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Chapter

biomechanic noteT1.docx


Department
Kinesiology
Course Code
Kinesiology 2241A/B
Professor
bob

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Chapter 1: study and analysis of human movement
sports; animals, work
Biomechanics; mechanics (static/dynamic; kinematics)structure and function of living
Best for old and young; info on bones, joints muscles determine right movements
Anthropometrics: stats of person; A. gender, age, body type or B. athletic participation area
Quantitive; measure & count *Qualitative
objective
hard due to instruments and film
hypotheses, recognize critical skills, subjective
rejected/confirmed based on quan.
Coaching; videos; visual feedback
Efficient: max work, min energy; marathon, factory workers; aerobic
*Effectiveness: best movement for performance objective; angles point of release; energy not taken important
100 run more efficient by slow runner, but less effective than fast runner
max (fast sprint but not efficient), min (energy conserve, but not effective), optimize rate of energy expenditure
effective movement is optimally efficient, but not vice versa
Module A: Skeletal system and its articulations
Skeletal system; osteology
1. protect vital organs
2. support soft tissue
3. make RBC
4. reservoir for minerals (calcium, phosphates)
5. attach skeletal muscles
6. machine to receive muscle torques and movement
axial skeleton(4): skull (29), thorax (25 sternum;3), pelvis (26), vertebral column; cervical (7), thoracic spine
(12), lumbar spine (5), sacrum (5 into 1), coccyx (4)
appendicular skeleton: upper(32) shoulder girdle complex to fingertips and lower extremities(31) pelvic girdle to
toes
only talus (weight) and calcaneus (big heal) tarsals contribute to sports; no other carpals/tarsals
Classification
wolff’s law: shape determines function; conversely function alters shapeexercise good for bone tissue
a) long bones; lever, strong; away from trunk is distal; upper body is lighter for grabbing
b) small bones; elasticity, movement, shock absorb, flex
c) flat; protection and muscular attachment
d) irregular; vertebrae; protect and shock absorption
nature and nurture (nutrition)how injury prone (composition
and structure)
cortex outside and inside; peri and endo respectively
epi, epiphyseal plate, meta dia
dia epiphyseal plates; spongy/trabecular/trabecular bone
osteoblasts at epiphyseal plates on metaphysis side to grow
until maturation/nutritional signal say stop ossification (plates
close); different for bones and sexes
apophysis; raise bone for muscle/tendon insertions; like epi
structure, separated from cortex by apophyseal plate
more muscle=more bones at apophysis for attachment
bone tissue changes in diameter in medullary canal, cortical bone, mineral content of tissue, length, girth and density
mechanicsstatic dynamic
kinetics
kinematics
Forcemove
T vs. s
Bone marrow

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condyle: round that articulates (epi; small)
facet: smooth, flat ; usually on articular surface
foramen: hole in bone; nerves/vessels pass
fossa: shallow, dish-shape; space for articulation/muscle attachment
process: bon prominence
tuberosity: raised section of bone for ligament, tendon, or muscle attachment; bigger w/ stress of muscles pulling on that bone
during growth
physical stress
stress compression; stability, pain and deterioration if arthritic; rubbing
tension; pull muscle off bone, but develop stronger bony attachments
torsion; skiing; knee joint damage
shear force; blow from behind; clipping lower leg (Calf) and pushed forward; damages disuse surrounding knee
Mechanical properties:,
strength; fracture resistance from physical stresses
elasticity; bones ability to reform after stress on it; how much deforms w/ given load (stress-strain relationship); different
speeds result in different responses; energy absorption of bone
stress (force)-strain (deformation) relationships
energy absorption
fatigability; age, nutrition, type of bone tissue, hormone, length and magnitude of stress on bone; resistance of weakening
from stresses (overuse injury/repetitive stress disorder)
Growth
compression of epiphyseal plates b/f closure stunts growth; kids shouldn’t lift or have intense training
tension activates bone cell growth; stretching is key
growth factor/rate b/w bone and muscle tendon causes harm; bone grows faster and tendon not strong enough to support
Osgood-schlatter’s disease: micro-tears in tendon, apophysis, or bony epiphysis due to increase tension; males in mid-
teens; fast stop and plant w/ flexing knee; jumping
Imbalance b/w muscle strength and strength of attachment to bone; pull off from attachment
+Overuse of muscles from a sport stimulates bone growth (shape/strength/muscle joint attachment) in apophyseal plate
-start children young, but injuries by wearing of bone, chipping of cart., plate close earlier; more severe b/f plate closure;
separation of medial epicondyle of humerus
Avulsion fractures of apophysis and osteochondritis, stress fractures; overuse injuries
Even a tall child can grow bigger and stronger bones w/ safe exercising
In animals high intensity training stimulates growth (length and girth) and density, but not lower
Bone changes in adults after ossification (30 males, 40 females)
Change in density and strength (diameter, cortical width, calcium); loss, demineralization and reduced strength;
wheelchairs; 0 gravity stress, weight, intensity or exercise, hormones; estrogen, osteoporosis decrease bone mineral
concentration; specific to where stress is
Amenorrheic female athletes; less estrogen and body fat due to over exercising
2%/decade decrease of tensile strength and elasticity; 20-90 yrs. Old; less w/ exercise
not enough evidence showing exercise stress on bones help control bone loss for elderly
Module B: Body’s link system and its movements
Articulations: bone segments/links; for muscle attachment
hyaline cart. Covers ends; smooth, elastic for shock absorption and frictionless surface; may crack, chip; arthritis
synovial fluid in joint cavities; space for two bones to move; viscous (change w/ activity; warm-up), lubricates hyaline
cart.
classified by movement

