Neuromuscular Control PDF

force-velocity relationship...

force-velocity relationship > n e u ro m u s c u l a r con + r01 length-tension / ) ↳ muscle tension > Functions of muscle develop tensions exert force - · · working unit of the body · 3 contraction types : · protect organs concentric - physical muscle shortening · provide sensory feedback eccentric - physical muscle lengthening · regulates metabolism isometric - no physical d in muscle length ↳ active vs passive > neuromuscular junction (motor end plate) active tension tension developed by the contractile - · : > activ ↳ myosin - · connection between alpha motor neuron ? muscle fibre elements of the muscles croll-bridging · link btwn nervous system muscle · passive tension : elastic tension caused by connective It Ove & elastic energy tissues Cepimysium perimylium tendous) , , > motor unit · an alpha motor neurons all muscle fibre it innervates firing of motor unit, is an all or none activation so that · , all fibres contract ↳ motor unit size · smaller motor unit facilitates fine motor control (hands , eyes) large moter unit produce more force /gross motor control (legs) · fibre contraction amt of fatigue motor unit type size type speed force resistance slow-twitch fatigue resistant (s) I small SIOW 10 W nigh fast-twitch fatigue 119 intermediate fast moderate moderate resistant (FR) fast - +Witch 11b large falt nigh IOW fatigable (FF) ↳ motor recruitment Iweakest( ↓ size principle : recruitment of smallest motor units then progresses to I most powerfull largest motor unit => spatial summation · allows for performance of s mooth efficient movements. 2 rate coding : freg I. rate of firing motor units. Toa force production , motoranit fives more often · allows force generated with each firing to accumulate , 10 that greater force is produced => temporal summation  · cross activation : activation of one hemisphere leads to associated movements in the opp limb magnitude of transfer is dependent proficiency · on the of the limb. The more proficient the person is at both limbs , the smaller the magnitude of transfer sensorimot or con + rol · inverse relationship Hebbian's theory / Heby's law (neuroplasticity) llower speed actin-myosin cross-bridging when an axon A is excite cell B3 repeatedly · : more near enough to takes · · faster speed : less actin-myosin croll-bridging part in fiving it , some growth process /metabolic change takes place · power : force x velocity in one or both cells such that As efficiency is ↳ application · training specificity may lead to the other factory Nervous system · shifting the curre right and upwards CNS DNS adaptations motor sensoryis < brain spinal neurons Loud ↳ muscle somatic automatic hypertrophy sympatheticParasympathetic · muscle fibre type composition division division INS ci ontrocentrefor · muscle stiffnes our more e s ↳ tendon ↑ tendon stiffness generates responses · - ↳ neuval - sends responses to muscles for execution · interlimb coordination · PNS : nerves connecting spinal cord with other parts of the body · ↑ agonist antagonist coordination - neurons transmits impulse, from one part of · ↑ motor recruitment the body to another ↳ done through ↳ flexibility electrochemical process ↑ range in motion · ~ bilateral transfer · transfer of learning or strength from one limy to the other · bilateral access simultaneous involvement of both left : ? righthemispherecontrolling executingmovements pyramidal nemispheres.  > Y - CNs motor control cerebrum : consists of cerebral hemispheres · · corpus callosum : connects left &right hemisphere , · cerebral cortex : Outer surface of cerebrum > neural transmission · subcortical structures /below cerebral cortex) milivolts ↑ - absolute ↳ cerebrum · surface layer of cerebrum consists of grey matter (nerve cell bodies) folded into ridges (gyri) & grooves Isnicil highest centre of processing · relative - 20 - interpretation integration of sensory info miliseconds ! 2 ~ planning organisation of complex movement - ↳ refractory periods Horage & memory of learnt behaviour - · depolarisation & repolarisation occur very quickly (Imsec) · causes refractory period /period of reduced excitability of neurons consisting I of brief periods of time ↳ frontal lobe 1 absolute refractory period (PMA) cortical involved in planning · premotor area : area · occurs immediately after action potential motor movement organising coordination of movement programme · period when it cannot produce another action potential · supplemental motor area (SMA) : cortical area crucial in 1. relative refractory period preparation organising of movement · period when stimulus must be stronger than normal levels to generate action primary motor cortex (m1) : cortical area impt in movement potential because neuron has not returned to its resting (polarised) state · Initiations execution > neural transmission ↳ bacal ganglia · all-or-none activation · subcortical structure located within cerebrum 14 nuclei) · intensity coding (info about intensity of censory stimulus) · scaling /modifying parameters of movements neuron five at higher frequency Itemporall more neurons fire Ispatial) adjust 'Commands' sent from M1 to match movement task reg -. , · Idependent conduction speed on cross-sectional diameter myelination of axon) basal ganglia disorders : barkinson's /understimulation of BG) , · synaptic transmission nunington's loverstimulation of BG) ↳ Cerebellum (small brain) c 0gni + ive approach · I wrinkled nemispheres below " behind cerebrum · coordinating monitoring movement , mainly in error detection correction motor control theories attempt to explain how we learn & control movement receives a copy of commands sent by M1 & adapt to movement situation · now we · compares intended 3 actual movement · approaches : Cognitive dynamic system · disorders of cerebellum : - hypotonia (reduced resistance or tension to movement in muscle) · scientific law : a consistent , observable phenomenon in nature. It - ataxia (1011 in ability to regulate body posture voluntary control of limb States what happens under certain conditions but does not explain why movement) · theory : a comprehensive , well-substantiated explaination of a - tremor (involuntary rhythmical alternating movement of limb) that occur. Built broad aspect of the natural world on a body of evidence C1 - during movement) C8 - cervical which explains why certain phenomena occur TI - Vertebrae thoracic T12 > spinal cord ) characteristics of movement ↳ - - L - lumbar 15 equivalence (flexibility - relay messages motor of movement) talk can be completed · · - : - Si · lubconscious