Current Search: Human mechanics (x)
View All Items
(1 - 11 of 11)
- Title
- Functional stabilization of unstable systems.
- Creator
- Foo, Patrick Stephen, Florida Atlantic University, Kelso, J. A. Scott
- Abstract/Description
-
Humans are often faced with tasks that require stabilizing inherently unstable situations. We performed four experiments to explore the nature of functional stabilization. In Experiment 1 participants balanced a pole until a time criterion was reached. The geometry, mass, and characteristic "fall time" of the pole were manipulated. Distributions of timing between pole and hand velocities showed strong action-perception coupling. When actions demonstrated a potential for failure, the period of...
Show moreHumans are often faced with tasks that require stabilizing inherently unstable situations. We performed four experiments to explore the nature of functional stabilization. In Experiment 1 participants balanced a pole until a time criterion was reached. The geometry, mass, and characteristic "fall time" of the pole were manipulated. Distributions of timing between pole and hand velocities showed strong action-perception coupling. When actions demonstrated a potential for failure, the period of hand oscillation correlated significantly with the "time to balance" (t bal=theta/theta.), where q is pole angle re: the vertical balance point, but not other quantities such as theta and theta. alone. This suggested that participants were attending to available t bal information during critical situations. In a model analysis and simulation, we demonstrated how discrete t bal information may be used to adjust the parameters of a controller to perform this task. In Experiment 2 participants balanced a virtual inverted pendulum under manipulations designed: (1) to decouple the mechanics of the system from its visual image; (2) to alter the mapping of perception and action; and (3) to perturb successful balancing. A replication of the correlation analysis of Experiment 1 revealed that across all conditions, significant relationships existed between visually specified t -variables and hand oscillation during critical motions of the pole. These results suggested that participants use the same t bal information to successfully stabilize both virtual and physical unstable systems, despite quite dramatic visual and mechanical transformations. In Experiments 3 and 4 we investigated how parts of the body, or individuals in a social dyad cooperate to perform a functional stabilization task. Participants balanced a pole either intermanually (using 2 separate hands) or interpersonally (2 persons each using their preferred right hand) until a time criterion was reached. Although the magnitudes of the forces exerted by each hand were different, an analysis of the timing of the forces revealed that intermanual (interpersonal) participants developed a consistent antiphase (inphase) coordination pattern. These different coordination patterns allowed for the recruitment of previously unavailable efferent and afferent connections to produce the net forces that served to stabilize the pole via theta. (see Experiment 1).
Show less - Date Issued
- 2000
- PURL
- http://purl.flvc.org/fcla/dt/12656
- Subject Headings
- Psychology, Experimental, Human mechanics
- Format
- Document (PDF)
- Title
- The coordination dynamics of single limb multijoint movement patterns: Spatial bifurcations and hysteresis.
- Creator
- Buchanan, John J., Florida Atlantic University, Kelso, J. A. Scott
- Abstract/Description
-
The aim of this research was to study the coordinative dynamics of multijoint arm movements as a function of forearm spatial orientation. Six subjects rhythmically coordinated flexion and extension of the right elbow and wrist under the following conditions: (1) forearm supine: wrist flexion/elbow flexion and vice versa; and (2) forearm prone: wrist flexion/elbow extension and vice versa. Starting in either pattern, subjects rotated the forearm in eight 20 steps, producing 15 cycles of motion...
Show moreThe aim of this research was to study the coordinative dynamics of multijoint arm movements as a function of forearm spatial orientation. Six subjects rhythmically coordinated flexion and extension of the right elbow and wrist under the following conditions: (1) forearm supine: wrist flexion/elbow flexion and vice versa; and (2) forearm prone: wrist flexion/elbow extension and vice versa. Starting in either pattern, subjects rotated the forearm in eight 20 steps, producing 15 cycles of motion at a frequency of 1.25 Hz. Switching from pattern (1) to pattern (2) and vice versa was observed at a critical spatial orientation. The critical point depended on the direction of forearm rotation, thus revealing the hysteretic nature of the switching. En route to the transition, regardless of direction of change, critical fluctuations and critical slowing down were observed in the relative phasing between the joints. Such results provide definitive evidence that relative phase is a viable order parameter, spatial orientation a relevant control parameter and loss of stability the chief mechanism leading to observed changes in coordination.
