Kinesiology Ch.2
proprioceptors
internal receptors located in skin, joints, muscles, and tendons that provide feedback relative to tension, length, and contraction state of muscle, position of body and limbs, and movements of joints
muscle shape (length)
longer muscles can shorten through greater range more effective in moving joints through larger ROM
what fibers produce greater ROM than similar sized muscles with pennate arrangement?
parallel
extrinsic
pertaining usually to muscles that arise or originate outside of (proximal to) body part upon which they act
intrinsic
pertaining usually to muscles within or belonging solely to body part upon which they act
muscle size (diameter)
plays role in muscle's ability to exert force increased diameter = increased force extension
what does the muscle tend to do as it contacts?
pull both ends towards the gaster
active insufficiency
reached when muscle becomes shortened to the point that it can not generate or maintain active tension (cannot shorten any farther)
passive insufficiency
reached when opposing muscle becomes stretched to point where it can no longer lengthen and allow movement
location nomenclature
rectus femoris
unipennate fibers
run obliquely from tendon on one side only
bipennate fibers
run obliquely on both sides from central tendon
innervation
segment of nervous system that provides stimulus to muscle fibers
shape and location nomenclature
serratus anterior
action
specific movement of joint resulting from concentric contraction of muscle that crosses joint
proprioception
subconscious mechanism where body is able to regulate posture and movement by responding to stimuli originating in proprioceptors of the joints, tendons, muscles, and inner ear
what's happening at the contralateral leg while kicking a ball? (muscle roles)
synergists in hip (flex/ext/ab/add/rot) and pelvic area help stabilize the pelvis on that side to provide a relatively stable base for the hip flexors on the involved side to contract against
types of pennate fibers
unipennate bipennate multipennate
example of neutralizers during supination
when only supination action of biceps brachii is desired, the triceps brachii contracts to neutralize the flexion action of biceps brachii
2 types of isotonic contraction
concentric (shortening) eccentric (lengthening)
kinesthesis
conscious awareness of position and movement of the body in space
stabilizers (fixators)
contract to fixate/stabilize area to enable another limb or body segment to exert force and move
neutralizers
contract to resist/counteract/neutralize another muscle to prevent undesirable movements
points of attachment nomenclature
coracobrachialis (origin: coracoid process of scapula) (insertion: middle 1/3 of medial humerus)
dermatome
defined area of skin supplied by a specific spinal nerve
shape nomenclature
deltoid rhomboid
action nomenclature
erector spinae supinator pronator teres extensor digiti minimi
action and attachment nomenclature
extensor digitorum longus extensor hallucis longus
fiber direction nomenclature
external obliques
parallel fibers
fibers arranged parallel to length of muscle
tendon
fibrous connective tissue (cordlike) that connects muscles to bones and other structures
types of parallel fibers
flat fusiform strap
depth nomenclature
flexor digitorum superficialis (superficial) flexor digitorum profundus (deep)
size nomenclature
gluteus maximus gluteus minimus
multipennate fibers
have several tendons with fibers running diagonally between them
concentric contraction
-muscle develops active tension as it shortens -results in joint angle changing in direction of applied muscle force -accelerate movement or causes movement against gravity or external forces -total muscle length decreases under tension F is greater than R
isotonic contaction (dynamic)
-muscle develops active tension to either cause or control joint movement -varying degrees of muscle tension result in joint angles changing
eccentric contraction
-muscle lengthens under active tension -decelerates movement and controls body part to allow movement with gravity or external forces -total muscle length increases under tension R is greater than F
proprioceptors in muscles
-muscle spindle -Golgi tendon organs
proprioceptors in joints and skin
-Meissner's corpuscles -Ruffini's corpuscles -Pacinian corpuscles
isometric contraction (static)
-active muscle tension is developed but joint angle stay constant -often used to prevent movement in body segment -total muscle length stays the same under tension R = F
example of active and passive insufficiency while rectus femurs contracts concentrically to both flex hip and extend knee
-can completely perform either action one at a time but actively insufficient to obtain full ROM at both joints simultaneously -hamstrings can not stretch enough to allow both maximal hip flexion and maximal knee extension due to passive insufficiency
motor neurons (efferent)
-carry impulses from CNS to outlying body regions -innervated muscle fiber receives stimulus --> muscle contracts --> movement occurs
insertion
-distal attachment or part that attaches farthest from midline or center of body -most moveable part
synergist
-guiding muscles -work together to assist in refined action of agonists
antagonist muscles
-located on opposite side of joint from agonist and has opposite concentric action -reciprocal inhibition (to work in cooperation with agonist)
strap parallel fibers
-more uniform in diameter -long parallel manner -allows power to be focused onto small and bony targets
neural control of movement
-muscle contraction results from stimulation by the nervous system -single nerve cell (neuron) consists of cell body and projections (axons and dendrites) to carry impulses
2 types of fiber arrangement
-parallel -pennate
origin
-proximal attachment of muscle or part that attaches closest to midline -least movable part or attachment of muscle
examples of using sensory input for motor response
-see ball coming, catch it -feel a bug land on your arm, swat it away -feel like we are getting off balance, adjust -bottom getting sore, reposition/walk around
fusiform parallel fibers
-spindle shaped -central belly tapers to tendons on each end -allows them to focus their power onto small and bony targets
flat parallel fibers
-thin and broad -originating from broad, fibrous, sheet-like aponeuroses -allows force to be spread over broad area
sensory neurons (afferent)
-transmit impulses from receptors in the skin, joints, muscles, and other peripheral aspects of body to CNS -neuron may terminate in spinal cord or brain
action and size nomenclature
adductor brevis/longus/magnus
what are the agonist and antagonist muscles during elbow flexion?
agonist: biceps antagonist: triceps
what are the agonist and antagonist muscles during knee flexion?
agonist: hamstrings antagonist: quadriceps
example of muscle roles in kicking a ball (agonist, antagonist, synergists)
agonist: hip flexors and knee extensors (concentric) antagonist: hip extensors and knee flexors (relax) synergists: muscles that guide/refine the movement
what happens to the antagonist when the agonist contracts?
antagonist relaxes to lengthen allowing motion
pennate fibers
arranged obliquely to their tendons (like a feather) which increases cross sectional muscle area then increases power
number of divisions nomenclature
biceps brachii triceps brachii
what fibers produce the strongest contraction?
bipennate and unipennate fibers
agonist muscles
cause joint motion through a specified plane of motion when contracting concentrically
gaster (belly or body)
central, contractile portion of muscle that generally increases in diameter as muscle contracts
myotome
muscle or group of muscles supplied by a specific spinal nerve
what are the stabilizers during bicep curls?
muscles of scapula and glenohumeral joint (stabilizes shoulder and humerus so biceps can effectively do curls)