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Author | Liebermann, D.G.; Hoffman, J.R. | ||||
Title | Timing of preparatory landing responses as a function of availability of optic flow information | Type | Journal Article | ||
Year | 2005 | Publication | Journal of Electromyography and Kinesiology : Official Journal of the International Society of Electrophysiological Kinesiology | Abbreviated Journal | J Electromyogr Kinesiol |
Volume | 15 | Issue | 1 | Pages | 120-130 |
Keywords | Adult; Cues; Electromyography; Humans; Male; Movement/physiology; Muscle, Skeletal/*physiology; Posture/physiology; Psychomotor Performance/*physiology; Vision, Ocular/*physiology | ||||
Abstract | This study investigated temporal patterns of EMG activity during self-initiated falls with different optic flow information ('gaze directions'). Onsets of EMG during the flight phase were monitored from five experienced volunteers that completed 72 landings in three gaze directions (downward, mid-range and horizontal) and six heights of fall (10-130 cm). EMG recordings were obtained from the right gastrocnemius, tibialis anterior, biceps femoris and rectus femoris muscles, and used to determine the latency of onset (L(o)) and the perceived time to contact (T(c)). Impacts at touchdown were also monitored using as estimates the major peak of the vertical ground reaction forces (F(max)) normalized to body mass, time to peak (T(max)), peak impulse (I(norm)) normalized to momentum, and rate of change of force (dF(max)/dt). Results showed that L(o) was longer as heights of fall increased, but remained within a narrow time-window at >50 cm landings. No significant differences in L(o) were observed when gaze direction was changed. The relationship between T(c) and flight time followed a linear trend regardless of gaze direction. Gaze direction did not significantly affect the landing impacts. In conclusion, availability of optic flow during landing does not play a major role in triggering the preparatory muscle actions in self-initiated falls. Once a structured landing plan has been acquired, the relevant muscles respond relative to the start of the fall. | ||||
Address | Department of Physical Therapy, Sackler Faculty of Medicine, Stanley Steyer School of Health Professions, University of Tel Aviv, Ramat Aviv, 69978 Tel Aviv, Israel | ||||
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Language | English | Summary Language | Original Title | ||
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ISSN | 1050-6411 | ISBN | Medium | ||
Area | Expedition | Conference | |||
Notes | PMID:15642660 | Approved | no | ||
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Serial | 39 | |||
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Author | Liebermann, D.G.; Katz, L.; Hughes, M.D.; Bartlett, R.M.; McClements, J.; Franks, I.M. | ||||
Title | Advances in the application of information technology to sport performance | Type | Journal Article | ||
Year | 2002 | Publication | Journal of Sports Sciences | Abbreviated Journal | J Sports Sci |
Volume | 20 | Issue | 10 | Pages | 755-769 |
Keywords | *Biofeedback, Psychology; *Computer Simulation; Humans; Models, Biological; Physical Education and Training/*methods; Psychomotor Performance/physiology; Sports Medicine/methods; *Task Performance and Analysis; Videotape Recording | ||||
Abstract | This paper overviews the diverse information technologies that are used to provide athletes with relevant feedback. Examples taken from various sports are used to illustrate selected applications of technology-based feedback. Several feedback systems are discussed, including vision, audition and proprioception. Each technology described here is based on the assumption that feedback would eventually enhance skill acquisition and sport performance and, as such, its usefulness to athletes and coaches in training is critically evaluated. | ||||
Address | Department of Physical Therapy, Sackler Faculty of Medicine, University of Tel Aviv, Israel | ||||
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Language | English | Summary Language | Original Title | ||
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Series Volume | Series Issue | Edition | |||
ISSN | 0264-0414 | ISBN | Medium | ||
Area | Expedition | Conference | |||
Notes | PMID:12363293 | Approved | no | ||
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Serial | 40 | |||
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Author | Mindy F. Levin; Osnat Snir; Dario G. Liebermann; Harold Weingarden; Patrice L. Weiss | ||||
Title | Virtual Reality Versus Conventional Treatment of Reaching Ability in Chronic Stroke: Clinical Feasibility Study | Type | Journal Article | ||
Year | 2012 | Publication | Neurology and Therapy | Abbreviated Journal | |