Show less - Date Issued
- 1992
- PURL
- http://purl.flvc.org/fcla/dt/14806
- Subject Headings
- Arm, Forelimb, Human mechanics, Kinesiology
- Format
- Document (PDF)
- Title
- Bereitschaftspotentials and the frequency and phase characteristics of the EEG preceding bimanual finger movements.
- Creator
- Wallenstein, Gene Vincent, Florida Atlantic University, Nash, Allan J.
- Abstract/Description
-
A delayed response paradigm was used to investigate the cerebral electroencephalographic (EEG) signal preceding bimanual finger flexions of continuously increasing and decreasing movement rates. The Bereitschaftspotential displayed larger amplitudes at faster required response rates as did two spectral frequency modes, which also showed magnitude reversals depending on the initiating finger. Furthermore, at these specific frequency modes, the averaged relative phase between electrode...
Show moreA delayed response paradigm was used to investigate the cerebral electroencephalographic (EEG) signal preceding bimanual finger flexions of continuously increasing and decreasing movement rates. The Bereitschaftspotential displayed larger amplitudes at faster required response rates as did two spectral frequency modes, which also showed magnitude reversals depending on the initiating finger. Furthermore, at these specific frequency modes, the averaged relative phase between electrode locations C3 and C4, as well as the variance in this measure was found to correspond closely to the variance in inter-response times derived from the subjects' movements. The results suggest the existence of possible signatures on the neurophysiological level which may yield information regarding the efficacy and parametric properties of the impending movement.
Show less - Date Issued
- 1992
- PURL
- http://purl.flvc.org/fcla/dt/14847
- Subject Headings
- Electroencephalography, Arm, Forelimb, Human mechanics, Neurophysiology
- Format
- Document (PDF)
- Title
- Flexible modification of biological coordination: The recruitment and suppression of degrees of freedom.
- Creator
- Buchanan, John J., Florida Atlantic University, Kelso, J. A. Scott
- Abstract/Description
-
The dynamics of recruitment and suppression processes are studied in the coupled pendulum paradigm developed by Kugler and Turvey (1987). Experimentally, the main concern is whether pendulum motion in this task is purely planar. Theoretically, the main concern is whether one-dimensional phase equations developed originally by Haken, Kelso and Bunz (1985) and the symmetry breaking extension by Kelso, Delcolle and Schoner (1990), can capture the richness of the dynamics of this experimental...
Show moreThe dynamics of recruitment and suppression processes are studied in the coupled pendulum paradigm developed by Kugler and Turvey (1987). Experimentally, the main concern is whether pendulum motion in this task is purely planar. Theoretically, the main concern is whether one-dimensional phase equations developed originally by Haken, Kelso and Bunz (1985) and the symmetry breaking extension by Kelso, Delcolle and Schoner (1990), can capture the richness of the dynamics of this experimental model system. In experiment 1, subjects swung single hand-held pendulums in time with an auditory metronome whose frequency increased. Bifurcations from planar to spherical pendulum motion occurred at critical cycling frequencies. Typically, these frequencies were above the pendulum's eigenfrequency. Spectral measures showed that spherical pendulum motion was generated through the recruitment of wrist abduction and adduction. The spectral measures revealed that elbow flexion and extension was recruited as movement rate increased, presumably to stabilize pendulum motion. When recruited, both components frequency- and phase-entrained with the primary pendulum mover, wrist ulnar flexion-extension. In experiment 2, subjects swung coupled pendulums in either an in-phase or anti-phase coordinative mode as movement rate increased. Transitions between coordinative modes were not observed. Pattern stability, as defined by the variability of the phase relation between the pendulums, was not affected to any large degree by increasing movement rate. Bifurcations from planar to spherical motion emerged at critical cycling frequencies. Spectral measures demonstrated that this motion was generated by abduction and adduction of the wrist. Elbow flexion-extension motion was also recruited. The newly active components frequency- and phase-entrained with wrist ulnar flexion-extension. When the same neuromuscular components were recruited simultaneously, e.g., elbow motion in both arms, the components exhibited frequency- and phase-entrainment with the task defined pattern. The results demonstrate that recruitment processes stabilize the coordinative modes, thereby reducing the need to switch patterns. Both experiments revealed a much richer dynamics than ever observed in the coupled pendulum paradigm and question the application of one-dimensional phase equation models to the coupled pendulum paradigm.
