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KINE 3020 Midterm 2 Readings 1-15

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York University
Kinesiology & Health Science
KINE 3020
Merv Mosher

Readings 1- Skill Definitions Skill Definitions  Psychologist E.R. Guthrie (1952) has provided a definitions that captures most of the critical features of skills Skill- consists in the ability to bring about some end result with maximum certainty and minimum outlay of energy, or of time and energy  There is several important features from this definition 1. First performing skills implies some desired Environmental goal o such as holding a handstand in gymnastics or completing a forward pass in football o skills consist of movements because the performer cannot achieve an Environmental goal without making at least one movement 2. To be skilled implies meeting this Performance goal, this “end result,” with Maximum Certainty o If you threw a dart and it landed on bull’s eye it may be due to luck but if you repeatedly do it then that mean you are skilled 3. A major feature in many skills is Minimization, and thus Conservation of energy required for performance o This includes physiological, and psychological energy o For some skills this will not be a goal, like Shot put where the goal is to get the furthest distance o But for a Marathon runner it is important for them to save energy o Some skills that are practiced so much, you do them without thinking. Like strategies in basketball or expressive dance o A major contributor to the efficiency of skilled performance is practice with learning and experience leading to the relatively effortless performances 4. Highly proficient performers to achieve their goals in Minimum time o Swimming race’s use this as a competition goal o Some other skills that are effective with minimal time are boxing jabs and basketball passes o Speeding up performance often results in sloppy movements that have less certainty in terms of achieving the Environmental goal o Increased speed generates movements that use more energy o Understanding skills require Optimizing and Balancing several skill aspects that are important to different extents in different settings  Summary: Skills generally involve achieving some well-defined Environmental goal by 1. Maximizing the achievement certainty 2. Minimizing the physical and mental energy costs of performance 3. Minimizing time used The Many Components of Skills  Skilled performers achieve their goals through complex combination of interacting mental and motor processes o Many skills have considerable emphasis on Sensory- perceptual factors  Detecting that a tennis opponent is going to hit a shot to the left 1. Sensory factors require the split-second analysis of patterns of sensory input such as making the judgement that the combined movements of an entire football team indicate the play will be a run to the left side 2. These perceptual events lead to decisions about What to do, How to do it, and When to do it- these decisions are a major determinant of success  Like whether to take a shot in basketball 3. Skills depend on quality of movement generated from these decisions  Even if the situation is correctly Perceived and the Response decisions are appropriate, the performer will not be effective in meeting the Environmental goal if he or she Executes the actions poorly  Summary: These three elements are critical to almost any skill: 1. Perceiving the relevant environmental features 2. Deciding what to do and where and when to do it 3. Producing organized muscular activity to generate movements  The movements have several recognizable parts 1. Postural components support the actions  Arms of archers need to be supported by a stable platform to shoot accurately 2. Body transport or Locomotor components move the body toward the point where the skill will take place  Setting a return on the tennis court or moving a limb toward a place where the action can occur 3. Manipulation components are coupled and coordinated with these other elements and can make up the major focus of the skill  Finger and wrist movements in a complex video game  Summary: The three kinds of components involved in the production of many skills 1. Postural components provide a platform to support the actions 2. Body transport components bring the body or limb to the action 3. Manipulation components produce the action  It is unfortunate that each of these skill components seem to be recognized and studied in isolation from the others 1. Sensory factors in Perception are studied by Cognitive Psychologists, Scientists interested in the complex information processing activities involved in seeing, hearing, and feeling o Sometimes these factors are in the realm of Psychophysics, the branch of Psychology that examines the relationship between objective physical stimuli (eg. Vibration intensity) and the subjective sensation these stimuli create when perceived (loudness) 2. Decision making processes are studied by Scientists in Cognitive and Experimental Psychology 3. Factors in the control of the movement itself are studied by Scientists in Neurosciences, Kinesiology, Biomechanics, Physical education, and Physiology often with little concern for the Perceptual and Decision making 4. Skill learning is studied by Scientist in Kinesiology, Experimental or Educational Psychology o A major problem for the study of Skills is that there is no communication among the Scientist that study these components  Summary: these are the major processes underlying actions 1. Sensory or perceptual processes, studied in cognitive Psychology and Psychophysics 2. Decision making processes, studied in cognitive and experimental Psychology 3. Motor control or movement production processes, studied in the Neurosciences, Kinesiology, Bioengineering, Biomechanics, Physical education, and Physiology 4. Learning processes, studied in Kinesiology, Physical Education, and Educational and Experimental Psychology Skill Classifications  Several classification systems that help organize the research findings and make application somewhat more straightforward Open and Closed Skills- one of the ways to classify movement skills concern the extent to which the environment is stable and predictable throughout performance  Open skill- the environment is variable and unpredictable during the action o Carrying the ball against a defensive team in Football where it is difficult to predict the future moves of the opponent very effectively o Playing soccer, wrestling, chasing a rabbit  Closed skill- the environment is stable and predictable o Gymnastic routines and swimming in an empty lane in a pool o Archery, typing  Open and Closed mark the end points of a spectrum- in between are varying degrees of environmental predictability or variability o In the middle- walking a