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a) synarthrodial articulation; immovable joint; slight w/ applied force; shock absorber; skull
b) amphiarthrodial articulations; slightly movable; fibrocartilaginous disc; vertebrae or ligament/membrane linking bones
(connective tissue); scapula to clavicle; shock absorption
c) diarthrodial articulation; free moving, common
synovial membrane does not cover hyaline cart.; surround joint cavity
nerve endings in capsule detect pressure; bone spurts
articular capsule; outside articulation holding bones together
ligaments connect bones outside capsule; tendons same but connect to muscle and bone
some muscles attach to periosteum
tendinous attachment concentrates force of muscles to small area of bone and more freedom
in angles that muscle pulls on the bone; muscle mechanics vs. fibrous attachemnts of muscles
at origin; less movable; large muscles, force and bones
Biomechanics of articular connective tissue
stress-strain/force-deformation determines tissue’s elastic limit; strength and flex.
Elasticity: tissue stretched and comes back unless reached elastic limit: plasticity; stays deformed
Elastic limit enhanced for tendon/ligament by exercise, but reduced by aging
Tendon’s strain less affected by stress than ligament: stress-strain curve; more stretch to ligament (12-50%) than tendon
(9-30%) w/ same force (ligament=bone to bone, tendon=muscle to bone)
Musculotendinous junctions (MTJs)/bone ligament junctions; age b/f epiphyseal closure; less stress ligaments can take
before detachment
Immobilized connective tissue recovers 100% (bone), but not mobile connective tissue; ligament-bone complex; sprains
worse than fractures
Steroids; avulsion of an apophysis; weakens tendons, string muscles too strong pullinginjuries; light children w/ strong
muscle training
Stability: take shock and motion avoiding injury to joints and tissues around; joint sprain of ligaments/muscle tissue
Depends on the structures; quality and quantity…only as strong as weakest link
1) strong bones in joint; fits like puzzle pieces
2) strong ligaments; quality and quantity to resist dislocating forces; exercise helps
3) strong muscular arrangements around joint; lines of force pull bones together; exercise helps; esp. knee
Motility (flex) measured in ROM in degrees of which articulation segments can pass
move w/o restrictions; musculoskeletal flex.
Depends on shape of articulation bones and muscle and ligament tightness around
Articulation ROM restricted by
1) bone
2) musculotendinous restriction (tight)
3) muscle tissue restriction (too much muscle/fat); muscle-bound; don’t stretch
motility and stability; can be both; flexible and strong gymnasts; strong muscles good for reinforcement for flexible joints
double jointed; weak muscle and ligament stability in joints; cant do some things b/c requires more force; inefficient angle
to move
directions of body movements may be described by body's reference system rather than this spatial system
linear displacement of a system
curvilinear
rotary/angular motion or axis of rotation
angular displacement; theta ; degrees or radians (57.3 degree)
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