Show less - Date Issued
- 1996
- PURL
- http://purl.flvc.org/fcla/dt/12439
- Subject Headings
- Kinesiology, Human mechanics, Movement, Psychology of, Motor learning
- Format
- Document (PDF)
- Title
- An investigation of the possible intermittent dynamics in the transition region between two modes of behavior using delays.
- Creator
- Holroyd, Tom, Florida Atlantic University, Kelso, J. A. Scott, Charles E. Schmidt College of Science, Department of Psychology
- Abstract/Description
-
In this thesis the transition region between two modes of behavior is explored using a novel technique, delayed feedback, and a variety of dynamical systems measures. In a previous study, Engstrom, Kelso, and Holroyd (to appear) established the existence of a transition between anticipatory and reactive behavior in a sensorimotor coordination task as a control parameter (frequency) was varied. Here, in order to explore the hypothesis that the behavioral dynamics during this transition are...
Show moreIn this thesis the transition region between two modes of behavior is explored using a novel technique, delayed feedback, and a variety of dynamical systems measures. In a previous study, Engstrom, Kelso, and Holroyd (to appear) established the existence of a transition between anticipatory and reactive behavior in a sensorimotor coordination task as a control parameter (frequency) was varied. Here, in order to explore the hypothesis that the behavioral dynamics during this transition are intermittent in character, subjects were asked to synchronize with a metronome that was actually a delayed copy of their own response pattern. The use of delayed feedback was expected to destabilize the behavioral dynamics enough to allow the observation of hypothesized intermittent phenomena. Use of delayed feedback was shown to destabilize synchronization, resulting in the emergence of a new behavioral pattern in the transition region that exhibited complex "bursting" dynamics. Analysis revealed that this bursting behavior displays many of the characteristics common to intermittency, which supports the idea that the anticipation-reaction transition is the result of a neurobehavioral dynamical system losing stability. Living in the vicinity of instabilities may be an important mechanism for biological organisms to maintain both flexibility and stability.
Show less - Date Issued
- 1994
- PURL
- http://purl.flvc.org/fcla/dt/15042
- Subject Headings
- Biological rhythms, Human mechanics, Circadian rhythms, Biological control systems
- Format
- Document (PDF)
- Title
- A Hybrid System for Simulation of Athletic Activities Related to Lower Extremity Biomechanics.
- Creator
- Trepeck, Cameron, Hashemi, Javad, Florida Atlantic University, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
- Abstract/Description
-
In this dissertation, the design and development of a hybrid robotic system that simulates dynamic biomechanical tasks of the lower extremity with emphasis on knee and hip joints are presented. The hybrid system utilizes a mechanical hip and a cadaveric knee/ankle component and can accelerate the whole complex towards the ground. This system is used to simulate complex athletic movements such as landing from a jump at various anatomical orientations of the lower extremity with muscle action....
