Muscles

Functions of the Muscular System

• All movements of the body• Move blood through the circulatory system• Move food through the digestive system • Control the movement of air in and out of

the lungs

Types of Muscle Tissue

3 types

Cardiac Muscle

• orchestrate the sequence of cardiac muscle contraction

• Where is it found???– Only the Heart

• Involuntary

Smooth Muscle

• Close pores• Move hairs• Constricts vessels• Moves the contents of the digestive

system and circulatory system– Rhythmic contractions

• Involuntary

Skeletal Muscle

• Moves bones at the joints• Constricts cavities• Moves the skin

What is Skeletal Muscle

• Long, striated and multi-nucleated• Attaches to bone or other muscle at the

tendinous ends• between bony attachments, it crosses 1 or

more joints, moving them• muscle ALWAYS PULLS

Role of Muscle

Agonist

Moves a body segment in the intended direction – causes a movement

Antagonist

Muscle generating torque opposing that generated by the agonists, acts in the opposite direction

Examples

• Bicep Curl

• Bench Press

• Squat

• Basketball Chest pass

Muscle Contractions

3 Types

Concentric

• Muscle shortens

• Joint Moves

• Shortens through its optimal length

Eccentric

• Muscle lengthens

• “negative contraction”

• Greater increase in strength but very dangerous because of to much protein breakdown

Isometric

opposing torque at the joint is equal to the torque produced by the muscle therefore muscle length remains unchanged

No movement at the joint

Muscle actions

• Static (Isometric)– Large increase in

muscle force

– BUT –

– Specific to joint angle

• Dynamic– Concentric and

Eccentric

– Most people build muscle through both movements

Golgi Tendon Organ

• Sensory receptor that inhibits tension development in a muscle and initiates tension development in the antagonist muscles

• KEY: sense tension– stimulated by the presence of active tension

in a muscle

Golgi Tendon Organ

• Location: in the junctions between muscles and their tendons

Golgi Tendon Organ

• Action: inhibits muscle tension in the muscle generating too much force and initiates development of muscle tension in the antagonist muscle (excites)

Muscle Fiber Types

Fast twitch Vs.

Slow twitch

Type 1

• Slow twitch• Slow to contract• slow to fatigue• lowest exercise intensity• Energy source: muscle glycogen,

triglycerides, oxygen

Type 2a

• Fast to contract• Intermediate fatigue rate• Higher exercise intensity• Energy source muscle glycogen

Type 2b

• Fastest to contract• Fast fatigue rate• Highest exercise intensity• Energy source ATP-CP

FT : Fast twitch

ST: Slow twitch

http://muscleplusfitness.com/wp-content/uploads/2009/03/human-body-muscle-diagram.jpg