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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 |
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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. | ||||
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Call Number | Penn State @ write.to.jason @ | Serial | 26 | ||
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Author | Portnoy, S.; Mimouni-Bloch, A.; Rosenberg, L.; Offek, H.; Berman, T.; Kochavi, M.; Orman, G.; Friedman, J. | ||||
Title | Graphical Product Quality and Muscle Activity in Children With Mild Disabilities Drawing on a Horizontally or Vertically Oriented Tablet | Type | Journal Article | ||
Year | 2018 | Publication | American Journal of Occupational Therapy | Abbreviated Journal | Am J Occup Ther |
Volume | 72 | Issue | 6 | Pages | 1-7 |
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Abstract | OBJECTIVE. We compared performance level and muscle activity patterns during shape copying and tracing in two positions, while sitting at a desk and while standing in front of a wall, between typically developing (TD) preschool children and children with mild disabilities (MD). METHOD. Twenty-two TD children (8 boys, 14 girls; mean [M] age 5 5.2 yr, standard deviation [SD] 5 0.1) and 13 children with MD (9 boys, 4 girls; M age 5 4.9 yr, SD 5 0.5) participated in this study. RESULTS. The children performed faster and smoother movements when copying shapes on the vertical surface, with no reduction of accuracy, than on the horizontal surface. Children with MD exerted their upper trapezius while performing the short tasks on the vertical surface compared with their muscle activity on the horizontal surface. CONCLUSION. Incorporating short copying or drawing tasks on a vertical surface may increase the control of proximal muscles and ease graphomotor performance in children with MD. |
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ISSN | 0272-9490 | ISBN | Medium | ||
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Notes | Approved | no | |||
Call Number | Penn State @ write.to.jason @ | Serial | 91 | ||
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Author | Kaufman-Cohen, Y.; Friedman, J.; Levanon, Y.; Jacobi, G.; Doron, N.; Portnoy, S. | ||||
Title | Wrist Plane of Motion and Range During Daily Activities | Type | Journal Article | ||
Year | 2018 | Publication | American Journal of Occupational Therapy | Abbreviated Journal | Am J Occup Ther |
Volume | 72 | Issue | 6 | Pages | 1-10 |
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Abstract | OBJECTIVE. The dart-throwing motion (DTM) is a multiplane wrist motion that is needed for many daily occupations. Mobilization along the DTM plane may be essential for rehabilitation after wrist injury, but DTM angles are reported for the dominant hand alone, so their relevance to injury in the nondominant hand cannot be surmised. The aim of this study was to quantify the DTM plane angles for both hands during different activities of daily living (ADLs). METHOD. Forty-three healthy participants wore a twin-axis electrogoniometer during ADLs. RESULTS. No significant differences were found between the DTM plane angles of the dominant (20°�45°) and nondominant (15°�40°) hands. These angles varied by task and across participants. CONCLUSION. The DTM plane is a functional motion used by both hands during ADLs. Because the DTM plane angle differs among hands, tasks, and individual clients, wrist rehabilitation involving the DTM plane should not be limited to a singular DTM plane angle.OBJECTIVE. The dart-throwing motion (DTM) is a multiplane wrist motion that is needed for many daily occupations. Mobilization along the DTM plane may be essential for rehabilitation after wrist injury, but DTM angles are reported for the dominant hand alone, so their relevance to injury in the nondominant hand cannot be surmised. The aim of this study was to quantify the DTM plane angles for both hands during different activities of daily living (ADLs). METHOD. Forty-three healthy participants wore a twin-axis electrogoniometer during ADLs. RESULTS. No significant differences were found between the DTM plane angles of the dominant (20°�45°) and nondominant (15°�40°) hands. These angles varied by task and across participants. CONCLUSION. The DTM plane is a functional motion used by both hands during ADLs. Because the DTM plane angle differs among hands, tasks, and individual clients, wrist rehabilitation involving the DTM plane should not be limited to a singular DTM plane angle. |
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ISSN | 0272-9490 | ISBN | Medium | ||
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Notes | Approved | no | |||
Call Number | Serial | 92 | |||
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Author | Salzer, Y.; Friedman, J. | ||||
Title | Reaching trajectories unravel modality-dependent temporal dynamics of the automatic process in the Simon task: a model-based approach | Type | Journal Article | ||
Year | 2020 | Publication | Psychological Research | Abbreviated Journal | Psychol Res |
Volume | 84 | Issue | 6 | Pages | 1700-1713 |
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Abstract | The Simon effect represents a phenomenon in which the location of the stimuli affects the speed and accuracy of the response, despite being irrelevant for the task demands. This is believed to be due to an automatic activation of a response corresponding to the location of the stimuli, which conflicts with the controlled decision process based on relevant stimuli features. Previously, differences in the nature of the Simon effect (i.e., the pattern of change of the effect across the distribution of response times) between visual and somatosensory stimuli were reported. We hypothesize that the temporal dynamics of visual and somatosensory automatic and controlled processes vary, thus driving the reported behavioral differences. While most studies have used response times to study the underlying mechanisms involved, in this study we had participants reach out to touch the targets and recorded their arm movements using a motion capture system. Importantly, the participants started their movements before a final decision was made. In this way, we could analyze the movements to gain insights into the competition between the automatic and controlled processes. We used this technique to describe the results in terms of a model assuming automatic activation due to location-based evidence, followed by inhibition. We found that for the somatosensory Simon effect, the decay of the automatic process is significantly slower than for the visual Simon effect, suggesting quantitative differences in this automatic process between the visual and somatosensory modalities. | ||||
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Language | English | Summary Language | Original Title | ||
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ISSN | 0340-0727 | ISBN | Medium | ||
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Notes | PMID:30980236 | Approved | no | ||
Call Number | Serial | 97 | |||
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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 (� 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 (� 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 � 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 � 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 | ||||
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Language | English | Summary Language | Original Title | ||
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ISSN | 0959-3985 | ISBN | Medium | ||
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Notes | PMID:35125048 | Approved | no | ||
Call Number | Serial | 116 | |||
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