Theories of Movement Control - Essay Example

Theories of Movement Control Introduction A field of Applied Mathematics pertinent to the regulation or control of certain physical processes and systems is referred to as the Control Theory. With time passing by, the rise in problems involved in Engineering and Economics were recognized as variants of various problems in differential equations and in the calculus of variations, although, they were not wrapped up by the existing theories. Many amendments of classical techniques and theories were formulated in order to seek solutions to those intricacies, within which the Control Theory emerged. It is an interdisciplinary branch of engineering and mathematics dealing with the nature of dynamic systems. According to Schmidt and Wrisberg, there are at least two ways of conceptualizing the term 'motor skill' which can be construed as a talk or an act, where motor skills can be distinguishable along a number of aspects or on the basis of a variety of high-flying characteristics (Schmidt and Wrisberg, 2008). The second way construes to the conceptualization of motor skill in terms of the ability a person delineates while performing a movement. Utley and Astill, in their book, have stated that the motor skills can efficiently be implemented in the brain and nervous system as well and also that they can be improvised (Utley and Astill, 2008). The development in motor skills defines the field of measurement as well as movement, thereby, learning the ways to control movement as a whole. This paper delineates the contrasting nature of both the theories of motor control, i.e. the open-loop and the closed-loop theory, thereby, stating examples which demonstrate the different explanations of human coincidence-anticipation performance. 2. The Open-Loop Theory In open loop controller theory, the controller does not ensure whether the output, i.e. the position or velocity, equals the anticipated output during the operation of the system. In an open loop system, the controller output indication is settled on by the input signal from the computer or any other non-essential device. In response to incorrect calculation of the system response, or the affect of some other occurrence in the output signal, the system might turn aside from the desired path. As a result, it is necessary for the controller to assume that each part of the system is at its absolute position and has moved there at the correct pace. No feedback is conceived from the system, which would enable the controller to weigh against the actual position to the programmed position. In such a case, it is not possible for the controller to check and correct himself. Under this kind of a system, it is feasible to incline against the designated positions and paces, and not be able to correct the difficulties. This theory is significant for well-defined systems where the relationship between input and the resultant state can be modeled by a mathematical formula. For example, determining the voltage to be supplied to an electric motor which drives a consistent load, so as to acquire a desired pace can be considered as an appreciable implementation of open-loop control system. However, on the other hand, if the load were not predictable, the motor's pace might vary as an operation of the load as well as of the voltage. As a result, the open-loop controller would not be satisfactory enough to ensure the repeatable control of the speed. To comprehend the open-loop control system, an example of a conveyer system which is required to travel at a constant speed can be taken into account. For a consistent electrical energy, the conveyer moves at a different speed depending on the load of the motor. In order for the conveyer to work at a consistent speed, it is compulsory for the motor to be adjusted in accordance with the load. This signifies the system of closed-loop control on the other hand. 3. Schmidt's Schema Theory or the Closed-Loop Theory Schmidt's schema theory of motor control was devised from a theory of motor learning involving the concept of generalized motor program being featured as a prime construct (Schmidt, 1975). In his theory, the relationship between the parameters and outcomes are collected in two schemes or schema, by which the theory is hence, known. Schmidt devised the generalized motor course framework responsive to the two prevailing views, one of which was the closed-loop control which involved the evolution of movement in a cascade of chained reactions which used pro-prioceptive response as the sensory stimulant for the generation of the forthcoming efferent indication in the movement. A considerable example for such an action could be the theory of Adams, which was deliberately restricted to explaining the generation of slow positioning movements and, as such, left inexplicable the way to achieve regulation and control over fast movements. Schmidt, in the Schema theory, proposed the existence of two creations, one of