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Review. Dynamical systems theory explains change in systems that exchange energy with the surrounding environment DST explains how behavior changes through self organization typically no one teaches a child to run… speed is the catalyst. Motor Development.
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Review • Dynamical systems theory explains change in systems that exchange energy with the surrounding environment • DST explains how behavior changes through self organization • typically no one teaches a child to run… • speed is the catalyst
Motor Development Re-conceptualizing Developmental Change in Movement Patterns
Life Span Motor Development Evolution of a Theory & Research Program
In the beginning...a clinician! • a knowledge of neurodevelopmental theory • a fascination with righting and equilibrium reactions • a love for movement analysis
Neurodevelopmental Theory • development is a process of reflex integration • lower level automatic behavior gives way to higher level volitional control Motor Ctx Midbrain Brain stem Level Spinal Level
Neurodevelopmental Theory • Progressive • Positive • Add Abilities • End State Oriented (maturity is the end state)
Neurodevelopmental Theory • CNS = Cause of Change
Biological Theory of Aging... • Regressive • Negative • Loss of Abilities • End state oriented (end state = death)
Life Span Theory • Development followed by Aging
Roberton’s Component Model Developmental Stages of Throwing Reliability of assigning Stages Developmental Change within Components of Body Action
Component Model of Development • Upper Limbs • Axial Region • Lower Limbs
Three descending control systems • medial system – controls axial region • lateral system – controls proximal limb movements • in primate studies the lateral system allowed for differentiated arm movements • cortical system – controls distal movements • in primate studies allowed individuated finger movments
Straying into Systems models • Not just one big hierarchy • Roberton was studying development in those systems!
Applying Roberton’s Method • Taking it to a new task • From Throwing to Righting
Righting Reactions • Developed during 1st year of life • Rolling to prone • Up on hands and knees • Into sitting • Quadruped to kneeling • Kneeling to Half Kneel • Up to Stand
Righting Reactions • Movements couple together to assume erect stance • Foundation for Physical Independence
Righting Reactions • First Rotational movements then Symmetrical • But observations of young adults in PT school revealed all were not using symmetrical form
Studies of Righting • Rising to Standing from the Floor • Young Adults
Why Young Adults? • variability in PT students impressive • a very few showed symmetrical form when rising • Roberton examined variability to get stages of throwing • Lifespan perspective • hypothesis: variation was “developmental”
Sequences • If person is in a stage he/she shows stable behavior characteristic of that stage • If a person is moving from one stage to another • shows variable behavior characteristic of those two neighboring stages
Studies of Righting • Rising to Standing from the Floor • Young Adults • Variability continued to be impressive across 10 trials • Described action in each of three components of body action • able to identify neighboring stages for each body region
Studies of Righting • Rising to Standing from the Floor • Children • Age differences confirmed sequences of movement pattern development identified from adult patterns of variation • Component Model affirmed