Show moreIn this dissertation, the design and development of a hybrid robotic system that simulates dynamic biomechanical tasks of the lower extremity with emphasis on knee and hip joints are presented. The hybrid system utilizes a mechanical hip and a cadaveric knee/ankle component and can accelerate the whole complex towards the ground. This system is used to simulate complex athletic movements such as landing from a jump at various anatomical orientations of the lower extremity with muscle action. The dynamic response of the lower extremity is monitored and analyzed during impulsive contact between the ground and the cadaveric leg. The cadaveric knee is instrumented to measure strain of the Anterior Cruciate Ligament (ACL) during simulated high impact sports activities. The mechanical hip allows various kinematics of the hip including flexion as well as abduction. In addition to the flexion and abduction of the mechanical hip, the controlled flexion and extension of the cadaveric knee allows for simulation of complex tasks such as landing from a jump. A large number of tests were performed at various anatomical positions utilizing this device to simulate landing from a jump. ACL strain was measured during these tasks using a Differential Variance Resistance Transducer (DVRT). Ground Reaction Force and muscle forces were measured and monitored using AmCell load cells recorded using the LabView software. one-inch and 6-inch jump landing heights were used for all the simulations. The tests were performed at differing angles of hip flexion (0°, 30°, 45°, 60°) and at two different ankle positions. Plantar flexion and flat-footed landing conditions were simulated and compared in all degrees of hip flexion. These tests were repeated with and without hip abduction in order to study the effects of these landing positions on ACL strain. Hip flexion was found to effect ACL strain: as angle of hip flexion increases, ACL strain decreases. This occurred in both abducted and non-abducted hip positions. Ankle landing position had an effect only in small drop heights, while hip abduction had an effect in large drops. Future tests must be completed to further study these effects. These studies showed that the robotic system can simulate dynamic tasks, apply muscle forces, and move the cadaveric tissue in three dimensional biomechanical positions.
Show less - Date Issued
- 2017
- PURL
- http://purl.flvc.org/fau/fd/FA00004898, http://purl.flvc.org/fau/fd/FA00004898
- Subject Headings
- Musculoskeletal system--Wounds and injuries., Musculoskeletal system--Mechanical properties., Biomechanics--Computer simulation., Human mechanics., Artificial joints.
- Format
- Document (PDF)
- Title
- Relationship Between Anthropometric Measurements and Average Concentric Velocity In The Back Squat.
- Creator
- Cooke, Daniel M., Zourdos, Michael C., Florida Atlantic University, College of Education, Department of Exercise Science and Health Promotion
- Abstract/Description
-
The purpose of the present study was to investigate if any relationship exists between anthropometric measurements with average concentric velocity (ACV) at various intensities in the back squat and the number of repetitions able to be performed during a set to volitional fatigue at 70% of one-repetition maximum (1RM). It was hypothesised that short femurs and total height would be related to slower ACVs and lower total number of repetitions performed. 58 resistance trained subjects were...
Show moreThe purpose of the present study was to investigate if any relationship exists between anthropometric measurements with average concentric velocity (ACV) at various intensities in the back squat and the number of repetitions able to be performed during a set to volitional fatigue at 70% of one-repetition maximum (1RM). It was hypothesised that short femurs and total height would be related to slower ACVs and lower total number of repetitions performed. 58 resistance trained subjects were recruited and attended one day of data collection. Subjects performed 1RM testing of the back squat followed by two single repetition sets at 30-90% of 1RM and a 70% of 1RM set to fatigue. There was no significant correlation between femur length and height with ACV at any intensity (p>0.05). A significant negative correlation existed between both height (r=-0.39, p=0.003) and femur length (r=-0.31, p=0.018) with total number of repetitions performed.
Show less - Date Issued
- 2017
- PURL
- http://purl.flvc.org/fau/fd/FA00004946, http://purl.flvc.org/fau/fd/FA00004946
- Subject Headings
- Sports--Physiological aspects., Exercise--Physiological aspects., Body composition--Measurement., Human mechanics., Muscle strength--Measurement.
- Format
- Document (PDF)
- Title
- Finite element analysis and modeling of the anterior cruciate ligament in the human knee.
- Creator
- Savage, Tabatha Jordan, Hashemi, Javad, Florida Atlantic University, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
- Abstract/Description
-
The Anterior Cruciate Ligament (ACL) resists excessive anterior translation and internal rotation of the tibia during athletic activities and stabilizes the knee. In the US, annually, over 200,000 cases of ACL disruption are reported. The impact on the quality of life of the subject and its cost to healthcare is tremendous. The objectives of this study were to determine any significant associations between the size of the tibial eminence and ACL injury and to develop a finite element model...