which is the generalized motor program and the other one is the schema. Schmidt's Schema theory is presently the most widespread recognized psychological advancement to human movement. As Schmidt proposed that a fundamental aspect of the learning of motor skills involves the attainment of schemata which define the relationships amongst the information involved in the generation and evaluation of motor responses, in context of the summary by Shapiro and Schmidt, the schema theory comprises mainly of three major constituents: the generalized motor program, the recall schema, and the recognition schema (Shapiro and Schmidt, 1982, pp. 115). To be elaborative, the generalized motor program is a conceptual memory anatomy which causes movement to occur and can be executed in several ways so as to yield various movement upshots. In order to acquire various results, it is significant to determine certain parameters like speed and force of the program. As a result, a generalized motor program can be construed as a program which governs a given category of movements that requires a common movement framework. The ideology of the generalized motor program evolved from the scrutiny that movements which were slightly different in comparison to each other in some or the other way, seemed to be similar in certain other ways as well. In context to Armstrong's findings, when a movement sequence was speeded up accidentally, the entire movement sequence was speeded up as a unit, which is usually called as relative timing or phasing (Armstrong, 1970). It appeared to remain consistent in the faces of overall movement time which resulted in the discovery of another invariant feature of the generalized motor program, called as the relative force, or the relations amongst the forces called up in the influences which took part in the action. Furthermore, in order to achieve an anticipated result, an independent memory state, recall schema, opts for the parameters in requirement for the implementation of the generalized motor program properly. Eventually, another independent memory state which is the recognition schema is responsible for the evaluation of response. Initial conditions, past genuine results, and past sensory consequences are what comprises of the recognition schema. 4. Distinction between open-loop and closed-loop theory Let us not get into an elaborative explanation of the specifics of the control theory, as it is easier to make simple distinction between the open and closed loop theory. Open-loop theory is inclusive of the systems which involve no feedback from the object being controlled. An input stimulus is facilitated and the controller operates the system in order to go to a meticulous location, speed, and anticipates the system to respond accordingly. There is no information available from the system's side under control so as to indicate that it even conceived a command, much less acted upon (Ruff, 2005). The means to a closed-loop control system is the introduction of feedback, for id speed is being regulated, a measure of the current speed is provided back to the controller, which allows it to adjust its commands with response to the system. In the similar manner, it is true with position as well. in order to seek for a perfect description of a closed-loop system, let us consider a gymnast on a balance beam. They are consistently commanding their muscles in order to adjust the pressure and position of their feet so as to maintain a set position. It can be done on the basis of inputs from vision, sagacity of balance, and a perceptible response from contact with the beam itself (Ruff, 2005). The two general models which are used to describe the motor function are the open system and the closed system. Where the open system is characterized by a single transfer of information without any response from the loops, the closed loop theory stresses on the usage of feedback, meticulously in learning new tasks. The usage of feedback holds equal significance during new tasks as the individual makes use of the internal trial and error as opposed go chiefly external trial and error in adjudging about the absoluteness of the motor performance. The open system model signifies its use in the conventional reflexive hierarchal theory of motor control. Nonetheless, the closed system theory involves multiple feedback loops and supports the concept of distributed control. Furthermore, in the closed-loop theory, the nervous system is viewed as the active agent involving anatomies which allow for the initiation and production of movement, and not simply an agent reacting to incoming stimuli. On the other hand, open-loop theory accounts for the skills that are well-established and performed in a rapid way, and where response id not utilized due to the speed required for accomplishing the task. Usually, open-loop systems are subject to attainment in various fields of movement theories, closed-loop theory is used during the early intervention period (Montgomery and Connolly, 2002). 