KinesiologyQuiz1Weeks1-3 Flashcards
Kinematics
branch of mechanics that describes the motion of a body, without regard to the forces or torque that may produce the motion
Translation vs. Rotation
Translation: linear motion in which all parts of a rigid body move parallel to and in the same direction as every other part of the body Rotation: motion in which an assumed rigid body moves in a circular path around some pivot point (axis of rotation)
Motion of the body during walking
center of mass of the human body (just anterior to the sacrum) moves in a curvilinear manner
Active vs. Passive movements
Active: caused by stimulated muscles Passive: caused by sources other than active muscle contraction i.e. gravity, tension in connective tissue, etc.
Osteokinematics
motion of bones relative to the three principal planes of the body: sagittal, frontal, and horizontal
Sagittal Plane
flexion and extension; dorsiflexion and plantar flexion; forward and backward bending
Frontal Plane
abduction and adduction; lateral flexion; ulnar and radial deviation; eversion and inversion
Horizontal Plane
internal (medial) and external (lateral) rotation; axial rotation
Axis of Rotation
bones rotate around a joint in a plane that is perpendicular to the axis of rotation, axis of rotation will shift throughout movement (imperfect sphere)
Medial-lateral (ML) axis of rotation (shoulder)
flexion and extension
Anterior-posterior (AP) axis of rotation (shoulder)
abduction and adduction
Vertical axis of rotation (shoulder)
internal and external rotation
Degrees of Freedom
number of independent movements allowed at a joint; up to 3 degrees of angular freedom at a joint (3 dimensions of space)
Accessory movements
slight passive translations that occur in most joints defined in 3 linear directions
Two perspectives of joint movement
1) proximal segment can rotate against the relatively fixed distal segment; 2) distal segment can rotate against a relatively fixed proximal segment; (knee flexion only describes relative motion)
Kinematic Chain
Open: distal segment of a kinematic chain is not fixed to the earth or other immovable object; Closed: distal segment is fixed to the earth or other immovable object; (used to describe relative segment kinematics)
Arthrokinematics
describes the motion that occurs between the articular surfaces of a joint, most surfaces are curved (convex and concave)
Fundamental movements between joint surfaces
Roll: multiple points contact multiple points; Slide: single point contacts multiple points; Spin: single point contacts single point
Convex-on-concave movement
roll and slide occur in opposite directions (abduction of shoulder)
Concave-on-convex movement
roll and slide occur in same direction (tibial-on-femoral knee extension)
Example of spin movement
radius of forearm on capitulum of humerus during pronation; internal and external rotation of the 90-degree abducted glenohumeral joint; flexion and extension of the hip
Close-packed position
position of joint’s maximal congruency, accessory motions are minimal (usually near the end range, knee’s is full extension)
Open (Loose)-packed position
all positions other than a joint’s close-packed position, accessory movements are maximal (typically at mid-range, biased toward flexion)
Kinetics
branch of mechanics that describes the effect of forces on the body
Force
a push or pull that can produce, stop, or modify movement (force is 0 when acceleration is 0 and vice versa)
Most common musculoskeletal forces
tension, compression, bending, shear, torsion, combo loading
Stress-strain curve
Small tension: collagen fibers within tissue must be drawn taut for tension to be measured; Elastic zone: initial nonlinear and subsequent linear region of the curve, tissue can return to original length if healthy; Yield point: tissue elongated beyond its physiologic range; Plasticity: behavior of an overstretched or over-compressed tissue, microscopic failure has occurred and tissue is permanently deformed ; Initial failure: tissue begins to lose ability to hold tension; Mechanical failure: tissue separates partially or completely and loses all ability to hold tension
Time load of application for stress-strain curve
Viscoelasticity: factor of time, causing curve to change; Creep: progress strain of a material when exposed to constant stress over a period of time
Internal vs. External forces
Internal: produced from structures located within the body and may be passive (gravity, tension in connective tissue) or active (muscles); External: produced by forces acting outside the body
Line of Force or Line of Gravity
direction of a muscle force and the direction of gravity
Angle of Insertion
angle formed between a tendon of a muscle and the long axis of the bone to which it inserts (changes depending on the bone’s spatial orientation)
Joint Reaction Force
force through the center of a joint, produced between the surfaces of the joint
Center of Mass
gravity always acts on this portion of the body segment
Static Linear Equilibrium