tightrope, chess, steering a car Discrete, Continuous, and Serial skills- movement is an ongoing stream of behaviour, not a well- defined action. This is also on a spectrum  Discrete skill- easily defined beginning and end- important in sport performances, especially considering the large number of discrete hitting, kicking, throwing, and catching skills that make up many popular games and sport activities o Brief duration movements- kicking a ball, firing rifle, catching a pass  Continuous skill is at the other end of the spectrum- it has no particular beginning or end, the behaviour is flowing on for many minutes o Such as swimming, pedaling bicycle o One important Continuous skill is Tracking- Performer’s limb movements control a lever, a wheel, handle, or some other device to follow the movements of some target track like Steering a car and it follows the road  Serial skill- is in the middle- often thought as a group of Discrete skills to make a more complicated skilled action. Order of the elements is usually critical for successful performance o Shifting car gears has three discrete shift lever action elements and accelerator and clutch elements o Serial skills differ from Discrete in that movement durations are longer but each movement retains a Discrete beginning and end Motor and Cognitive Skills  Motor skill- the primary determinant of success is the quality of the movement itself, where perception and subsequent decisions about which movement to make are nearly absent o High jumper knows exactly what to do but the problem is that the movements must be made effectively to reach maximum height  Cognitive skill- nature of movement is not particularly important, but the decisions about which movement to make are critical o In Chess it does not matter whether you move the pieces quickly but it is important that the player know which piece to move where and when  Cognitive skill mainly involves selecting what to do and Motor skill involves how to do it o This dimension is like the others and is on a continuum there is no completely Cognitive or Motor skill, each skill always has an element of the other in it o Most sport skills weigh heavily towards movement but there is a strong Cognitive and Decision making component like in Quarterbacking football o Recognizing this combination of Perceptual and Cognitive factors with Motor control factors has produced labels for skills like Perceptual Motor skills and Psychomotor skills Reading 2- Measurement of Motor Performance Psychological Measures  There are three models of Motor control and their validity can be tested at a Psychological level of analysis, these measures can be divided into two basic categories  The measures applied to test the early reflex models of motor control were used primarily to describe the end result, or response outcome, observed as a function of manipulating one or more experimental variables  However in more recent hierarchical and dynamic systems models have been tested using research paradigms and measurement techniques also to describe How the movement was controlled to reach an outcome Response Outcome Measures  The Chronometry, or timing and duration, of cognitive operations involved in the planning of voluntary movements has been explored using different types of Reaction Time measures  RT is the time interval between the presentation of a signal and initiation of movement o It can be used for to measure how quickly a sprinter reacts to the start signal o Provides information about Decision making processes involved Simple, Choice, and Discrimination Reaction Times  Simple Reaction Time (SRT)- movements of the sprinter are in response to the presentation of a single stimulus  Choice Reaction Time (CRT)- many possibilities for action are available to the quarterback. Depending on the snap the quarterback will choose which receiver to pass to  Discrimination Reaction Time (DRT)- also involves presentation of multiple stimulus- instead of requiring a particular movement response to a specific signal like CRT; in a DRT setting performers are required to respond to only one of several signals o Coach tells quarterback to send to specific receiver even though several are open  These RT situations can be easily replicated in a Lab environment which has provided researchers working at a Psychological level of analysis with an important means of testing certain predictions associated with hierarchical models without resorting to more invasive measurement techniques  SRT and CRT measures are used in Lab to study the speed of the Decision making processes observed in a number of different types of movement situations Fractionated Reaction Time (FRT)  Is a more precise RT method used to study closely the cognitive processes involved in the planning of action  It requires Electromyography (EMG) to partition RT into two parts: Premotor Time (PRMOT) and Motor time (MOT)  PRMOT is the time that elapses between the presentation of a reaction signal and the first change in EMG activity in the muscle that is identified as the prime mover in the action being observed o The prime mover might be the Biceps brachialis muscle in simple flexion movements at the elbow  PRMOT reflects the time required to receive and interpret the sensory signal presented, develop an action plan, and convey it to the appropriate musculature  MOT begins with the first change in electrical activity recorded in the prime moving muscle and continues until the movement begins o Unlike PRMOT the second component is not directly observable and must be calculated by subtracting PRMOT from overall RT o This allows it to be possible to separate the more purely cognitive processes from the mechanical processes, providing researchers with more precise information about the action planning process  FRT has been helped researchers identify a number of movement characteristics that appear to influence the speed of Decision making process significantly o Movement complexity, Accuracy demands, and the Anatomical characteristics of the responding limb o Separating RT into Central and Motor component has made it easier to determine whether delays in the initiation of movement are due to the slowing of certain cognitive processes or are purely mechanical characteristics associated with the limbs performing the movement Variables Influencing RT  RT measures have been used in formal experimental settings to learn how certain variables affect the time needed to plan and execute movements  Supporters of hierarchical models of Motor control have found RT measures particularly useful in their quest to identify the types of variables most likely to influence each of the hypothetical mental processes stimulus identification, response selection, and response programming involved in preparing a given action  From Experimental manipulations researchers have identified a number