Modeling the force-velocity dependence of a muscle-tendon unit has been one of the most interesting objectives in the field of muscle mechanics. The so-called Hill’s equation [1,2] is widely used to describe the forc...Modeling the force-velocity dependence of a muscle-tendon unit has been one of the most interesting objectives in the field of muscle mechanics. The so-called Hill’s equation [1,2] is widely used to describe the force-velocity relationship of muscle fibers. Hill’s equation was based on the laboratory measurements of muscle fibers and its application to the practical measurements in muscle mechanics has been problematic. Therefore, the purpose of this study was to develop a new explicit calculation method to determine the force-velocity relationship, and test its function in experimental measurements. The model was based on the motion analysis of arm movements. Experiments on forearm rotations and whole arm rotations were performed downwards and upwards at maximum velocity. According to the present theory the movement proceeds as follows: start of motion, movement proceeds at constant maximum rotational moment (Hypothesis 1), movement proceeds at constant maximum power (Hypothesis 2), and stopping of motion. Theoretically derived equation, in which the motion proceeds at constant maximum power, fitted well the experimentally measured results. The constant maximum rotational moment hypothesis did not seem to fit the measured results and therefore a new equation which would better fit the measured results is needed for this hypothesis.展开更多
Statement of the Problem: Upper limb hemiparesis is a common impairment underlying disability after Stroke. Transfer of treatment to daily functioning remains a question for traditional approaches used in treatment of...Statement of the Problem: Upper limb hemiparesis is a common impairment underlying disability after Stroke. Transfer of treatment to daily functioning remains a question for traditional approaches used in treatment of upper extremity hemiparesis. Approaches based on Motor Learning principles may facilitate the transfer of treatment to activities of daily living. Methodology: Forty one subjects with chronic stroke, attending department of occupational therapy, National Institute for the Orthopaedically Handicapped, Kolkata, West Bengal, India participated in a single blinded randomized pre-test and post-test control group training study. Subjects were randomized over three intervention groups receiving modified Constraint Induced Movement Therapy (n = 13), Bilateral Arm training (n = 14), and an equally intensive conventional treatment program (n = 14). Subjects in the bilateral arm training group participated in bilateral symmetrical activities, where as subjects in constraint induced movement therapy group performed functional activities with the affected arm only and conventional group received conventional Occupational Therapy. Each group received intensive training for 1 hour/day, 5 days/week, for 8 weeks. Pre-treatment and post-treatment measures included the Fugl-Meyer measurement of physical performance (FMA- upper extremity section), action research arm test, motor activity log. Assessments were administered by a rater blinded to group assignment. Result: Both m-CIMT (p = 0.01) and bilateral arm training (p = 0.01) group showed statistically significant improvement in upper extremity functioning on Action Research Arm Test score in comparison to the conventional therapy group (p = 0.33). The bilateral arm training group had significantly greater improvement in upper arm function (Proximal Fugl-Meyer Assessment score, p = 0.001);while the constraint induced movement therapy group had greater improvement of hand functions (Distal Fugl-Meyer Assessment score, p = 0.001. There is an improvement seen in Quality of movement in the Conventional Therapy group. (p = 0.001). Conclusion: Both the treatment techniques can be used for upper extremity management in patients with chronic stroke. Bilateral arm training may be used to improve upper arm function and m-CIMT may be used to improve hand functions, while the group that received modified constraint induced movement therapy had greater improvement.展开更多
