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Author (up) Harel Arzi; Tal Krasovsky; Moshe Pritsch; Dario G. Liebermann doi  openurl
  Title Movement control in patients with shoulder instability: a comparison between patients after open surgery and nonoperated patients Type Journal Article
  Year 2014 Publication Journal of Shoulder and Elbow Surgery Abbreviated Journal  
  Volume 23 Issue 7 Pages 982–992  
  Keywords Smoothness; kinesthesis; arm kinematics; shoulder instability; open surgery  
  Abstract Background

Open surgery to correct shoulder instability is deemed to facilitate recovery of static and dynamic motor functions. Postoperative assessments focus primarily on static outcomes (e.g., repositioning accuracy). We introduce kinematic measures of arm smoothness to assess shoulder patients after open surgery and compare them with nonoperated patients. Performance among both groups of patients was hypothesized to differ. Postsurgery patients were expected to match healthy controls.

Methods

All participants performed pointing movements with the affected/dominant arm fully extended at fast, preferred, and slow speeds (36 trials per subject). Kinematic data were collected (100 Hz, 3 seconds), and mixed-design analyses of variance (group, speed) were performed with movement time, movement amplitude, acceleration time, and model-observed similarities as dependent variables. Nonparametric tests were performed for number of velocity peaks.

Results

Nonoperated and postsurgery patients showed similarities at preferred and faster movement speeds but not at slower speed. Postsurgery patients were closer to maximally smoothed motion and differed from healthy controls mainly during slow arm movements (closer to maximal smoothness, larger movement amplitude, shorter movement time, and lower number of peaks; i.e., less movement fragmentation).

Conclusions

Arm kinematic analyses suggest that open surgery stabilizes the shoulder but does not necessarily restore normal movement quality. Patients with recurrent anterior shoulder instability (RASI) seem to implement a “safe” but nonadaptive mode of action whereby preplanned stereotypical movements may be executed without depending on feedback. Rehabilitation of RASI patients should focus on restoring feedback-based movement control. Clinical assessment of RASI patients should include higher order kinematic descriptors.
 