control of movement (reflex/ sacral using diff movements - 34 - regulation of timing of muscle activation uniqueness movements are not identical · moment-to-moment control : : patterns minor adjustments of movement patterns · stability & consistency : close similarity over series of performance modifiability : movement can be altered during performance · ↳ grey & white matter to match environmental needs grey : centre of cord skill acquisition motor learning : motor control changes as we · - cencory info dorcal horns receive learn s improve on a skill - ventral horns transmit motor info · serial order : movement elements are reliably produced in their · interneurons Ivenshaw cells) : influence motor activity at Spinal cord NVI desired sequence degrees of freedom coordination of independent · : control all variables in a motor skill performing · coordination : producing movements that are smooth ? match environment ↳ pathways sensory pathway (ascending tract) ↳ cognitive approach dorsal column tract proprioception , touch 3 pressure · cognition : mental process of acquiring knowledge understanding /pinothalamic tract , pain 3 temp. through thought experiences , Censes · Also refers to an info processing · motor pathway (descending) view of an individual's psychological functions open-loop closed-loop corticospinal tract (pyramidal) /fine motor control & very fast - transmission of movement command / motor muscie motor muscie movement command moveme command ↑ brainstem system (extrapyramidal) >reflexes postural control feedback L  ↳ close us open loop ↳ parameters closed : · features of amp learners can modify - accurate 1. Overall duration - can make adjustments to correct any errors or to respond to. overall force 2 changes in environment.. direction of movement 3 - slower 4. limys & muscles used > same movement with diff limbs /muscles open : accurate it initial commands ↳ schema only are correct -. - Does not allow error correction/adjustment to environment during · set of rules that learners use to modify parameter , of amp movement help, make decision aboutn ow to modify movement in a specific situation · faster - initial condition recall schema s organise motor program X speed - accuracy trade-off : response specification - - more faster >unable to make corrections to movement dynamic system cognitive-based models top-down of control complex motor control system · : · command centre , motor program (effectors · based on non-linear dynamics to explain changes in complex systems > unable to predict ↳ problems with many interacting parts (weather systems , traffic flow) transitions · storage : now to store motor programs · non-linear dynamics : abrupt changes , occurs naturally novelty : now to perform a movement when we don't have the program assumptions : self-organising has constraints , non-linear & in movement · · , ↳ generalised motor program /Gmp) ↳ boundaries => influences movement capacities · stove a Gmb rather than specific movement for each specific movement limit movement : learning opportunities motor program that represents class of similar skills or skill variation individual · that can be modified. · storage > only 1 amp needs to be stored , which can be modified environmental task novelty > amp is generalised to class of actions 10 it can be modified self-organisation : when specific constraints are present system organises · · , to perform a novel I kill * attractor : preferred/energy into specific Stable states of movement efficient way of moving that & deep attractors shallow attractor ↳ invarient features the system is drawn to · some movements are more attractive than others 7 in btwn welll feature , ofGrup that learners can't modify Wells Stable state unitable · · : : , J shallow ~ 1. sea of movements : order of movements · system is drawn to stability deep. relative 2 time : each component takes same amt of time · dynamic interaction of constraints on movement oppose, to motor 3. relative force : force for each component remain consistent program views where movement is determined centrally  > perception action coupling - In PE 3 Sport Science to more we must perceive but to perceive we must more PE : 1 perception, action help teacher , make informed decisions about instructions. informs curriculum 2 design ( kill about motor learning / port science : individual - ↓ provide guidelines for talent identification - interaction of constraints environmental task - motor skill voluntary goal directed activity that is learnt through practice/exp ~ · have a purpose - · characteristics : goal directed , voluntary learnt , require body movement , S perception - perception action - coupling action - ↳ fundamental motor skill /provide basis for specialised motor skill) - Stability control of body in term , of balance/bending twisting · : v , movement = self-organisation of movement · locomotor : more an individual through space /crawling walking) , manipulative : control of an object (throwing catching · , > affordances opportunities for action in relation to performer's capabilities skilled performer · · high affordance : walking running , leasy) · bring out max certainty of goal achievement (consistency , probability) · low affordance : rock climbing complex , dance routine (difficult) · herform in minimum time adaptability ↳ influence on perception action coupling - · use minimum energy · action , are influenced by the affordance that we perceive , because abilities : inherited traits , Itable , influence performance of skill we are always searching for affordance in our actions I hand-eye coordination , reaction time , strength · perceive to have high affordance perform action c) accification of skill clear beginning end one distinct movement, v ev is i on ) one ↳ dimensional Inort duration 7 > repetitive movement 3 domains of motor behaviour gross fine discrete serial) continuous Stable predictable > variable , unpredictable environment, [ environment , self extremely paced , movement adapted to 1 motor learning : individuals acquire motor skills through practice paced closed) (open environment. motor 2 control : nervous system coordinates muscles limbs to produce · limitations : difficult to place one skill into one category , do not provide movement. sufficient picture of performance demands of a skill. motor 3 development : now motor skills change throughout the lifespan Importance of studying motor behaviour Fitt's law · skill acquisition : · speed -accuracy trade off 1 informs the guidelines of professional practice. 2 planning development of appropriate curriculum. 3 delivery of effective pedagogies