of variables that influence the time required to complete the mental processes believed to precede the actual movement o Factors: numbers of response choices available, Complexity of the response to be performed, Accuracy demands associated with the movement, and amount of practice provided on a specific task- Practitioner must consider the influence of each of these variables when developing and implementing strategies designed to facilitate the learning or relearning of movements  RT has also been used to investigate the impact of various types of neurological diseases and trauma on the time required to plan and initiate rapid movements o SRT and CRT measures have been used to assess the ability of patients with Parkinson’s disease to prepare to execute a variety of different actions o The movement preparation abilities of individuals with cerebral palsy have been explored using the more precise FRT technique Movement Time  A second Chronometric measure used in conjunction with RT is movement time MT  MT is the time between start of a movement and its completion  Useful for demonstrating a phenomenon in motor control known as Speed Accuracy Trade Off o SATO is likely to occur in movement situations where the performer is required to move quickly and accurately  Recording MT in something like a Slalom kayak event would provide insight into the strategy a performer uses to optimize success  MT and RT can also provide important clues to whether a particular movement is being planned in advance of the movement or during its execution o In certain movement situations only a portion of movement is planned in advance and then continue to plan later segments as the movement progresses o Evident in movement sequences that have multiple segments or exceed 500ms in duration Performance Errors  Commonly used by teachers to assess performers ability to perform a skill or how well they are progressing in learning a new sport skill  Researchers use different types of error scores to determine whether the goal of a movement was actually achieved o Ex. Did the performer succeed in hitting the target or execute the movement sequence in its correct order?  Certain error scores can help us understand why the outcome occurred o Whether overshot or undershot and how consistently it was performed o The error scores are Absolute Error (AE), Variable Error (VE), Constant Error (CE), and Absolute constant error ( |CE| ), and Total error (E)  AE- the quickest one to calculate and commonly used to evaluate performance; measures the amount of error associated with a particular performance o Does not provide information about direction of error  VE a score that represents the degree of consistency or the variability associated with a given performance o It is obtained by calculating the Standard Deviation o The lower the SD the more consistent the performance  CE provides information about the nature of the error, provides a measure of response bias because it considers the amount of error and direction of error o Ex. A shooter tended to shoot to the left of the target. A Coach can use this information to develop a plan to correct this  CE is useful for evaluating individual scores but less accurate when applied to group scores. This is because performers can cancel each other’s scores o If a shooter scored a 7 for landing on the left side and another shooter scored 7 for landing on the right side then the sum would be zero  To overcome this absolute values are used on the performer’s CE scores o This is called Absolute Constant Error o This is reported more often in research studies than Constant Error because of it greater validity  E is a composite score that is an alternative to calculating both CE and VE o Measures the total variability surrounding a particular performance o Often considered the best means of capturing both response bias and variability in a single measure Response Process Measures  There are measurement techniques designed to capture the moment to moment control of movement  The techniques has helped develop more precise descriptions of movement and more comprehensive means of testing the validity of hierarchical and dynamic systems models  Four of the most popular techniques used to describe and quantify the coordination and/or control of movement are kinematic, or for related, measures; electromyography, kinetic, or production indices; and Angle- angle diagrams and phase plane portraits Kinematic Descriptors  Advances in filming equipment with increasing availability of commercial software have given researchers an opportunity to quantify more objectively  This technique provide information about limb displacement, acceleration, velocity, and other important movement related parameters  Recently have been used to demonstrate how the overall goal associated with an action can shape the observable movement pattern  In a study that was done using two actions results showed that subjects who were required to perform the more precise of the two movements tended to decelerate the arm for a longer time before reaching the disk o Spatial demands associated with the second component of the movement influenced how both components were planned and then ultimately controlled Electromyography (EMG)  EMG has enabled researchers to fractionate RT into a central and peripheral component  Provides information about muscle activity during movement  Spatial and temporal characteristics of the movement can be identified from the resulting output  Electrodes are place on the surface of the skin above the muscles of interest for the purpose of measuring the level of electrical activity that occurs in agonist and antagonist muscle groups during a movement  EMG wave form can answer questions related to the amount of force exerted by a given muscle, its amplitude and duration of contraction, and in the case of multiple recordings, the temporal coordination between the various muscle groups  Multiple EMG recordings have been used to describe how the various muscle groups in the leg and trunk are activated when we attempt to maintain and/or restore postural stability in a variety of environment conditions  EMG recordings have been used to demonstrate the types of muscle response patterns to forward and backward sway perturbations o An ankle strategy is used on normal, broad surface o Hip strategy is used on a narrow surface Brain Activity Measures  These techniques have been adapted from hospital and clinical settings where they are used for diagnostic purposes  These techniques provide researches who study at the neurophysiological level a window into brain activity as a person performs a motor skill  There are three techniques that are more prominent Electroencephalography (EEG)  The brain can also produce electrical activity which can be measured by EEG  Neurologists use EEG to assess brain disorders  