W5 - Principles of Movement Control & Motor Accuracy Flashcards
How do information-processing, ecological, and dynamic systems differ from each other?
These perspectives differ not only in the manner in which they define development and learning but also in how they examine behavior. In the information-processing approach, movement patterns are defined as GMPs, which include variables that cannot be modified (invariant features) and variables that can be modified (parameters). According to the ecological theories, we perceive objects as the actions they can afford us and those perceptions and actions are guided by body-scaled ratios. According to the dynamic systems theory, movement emerges as a function of the individual, the task, and the environment
What is the Information Processing Approach?
brain receives, processes, and interprets information in order to send signals to produce skilled coordinated movements
What is a Generalised Motor Program?
a representation of a pattern of movements that are modifiable to produce a movement outcome
How does the Information Processing Approach & GMP link to each other?
the combination explains the production of skilled movement, eg writiong with R hand or L Hand. Invariant features (don’t vary): Sequence of actions •Relative timing •Relative force Parameters (can be varied):
•Muscle selection •Overall duration •Overall force. This relate to the rhythm of the movement. Walking and running are different GMPs, but both can be varied in terms of duration, force etc
What is the difference between open-loop and closed-loop control?
Closed-loop control is used for relatively long- duration, continuous activities that provide the opportunity to make online corrections based on feedback received during the movement eg writing. Open-loop control is used for movements that are more rapid and discrete such that the performer needs to preplan the movement. Often associated with a point of no return
develop invariant features and parameters in generalised motor programs
Invariant Features
Sequence of actions: An American football punt sequence is catch, approach, drop, kick.
Relative timing: When you swing to hit a volleyball during a serve must be relative to the timing of your toss.
Relative force: The force of your foot making contact with a ball during a kick should be relative to the force with which you approached the ball and the movement of your leg.
Parameters
Muscle selection: The GMP is the same for throwing with your left hand as it is for throwing with your right hand.
Overall duration: The GMP is the same for running slowly as it is for running faster. Overall force: The GMP is the same for batting with more overall force as it is for batting with less overall force.
What is Dynamic Sytems Theory?
emphasized that movements are controlled by more than just the central nervous system; they are also controlled by interactions within various body systems as well as with the environment. Many factors are involved in how we move, which can cause us to move differently from one day to the next as a result of changes in the environment (physical or sociocultural), the task (goal, equipment, rules), or personal factors (motivation, attention, interest, fatigue). However, the information-processing theory does not account for the continuous interaction of the person with the environment. Bench pressing with a comfortable weight is an example of a strong attractor. As the amount of weight is increased (control parameter), the person’s form will become progressively less stable until at some point the person will change form to be able to continue to lift. The amount of increased weight that causes this change to poor form is an example of a rate limiter. The change from good form to bad form is an example of a phase shift.
How does perception linked to movement?
perception enables us to interact with the environment in a meaningful way. For instance, we perceive the sizes of objects and determine how to adjust our grip to manipulate them. We perceive through our senses (vision, hearing, and kinesthesis), but perception is also affected by our personal experiences and understanding.
differentiate information-processing theory and the ecological approach to perception
Ecological psychology rejects the idea that there is a need to search for memory stores to determine how or whether to interact with an object (info processing model). Instead, the acts of perceiving and moving occur simultaneously. We cannot move without perceiving, just as we cannot perceive without acting. For example, a hiker walking through the woods who sees a fallen log does not see the log, perceive what it is, decide how to act on it, and then act on it. Instead, the log “affords” the hiker a place to sit. The perception and action are the same.
understand the speed-accuracy trade-off in simple aiming movements
Fitts (1954) extended this research and discovered that speed decreased when either the distance between the targets was increased or the size of the targets was decreased when focusing on accuracy. nterestingly, this relationship exists only for spatial accuracy. In regard to temporal accuracy, such as the speed of a swing, accuracy improves with increased speed. For example, Estimates of time are more accurate with less time than with more time. You could try this by estimating time with a stopwatch. Compare your estimates of shorter periods of time (e.g., one or five seconds) to longer periods of time (e.g., one minute).
understand logarithmic and linear relationships between speed and accuracy
lncreases in movement distance and decreases in MT can be traded off with each other to maintain movement accuracy. Spatial accuracy
understand the relationship between timing accuracy and movement time
for many skills the main goal is temporal accuracy (e.g., batting a baseball). In such skills a movement must be timed so that some part of it is produced at a particular moment (e.g., the bat must cross the plate at the same time the ball is there). The timing accuracy is critical to the success of the movement. For example, a perfectly struck chord on the guitar makes the most contribution to the music when it is timed just right.
understand the principles of bimanual timing and the role of self-organising principles
Controlling the continuous movement of two limbs, each with its own spatial or temporal goal (or both), represents a different problem for the motor control system (e. g., rubbing your head while patting your tummy). Movements involving more than one limb are not controlled independently, but rather by a command structure that coordinates both actions simultaneously. Because the movements are ongoing, the executive has the flexibility to use a common movement command to control the movements of both limbs (as discussed for discrete movements) or to switch attention rapidly between the executions of the two tasks.
what are self-organising principles (dynamic systems theory)
The notion of the motor program is not without its critics. Some argue that the program notion assumes too much cognition, neural computation, and direct control by brain and spinal cord mechanisms, so that every movement must have an explicit representation stored in the central nervous system. Investigators from the self-organization perspective hold that the regularities of movement patterns are not represented in programs but rather emerge naturally (that is, through physics) out of the complex interactions among many connected elements
