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	Author	Friedman, Jason; Flash, Tamar
	Title	Task-dependent selection of grasp kinematics and stiffness in human object manipulation			Type	Journal Article
	Year	2007	Publication	Cortex	Abbreviated Journal
	Volume	43	Issue	3	Pages	444-460
	Keywords
	Abstract	Object manipulation with the hand is a complex task. The task has redundancies at many levels, allowing many possibilities for the selection of grasp points, the orientation and posture of the hand, the forces to be applied at each fingertip and the impedance properties of the hand. Despite this inherent complexity, humans perform object manipulation nearly effortlessly. This article presents experimental findings of how humans grasp and manipulate objects, and examines the compatibility of grasps selected for specific tasks. This is accomplished by looking at the velocity transmission and force transmission ellipsoids, which represent the transmission ratios of the corresponding quantity from the joints to the object, as well as the stiffness ellipsoid which represents the directional stiffness of the grasp. These ellipsoids allow visualization of the grasp Jacobian and grasp stiffness matrices. The results show that the orientation of the ellipsoids can be related to salient task requirements.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN		ISBN		Medium
	Area		Expedition		Conference
	Notes				Approved	no
	Call Number	Penn State @ write.to.jason @			Serial	14
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	Author	Friedman, J; Latash, M.L.; Zatsiorsky, V.M.
	Title	Directional variability of the isometric force vector produced by the hand in multi-joint planar tasks			Type	Journal Article
	Year	2011	Publication	Journal of Motor Behavior	Abbreviated Journal
	Volume	43	Issue	6	Pages	451-463
	Keywords
	Abstract	Numerous studies have examined control of force magnitude, but relatively little research has considered force direction control. In this study, subjects applied isometric forces to a handle and we compared within-trial variability when producing force in different directions. The standard deviation (SD) of the force parallel to the prescribed direction of force production increased linearly with the targeted force level, as did the SD of the force perpendicular to the instructed direction. In contrast, the SD of the angle of force production decreased with increased force level. In the four (of eight) instructed force directions where the endpoint force was generated due to a joint torque in only one joint (either the shoulder or elbow) the principal component axes in force space were well aligned with the prescribed direction of force production. In the other directions, the variance was approximately equal along the two force axes. The variance explained by the first principal component was significantly larger in torque space compared to the force space, and mostly corresponded to positive correlation between the joint torques. Such coordinated changes suggest that the torque variability was mainly due to the variability of the common drive to the muscles serving two joints, although this statement needs to be supported by direct studies of muscle activation in the future.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN		ISBN		Medium
	Area		Expedition		Conference
	Notes				Approved	no
	Call Number	Penn State @ write.to.jason @			Serial	26
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	Author	Prushansky, T.; Kaplan-Gadasi, L.; Friedman, J.
	Title	The relationship between thoracic posture and ultrasound echo intensity of muscles spanning this region in healthy men and women			Type	Journal Article
	Year	2023	Publication	Physiotherapy Theory and Practice	Abbreviated Journal	Physiother Theory Pract
	Volume	39	Issue	6	Pages	1257-1265
	Keywords	Ultrasound imaging; muscle echogenicity; posture; thoracic kyphosis
	Abstract	PURPOSE: Skeletal muscle echogenicity intensity (EI) is considered a measure of muscle quality, being associated with old age and pathologies. Whether EI variations can be identified in healthy adults, due to habitual shortened or elongated muscle position is unknown. Thus, this study aimed to assess the relationship between thoracic kyphosis angulation and EI scores of muscles spanning this region ((Lower Trapezius (LT), Rhomboid Major (RM), Erector Spine (ES)) in healthy young people and in addition to examine the relationship between the change in thoracic kyphosis angle from relaxed to upright position (â�� degrees ) and the EI of these muscles. METHODS: Thoracic kyphosis in relaxed and erect standing was measured using a digital inclinometer in 29 healthy adults (16 women, 13 men), aged 25-35 years. The thoracic kyphosis angles including the difference between relaxed and erect postures (â�� degrees ) were correlated to the EI scores of right and left LT, RM and ES. RESULTS: No significant differences in EI were found between the 3 muscles EI or between sides, hence they were pooled together to a total thoracic EI score (TTEI). Although the TTEI did not correlate with relaxed or erect thoracic kyphosis, it was significantly but negatively correlated with â�� degrees in the entire group: Pearson's correlation coefficient of r = -0.544; p = .01 and in men; r = -0.732; p = .01, failing to reach significance in women; r = -0.457. CONCLUSION: The negative association between the EI of the explored muscles and â�� degrees could imply a possible relationship between these muscles range of movement excursions and their composition.
	Address	Department of Physical Therapy, the Stanley Stayer School of Health Professions, Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language	English	Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0959-3985	ISBN		Medium
	Area		Expedition		Conference
	Notes	PMID:35125048			Approved	no
	Call Number				Serial	116
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	Author	Thorpe, A.; Friedman, J.; Evans, S.; Nesbitt, K.; Eidels, A.
	Title	Mouse Movement Trajectories as an Indicator of Cognitive Workload			Type	Journal Article
	Year	2022	Publication	International Journal of Human-Computer Interaction	Abbreviated Journal	International Journal of Human-Computer Interaction
	Volume	38	Issue	15	Pages	1464-1479
	Keywords
	Abstract	Assessing the cognitive impact of user interfaces is a shared focus of human-computer interaction researchers and cognitive scientists. Methods of cognitive assessment based on data derived from the system itself, rather than external apparatus, have the potential to be applied in a range of scenarios. The current study applied methods of analyzing kinematics to mouse movements in a computer-based task, alongside the detection response task, a standard workload measure. Sixty-five participants completed a task in which stationary stimuli were tar;geted using a mouse, with a within-subjects factor of task workload based on the number of targets to be hovered over with the mouse (one/two), and a between-subjects factor based on whether both targets (exhaustive) or just one target (minimum-time) needed to be hovered over to complete a trial when two targets were presented. Mouse movement onset times were slower and mouse movement trajectories exhibited more submovements when two targets were presented, than when one target was presented. Responses to the detection response task were also slower in this condition, indicating higher cognitive workload. However, these differences were only found for participants in the exhaustive condition, suggesting those in the minimum-time condition were not affected by the presence of the second target. Mouse movement trajectory results agreed with other measures of workload and task performance. Our findings suggest this analysis can be applied to workload assessments in real-world scenarios.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	1044-7318	ISBN		Medium
	Area		Expedition		Conference
	Notes				Approved	no
	Call Number				Serial	117
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	Author	Raveh, E.; Friedman, J.; Portnoy, S.
	Title	Visuomotor behaviors and performance in a dual-task paradigm with and without vibrotactile feedback when using a myoelectric controlled hand			Type	Journal Article
	Year	2018	Publication	Assistive Technology	Abbreviated Journal	Assistive Technology
	Volume	30	Issue		Pages	274-280
	Keywords
	Abstract
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	1040-0435	ISBN		Medium
	Area		Expedition		Conference
	Notes				Approved	no
	Call Number				Serial	85
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