EEG like EMG is non-invasive and painless- it places electrodes on the scalp o 4-16 are typically used o Even numbers represent the right hemisphere and odd numbers are left  Brain activity is rhythmic and recorded as waves  Four waves can be identified according the speed of the rhythmic activity, listed in order of fastest to slowest o Beta waves- the fastest wave- occurs when an area of the cortex is active o Alpha waves- occur during quiet, awake states o Theta waves- occur during some sleep states o Delta waves- slowest wave- characteristic of deep sleep  Mental activity generates the fast beta waves, while non-dreaming sleep and coma produce slow theta waves  EEG is popularly used to describe brain cortex excitability characteristics of skilled athletes in sport such as rifle sharpshooting, pistol shooting, darts, golf, an archery  Less popularly used to study learning of motor skills PET (Positron Emission Topography)  One of the limitations of EEG as a technique for assessing brain activity is that it is limited to activity in the brain cortex surface and does not show the anatomical structures that are active in specific brain regions  Development of Neuroimaging techniques overcame this limitation  PET was the first of these techniques  PET scans show blood flow or metabolic activity in the brain and provide a window into all areas of the brain  The technique involved injection into the bloodstream or the inhalation of a radioactive solution in which atoms emit positively charged electrons  Areas of the brain with activity are lighted up and are in different colors according to a color spectrum representing levels of activity  PET is popular as a neuroimaging technique for researchers interested in the neural substrates of cognitive and motor activities, its use for this type of research has diminished o This is because better technology has been made that has a higher resolution, more cost effective, and does not require injection of a radioactive isotope into the bloodstream fMRI  MRI is Magnetic resonance imaging  Contains a magnetic field that realigns the body’s hydrogen atoms to create clear 2D and 3D images of body tissue can produce images of any part of the body in slices that are millimetres thick  It can assess changes in blood flow  fMRI (f is functional)- the term functional is important because researchers use this technique to observe brain function while a person performs a task  The fMRI detects blood flow changes and can provide coloured images that show active brain areas at a specific time, and it can provide quantitative results by computing BOLD (Blood Oxygenated Level Dependent) amplitudes which researchers use to determine active areas of the brain  fMRI has the limitation like PET of having participants move in a confined space Reading 3- Speed Accuracy and Fitts’ Law Speed Accuracy Skills  many motor skills require speed and accuracy like penalty kick in soccer, fastball for a strike, playing a song on a piano  other motor skills require limb movement accuracy but not speed o like Manual aiming skills require the hand arrive at the target but at a speed that the performer determines like putting a key into a keyhole, typing on keyboard  In these two types of movement we observe a phenomenon known as the Speed Accuracy Trade-Off o This means that accuracy requirements of the movement will influence the movement speed so that an emphasis on accuracy will reduce speed, while an emphasis on speed will reduce accuracy o Ex. Penalty kick- a faster kick will reduce accuracy Fitts’ Law  Fitts’ Law developed by Paul Fitts is a mathematical law to predict movement speed given specific accuracy characteristics o Predicts the movement time for a situation requiring both speed and accuracy in which a person must move to a target as quickly and accurately as possible  Variables that predict the performance outcome are the distance to move and the target size o According to Fitts’ law if we know the spatial dimensions of these two variables, we can predict the movement time required to hit the target, this relationship is described as  MT= a + b log (2D/W)  MT= movement time  a and b are constants  D= distance moved  W= target width, or size  As the target size becomes smaller or as the distance becomes longer, the movement speed will decrease in order to allow for an accurate movement  Because of the relationship between target size and movement distance the equation log 2 (2D/W) provides an Index of Difficulty (ID) for speed accuracy skills o The higher the ID the more difficult the task will be, more difficult task will require more movement time Fitts’ law applies to many skills  Fitts based his calculations on a reciprocal tapping task in which participants made repetitive back and forth movements as fast as possible between two targets for a specified period of time o Subjects were told to place an emphasis on accuracy o Researcher found that speed- accuracy relationship generalizes to a wide range of motor skill performance situations like manual aiming tasks  For a soccer player practicing kicking a penalty goal to three different sized areas, Fitts’ law will predict the highest speeds for the largest area and slowest for smallest area Motor control processes related to the SAT-O  There are several hypotheses explaining motor control related to SAT-O  Most have elaborated Woodworth’s original hypothesis which was that two motor control processes operate during the rapid limb movement to a target o One which occurs initially and moves the limb into the vicinity of the target, is an Open Loop Control process where the initial movement’s speed, direction, and accuracy are under CNS control o Second process involves Closed Loop Control in which visual feedback about the limb’s relative position to that target is used to guide the “homing in” phase of the limb to ensure its accurate landing on the target  If the movement speed is too fast during the initial Open- loop phase there will not be sufficient time for visual feedback to generate a movement adjustment as the limb nears the target The Role of Visual Information in the Speed Accuracy Trade- Off  The role of vision depends on the phase of movement  The previous section suggest two phases but researchers agree that including a third phase is important to understand the role of vision in the control process  This phase involves the preparation of the movements required to perform the skill  The first phase is the Movement Preparation Phase- which begins when the person makes the decision to perform the skill involving a Speed Accuracy Trade- Off o The person uses vision to determine the regulatory conditions that characterize the environmental context in which the action will occur o Ex. Putting a key into a keyhole, the regulatory conditions would be the size, shape, and weight of the key