Jason Friedman's literature database -- Query Results

	Jason Friedman's literature database Home \| Show All \| Simple Search \| Advanced Search	Login Quick Search: Field: contains: ...
	1-5 of 102 records found matching your query:

Search & Display Options

Select All Deselect All

<< 1 2 3 4 5 6 7 8 9 10 >> [11–20]

List View

Citations

Details

	Records
	Author	Liebermann, D.G.; Goodman, D.
	Title	Effects of visual guidance on the reduction of impacts during landings			Type	Journal Article
	Year	1991	Publication	Ergonomics	Abbreviated Journal	Ergonomics
	Volume	34	Issue	11	Pages	1399-1406
	Keywords	Adult; Analysis of Variance; Biomechanics; Cues; Humans; Male; Motor Activity/physiology; Psychomotor Performance/physiology; Vision, Ocular/*physiology
	Abstract	While a common view is that vision is essential to motor performance, some recent studies have shown that continuous visual guidance may not always be required within certain time constraints. This study investigated a landing-related task (self-released falls) to assess the extent to which visual information enhances the ability to reduce the impacts at touchdown. Six individuals performed six blocked trials from four height categories in semi-counterbalanced order (5-10, 20-25, 60-65, and 90-95 cm) in vision and no-vision conditions randomly assigned. A series of two-way ANOVA with repeated measures were carried out separately on each dependent variable collapsed over six trials. The results indicated that vision during the flight did not produce softer landings. Indeed, in analysing the first peak (PFP) a main effect for visual condition was revealed in that the mean amplitude was slightly higher when vision was available (F(1,5) = 6.57; p less than 0.05), thus implicating higher forces at impact. The results obtained when the time to the first peak (TFP) was applied showed no significant differences between conditions (F(1,5) less than 1). As expected, in all cases, the analyses yielded significant main effects for the height categories factor. It appears that during self-initiated falls in which the environmental cues are known before the event, visual guidance is not necessary in order to adopt a softer landing strategy.
	Address	Research Department, Wingate Institute, 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	0014-0139	ISBN		Medium
	Area		Expedition		Conference
	Notes	PMID:1800107			Approved	no
	Call Number				Serial	55
Permanent link to this record



	Author	Latash, M.L., Friedman, J., Kim, S.W., Feldman, A.G., Zatsiorsky, V.M.
	Title	Prehension Synergies and Control with Referent Hand Configurations			Type	Journal Article
	Year	2010	Publication	Experimental Brain Research	Abbreviated Journal	Exp Brain Res
	Volume	202	Issue	1	Pages	213-229
	Keywords
	Abstract	We used the framework of the equilibrium-point hypothesis (in its updated form based on the notion of referent configuration) to investigate the multi-digit synergies at two levels of a hypothetical hierarchy involved in prehensile actions. Synergies were analyzed at the thumb-virtual finger level (virtual finger is an imaginary digit with the mechanical action equivalent to that of the four actual fingers) and at the individual finger level. The subjects performed very quick vertical movements of a handle into a target. A load could be attached off-center to provide a pronation or supination torque. In a few trials, the handle was unexpectedly fixed to the table and the digits slipped off the sensors. In such trials, the hand stopped at a higher vertical position and rotated into pronation or supination depending on the expected torque. The aperture showed non-monotonic changes with a large, fast decrease and further increase, ending up with a smaller distance between the thumb and the fingers as compared to unperturbed trials. Multi-digit synergies were quantified using indices of co-variation between digit forces and moments of force across unperturbed trials. Prior to the lifting action, high synergy indices were observed at the individual finger level while modest indices were observed at the thumb-virtual finger level. During the lifting action, the synergies at the individual finger level disappeared while the synergy indices became higher at the thumb-virtual finger level. The results support the basic premise that, within a given task, setting a referent configuration may be described with a few referent values of variables that influence the equilibrium state, to which the system is attracted. Moreover, the referent configuration hypothesis can help interpret the data related to the trade-off between synergies at different hierarchical levels.
	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	19
Permanent link to this record