Show moreThe Anterior Cruciate Ligament (ACL) resists excessive anterior translation and internal rotation of the tibia during athletic activities and stabilizes the knee. In the US, annually, over 200,000 cases of ACL disruption are reported. The impact on the quality of life of the subject and its cost to healthcare is tremendous. The objectives of this study were to determine any significant associations between the size of the tibial eminence and ACL injury and to develop a finite element model for structural analysis. The results suggest that the size of the tibial eminence plays a role in loading the ACL and is therefore a risk factor. In addition to the epidemiological analysis, a finite element model of the knee was developed that with added modifications can be used for complex knee loading situations. The results in this thesis may be used to develop strategies for ACL injury prevention and rehabilitation.
Show less - Date Issued
- 2014
- PURL
- http://purl.flvc.org/fau/fd/FA00004327, http://purl.flvc.org/fau/fd/FA00004327
- Subject Headings
- Arthroscopy, Athletic injuries -- Prevention, Biomedical materials, First aid in illness and injury, Human mechanics, Joints -- Pathophysiology, Sports -- Physiological aspects, Sports medicine
- Format
- Document (PDF)
- Title
- Hippocampal CA1 activation during object memory encoding in the novel object recognition task.
- Creator
- Cinalli, David A., Stackman, Robert W., Florida Atlantic University, Charles E. Schmidt College of Science, Department of Psychology
- Abstract/Description
-
Transcription and translation of proteins are required for the consolidation of episodic memory. Arc, an effector immediate early gene, has been linked to synaptic plasticity following learning and memory. It is well established that the rodent hippocampus is essential for processing spatial memory, but its role in processing object memory is a point of contention. Using immunohistochemical techniques, hippocampal sections were stained for arc proteins in the CA1 region of the dorsal...
Show moreTranscription and translation of proteins are required for the consolidation of episodic memory. Arc, an effector immediate early gene, has been linked to synaptic plasticity following learning and memory. It is well established that the rodent hippocampus is essential for processing spatial memory, but its role in processing object memory is a point of contention. Using immunohistochemical techniques, hippocampal sections were stained for arc proteins in the CA1 region of the dorsal hippocampus in mice following two variations of the novel object recognition (NOR) task. Results suggest mice that acquired strong object memory showed significant hippocampal activation. In mice that acquired weak object memory, hippocampal activation was not significantly different from controls. Arc expression was also examined in other hippocampal sub-regions, as well as in the perirhinal cortex. These results suggest that the mice must acquire a threshold amount of object information before the hippocampal CA1 region is engaged.
Show less - Date Issued
- 2015
- PURL
- http://purl.flvc.org/fau/fd/FA00004436, http://purl.flvc.org/fau/fd/FA00004436
- Subject Headings
- Association of ideas, Cellular control mechanisms, Cellular signal transduction, Episodic memory, Hippocampus (Brain) -- Physiology, Human information processing, Mice as laboratory animals
- Format
- Document (PDF)
- Title
- Martial Arts as a markup language.
- Creator
- Vo, Thomas, Shankar, Ravi, Florida Atlantic University, College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
- Abstract/Description
-
This thesis describes the modeling of Martial Arts as a markup language. Up until now Martial Arts has already been documented in books, videos, tradition and other methods. Though to represent Martial Arts knowledge consistently and uniformly in a digital era, we introduce the Martial Arts Markup Language (MAML), which is based on XML. Because XML provides a standardized, serializable and portable format, MAML also enables sharing among students, teachers and their peers across different...