and the size, location, and spatial orientation of the keyhole- these characteristics would change how you would move  The Second Phase which is the first movement phase in the hypothesis in the preceding section, is commonly referred to as the Initial Flight Phase o It includes the beginning of the limb movement in the direction of the target, which in our example is the keyhole o This movement is fast and occurs without the influence of sensory feedback o Vision plays a minor role in this phase, it acquires limb displacement and velocity information and acquires time to contract information that will used later as the movement nears the target to make movement modifications  The third phase is Termination phase it begins just before and ends when the target is hit o Vision of the limb and target are important in this phase so that movement accuracy information can be transmitted to the CNS and any needed movement corrections can occur to allow the person to achieve the action goal of hitting the target Prehension  Prehension- the action of reaching for and grasping an object that may be stationary or moving Reading 4- 3 types of Reaction Time Reaction Time  Figure 2.1 shows RT is the time between “Go” signal to the Initiation of the response o MT is Initiation of response to Termination of response o Response time is the combined RT and MT  To assess optimal RT some type of warning signal should be given prior to the stimulus signal The Use of RT as a Performance Measure  RT is used to assess how quickly a person can initiate a required movement o It can also be used as a basis for inferring other characteristics related to performing a motor skill o Most common is to identify the environmental context information a person may use while preparing to produce a required action o Ex. If one performance had a longer RT than another then we can look at what may have led to a longer RT signal, what influences the time to prepare an action  RT can assess the capabilities of a person to anticipate a required action and determine when to initiate it o In basketball the coach may want to know how long it takes a point guard to recognize that the defenders actions indicate the guard should pass the ball rather than shoot it o This way RT provides information on Decision making o This shows how RT provides a window for examining how a person interacts with the environment to prepare for an action Relating RT to MT and Response Time  In any situation when a person must move in response to a signal, two additional performance measures can be assessed. Movement Time and Response Time  RT and MT are relatively Independent measures o RT does not predict MT and vice versa Types of RT Situations  Simple RT- when there is one signal and requires only one response o When a sprinter hears the gun sound  Choice RT- more than one signal and each has a specified response o Coming to a traffic light  Discrimination RT- more than one signal but only one response o There are 3 lights (R,G,B) only make a response when R comes on Examples of the Use of RT and MT to Assess Skill Performance Problems in Decision Making Situation Sport Skill Example  An offensive lineman in football must perform his assignment as quickly as possible after the centre snaps the ball. By determining if the lineman has a problem in RT or MT can allow the coach to improve on the specific part Car Driving Example  You are helping a student in a driving simulator to reduce the amount of time he or she requires to stop the car when an object suddenly appears in the street  Separating RT and MT would let you know if the slow stopping time is related to a decision making or a movement speed problem  Problem would be related to Attention or Decision making if RT (the time between appearance of object and taking foot off accelerator) increases but MT (the time from taking foot off accelerator to contact with brake pedal) is constant  Movement related if RT is constant and MT changes Reading 5- Defining and Assessing Learning Application  Two important characteristics of learning that need to be taken into account whenever you assess skill learning  First we do not directly observe learning; we directly observe behaviour  Second because of this, we must make inferences about learning from the behaviour we observe Discussion Performance Distinguished from Learning Performance Learning Observable behaviour Inferred from performance Temporary Relatively permanent May not be due to practice Due to practice May be influenced by performance variables Not influenced by performance variables  Performance is observable behaviour  If you observe a person walking down a corridor, you are observing him perform a skill of walking o The term performance here refers to the execution of a skill at a specific time and in a specific situation  Learning cannot be observed directly but can only be inferred from characteristics of a person’s performance  We base our inference on observed behaviour , it is possible for use to make an incorrect inference o If a student yawns you may think that they are tired but in fact they are bored  Learning defined- a change in the capability of a person to perform a skill that must be inferred from a relatively permanent improvement in performance as a result of practice or experience  Performance variables determines if the skill will be performed consistently  These factors affect a person’s performance but not the degree of learning achieved o Alertness of the person, the anxiety created by a situation, fatigue General Performance Characteristics of Skill Learning  We generally observe four performance characteristics as skill learning takes place 1. Improvement- first, performance of the skill shows improvement over a period of time. This means that the person performs at a higher level of skill at some later time than at some previous time o Sometimes practice will result in bad habits which in turn result in the observed performance’s failure to show improvement 2. Consistency- Second, as learning progresses performance becomes more consistent o A related term is Stability- as performance consistency of a skill increases, certain behavioural characteristics of performance become more stable 3. Persistence- Third, as the person progresses in learning the skill, the improved performance capability lasts over increasing periods of time o A person who has learned a skill should be able to demonstrate the improved level of performance any time but may not achieve the same performance level because of forgetting factor 4. Adaptability-Fourth, improved performance is adaptable to a variety of performance context characteristics o As a person progresses in learning a skill, his or her capability to perform the skill successfully in these changed circumstances also increases Assessing Learning by Observing Practice