The purpose of this study was to further develop the constant power model of a previous study and to provide the final solution of Hill’s force-velocity equation. Forearm and whole arm rotations of three different su...The purpose of this study was to further develop the constant power model of a previous study and to provide the final solution of Hill’s force-velocity equation. Forearm and whole arm rotations of three different subjects were performed downwards (elbow and shoulder extension) and upwards (elbow and shoulder flexion) with maximum velocity. These arm rotations were recorded with a special camera system and the theoretically derived model of constant maximum power was fitted to the experimentally measured data. The moment of inertia of the arm sectors was calculated using immersion technique for determining accurate values of friction coefficients of elbow and whole arm rotations. The experiments of the present study verified the conclusions of a previous study in which theoretically derived equation with constant maximum power was in agreement with experimentally measured results. The results of the present study were compared with the mechanics of Hill’s model and a further development of Hill’s force-velocity relationship was derived: Hill’s model was transformed into a constant maximum power model consisting of three different components of power. It was concluded that there are three different states of motion: 1) the state of low speed, maximal acceleration without external load which applies to the hypothesis of constant moment;2) the state of high speed, maximal power without external load which applies to the hypothesis of constant power and 3) the state of maximal power with external load which applies to Hill’s equation. This is a new approach to Hill’s equation.展开更多
Human arm movements may be adversely affected in the event of stroke or spinal cord injuries, eventually causing the patient to lose control of arm movements. Electromyography (EMG) is con-sidered the most effective t...Human arm movements may be adversely affected in the event of stroke or spinal cord injuries, eventually causing the patient to lose control of arm movements. Electromyography (EMG) is con-sidered the most effective technique for the restoration of arm movement in such cases. The reha-bilitation period for such patients is usually long. Moreover, complex treatment techniques may demoralize them. Therefore, this study, attempts to contribute to the development of a relaxing rehabilitation environment through electromyography control of a computer model of the arm. The model is created using MATLAB? and Data LINK software and other requisite components for training the targeted participants to control their arm movements. Six male participants with no history of injury to the arms or back were selected using the set protocol. The results and data collected are analysed using three performance measures i.e. the number of target hits, average time to target, and path efficiency for each target. Then, the main results in terms of the obtained performance measures are discussed and compared with those of previous studies.展开更多
A simple ballistic movement and two of its attributes (namely, reversal in time and synchronization with external events) are formulated. A three-dimensional, three-link musculoskeletal arm is subjected to a fast ball...A simple ballistic movement and two of its attributes (namely, reversal in time and synchronization with external events) are formulated. A three-dimensional, three-link musculoskeletal arm is subjected to a fast ballistic type movement. The central components of the movement from hippocampal, cerebellar, basal ganglia and reticular formation structures that may be involved in timing are identified. The role of agonist muscles and spinal reflexes in the execution of ballistic movements (namely, in fast starts and fast stops) is discussed. The needed three time intervals are constructed in real time and can be coordinated with external events. Delaying or advancing in time, synchronization, time scaling and inverting events in time relative to the movement is formulated. Digital computer simulations are presented to test the behavior of the formulated neural and spinal processing and demonstrate the behavior of the arm under such control.展开更多
文摘Modeling the force-velocity dependence of a muscle-tendon unit has been one of the most interesting objectives in the field of muscle mechanics. The so-called Hill’s equation [1,2] is widely used to describe the force-velocity relationship of muscle fibers. Hill’s equation was based on the laboratory measurements of muscle fibers and its application to the practical measurements in muscle mechanics has been problematic. Therefore, the purpose of this study was to develop a new explicit calculation method to determine the force-velocity relationship, and test its function in experimental measurements. The model was based on the motion analysis of arm movements. Experiments on forearm rotations and whole arm rotations were performed downwards and upwards at maximum velocity. According to the present theory the movement proceeds as follows: start of motion, movement proceeds at constant maximum rotational moment (Hypothesis 1), movement proceeds at constant maximum power (Hypothesis 2), and stopping of motion. Theoretically derived equation, in which the motion proceeds at constant maximum power, fitted well the experimentally measured results. The constant maximum rotational moment hypothesis did not seem to fit the measured results and therefore a new equation which would better fit the measured results is needed for this hypothesis.
