4.2 Joint and Movement Type

Transcription

1 TOPIC 4 MOVEMENT ANALYSIS Jint and Mvement Type Outline the types f mvement f synvial jints The musculskeletal system is the arrangement f bnes, jints and muscles that permits mvement f the human bdy in sprt and exercise The bdy segments are articulated by the synvial jints at which tw r mre bnes meet Usually mvement cnsists f rtatin f ne segment relative t anther at the jint The rtatin is caused by frces riginating frm the muscles, ther parts f the bdy r external actrs (such as gravity, sprting implements r ther peple) Synvial jints can be classified depending n hw many axes f rtatin the bnes have TERM TYPE EXAMPLE STRUCTURE Nn- Axial Gliding Jints Between the carpal bnes in the palm f The bnes slide in relatin t each ther the hand Therefre, there are n axes f Uniaxial Biaxial Triaxial Hinge and Pivt Jints Cndylar and Saddle Jints Ball and Scket Jints The elbw and the radi-ulnar jint The knee and the base f the thumb The shulder and the hip rtatin in this type f jint There is nly ne axis f rtatin This means that the structure f the bnes at the jint restricts rtatin t mvement There are tw kinds f axis rtatin Therefre, the nes can mve in tw different ways There are three kinds f axis rtatin Therefre, these bnes permit the greatest mvement, as they allw the limbs attached at them t mve thrugh a large vlume f space

2 2 TOPIC 4 MOVEMENT ANALYSIS MOTION IN THE SAGITTAL PLANE Flexin Clsing f the jint angle arund the transverse axis at the clsing jint Extensin Opening f the jint angle arund the transverse axis at the jint MOTION IN THE FRONTAL PLANE Abductin Opening f the jint angle arund the anterpsterir axis at the jint Adductin Clsing f the jint angle arund the anterpsterir axis at the jint MOTION IN THE TRANSVERSE PLANE Medial (inward) Rtatin The anterir surface f the mving bne mves twards the medial (inside) aspect f the bdy Lateral (utward) Rtatin The anterir surface f the mving bne mves twards the lateral (utside) aspect f the bdy These are the main fundamental mvements that apply t all jints, as lng as the structure permits mvements arund the apprpriate axes The Elbw Jint Flexes when it bends Extends when it straightens The structure f the jint des nt permit; abductin, adductin, medial r lateral rtatin The Shulder Jint Flexes when the arm is raised Extends when it is lwered These tw mvements are the ppsite t what might be expected Abducts when the arm is raised frm the side Adducts when it is lwered again

3 TOPIC 4 MOVEMENT ANALYSIS 3 The Humerus (Upper Arm) Can underg rtatin arund the transverse axis at the shulder jint When the elbw is kept fully extended, the hand can still g frm facing anterirly t psterirly (medial rtatin) and back again (lateral rtatin) When the wrd Hyper is added t any f these terms, this usually indicates that the actin is beynd 180 r back past the starting psitin It is als defined as mvement f a bdy segment int the space psterir t the bdy when it is in the anatmical psitin Example: Hyperextensin f the shulder When the arm extends in the sagittal plane and then cntinues past the anatmical psitin behind the bdy TYPE OF JOINT MOTION MOVEMENT DESCRIPTION Drsiflexin Flexin f the ankle jint These mvement mve Plantar Flexin Extensin f the ankle jint the ft up and dwn in the sagittal plane Prnatin Medial rtatin f the radiulnar jint (nt the wrist jint) These mvements allw the frearm (and the hand) t rtate Supinatin Eversin Inversin Hrizntal Abductin (Hrizntal Extensin) Hrizntal Adductin (Hrizntal Flexin) Lateral rtatin f the radiulnar jint (nt the wrist jint) Medial rtatin at the ankle jint Lateral rtatin at the ankle jint Opening f the jint angle arund the transverse plane when the bdy segment has already been flexed t 90 Clsing f the jint angle arund the transverse plane when the bdy segment has already been flexed t 90 Even when the elbw is flexed t 90 frm the anatmical psitin Prnatin wuld take the hand frm palm upwards t palm dwnwards and vice versa fr supinatin These mvements invlve rlling f the ft and ankle, frm the anatmical psitin If the ft is mved s that the sle faces inwards, this is inversin If the ft is mved s that the sle faces utwards, this is eversin These actins are cmmn at the shulder If the arm is flexed (raised in the sagittal plane) t 90 and then brught tward the midline f the bdy hrizntal, this is hrizntal adductin If the arm is mved hrizntally away frm the midline when already