Performance  One way we can assess learning is to record levels of a performance measure during the period of time a person practices a skill  A common way to do this is to illustrate performance graphically in the form of a performance curve  For any performance curve the levels of performance measure are always in the Y-axis and the time over which the performance is measured is on the X-axis Performance curves for outcome measures Figure.1  This graph can readily show two of the four behavioural characteristics associated with learning  First, Improvement is evident by the general direction of the curve, a downward trend showing decreasing error  We can also see increased performance Consistency, there were inconsistent in the first few trials then slowly became more consistent and more evident near the end  When a person is acquiring a new skill, the performance curve for an outcome measure typically will follow one of four general trends from the beginning to the end of the practice period for a skill  The trends are represented by the four different shapes of curves o Linear curve or a straight line- means proportional performance increases over time. As X increase so does Y o Negatively Accelerated curve- means a large amount of improvement occurred early in practice, with smaller amounts of improvement later  Represents the classic power function curve of skill learning o Positively Accelerated- this curve indicates slight performance gain early in practice, but a substantial increase o Ogive or S shaped curve- combination of all three curves  Sometimes when the curve is a downward direction indicates performance improvement o Occurs when the performance measure is one for which a decrease in performance level means better performance o Measures involving error or time ( absolute error and reaction time)  Performance curves are typically not smooth and are erratic but there are procedures to smooth out the curves  Various individual, instructional, and motor skill characteristics can influence the type of curve that will characterize a person’s performance as he or she learns a skill Performance curves for kinematic measures  Kinematic measures cannot make graphs like Figure 1 because it does not lend itself to being represented by one number value for each trial  Kinematic measures involve performance over time within a trial o It is important to include this time component in the graphic representation of a kinematic measure  To assess improvement and consistency in performance for a series of practice trials o Researchers commonly show one performance curve graph for each trial. To show improvement and consistency changes they depict a representative sample of trials from different stages of practice  Ex. Graph for trials 1-10, graph for trials 51-60  To determine Improvement in performance compare the early to later practice trials by examining how the shape of the person’s produced pattern corresponds to the shape of the Criterion pattern o As the person practiced more, the produced pattern became more like the Criterion pattern  To assess changes in Consistency, compare how far the SD lines are from the mean pattern for each block of trials Assessing Learning by Retention Tests  Another means of inferring learning from performance examines the persistence characteristic of improved performance due to practicing a skill- this can be done with a Retention test  Teachers often give test that cover units of instruction, they use Retention tests to determine how much you know  To administer a Retention test in a motor skill situation is to have people perform the skill they have been practicing after a period of time during which they have not actually practiced the skill o The purpose is to determine the persistence of the performance level, having a period of time with no practice allows this type of assessment  The amount of time should be sufficiently long to allow the influence of any Performance variables to dissipate to determine what was learning during practice  The critical assessment is the difference between the person’s performance level on the first practice day and that on the test Assessing Learning by Transfer Tests  The third means of inferring learning examines the adaptability aspects of performance changes related to learning- this assessment method uses Transfer tests  Transfer test involve some novel situation, so that people must adapt the skill they have been practicing to the characteristics of a new situation  Two types of novel situations: one is a new context in which people must perform the skill and the other is a variation of the skill itself Novel context characteristics  Test administrators can use various kinds of context changes in transfer test  One characteristic they can change is the Availability of Augmented Feedback, which is the performance information a person receives from some external source  If you were assessing learning to discover how well the person can rely on his or her own resources to perform the skill, then your requirement that the person perform without augmented feedback availability would be a useful context change for the transfer test o Some researchers consider this to be a retention test because the practiced skill is performed during the test  Another context that can be changed is the Physical environment in which a person performs o Effective for a learning situation in which the goal is to enable a person to perform in locations other than those in which he or she has practiced  The third context that can be changed is the Personal characteristics of the test taker as they relate to skill performance o The focus is on how well a person can perform the skill while adapting to characteristics of himself or herself that were not present during practice  Ex. Performing while stressed. Novel skill variations  Novel skill variations is like walking different speeds or grabbing different type of cups  One of the ways to assess how well a person can do this is to use a transfer test that incorporates this movement adaptation characteristic o We can alter the performance context in some way so that they must adapt their movements to it Assessing Learning from Coordination Dynamics  Another method of assessing learning involves the observation of the stabilities and transitions of the dynamics of movement coordination related to performing a skill  It is assumed that when a person begins to learn a new skill, he or she is not really learning something new, but evolving a new spatial and temporal coordination pattern from an old one  Stability and Consistency of the coordination pattern are important criteria for determining which coordination state (initial, transition, or new) characterizes the person’s performance o Ex. A person who is learning handwriting experiences an initial state represented by the