文摘Statement of the Problem: Upper limb hemiparesis is a common impairment underlying disability after Stroke. Transfer of treatment to daily functioning remains a question for traditional approaches used in treatment of upper extremity hemiparesis. Approaches based on Motor Learning principles may facilitate the transfer of treatment to activities of daily living. Methodology: Forty one subjects with chronic stroke, attending department of occupational therapy, National Institute for the Orthopaedically Handicapped, Kolkata, West Bengal, India participated in a single blinded randomized pre-test and post-test control group training study. Subjects were randomized over three intervention groups receiving modified Constraint Induced Movement Therapy (n = 13), Bilateral Arm training (n = 14), and an equally intensive conventional treatment program (n = 14). Subjects in the bilateral arm training group participated in bilateral symmetrical activities, where as subjects in constraint induced movement therapy group performed functional activities with the affected arm only and conventional group received conventional Occupational Therapy. Each group received intensive training for 1 hour/day, 5 days/week, for 8 weeks. Pre-treatment and post-treatment measures included the Fugl-Meyer measurement of physical performance (FMA- upper extremity section), action research arm test, motor activity log. Assessments were administered by a rater blinded to group assignment. Result: Both m-CIMT (p = 0.01) and bilateral arm training (p = 0.01) group showed statistically significant improvement in upper extremity functioning on Action Research Arm Test score in comparison to the conventional therapy group (p = 0.33). The bilateral arm training group had significantly greater improvement in upper arm function (Proximal Fugl-Meyer Assessment score, p = 0.001);while the constraint induced movement therapy group had greater improvement of hand functions (Distal Fugl-Meyer Assessment score, p = 0.001. There is an improvement seen in Quality of movement in the Conventional Therapy group. (p = 0.001). Conclusion: Both the treatment techniques can be used for upper extremity management in patients with chronic stroke. Bilateral arm training may be used to improve upper arm function and m-CIMT may be used to improve hand functions, while the group that received modified constraint induced movement therapy had greater improvement.
文摘The purpose of this study was to further develop the constant power model of a previous study and to provide the final solution of Hill’s force-velocity equation. Forearm and whole arm rotations of three different subjects were performed downwards (elbow and shoulder extension) and upwards (elbow and shoulder flexion) with maximum velocity. These arm rotations were recorded with a special camera system and the theoretically derived model of constant maximum power was fitted to the experimentally measured data. The moment of inertia of the arm sectors was calculated using immersion technique for determining accurate values of friction coefficients of elbow and whole arm rotations. The experiments of the present study verified the conclusions of a previous study in which theoretically derived equation with constant maximum power was in agreement with experimentally measured results. The results of the present study were compared with the mechanics of Hill’s model and a further development of Hill’s force-velocity relationship was derived: Hill’s model was transformed into a constant maximum power model consisting of three different components of power. It was concluded that there are three different states of motion: 1) the state of low speed, maximal acceleration without external load which applies to the hypothesis of constant moment;2) the state of high speed, maximal power without external load which applies to the hypothesis of constant power and 3) the state of maximal power with external load which applies to Hill’s equation. This is a new approach to Hill’s equation.
文摘Human arm movements may be adversely affected in the event of stroke or spinal cord injuries, eventually causing the patient to lose control of arm movements. Electromyography (EMG) is con-sidered the most effective technique for the restoration of arm movement in such cases. The reha-bilitation period for such patients is usually long. Moreover, complex treatment techniques may demoralize them. Therefore, this study, attempts to contribute to the development of a relaxing rehabilitation environment through electromyography control of a computer model of the arm. The model is created using MATLAB? and Data LINK software and other requisite components for training the targeted participants to control their arm movements. Six male participants with no history of injury to the arms or back were selected using the set protocol. The results and data collected are analysed using three performance measures i.e. the number of target hits, average time to target, and path efficiency for each target. Then, the main results in terms of the obtained performance measures are discussed and compared with those of previous studies.
文摘A simple ballistic movement and two of its attributes (namely, reversal in time and synchronization with external events) are formulated. A three-dimensional, three-link musculoskeletal arm is subjected to a fast ballistic type movement. The central components of the movement from hippocampal, cerebellar, basal ganglia and reticular formation structures that may be involved in timing are identified. The role of agonist muscles and spinal reflexes in the execution of ballistic movements (namely, in fast starts and fast stops) is discussed. The needed three time intervals are constructed in real time and can be coordinated with external events. Delaying or advancing in time, synchronization, time scaling and inverting events in time relative to the movement is formulated. Digital computer simulations are presented to test the behavior of the formulated neural and spinal processing and demonstrate the behavior of the arm under such control.