	Author	Friedman, J.; Korman, M.
	Title	Observation of an expert model induces a skilled movement coordination pattern in a single session of intermittent practice			Type	Journal Article
	Year	2019	Publication	Scientific Reports	Abbreviated Journal	Sci Rep
	Volume	9	Issue	1	Pages	4609
	Keywords
	Abstract	We tested how observation of a skilled pattern of planar movements can assist in the learning of a new motor skill, which otherwise requires rigorous long-term practice to achieve fast and smooth performance. Sixty participants performed a sequence of planar hand movements on pre-test, acquisition, post-test and 24 h post-training blocks, under 1 of 4 conditions: an observation group (OG), a slowed observation group (SOG), a random motion control group (RMCG) and a double physical training control group (DPTCG). The OG and SOG observed an expert model's right hand performing the study task intermittently throughout acquisition, RMCG observed random dots movement instead of a model. Participants in the DPTCG received extra physical practice trials instead of the visually observed trials. Kinematic analysis revealed that only in conditions with observation of an expert model there was an instant robust improvement in motor planning of the task. This step-wise improvement was not only persistent in post-training retests but was also apparently implicit and subject to further incremental improvements in movement strategy over the period of 24 hours. The rapid change in motor strategy was accompanied by a transient within-session increase in spatial error for the observation groups, but this went away by 24 h post-training. We suggest that observation of hand movements of an expert model coaligned with self-produced movements during training can significantly condense the time-course of ecologically relevant drawing/writing skill mastery.
	Address
	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	2045-2322	ISBN		Medium
	Area		Expedition		Conference
	Notes	PMID:30872661			Approved	no
	Call Number				Serial	94
Permanent link to this record



	Author	Biess, A.; Flash, T.; Liebermann, D.G.
	Title	Riemannian geometric approach to human arm dynamics, movement optimization, and invariance			Type	Journal Article
	Year	2011	Publication	Physical Review. E, Statistical, Nonlinear, and Soft Matter Physics	Abbreviated Journal	Phys Rev E Stat Nonlin Soft Matter Phys
	Volume	83	Issue	3 Pt 1	Pages	031927
	Keywords	Arm/physiology; Biomechanics; Computer Simulation; Humans; Kinetics; Male; Models, Biological; Models, Statistical; Models, Theoretical; Movement; Psychomotor Performance/physiology; Range of Motion, Articular/physiology; Reaction Time/physiology; Space Perception/physiology; Torque
	Abstract	We present a generally covariant formulation of human arm dynamics and optimization principles in Riemannian configuration space. We extend the one-parameter family of mean-squared-derivative (MSD) cost functionals from Euclidean to Riemannian space, and we show that they are mathematically identical to the corresponding dynamic costs when formulated in a Riemannian space equipped with the kinetic energy metric. In particular, we derive the equivalence of the minimum-jerk and minimum-torque change models in this metric space. Solutions of the one-parameter family of MSD variational problems in Riemannian space are given by (reparameterized) geodesic paths, which correspond to movements with least muscular effort. Finally, movement invariants are derived from symmetries of the Riemannian manifold. We argue that the geometrical structure imposed on the arm's configuration space may provide insights into the emerging properties of the movements generated by the motor system.
	Address	Bernstein Center for Computational Neuroscience, DE-37073 Gottingen, Germany. armin@nld.ds.mpg.de
	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	1539-3755	ISBN		Medium
	Area		Expedition		Conference
	Notes	PMID:21517543			Approved	no
	Call Number				Serial	29
Permanent link to this record



	Author	Raveh, E.; Portnoy, S.; Friedman, J.
	Title	Adding vibrotactile feedback to a myoelectric-controlled hand improves performance when online visual feedback is disturbed			Type	Journal Article
	Year	2018	Publication	Human Movement Science	Abbreviated Journal	Hum Mov Sci
	Volume	58	Issue		Pages	32-40
	Keywords	Myoelectric prostheses; Sensorimotor control; Upper limb amputation; Visual feedback
	Abstract	We investigated whether adding vibrotactile feedback to a myoelectric-controlled hand, when visual feedback is disturbed, can improve performance during a functional test. For this purpose, able-bodied subjects, activating a myoelectric-controlled hand attached to their right hand performed the modified Box & Blocks test, grasping and manipulating wooden blocks over a partition. This was performed in 3 conditions, using a repeated-measures design: in full light, in a dark room where visual feedback was disturbed and no auditory feedback – one time with the addition of tactile feedback provided during object grasping and manipulation, and one time without any tactile feedback. The average time needed to transfer one block was measured, and an infrared camera was used to give information on the number of grasping errors during performance of the test. Our results show that when vibrotactile feedback was provided, performance time was reduced significantly, compared with when no vibrotactile feedback was available. Furthermore, the accuracy of grasping and manipulation was improved, reflected by significantly fewer errors during test performance. In conclusion, adding vibrotactile feedback to a myoelectric-controlled hand has positive effects on functional performance when visual feedback is disturbed. This may have applications to current myoelectric-controlled hands, as adding tactile feedback may help prosthesis users to improve their functional ability during daily life activities in different environments, particularly when limited visual feedback is available or desirable.
	Address	Physical Therapy Department, Sackler Faculty of Medicine, Tel Aviv University, Israel. Electronic address: jason@post.tau.ac.il
	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	0167-9457	ISBN		Medium
	Area		Expedition		Conference
	Notes	PMID:29353091			Approved	no
	Call Number				Serial	88
Permanent link to this record