all forces equal, no movement occurs
Two outcomes of forces exerted on the body
potentially translate a body segment; if applied at some distance perpendicular to the axis of rotation, can produce a potential rotation at the joint
Moment Arm
perpendicular distance between the axis of rotation of the joint and the force
Torque
product of force and its moment arm (rotary equivalent to force)
Static Rotary Equilibrium
internal torque = external torque; internal moment = external moment; No rotation, isometric status
Types of Muscle Activation
Isometric: muscle is producing a pulling force while maintaining a constant length; Concentric: muscle produces a pulling force as it contracts (shortens), internal torque > external torque; Eccentric: muscle produces a pulling force as it is being elongated by another more dominant force, external torque > internal torque
Muscle Action at a Joint
potential to cause a torque in a particular rotation direction and plane; can occur distal-on-proximal or opposite, depending on stability; ex. posterior deltoid at glenohumeral joint adduction in frontal plane, external rotation in horizontal plane, or extension in sagittal plane
Agonist vs. Antagonist
agonist: most directly related to the initiation and execution of a particular movement, ex. biceps flexion at elbow; antagonist: opposite action of a particular agonist, ex. triceps to biceps
Synergists
cooperate during execution of a particular movement, ex. glutes and hamstrings; injury to one muscle will affect the other
Force-Couple
two or more muscles simultaneously produce forces in different linear directions, although the resultant torques act in the same rotary direction, ex. hip flexors and back extensors
Musculoskeletal Levers
First Class: axis of rotation between the opposing forces, ex. head and neck extensor muscles that control the posture of the head; Second Class: axis of rotation is located at the end of a bone, muscle (internal force) possesses greater leverage than the external force, very rare in the body, ex. calf muscles producing torque to stand on toes; Third Class: axis of rotation located at the end of a bone, external force is greater than internal force, most common, ex. biceps during elbow flexion
Mechanical Advantage
ratio of the internal moment arm to the external moment arm; MA>1 - able to balance the torque equilibrium equation by an internal force that is less than external force; MA<1 - requires greater force (most of the musculoskeletal system)
Three Classifications of Joints
Synarthrosis (fibrous): dense connective tissue, no movement, ex. sutures of skull; Ampiarthrosis (cartilaginous): hyaline or fibrocartilage, restrained movement and shock absorption, ex. intervertebral discs, SC joint; Diarthrosis (synovial joint): synovial fluid and capsular, ex. glenohumeral, IP
Composition of Diarthrodial (Synovial) Joint
synovial fluid; articular cartilage; articular capsule; synovial membrane/bursa; capsular ligaments; blood vessels; sensory nerves; may also include labrum, fat pads, plica, menisci or discs
Hinge Joint
flexion and extension; ex. humero-ulnar, interphalangeal
Pivot Joint
spinning of one member around a single axis of rotation; ex. humeroradial, atlanto-axial
Ellipsoid Joint
biplanar motion (flexion-extension and abduction-adduction); ex. radiocarpal
Ball-and-Socket Joint
triplanar motion (flexion-extension, abduction-adduction, and internal-external rotation); ex. glenohumeral, coxofemoral (hip)
Plane Joint
typical movements include slide (translation) or combined slide and rotation; ex. carpometacarpal (digits II-IV), intercarpal, intertarsal
Saddle Joint
biplanar motion; spin may be limited by interlocking nature of joint; ex. carpometacarpal of thumb, SC
Condyloid Joint
biplanar motion; either flexion-extension and abduction-adduction or flexion-extension and axial rotation (internal-external rotation); ex. metacarpophalangeal, tibiofemoral
Four Primary Types of Tissue in the Body
connective tissue; muscle; nerve; epithelium
Connective Tissue Components
dense irregular connective tissue (tendons, fascia); articular cartilage; fibrocartilage (intervertebral discs); bone; loose connective tissue (fat); blood; *predominate in joints
Connective Tissue Biologic Materials
fibers: Type I and II collagen and elastin; ground substance: glycosaminoglycans; cells: maintenance and repair
Fibrous Proteins
Type I collagen: stiff structure for tendon, capsule, ligament (transmit force to bone); Type II collagen: thinner than Type I, framework for maintaining structure and general shape, form structure of hyaline cartilage; Elastin: elastic quality in ligaments to “give” when elongated
Ground Substance
glycosaminoglycan (GAG); water, solutes, play role in shock absorption/force distribution in articular cartilage
Dense Irregular Connective Tissue
found in the fibrous external layer of the articular capsule and ligaments, tendons; high proportion of type I collagen fibers; resist natural stresses on tissue, stiff structure, transmit force; function most effectively when stretched parallel to long axis