coordination characteristics of the upper arm, forearm and hand while engaged in handwriting at the beginning of practice o These characteristics make up the preferred spatial and temporal structure the person and the task itself impose on the limb, so the limb can produce movement approximating what is required o This initial stable state must be changed to a new stable state in which the person can produce fluent handwriting o Learning is the transition between these two states  Example of Assessing skill learning o The task required participants to learn a new bimanual coordination pattern o To perform the task, they simultaneously moved two levers toward and away from the body at the same rate o Goal was to produce ellipses on the computer monitor, but to accomplish this they had to coordinate the movement of their arms so that the right arm on each cycle was always 90 degrees out of phase with the left arm o Instability occurs during the transition between two stable states and characterizes the process of learning a new skill Practice Performance May Misrepresent Learning  It may be misleading to base an inference about learning solely on observed performance during practice  One reason being that the practice situation may involve a Performance variable, like having the potential to artificially inflate or depress performance  Second is that practice performance may be misleading if it involves performance plateaus Practice Performance may Overestimate or Underestimate Learning  One way to overcome these problems is to use Retention or Transfer tests to assess learning o Retention test will demonstrate persistence and Transfer test will show the capability to adapt to novel conditions Performance plateaus  Performance plateau- over the course of learning a skill sometimes there is a period that improvement seems to have stopped and then starts again  Performance plateaus are hard to find in motor learning research literature b/c most of it is based on group averages, to show a Performance plateau the results would have to come from an individual  At present researchers agree that plateaus are performance rather than learning characteristics which means that plateau occurs during practice bit learning continues  A reason that plateau occurs is that a plateau represents a period of transition between two phases of acquiring certain aspects of a skill o During this transition the person is developing a new strategy that the task requires to increase the level of performance already achieved o Consequently no performance improvement occurs until the new strategy is successfully implemented  Another reason may be that it represents a period of poor motivation, a time of fatigue, or a lack of attention directed to an important aspect of a skill  It is possible the plateau may be due not to these performance characteristics but to limitations imposed by the performance measure o This is the case when the performance measure involves what are known as ceiling or floor effects o These effects occur when the performance measure will not permit the score to go above or below a certain point Scale Example of Misrepresentation  With receiving concurrent augmented feedback , terminal feedback, and no feedback in the Retention test the results favoured the last group  The more valid way to determine which feedback condition is best for learning is when no augmented feedback is available because it reflects the therapy goal of enabling people to perform the partial weight bearing task in daily living conditions, which is with no augmented feedback  Concurrent feedback group during practice were able to correctly adjust their weight, but during the Retention test they fared the worst- this is an example where practice misrepresented learning Summary  To effectively study concepts and issues related to the learning of Motor skills, it is important to distinguish the terms Performance and Learning o Performance is an observable behaviour o Learning is inferred from the observation of performance  When people learn motor skills, they typically demonstrate four performance characteristics: Performance Improvement over a period of time, An increase in performance Consistency, a Persistence of an improved performance for long periods of time, and the capability to Adapt to a variety of performance context characteristics  There are four methods commonly used to assess skill learning  Look for Improvement and Consistency characteristics of performance as the person practices o We can see these when we plot performance curves of Outcome and Kinematic performance measures during practice  Another method is to use Retention test which assess the persistence characteristic by requiring a person to perform a practiced skill after a period of time that they have not practiced  Transfer test to assess their ability to adapt to a new performance condition either practice skill in a new situation or a new variation of the skill  Lastly, to observe the consistency and stability characteristics of coordination patterns during practice and on tests  To asses learning only based on practice can lead to invalid inferences o Certain Performance variables can inflate or depress performance so that the test over or underestimates the amount that a person has learned o Performance plateau can occur o Retention and transfer test provide a way to avoid these problems o Observation of additional practice will determine if a Performance Plateau occurred during the learning of a skill Reading 6- Degrees of Freedom The Degrees of Freedom Problem  How does the nervous system control the many muscles and joints involved in producing a complex movement pattern?  Bernstein proposed that to perform a well-coordinated movement the Nervous system had to solve the Degrees of freedom problem  DF of any system reflect the number of independent elements or components of the system  The DF problem arises when a complex system needs to be organized to produce a specific result  The determination of the actual number of DF that must be controlled in coordinated human movement depends on which level of control we are considering o At a very basic level we might consider motor units as elements to be controlled o Another level would be joints  When a person practices a skill and progresses from a beginner to a skilled performer, the Motor Control System solves the DF problem in ways that are evident from the changes we can observe in specific coordination characteristics Looking at the DF Problem at the Level of Muscles and Joints  There are 792 muscles in the body that can make the one hundred joints behave in different ways. Each joint has mechanical characteristics that define its DF for movement Reading 7- Stages of learning Application  People who are skilled often have difficulty teaching the activity to a beginner  The Expert