4 4 TOPIC 4 MOVEMENT ANALYSIS flexed t 90, this is hrizntal abductin TERM EXPLANATION EXAMPLE TYPE OF MOVEMENT Circumductin Circling f a bdy segment at a jint Prnatin and Supinatin Of the ft The mvements are ften used by sprts medicine practitiners when describing mtin f the ft at the ankle jint Mving the arm in a circle arund the shulder Cricketer bwling Walking Running Cmbinatin f hyperextensi n, abductin, extensin and adductin Circumductin may include ther mvements in the circling actin depending n the directin, axis f rtatin and the particular jint PRONATION Cmbines drsiflexin, eversin and abductin f the ankle and ft SUPINATION Plantarflexin, inversin and adductin OCCURRENCE IN Shulder Hip Wrist Ankle Thumb Requires at least a biaxial jint PRONATION Just after landing in walking r running as the bdy s weight is absrbed SUPINATION During push-ff in walking r running as the ankle is used t prpel the persn frward and upward Nt all individuals demnstrate prnatin n landing, hwever it depends n their bdy structure and their mvement technique

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6 6 TOPIC 4 MOVEMENT ANALYSIS Range f Mtin (ROM) depends n 4 factrs; 1. The shape f the surfaces f the articulating bnes in the jints 2. The psitin and length f the restraining ligaments 3. The effects f the muscles and tendns at the jint 4. The amunt f sft tissue (skin, fat, muscle) at the jint Outline the types f muscle cntractin When muscles cntract, the ends f the muscles are drawn twards the centre f the bdy due t the sliding filaments Hwever muscles can mve the bdy segments by varying the frce f cntractin and where the muscles line f actin is relative t the jint TERM Cncentric Cntractin Ismetric Cntractin Eccentric Cntractin Istnic Cntractin Iskinetic Mtin DESCRIPTION If the ends f the muscle are actually drawn tgether; this will result in the mvement f ne r mre bdy segments If the rtatinal effect f the frce (trque r mment) frm the muscle is greater than that f the resistance t be vercme Segment weight, external weight, ther muscles, ther persn If the muscle cntracts, but the rtatinal effect f the muscle frce (muscle trque r mment) is exactly equal t that it prvided by the resistance, then the muscle will nt physically shrten althugh it will be cntracted If the muscle is cntracting but the rtatin effect f the muscle frce (muscle trque r mment) is less than that f the resistance, then the ends f the muscles actually get further apart, even thugh the muscle is still cntracting This is because the muscle is nt relaxed, but is nt cntracting strngly enugh (and / r nt in a suitable psitin) t vercme r balance the resistance The lengthening f the muscle while still cntracting is thught t break the actin-mysin bnds mechanically, this means that greater muscle frces and trques can be prduced than in cncentric cntractin Fewer mtr units are recruited fr the same muscle frce and there is als a lwer xygen cst fr eccentric cntractins than cncentric cntractin f the same muscle The frce remains cnstant during the mvement f the bdy segment affected by the muscle The muscle will usually change due t the change in jint angle and therefre the angle f pull f the muscle relative t the jint will als change This means that the frce in the muscle will usually change thrughut the the range f mtin, even if the external resistance is cnstant Lifting a cnstant weight Includes CONCENTRIC & ECCENTRIC CONTRACTIONS When a muscle cntract s that the bdy segment t which it is attached mves at a cnstant speed arund the jint This type f mvement is very rare in sprt and exercise (mst mvements have an acceleratin phase and a deceleratin phase) Usually requires cmplex equipment t ensure the segment rtatinal speed is cnstant This type f mtin is useful t rehabilitatin when a therapist wants t make sure the speed f a limb is nt excessive Just because the bdy segment mves at a cnstant rtatinal speed, it can nt be assumed that the muscle is cntracting at a cnstant speed due t the different angles f pull thrugh the range f mtin

7 TOPIC 4 MOVEMENT ANALYSIS Explain the cncept f reciprcal inhibitin Reciprcal Inhibitin (RI) Is exercise attempts t achieve the simultaneus relaxatin f ne muscle by the the cntractin f its antagnist muscle In reality ther muscles are invlved bth in the cntractin and the ensuing relaxatin When an agnist cntracts t mve a bdy segment, it is usual fr the antagnist (the muscle with the ppsite cncentric cntractin actin) t relax This means that the agnist is nt being ppsed by any muscle trque acting in the ppsite directin t that f the mtin = RECIPROCAL INHIBITION REFLEX = An autmatic actin cntrlled by neurns When the agnist mtr neurn is stimulated, the mtr neurn t the antagnist is inhibited, preventing it frm cntracting strngly During sprt and exercise, the signals are very imprtant t ensure maximum trque arund the jints when the agnist muscles cntract Antagnist muscles cntract eccentrically In mst mvements this wuld be cunterprductive as the antagnist muscles wuld be prducing a trque in the ppsite directin t mtin Thus, lwering the net trque arund the jint Example: During the upward phase f bicep curls, the biceps brachii muscle cntracts cncentrically and the triceps brachii is still relaxed Occasinally it is necessary fr bth agnist and antagnist t cntract at the same time Example: T cntrl balance r make a jint stiffer when learning a task This is called c-activatin and in this case reciprcal inhibitin is verridden by the vluntary nervus system AGONIST Anterir Deltid Biceps Deltids Frearm Flexrs Hip Adductr Ilipsas Pectralis Majr Quadriceps Rectus Abdminis Tibialis Anterir Tibialis Anterir ANTAGONIST Levatr Scapula Triceps Latissimus Drsi Frearm Extensrs Gluteus Medius Gluteus Maximus Trapezius Rhmbids Hamstrings Hamstrings When knees are extended Gastrcnemius When knee is extended Sleus When knee is flexed