Articular Cartilage
specialized hyaline cartilage; forms load-bearing surface of joints; avascular and aneural; chondrocytes located within ground substance of different layers are nourished by nutrients within the synovial fluid (“milking” during joint loading)
Articular Cartilage Function
collagen fiber arrangement provides structural stability and weight-bearing capacity; distributes and disperses compressive forces to the subchondral bone; reduces friction between joint surfaces; significant damage to adult articular cartilage is often repaired poorly or not at all
Fibrocartilage
intervertebral discs, labrum, discs in pubic symphysis; shares properties of both dense connective tissue and articular cartilage; nourishment dependent on diffusion of nutrients through the synovial fluid (“milking”); direct blood supply penetrates outer rim where they attach to ligaments (spine) or joint capsules (knee); some repair can occur near vascularized periphery (outer 1/3 of knee menisci)
Bone
function: rigid support and equip the body with a system of levers on which muscle can act; outer cortex is thick, compact cortical bone; cancellous, spongy bone surrounded by compact bone; calcium phosphate allows bone to accept compressive forces; periosteum and endosteum are richly vascularized and innervated with sensory receptors for pressure and pain
Osteon
aka Haversian system; structural subunit of cortical bone
Bone Reaction to Stress
greatest strength - compressed along the long axis of shaft (Sierra!); stress to end of long bone - articular cartilage accepts force, directs to subchondral bone and then cancellous bone, then to long axis of cortical bone; remodeling constantly due to SAID and hormonal influences on systemic calcium balance
Aging and Bone
decreased GAG replacement and repair (decreased water binding, force distribution, ability to resist force, tolerance to compressive force); microtrauma accumulates to cause mechanical and structural failure; altered metabolism of bone leads to slower healing rate of fractures and osteoporosis
Effects of Immobilization
alters structure based on decreased external forces so less mechanical strength (SAID); resultant decreases in tensile strength las weeks after immobilization; often necessary but needs to be balance between the negative effects and what is needed to promote healing
Joint Injuries
acute vs. chronic; chronic: capsular/ligamentous injury may have instability concern; recurrent instability: may cause abnormal loading conditions; cartilage injury: loss of GAGs and lowered resistance to compressive and shear forces, can improperly dissipate forces, progression of injury reduces shock absorption
Stabilization vs. Movement
stable posture: balance of forces; movement: forces unbalanced (muscular control necessary for all stability and movement)
Muscle Fiber Composition
combination of collagen and elastin for strength, structural support, & elasticity to the muscle
Epimysium
surrounds muscle belly, tight collagen
Perimysium
surrounds fascicles (conduit), tight collagen
Endomysium
surrounds individual muscle fibers external to sarcolemma, metabolic exchange between it and muscle fibers
Pennate Muscle
fibers that approach tendon obliquely, generate relatively large forces, may be uni-, bi-, or multi-, ex. Latissimus
Fusiform Muscle
fibers running parallel to one another and to the tendon, ex. Biceps brachii
Physiologic Cross-Sectional Area
amount of contractile protein available to generate force
Maximal Force Potential
sum of the cross-sectional area of all the fibers (thicker muscle = greater force potential)
Pennation Angle
angle between the muscle fibers and central tendon; angle 0 is mostly parallel to tendon
Pennate Muscle Force
pennation angle of 0 all force is transferred to tendon, at 30 degrees 86% makes it to tendon but pennation allows for more fibers & larger physiologic cross-sectional area so large force generating capacity
Connective Tissue Functions in Muscle
gross structure; conduit for blood and nerves; passive tension regain shape after stretch; conveys contractile force to tendon and joint
Passive-Length Tension Curve
connective tissues generate resistive forces (tension) when elongated; stiffens when stretched to max and transfers forces; stabilization potential (loss of active force-generating ability)
Active-Length Tension Curve
amount of force muscle can generate is dependent on length of muscle fiber; ideal resting length of sarcomere allows greatest number of cross-bridges (usually mid-range, ex. biceps)
Myofibrils
forms muscle fiber; made of myofilaments: actin and myosin; web connection to endomysium (force distribution)
Myosin
A-Band or “H-Band”; dark and thick filament, contains cross bridges
Actin
I-Band; thin filament, overlaps myosin
Z-Disc
anchor of thin filaments, force generator Z-disc to Z-disc
H-Zone
no overlap of actin and myosin (aka M-line, thick mid region of myosin)