5. Examples of Human Coincident-Anticipation Performance The coincidence-anticipation research facilitates information about the anticipatory aspects of skills such as catching. Where older adults are somewhat less accurate and variable in their performance than the young performers, the differences are greater when the moving object becomes faster and the older adults are sedentary rather than active (Haywood, 1980). On the other hand, according to Victor, children who are capable of catching small balls in their hands may measure very large balls with their arms, conceivably, as a surer means of retaining it (Victors, 1961). As a result, the task can be construed as requiring a simpler or intricate movement response, with variance of the characteristics of the ball to further hinder the movement. As Schmidt and Wrisberg have stated in their work, hitting a pitched baseball is another example of coincidence-anticipation task where a professional pitcher can throw the ball at speeds which exceed 144.8 km per hour (Schmidt and Wrisberg, 2008). Since, the distance between the pitcher and the batter is about 18 m, it can be estimated that the ball would travel from the pitcher's hand to the coincidence point in about 460 m. Furthermore, Hubbard and Seng noted that a conventional movement of time of the swing for batters is about 160 ms (Hubbard and Seng, 1954). The internal signal in order to trigger a movement occurs about 170 ms before the action starts. As a result, batters must make all the decisions about swinging before the ball has traveled barely one-third of the way to the plate. Research by Halsband on motor learning suggests that for most people, the left hemisphere plays a significant role in learning the movement of trajectories (Halsband, 1992). For example, tracing a target figure within the visual field can be construed as a specific movement of trajectories. On the other hand, according to Dubrocard and Velay, the right hemisphere has a chief role in the programming of spatial movements, for example, directing the right hand to targets in a spatially defined sequence (Benoit-Dubrocard and Velay, 1999). However, the two hemispheres interact with each other in conditions which are in requirement of cooperation from both the sides of the body. A situation which involves the transfer of a motor skill mastered by one side of the body to the other is referred to as the Bilateral Transfer of Learning. 6. Conclusion Schmidt and Wrisberg believe that the fundamental concepts of the motor control theories in motor learning and performance are relevant to the life and work of many different kinds of people, which encourage ponder the possible relevance the concepts hold for them (Schmidt and Wrisberg, 2008). With a vast study of the fundamental control theories, many of the concepts and principles of motor performance and learning can be comprehended, and that those principles can be applied to a variety of real-world situations. Moreover, the acquirement of this knowledge can provide a solid grasp of the conceptual models of motor performance and develop other situation-based working strategies. In addition, Utley and Astill believe that a study of the development of motor skills lays the foundation of knowledge and information which is vital for any individual who is working in the movement context as a teacher, coach or a therapist (Utley and Astill, 2008). 7. References 1. Armstrong, T.R. 1970, Training for the production of memorized movement patterns. Technical Report, No.26, Human Performance Center, University of Michigan. 2. Benoit-Dubrocard, S. and Velay, J. 1999, Hemispheric asymmetry and interhemispheric transfer in reaching 3. programming. Neuropsychologia, 37. Pp. 895-903. 4. Gilinsky, Victor. 1961, The decay of bound muons. California Institute of Technology. 5. Halsband, U. 1992, Left hemisphere preponderance in trajectorial learning. Neuro Report, 3. Pp. 397-400. 6. Haywood, R. W. 1980, Analysis of Engineering Cycles. Pergamon Press. 7. Hubbard, A. W. and C. N. Seng. 1954, Visual movements of batters. Research Quarterly. The Alliance. 8. Montgomery, Patricia and Barbara H. Connolly. 2002, Clinical Applications for Motor Control. SLACK Incorporated. 9. Ruff, Matt. 2005, Servo Motor Control Application on a Local Interconnect Network (LIN). Freescale Semiconductor: Application Note. AN2396, Rev. 1.0. 10. Schmidt, R. A. 1975, A schema theory of discrete motor skill learning. Psychological Review, 82. Pp. 225-260. 11. Shapiro, D. C. and Schmidt, R.C. 1982, The Schema Theory: recent Evidence and Developmental Imlications. J. A. S. Kelso and J. E. Clark (eds.) The Development of Movement Control and Co-ordination. John Wiley and Sons, Ltd. Pp. 113-150. 12. Schmidt, Richard A. and Craig A. Wrisberg. 2008, Motor Learning and Performance. Human Kinetics. 13. Utley, A and Sarah Astill. 2008, Instant Notes in Motor Control, Learning and Development. Taylor and Francis. Read More