lectures 7 Flashcards
Skeletal Function
- Support • Protect • RBC development • Nutrient storage • Frame for movement
Origin & Insertion
The muscle’s origin is attached to the more stable bone
• The insertion of the muscle attaches to the bone that moves when the muscle contracts
Joints
• Joints between bones allow movement • Range of motion (ROM) of the joints may be influenced by – Structure of the bone – Type of joint it forms – Muscle attachment points – Muscle size – Flexibility
Joint structure
- fibrous
- cartilnginous
- synovial
Fibrous
– Lacks joint cavity
– Limited or no movement
Cartilaginous
– Lacks joint cavity
– Limited movement
Synovial
– Has a joint cavity
– Movement variable
Synovial joints movement limited by
– Structure of the bone
– Strength & tautness of ligaments & tendons
– Size & arrangement of muscles that span
the joint
synovial joints
– Gliding – Hinge – Pivot – Condyloid – Saddle – Ball & Socket
Movements
• Flexion & Extension • Abduction & Adduction • Rotation – Internal & external rotation • Circumduction • Pronation & Supination
define flexibility
The range of motion (ROM) in a joint or series of joints
Factors affecting flexibility
Anatomical factors – Muscle • Muscle bulk • Muscle extensibility • Muscle strength – Connective tissue • Tendon, ligament & joint capsule – Bone structure • Sets limits on joint ROM
What factors influence flexibility?
- Age
– Gender
– Physical activity & lifestyle
– Environmental conditions
Flexibility - Age
• Decreases as childhood progresses to early
adolescence
• Increases slightly at late adolescence
• Decreases throughout adulthood
Flexibility - Gender
- Women are more flexible than men at all ages
– Less prominent bony landmarks
– Less muscle bulk
– Less connective tissue around joints
what is the value of flexibility
– Increase ROM in a ballistic movement – More aesthetic positions can be adopted – Prevention of injury?
Exceptions of flexibility in sport
High contact sport • Strong joint capsules around ankles, knees & shoulders are essential – These joints should not be ultra flexible like those of swimmers & gymnasts
what is important in swimming for flexibility
– Arm F-E necessary in Fly, Fr & Ba but not Br
– Foot D-P flexion necessary in Fly, Fr & Ba
– Thigh lat rot and thigh flex for Br
– exception - girl Ba too high arm flex - adduct
what is important in gymnastics for flexibility
– Arm F-E is important
– Thigh F-E necessary
– Thigh abduction is important
– Foot plantar flexion
what is important in diving for flexibility
– Trunk F-E is important – Trunk rotation – Foot plantar flexion – Above average arm F-E • But not as great as gymnasts
what is important in running for flexibility
– Thigh F-E is important to maximise stride
length
What are the 3 main
characteristics of
muscle?
• Creates movement - Contractile component
– Shortens when developing tension
• Can stretch - Extensibility
– Being able to stretch a muscle beyond its normal
resting length
• Will return to original shape - Elasticity
– Ability to return to its normal length after being
stretched
skeletal muslce
• Connected to bones via tendons • Contraction is voluntary – You must think about the movement for it to happen • Muscle shorten during contraction • Only pull – they do not push
Neuromuscular function
• Info is sent via an electrical impulse
• Nerves act in a similar manner as an electric cable
• When neural messages are sent to the muscle from the CNS they travel along motor neurons
• Information is sent back via sensory neurons
• Information sent from the brain
• Down the spinal cord
• To the target muscle
• For muscle contraction &
movement to occur
what are the two types of stretching
- viscous
- elastic
elastic strecthing
- spring like behaviour
- strain immediate when stressed is applied
temporary or recoverable enlongation - energy stored during loading is returned
stretching techniques
– Static stretching
– Ballistic stretching
– Proprioceptive neuromuscular facilitation
(PNF)
neural pathways
- Information sent from the brain
- Down the spinal cord
- To the target muscle
- Movement occurs
- But how long does this take?
Spinal Reflexes
• Protect the body from harm
• Does not require input from the brain for skeletal muscle to contract
- Reciprocal Inhibition
• Muscle spindles & Golgi Tendon Organs (GTO)
– The stretch (myotatic) reflex
– The inverse stretch (myotatic) reflex
Reciprocal Inhibition
• Tendency for the antagonist to relax while the agonist
contract
• Mediated by spinal reflex but the higher centre has a modifying influence
Stretch reflex
- In response to a rapid stretch
- The muscle contracts
- Regulating muscle length
- Protecting the muscle from damage
Inverse stretch reflex
• Involuntary muscle relaxation triggered by the GTO • Slow contraction or stretch on the tendon exceeds a critical level • The reflex action inhibits muscle contraction • Reducing tension
Static Stretching
- Passive or active
- A slow steady movement where the muscles are gradually placed on stretch
- Then held for 30 s
- Relax
- Repeat after 60 s
- Uses the autogenic inhibition
what is active streching
• Active stretching requires the
athlete to provide the force for
the stretch
what is passive stretching
• Passive stretching requires the athlete to relax while a partner provides the force for the stretch (externally)
Ballistic Stretching
- Ballistic involves rapid muscle actions
• Invokes the stretch reflex that does not allow the involved muscle to relax
• Ballistic movements take place during competition so the athlete needs to be prepared
• Athletes are thoroughly warmed up before performing ballistic stretching
PNF
• A stretch is applied slowly to a muscle group
• The limb is resisted as that muscle is contracted
for approximately 6 sec,
• The athlete is then able to move the limb to new
position
• Steps 2 & 3 are repeated twice more
• Note: It is imperative that the partner does not
force the limb during the stretch phase