Sliding Filament Hypothesis
actin sliding on myosin; filaments do not shorten; narrowing H-Band
Active Insufficiency
inability to complete full motion across two joints (biceps)
Passive Insufficiency
inability of the two joint muscle to lengthen maximally across both joints (hamstrings)
Total-Length Tension Curve
passive and active together; as muscle fiber is further stretched, passive tension dominates curve (lengthened and weak)
Isometric Contraction
active process by which muscle produces force without change in length; internal moment arm shortens and less force is produced (movement stops); muscle produces most force isometrically than any speed of shortening (maximum number of attached crossbridges)
Maximal-Effort Torque-Angle Curve
shape is specific to each muscle group; function of active length tension + angle of insertion
Force-Velocity Relationship
rate of change of muscle length is related to muscle’s maximal force potential; for concentric activation, load is inversely proportional to velocity; for eccentric, load is directly proportional to contraction velocity
Eccentric Contraction Force
greater average force per crossbridge; more rapid reattachment; passive tension within muscle fibers; greater DOMS (metabolic cost)
Alpha Motor Neuron
muscle is excited by these, cell bodies located in the ventral horn of the spinal cord
Motor Unit
alpha motor neuron and all muscle fibers innervated by it
Recruitment
initial activation of motor neurons that causes excitation and activation of associated muscle fibers; muscle twitch; smaller neurons recruited before larger; more neurons = more muscle fibers activated = more force
Slow Oxidative (SO) Motor Unit
small motor neurons twitch responses long in duration and small amplitude, fatigue resistant, early excitation, “postural muscles” have high levels
Fast Oxidative Glycolytic (FOG) Motor Unit
intermediate motor unit between slow and fast, fast fatigue-resistant
Fast Glycolytic (FG) Motor Unit
large motor neurons have twitch responses brief in duration and high amplitude, fatigue easily, later excitation
Rate Coding
muscle force is modulated by increase in rate of excitation of motor neuron to regulate force
Tetanization
unfused tetanus: generation of a series of mechanical twitches; fused tetanus (tetanization): interval shortens, greater force generated until successive twitches fuse into a single, stable muscle force
Muscle Fatigue
even if rate of activation remains the same, force generated decreases due to: metabolic processes; failure of physiologic mechanisms of neuromuscular system; nuero response is increase rate coding or recruitment in assistive motor units
Electromyography (EMG)
recording of amplified AP through special electrodes; relative timing and relative level of neural drive; magnitude can indicate force; urface electrodes or fine wire electrodes
Newton’s Laws of Motion
framework for advanced analysis; relationship between forces applied to body and consequences on human motion; injuries; linear (translational) and angular (rotational)
Law of Inertia
body remains at rest or constant linear velocity unless acted upon by an external force to start/stop/alter its state (also applies to rotation); static equilibrium (not moving); dynamic equilibrium (velocity is not 0, but constant); inertia (to alter velocity); center of mass (center of gravity); mass moment of inertia (distribution of mass related to axis of rotation)
Law of Acceleration
force (torque)-acceleration relationship: if sum of forces acting on body is 0, acceleration is 0 so linear equilibrium; if net force produces acceleration, body will travel in direction of resultant force (torque produces angular acceleration proportional to and in direction of the torque, inversely proportional to the moment of inertia of the body)
Impulse-Momentum Relationship
average force and its acceleration time; used in design of footwear and bike helmets (increase time of impact to decrease force)
Work-Energy Relationship
W=F x d; no movement, no work; power is rate of work
Law of Action-Reaction
for every action there is an equal and opposite reaction; ground reaction force
Anthropometry
physical design features such as length, mass, volume, density, etc.; analysis of movement requires these measurements; factors muscle must overcome to generate movement
Free Body Diagram
all relevant forces acting on a system; forces produced by muscle, gravity, fluid, air resistance, friction, ground reaction forces
Joint Reaction Force
one joint pushes back against another with equal and opposite force; caused primarily by activation of muscle but also tension in stretched ligaments and gravity (BW)
Relative vs. Global
relative: one limb segment with respect to adjacent segment
Polygon Method
coplanar but not collinear (bowstringing force)
Changing Angle of a Joint
position of limb affects magnitude vector resolution forces (angle of insertion); greatest external torque applied against a joint occurs when resultant external force vector intersects the segment at a right angle (seated knee extension)