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  Call Number Serial 74  
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Author (up) Hoffman, J.R.; Liebermann, D.; Gusis, A. url  openurl
  Title Relationship of leg strength and power to ground reaction forces in both experienced and novice jump trained personnel Type Journal Article
  Year 1997 Publication Aviation, Space, and Environmental Medicine Abbreviated Journal Aviat Space Environ Med  
  Volume 68 Issue 8 Pages 710-714  
  Keywords *Aerospace Medicine; *Aviation; Biomechanics; Humans; Leg/*physiology; Male; Military Personnel/*education; *Physical Education and Training; Physical Fitness/*physiology; Range of Motion, Articular; Wounds and Injuries/etiology/*prevention & control  
  Abstract METHODS: There were 14 male soldiers who participated in this study examining the relationship of leg strength and power on landing performance. Subjects were separated into two groups. The first group (E, n = 7) were parachute training instructors and highly experienced in parachute jumping. The second group of subjects (N, n = 7) had no prior parachute training experience and were considered novice jumpers. All subjects were tested for one-repetition maximum (1 RM) squat strength and maximal jump power. Ground reaction forces (GRF) and the time to peak force (TPF) at landing were measured from jumps at four different heights (95 cm, 120 cm, 145 cm, and 170 cm). All jumps were performed from a customized jump platform onto a force plate. RESULTS: No differences were seen between E and N in either IRM squat strength or in MJP. In addition, no differences were seen between the groups for time to peak force at any jump height. However, significantly greater GRF were observed in E compared to N. Moderate to high correlations between maximal jump power and GRF (r values ranging from 0.62-0.93) were observed in E. Although maximal jump power and the TPF was significantly correlated (r = -0.89) at only 120 cm for E, it was interesting to note that the correlations between MJP and the time to peak force in E were all negative and that the correlations between these variables in N were all positive. CONCLUSIONS: These results suggest that experienced parachutists may use a different landing strategy than novice jumpers. This difference may be reflected by differences in GRF generated during impact and a more efficient utilization of muscle power during the impact phase of the landing.  
  Address Aeromedical Center, Physiological Training Unit, Israel Air Force, Israel  
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  Series Volume Series Issue Edition  
  ISSN 0095-6562 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:9262813 Approved no  
  Call Number Serial 60  
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Author (up) Issurin, V.B.; Liebermann, D.G.; Tenenbaum, G. url  doi
openurl 
  Title Effect of vibratory stimulation training on maximal force and flexibility Type
  Year 1994 Publication Journal of Sports Sciences Abbreviated Journal J Sports Sci  
  Volume 12 Issue 6 Pages 561-566  
  Keywords Adult; Humans; Male; Muscle Contraction/physiology; Muscle, Skeletal/*physiology; *Physical Education and Training; Vibration/*therapeutic use  
  Abstract In this study, we investigated a new method of training for maximal strength and flexibility, which included exertion with superimposed vibration (vibratory stimulation, VS) on target muscles. Twenty-eight male athletes were divided into three groups, and trained three times a week for 3 weeks in one of the following conditions: (A) conventional exercises for strength of the arms and VS stretching exercises for the legs; (B) VS strength exercises for the arms and conventional stretching exercises for the legs; (C) irrelevant training (control group). The vibration was applied at 44 Hz while its amplitude was 3 mm. The effect of training was evaluated by means of isotonic maximal force, heel-to-heel length in the two-leg split across, and flex-and-reach test for body flexion. The VS strength training yielded an average increase in isotonic maximal strength of 49.8%, compared with an average gain of 16% with conventional training, while no gain was observed for the control group. The VS flexibility training resulted in an average gain in the legs split of 14.5 cm compared with 4.1 cm for the conventional training and 2 cm for the control groups, respectively. The ANOVA revealed significant pre-post training effects and an interaction between pre-post training and 'treatment' effects (P < 0.001) for the isotonic maximal force and both flexibility tests. It was concluded that superimposed vibrations applied for short periods allow for increased gains in maximal strength and flexibility.  
  Address Ribstein Centre for Research and Sport Medicine Sciences, Wingate Institute, Wingate Post, Israel  
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  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0264-0414 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:7853452 Approved no  
  Call Number Serial 56  
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Author (up) Kapur, Shweta; Friedman, Jason; Zatsiorsky, Vladimir M.; Latash, Mark L. pdf  doi
openurl 
  Title Finger interaction in a three-dimensional pressing task Type Journal Article
  Year 2010 Publication Experimental Brain Research Abbreviated Journal  
  Volume 203 Issue 1 Pages 101-118  
  Keywords  
  Abstract Accurate control of forces produced by the fingers is essential for performing object manipulation. This study examines the indices of finger interaction when accurate time profiles of force are produced in different directions, while using one of the fingers or all four fingers of the hand. We hypothesized that patterns of unintended force production among shear force components may involve features not observed in the earlier studies of vertical force production. In particular, we expected to see unintended forces generated by non-task fingers not in the

direction on the instructed force but in the opposite direction as well as substantial force production in directions orthogonal to the instructed direction. We also tested a hypothesis that multi-finger synergies, quantified using the framework of the uncontrolled manifold hypothesis, will help reduce across-trials variance of both total force magnitude and direction. Young, healthy subjects were required to produce accurate ramps of force in five different directions by

pressing on force sensors with the fingers of the right (dominant) hand. The index finger induced the smallest unintended forces in non-task fingers. The little finger showed the smallest unintended forces when it was a non-task finger. Task fingers showed substantial force production in directions orthogonal to the intended force direction. During four-finger tasks, individual force vectors typically pointed off the task direction, with these deviations nearly

perfectly matched to produce a resultant force in the task direction. Multi-finger synergy indices reflected strong co-variation in the space of finger modes (commands to fingers) that reduced variability of the total force magnitude and direction across trials. The synergy indices increased in magnitude over the first 30% of the trial time and then stayed at a nearly constant level. The synergy index for stabilization of total force magnitude was higher for shear force components as compared to the downward pressing force component. The results suggest complex interactions between enslaving and synergic force adjustments, possibly reflecting the experience with everyday prehensile tasks. For the first time, the data document multi-finger synergies stabilizing both shear force magnitude and force vector direction. These synergies may play a major role in

stabilizing the hand action during object manipulation.
 
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  Notes in press Approved no  
  Call Number Penn State @ write.to.jason @ Serial 20  
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Author (up) Kaufman-Cohen, Y.; Friedman, J.; Levanon, Y.; Jacobi, G.; Doron, N.; Portnoy, S. pdf  url
doi  openurl
  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  
  Keywords  
  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°&#65533;45°) and nondominant (15°&#65533;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°&#65533;45°) and nondominant (15°&#65533;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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  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0272-9490 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number Serial 92  
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