matric finals sport science summary notes (IEB)

ANATOMY AND PHYSIOLOGY

JOINT FLEXIBILITY (JF)



 Less flexibility as you age
 No movement = no synovial fluid produced (released when movement happens) = stiff joints
 Bad posture = reduced mobility
 JF = ROM in each plane of motion of each joint
 Goniometer




 3 planes:
o Sagittal = longitude plane. Divides body into right and left
o Frontal plane = cornel plane. Divides body into back and front
o Transversal plane. Divides body into top and bottom




 Types of flexibility
o Static flexibility – otherwise known as passive ROM. Body segment is passively moved by a
partner (muscles are stretching and being moved without the person doing the work)
o Dynamic flexibility – achieved by actively moving a body part using a muscular contraction
(person is doing all the work)
 Flexibility is joint specific, not all joints are equally flexible)
 Factors that influence joint flexibility
o Shape of bone surface (i.e., Flat bones, carpals tarsals don’t allow for a lot of rotation
o Amount of muscle present
o Amount of fatty tissue present A lot of fat or muscle will limit movement
 Bilateral asymmetry – less ROM for the dominant arm (tennis) due to larger muscles = more
restriction
 Low flexibility, too much flexibility, or imbalance = higher risk of injury

, Limited flexibility = collagenous tissue and muscles crossing the joint are tight and have a higher
chance of tearing or rupturing.
 Flexion/extension/lateral bending/ rotation/ adduction/allocation = all differ based on the joint being
observed.

,GOLGI TENDONS AND MUSCLE SPINDLES



Specialized proprioceptors (GOT/muscle spindle apparatus) = awareness of pain/pressure/joint angles/muscle
tension and speed of actions.

Proprioception – ability to sense stimuli arising in body regarding position motion and equilibrium (where your
limbs are orientated in space)

GOLGI TENDONS: (SENSES TENSION)

 Belongs to the nervous system to influence movement. Works with muscle spindles to regulate
muscle stiffness.
 When stimulated it causes associated muscle to relax by interrupting its contraction
 When a muscle is inhibited by a GTO it is called autogenic inhibition.
 Its function is opposite to muscle spindle (produces muscle contraction)
 Also known as an organ proprioceptor sensing tension
 Found in small capsules through which a small bundle of tendon fibers run through and lie close to
where the tendon attaches to a muscle fiber
 5-25 muscle fibers connected with each Golgi tendon organ
 Contraction causes tension sends msg to CNS Golgi tendon sends feedback to CNS about the
amount of force the muscle is producing  too much force being produced = CNS sends a msg to stop
the contraction (reducing the force)
 Golgi tendon reflex = the quiver of muscles while doing heavy lifting. Due to the monitoring of the
neuromuscular overload to protect from muscles tearing.




MUSCLE SPINDLES: (INTERFUSIAL MUSCLE FIBERS)

 Detect changes in length of muscle and assist in regulating contractions by activation motor neurons.
 Structure – small sensory organs, elongated, consist of several modified muscle fibers enclosed in
connective tissue

,  2 sensory endings; 1: primary (respond to speed and size of muscle length change. 2: secondary
(respond to amount of stretch). Endings located in the middle of spindle
 Also known as intrafusal muscle fibers rather than extrafusal (normal) muscle tissue.
 Detect change in muscle length (stretch and speed of stretch)
 Response includes – activation of stretch and relax as well as reciprocal inhibition (inhibition of
tension development in the agonist muscle)
 The stretch and lighting pulls on spindle loses its spiral shape and so it stretchessignals muscle to
contract (spiral regains its spiral shape to protect from over stretching) = stretch relax process.
 When muscles contract muscle spindles come closer together stimulating the sensory and afferent
nerves which then passes on electrical impulses to CNS this allows NS to know abt changes in joint
angles and muscle length. Can stop muscle from lengthening or stretching too fast.
 Two things associated when muscle is rapidly stretched
o Muscles is told to contract to prevent it from stretching too far too quickly
o Can inhibit the opposing muscle (antagonist) to prevent contraction while agonist is relaxed
at the same time = reciprocal inhibition
 Importance
o Sending info to CNS abt muscle length
o Protect muscle from injury
o For coordinated movement
 Stretch protection - Reciprocal inhibition = reflective antagonism: muscles on one side of a joint
relaxes while the other contracts to prevent it working against the opposite muscle(group) making it
easier for the primary muscle to contract.
o Two stages
 Dynamic – initial reaction lasting only a few milliseconds, preventing injury
 Static – duration of stretch
o Steach 7secs = inc in muscle tension, activating GTO = temporary inhibition muscle spindle
activity = more stretch allowed.
 Signal to stop stretch (to fast or intense) = myotatic reflex. Maintaining the constant length of muscle.



TABLE SUMMARY OF GTO AND MUSCLE SPINDLES

Characteristic Golgi tendon organ Muscle spindle
Location In tendons when muscle (joins) Interspread among muscle fibers
bone
Stimulus Inc in muscle tension Inc in muscle length and the
speed of the stretch
Response 1) Inhibits tension in 1) Inhibits tension in
stretched muscle antagonist muscle
2) Initiates tension in 2) Initiates rapid, reflex
antagonist muscle contraction of stretched
muscle
Overall effect Promotes relaxation in a muscle Inhibits stretch in a muscle being
developing tension stretched



Stretch reflex/ myotic reflex Reciprocal inhibition
Stimulus Initiated by muscle spindle Initiated by muscle spindle activity
stretching