8 8 TOPIC 4 MOVEMENT ANALYSIS AGONIST Muscle cntracts cncentrically t mve the bne relative t the jint The muscle shrtens and the muscle trque is greater than any resistance trque There are different levels f agnist: prime, assistant r emergency Example: Lifting a weight (elbw flexin) during a bicep curl The prime mver r agnist wuld be the biceps brachii (the large muscle n the anterir surface f the upper arm) The assistant mvers wuld be the brachialis (a smaller muscle n the anterir surface f the elbw) and the brachiradialis (the muscle that runs frm abve the elbw t the wrist n the anterir surface f the frearm) ANTAGONIST If a muscle cntacts eccentrically, then it is ften acting as an antagnist fr the jint actin This means it acts in the ppsite directin t its usual cncentric functin and gets lnger even thugh it is cntracting Example: When lwering the weight during a bicep curl (elbw extensin) The biceps brachii and the ther tw muscles act as antagnists t slw the descent (if the muscles relaxed, the weight wuld simply fall due t gravity NOTE: The tricep brachii (the muscle n the psterir surface f the upper arm) des nt cntract in this actin This wuld simply thrw the weight t the flr as the elbw wuld be extended actively at speed rather than under cntrl Analyse mvements in relatin t jint actin and muscle cntractin FIXATOR (stabilizer) When muscles cntract, bth ends are drawn twards the middle f the muscle Hwever if nly ne end f the muscle is required t mve a bdy segment, then the bdy segment t which the ther end f the muscle is attached (usually the ther segment f the jint) must be kept statinary Therefre, this will require at least ne ther muscle t cntract (usually ismetrically) t prevent this segment frm mving s that the agnist may mve the desired segment This is ne f the main ideas behind the principle f cre stability - the muscles f the cre must be strng s they can hld the trunk f the bdy steady while the agnists r antagnists mve the limbs SYNERGISTS (neutralizer) Mst muscles have mre than ne actin at a jint Example: When the biceps brachii cntracts

9 TOPIC 4 MOVEMENT ANALYSIS 9 It flexes the elbw jint It supinates the radi-ulnar jint One r bth f the prnatr muscles wuld be used if supinatin was nt desired when the biceps brachii cntracts Synergists cntract (usually ismetrically) t prevent unwanted actins f the agnists r antagnists when underging mvement If a limb is being mved in the ppsite directin t a resistance frce (gravity) the agnists are underging cncrete Hwever if a limb is mving in the same directin as the resistance frce (but under cntrl) an eccentric cntractin is being perfrmed by the antagnists If n mvement is apparent, but the ther muscles are cntracting, then ismetric cntractin is likely t be ccurring Explain delayed nset muscle sreness (DOMS) in relatin t eccentric and cncentric muscle cntractins Muscle sreness is a cmmn respnse t an acute but f hard exercise, particularly unfamiliar exercises Example: A sessin f weightlifting fr smene wh has nt perfrmed resistance training fr a lng perid f time Sreness usually dissipates hurs after the exercise DOMS results primarily frm eccentric muscle actin and has a number f causes including: Structural muscle damage Over training Minute tears in the muscle tissue Pressure changes that prduce fluid retentin in the tissues surrunding the muscle Muscle spasms Overstretching and tearing f the cnnective tissue attached t the muscle Acute inflammatin A cmbinatin f these factrs Muscle sreness may be due t a variety factrs, but ne f the mst cmmn is the subcellular damage (and the assciated inflammatin) that becmes apparent 1 r 2 days after exercise Related t exercise which has large amunts f eccentric exercise Example: Running dwnhill The quadricep muscles cntract eccentrically at the knee t cntrl bdy weight

10 10 TOPIC 4 MOVEMENT ANALYSIS DOMS is prevented and minimized by reducing the eccentric cmpnent f muscle actin and the mst effective methd f treating DOMS is: Light exercise Massages Ice baths Warming dwn and cling dwn after exercise Start training at lw intensity and gradually increasing the intensity

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