reticulum
activate the release of Troponin from Myosin. Myosin heads bind to Actin creating a ‘pulling’ action. ATP contained in the Sarcoplasm provides energy for
release of binding.
Muscle Cell StructureMuscle Cell Structure
Sliding Filament Theory
3 Types exist:
• Type 1 –
•Slow Oxidative fibres (Slow-twitch fibres)
• Type 2(a) –
•Fast Oxidative Glycolytic fibres (Fast Twitch fibres)
• Type 2(b) –
•Fast Glycolytic fibres (Fast Twitch fibres)
Types of Skeletal Muscle Fibre
Type 1 – Slow Oxidative fibres
(Slow-twitch fibres)
•Red - Rich blood supply, more myoglobin
•Slow contraction – due to thin myelin sheath/slow nerve impulse.
•Aerobic - Posture & endurance events – Journeying, Hill walking.
Type 2(a)– Fast Oxidative Glycolytic fibres
(Fast-twitch fibres)
•Much Paler – Less myoglobin
•Faster contraction – due to thicker myelin sheath.
•More fibres in each motor-unit
•Mainly Anaerobic – but also Aerobic Capacity
•Sprints/400m, Short ‘difficult’ climb, Kayak Sprint
Type 2(b) – Fast Glycolytic fibres
(Fast-twitch fibres)
•White
•Fast contraction – due to thick myelin sheath.
•Motor Neurone Thicker – large impulse.
•Almost entirely Anaerobic
•Short Sprints, Powerful climbing moves, strong bursts of power strokes, intense uphill MTB
Fibre Type Fibre Type PropertiesProperties
Quality Type 1 Type 2a Type 2b
Contraction Speed
Slow(80 – 100 ms)
Fast(40-60 ms)
Very Fast(< 40ms)
Force Production
Low High Very High
Capillary Density
High Medium Low
Oxidative Capacity
High High Low
Exercise Capacity
Very High Fatigue QuicklyFatigue
Extremely Quickly!
Sports Specific Sports Specific PredominancePredominanceSports Specific Sports Specific PredominancePredominance
InnervatioInnervation of fibresn of fibres
‘All or Nothing’ Law
Dependent on sufficient impulse.
Muscle Twitch
Muscle Innervation
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