has difficulty understanding how a beginner approaches the skill  Predicting a person’s future achievement is often talked about with friends and colleagues as we watch beginners perform a skill o This is because we have a natural inclination to want to predict the future  There is a professional reason for doing this o Ex. Teacher needs to group students after having them do a skill  Prediction also happens in sports o Young athletes will be invited to participate in development leagues if they show potential to become national or international level players  In physical rehabilitation, therapist determine the therapy intervention strategies to use with a patient on the basis of the patient’s initial performance Discussion  People go through distinct stages as they acquire skills  Several models have been proposed to identify and describe these stages The Fitts and Posner Three Stage Model  The first stage is the Cognitive stage of learning o Beginner focuses on cognitively oriented problems o Beginners try to answer questions like what is my objective? How far should my arm move? o They must engage in cognitive activity as he/she listens to instructions and receives feedback from the instructor o Performance at this stage has a lot of errors, and tend to be large ones o Performance is also inconsistent- they generally don’t know how to improve  Second stage is Associative stage of learning o Transition to this stage is after an unspecified amount of practice and performance improvement o The person has learned to associate specific environmental cues with the movements required to achieve the goal of the skill o Makes few and less gross errors since they have acquired basic fundamentals although they need to be improved  Part of second stage- Refining stage o The person works on performing the skill successfully and being more consistent o Performance variability decreases o Ability to detect ones errors  Autonomous stage o After years and much experience they reach this final stage o The skill is almost automatic and habitual o They do not consciously think about the characteristics of the movement o Can often do another task at the same time (walking and talking) o Can detect own error and correct them o Not everyone will reach this stage when learning a skill o Quality of instruction and practice are important factors to achieving this stage  Important to think of these stages as parts of a continuum of practice time  Learners do not make abrupt shifts from one stage to the next, there is a gradual transition  It is difficult to detect which stage an individual is at Performer and Performance Changes across the Stages of Learning  Stages of learning models indicate that in each learning stage, both the person and the skill performance show distinct characteristics  This overview has two benefits: first, it provides a closer look at the skill learning process, and second it helps explain why instruction or training strategies need to be developed for people in different learning stages Changes in Rate of Improvement  A person progresses from beginner to skilled, the rate at which the performance improves changes  The Negatively accelerated pattern is more typical of motor skill learning than others o Large amounts of improvement in the beginning and amount of improvement decreases as practice continues  Snoddy formalized a law known as the Power Law of Practice o Early practice is characterized by large amounts of improvement. After this rapid improvement, further practice yields improvement rates that are much smaller. Exactly how long the change in rates takes to occur depends on the skill  Ex. Of Power law of practice o Workers producing a cigar in the beginning made 10,000 by the end of 7 years they made over 10 million o Performance improved mostly in the first two years, after that performance increments were notably smaller  Pedalo example o MT showed rapid decrease then decreased very little  The difference in rate of improvement between the start and later practice is due partly to the amount of improvement possible at that time o At the beginning the errors made are larger and easy to correct, so you see big improvements o Later on there are only smaller errors so not much of an improvement is seen Changes in Movement Coordination  For the beginning learner solving the DF is a critical part of the learning process  Solving this problem underlies the achievement of an important goal for the learner in Gentile’s initial stage of learning, which is to acquire a movement coordination pattern that would allow some success at achieving the action goal  Bernstein described a strategy beginners use to gain initial control of the many DF, this is now referred to as Freezing the Degrees of Freedom o Involves holding some joints rigid while performing the skill  Ex. Person performing racquetball forehand shot, involves 3 DF (wrist, elbow, shoulder) o Beginners would freeze their wrist and elbow joints making the arm like a stick o As the person practices, a freeing of the DF occurs and joints become unfrozen and allows the arm and hand segments to function as a multi-segment unit o This new unit eventually demonstrates characteristics of a Functional synergy  Meaning the individual arm and hand segments work together in a cooperative way to enable optimal performance  Freezing the Degrees of Freedom- common initial strategy of beginning learners to control the many degrees of freedom associated with the coordination demands of a motor skill in order to achieve the action goal; the person holds some joints rigid ( freezes them) while performing the skill  These coordination changes are not limited to sports. Stroke patients doing physical therapy need help learning how to go from sitting to standing and sitting again Changes in Altering an Old or Preferred Coordination Pattern  We have learned to perform a variety of motor skills throughout our lives so we have developed preferred ways of moving  When learning a new skill, we often determine whether it resembles a skill we already know how to perform  Thus we begin practicing a new skill with these familiar movements o Ex. Baseball players will use a swing resembling batting when playing golf  When a person is learning a new skill that requires altering an established coordination pattern, an interesting transition from old to new pattern occurs  Going back to the example of having to learn a bimanual task of moving two levers o The participants preferred way of coordinating their arms was to move both arms at the same time, this influence remained for over 60 trials, and did not consistently produce new patterns until 180 trials  This experiment showed several things o First it shows that people approach skill learning situations with distinct movement pattern biases t
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