Volume | 1 | Issue | 3 | Pages | 1-15 |
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Abstract | Introduction The objective of this study was to evaluate the potential of exercises performed in a 2D video-capture virtual reality (VR) training environment to improve upper limb motor ability in stroke patients compared to those performed in conventional therapy. Methods A small sample randomized control trial, in an outpatient rehabilitation center with 12 patients with chronic stroke, aged 33–80 years, who were randomly allocated to video-capture VR therapy and conventional therapy groups. All patients participated in four clinical evaluation sessions (pre-test 1, pre-test 2, post-test, follow-up) and nine 45-minute intervention sessions over a 3-week period. Main outcomes assessed were Body Structure and Function (impairment: Fugl–Meyer Assessment [FMA]; Composite Spasticity Index [CSI]; Reaching Performance Scale for Stroke), Activity (Box and Blocks; Wolf Motor Function Test [WMFT]), and Participation (Motor Activity Log) levels of the International Classification of Functioning. Results Improvements occurred in both groups, but more patients in the VR group improved upper limb clinical impairment (FMA, CSI) and activity scores (WMFT) and improvements occurred earlier. Patients in the VR group also reported satisfaction with the novel treatment. Conclusions The modest advantage of VR over conventional training supports further investigation of the effect of video-capture VR or VR combined with conventional therapy in larger-scale randomized, more intense controlled studies. |
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Notes | Approved | no | |||
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Serial | 42 | |||
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Author | Goodman, D.; Liebermann, D.G. | ||||
Title | Time-to-contact as a determiner of action: vision and motor control | Type | Book Chapter | ||
Year | 1992 | Publication | Vision and Motor Control | Abbreviated Journal | |
Volume | Issue | Pages | 335-349 | ||
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Publisher | Elsevier Pub. Co | Place of Publication | Amsterdam, Holland | Editor | D. Elliott; J. Proteau |
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Notes | Approved | no | |||
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Serial | 43 | |||
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Author | Melzer, I.; Liebermann, D.G.; Krasovsky, T.; Oddsson, L.I.E. | ||||
Title | Cognitive load affects lower limb force-time relations during voluntary rapid stepping in healthy old and young adults | Type | Journal Article | ||
Year | 2010 | Publication | The Journals of Gerontology. Series A, Biological Sciences and Medical Sciences | Abbreviated Journal | J Gerontol A Biol Sci Med Sci |
Volume | 65 | Issue | 4 | Pages | 400-406 |
Keywords | *Accidental Falls; Adult; Aged; Aged, 80 and over; Aging/*physiology; Attention/physiology; Cognition/*physiology; Gait/*physiology; Humans; Postural Balance/*physiology; Reaction Time | ||||
Abstract | BACKGROUND: Quick step execution may prevent falls when balance is lost; adding a concurrent task delays this function. We investigate whether push-off force-time relations during the execution of rapid voluntary stepping is affected by a secondary task in older and young adults. METHODS: Nineteen healthy older adults and 12 young adults performed rapid voluntary stepping under single- and dual-task conditions. Peak power, peak force, and time to peak force during preparatory and swing phases of stepping were extracted from center of pressure and ground reaction force data. RESULTS: For dual-task condition compared with single-task condition, older adults show a longer time to reach peak force during the preparation and swing phases compared with young adults (approximately 25% vs approximately 10%, respectively). Peak power and peak force were not affected by a concurrent attention-demanding task. CONCLUSION: Older adults have difficulty allocating sufficient attention for fast muscle recruitment when concurrently challenged by an attention-demanding task. | ||||
Address | Department of Physical Therapy, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel | ||||
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Publisher | Place of Publication | Editor | |||
Language | English | Summary Language | Original Title | ||
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Series Volume | Series Issue | Edition | |||
ISSN | 1079-5006 | ISBN | Medium | ||
Area | Expedition | Conference | |||
Notes | PMID:19939911 | Approved | no | ||
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Serial | 50 | |||
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