Muscle Structure & Function Muscle belly Muscle Fibre Bundles Muscle Fibres

Muscle Fibre Types SO FOG FG Colour RED RED / PINK WHITE Size SMALL STRUCTURE Colour RED RED / PINK WHITE Size SMALL INTERMEDIATE LARGE No of Mitochondria MANY FEW No of Capillaries Glycogen Stores LOW HIGH FUNCTION Contractile Speed SLOW FAST Contractile Strength Fatigue Resistance MODERATE Aerobic Capacity Anaerobic Capacity ATHLETE MARATHON 1500 M 100 M ACTIVITIES ENDURANCE MULTI SPRINT POWER

Muscle Fibre Types SO FOG FG Colour RED RED / PINK WHITE Size SMALL STRUCTURE Colour RED RED / PINK WHITE Size SMALL INTERMEDIATE LARGE No of Mitochondria MANY FEW No of Capillaries Glycogen Stores LOW HIGH FUNCTION Contractile Speed SLOW FAST Contractile Strength Fatigue Resistance MODERATE Aerobic Capacity Anaerobic Capacity ATHLETE MARATHON 1500 M 100 M ACTIVITIES ENDURANCE MULTI SPRINT POWER

Muscle Attachments Tendons Origin Insertion Origin Attach Muscle to Bone End of muscle that is stationary during contraction Origin Insertion End of muscle that moves during contraction Insertion

Muscle Contractions Isotonic Isometric Concentric Eccentric For muscles to work and cause movement they need to contract. There are different types of contraction: Isotonic Isometric Force produced without movement Eg tug or war / rugby scrum Forced produced with movement Concentric Eccentric Muscle Shortens Most common type of contraction Muscle Lengthens Braking action

Muscles Working Together Muscle can not push, they can only pull This means that as one muscle contracts and brings bones together, another is need to pull them back apart. For the body to work effectively muscles must work together Depending on the movement, muscles can adopt a variety of roles: Agonist The muscle that contracts to start the movement Antagonist The muscle that relaxes to allow the movement Synergist The muscle that stabilises the joint while the movement takes place

Sliding Filament Theory The mechanism by which muscle fibres contract Relaxed Muscle Muscle Filaments slide together, shortening fibre length Contracted Muscle