Methods of Analysis
static analysis: system in equilibrium, basic approach dynamic: linear or angular accelerations result from unbalanced sources, need anthropometrics and kinematic data (electrogoniometer)
Osteologic Features of Sternum
jugular notch; manubrium; clavicular facets (articulate with clavicles); costal facets (bilateral attachment sites for first 2 ribs); body; xiphoid process
Clavicle Degrees of Deviation
20 degrees posterior to the frontal plane
Scapula Degrees of Deviation
scapular plane deviated about 35 degrees anterior to the frontal plane
Osteologic Feature of the Clavicle
shaft (anterior surface medially convex and laterally concave); sternal end (medial, articulate with sternum); costal facet (rests against 1st rib); costal tuberosity (costoclavicular ligament); acromial end (lateral); acromial facet (articulates with acromion); conoid tubercle (conoid ligament); trapezoid line (trapezoid ligament)
Osteologic Features of the Scapula
angles: superior, inferior, lateral; medial or vertebral border (anterior: serratus anterior; posterior: levator scapulae, rhomboids); lateral or axillary border (teres major and minor) superior border; supraspinatous fossa; infraspinatous fossa; spine (superior: lower and middle trap, inferior: posterior delt); root of the spine (rhomboid minor); acromion (anterior: middle and anterior delt; posterior: posterior delt); clavicular facet (acromioclavicular joint); glenoid fossa (glenohumeral joint articulates with humerus); supraglenoid tubercle (long head biceps); infraglenoid tubercle (long head triceps); coracoid process (ligaments: conoid, trapezoid, coracohumeral, coracoacromial; muscles: pectoralis minor,; short head biceps, coracobrachialis); subscapular fossa
Osteologic Features of the Proximal-to-Mid Humerus
head of the humerus; anatomic neck (separates smooth, articular head and shaft); lesser tubercle (superior: subscapularis; inferior: teres major); greater tubercle (pectoralis major, others attached on facets); upper (supraspinatous), middle (infraspinatous), and lower (teres minor) facets on greater tubercle; intertubercular or bicipital groove (long head of biceps and latissimus dorsi on the floor); deltoid tuberosity (deltoid); radial (spiral) groove (separates lateral and medial triceps with the radial nerve through groove)
Humeral Head Degrees of Deviation
approx. 135 degree angle of inclination with the long axis of the humeral shaft; humeral head also rotated posteriorly (retroversion) about 30 degrees relative to medial-lateral axis of elbow (in order to line up with scapular plane)
Four Joints within the Shoulder Complex
sternoclavicular (SC); acromioclavicular (AC); scapulothoracic (ST); glenohumeral (GH); movement describes combined motion at GH and ST
Movements of Scapulothoracic Joint
elevation and depression; protraction (external rotation, abduction) and retraction (internal rotation, adduction); upward and downward rotation (raising and lowering arm)
Sternoclavicular (SC) Joint
medial end of clavicle, clavicular facet of sternum, superior border of cartilage of first rib; “saddle” joint; moves with scapular abduction, elevation, superior rotation; difficult to injure but could be life-threatening (carotid)
SC Joint Connective Tissue
tremendous stability!; anterior and posterior sternoclavicular ligaments; interclavicular and costoclavicular ligaments; articular disc; muscular attachments
SC Joint Osteokinematics
three degrees of freedom; essentially all movement in shoulder involves at least some movement of the clavicle about the SC joint; elevation and depression; protraction and retraction; axial rotation of the clavicle
SC Joint Arthrokinematics
elevation and depression: frontal plane, convex clavicle moving on concave sternum (clavicle roll superior and slide inferior during elevation); protraction and retraction: horizontal plane, concave clavicle moving on convex sternum (clavicle roll posterior and slide posterior during retraction); longitudinal rotation: spin/posterior rotation during flexion or abduction (occurs at about 90 degrees to accommodate head of humerus at AC joint)
Acromioclavicular (AC) Joint
lateral end of clavicle and acromion of scapula; articular disc; flat joint surfaces, roll-and-slide arthrokinematics not described
AC Joint Connective Tissue
superior and inferior AC joint capsular ligaments; deltoid and upper trapezius; coracoclavicular ligaments; conoid (medial); trapezoid (lateral); fibrocartilage disc; (coracoacromial ligament has no purpose)
AC Joint Osteokinematics
permits subtle and slight movements of scapula; three degrees of freedom 1. upward and downward rotation 2. horizontal plane rotational adjustments 3. sagittal plane rotational adjustments
Scapulothoracic Joint
not true joint; point of contact between anterior surface of scapula and posterior-lateral wall of thorax; range of motion in shoulder is due in part to motion at ST joint; cooperation between SC and AC joints