Show moreThis thesis describes the modeling of Martial Arts as a markup language. Up until now Martial Arts has already been documented in books, videos, tradition and other methods. Though to represent Martial Arts knowledge consistently and uniformly in a digital era, we introduce the Martial Arts Markup Language (MAML), which is based on XML. Because XML provides a standardized, serializable and portable format, MAML also enables sharing among students, teachers and their peers across different platforms, media and networks. MAML provides the ability, with appropriate XML tools, to document a Martial Arts style in a structured way. To achieve this, we first analyze the aspects that comprise Martial Arts; and how its states and processes relate to one another. We model in MAML describing the stances, transitions, punches, blocks, techniques, combinations, reactions and patterns used in Martial Arts. We discuss the implementation of MAML by observing and extracting the definable aspects in existing Martial Art Instructive Documents. The MAML Schema assures that the details of a Martial Arts Style’s elements are consistent. Current simulation efforts will be explained as well as areas for future development. We have described Martial Arts by observing what has already been done and creating a structured standard to document them. We hope to enable practitioners’ abilities to learn from and develop their arts by providing a resource in which they can interact with.
Show less - Date Issued
- 2014
- PURL
- http://purl.flvc.org/fau/fd/FA00004232, http://purl.flvc.org/fau/fd/FA00004232
- Subject Headings
- Martial arts--Digital techniques., Human mechanics--Digital techniques., Document markup langauges., Computer graphics., XML (Document markup language), MAML (Document markup language), Labanotation.
- Format
- Document (PDF)
- Title
- Of Mice, Men and Memories: The Role of the Rodent Hippocampus in Object Recognition.
- Creator
- Cohen, Sarah J., Stackman, Robert W., Florida Atlantic University, Charles E. Schmidt College of Science, Center for Complex Systems and Brain Sciences
- Abstract/Description
-
Establishing appropriate animal models for the study of human memory is paramount to the development of memory disorder treatments. Damage to the hippocampus, a medial temporal lobe brain structure, has been implicated in the memory loss associated with Alzheimer’s disease and other dementias. In humans, the role of the hippocampus is largely defined; yet, its role in rodents is much less clear due to conflicting findings. To investigate these discrepancies, an extensive review of the rodent...
Show moreEstablishing appropriate animal models for the study of human memory is paramount to the development of memory disorder treatments. Damage to the hippocampus, a medial temporal lobe brain structure, has been implicated in the memory loss associated with Alzheimer’s disease and other dementias. In humans, the role of the hippocampus is largely defined; yet, its role in rodents is much less clear due to conflicting findings. To investigate these discrepancies, an extensive review of the rodent literature was conducted, with a focus on studies that used the Novel Object Recognition (NOR) paradigm for testing. The total amount of time the objects were explored during training and the delay imposed between training and testing seemed to determine hippocampal recruitment in rodents. Male C57BL/6J mice were implanted with bilateral dorsal CA1 guide cannulae to allow for the inactivation of the hippocampus at discrete time points in the task. The results suggest that the rodent hippocampus is crucial to the encoding, consolidation and retrieval of object memory. Next, it was determined that there is a delay-dependent involvement of the hippocampus in object memory, implying that other structures may be supporting the memory prior to the recruitment of hippocampus. In addition, when the context memory and object memory could be further dissociated, by altering the task design, the results imply a necessary role for the hippocampus in the object memory, irrespective of context. Also, making the task more perceptually demanding, by requiring the mice to perform a two-dimensional to three-dimensional association between stimuli, engaged the hippocampus. Then, in the traditional NOR task, long and short training exploration times were imposed to determine brain region activity for weak and strong object memory. The inactivation and immunohistochemistry findings imply weak object memory is perirhinal cortex dependent, while strong object memory is hippocampal-dependent. Taken together, the findings suggest that mice, like humans, process object memory on a continuum from weak to strong, recruiting the hippocampus conditionally for strong familiarity. Confirming this functional similarity between the rodent and human object memory systems could be beneficial for future studies investigating memory disorders.
Show less - Date Issued
- 2016
- PURL
- http://purl.flvc.org/fau/fd/FA00004580
- Subject Headings
- Memory--Research., Mice as laboratory animals., Hippocampus (Brain)--Physiology., Episodic memory., Neurotransmitter receptors., Cellular control mechanisms., Cellular signal transduction., Human information processing.
- Format
- Document (PDF)
