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Sample records for shoulder joint forces

  1. Can shoulder joint reaction forces be estimated by neural networks?

    PubMed

    de Vries, W H K; Veeger, H E J; Baten, C T M; van der Helm, F C T

    2016-01-04

    To facilitate the development of future shoulder endoprostheses, a long term load profile of the shoulder joint is desired. A musculoskeletal model using 3D kinematics and external forces as input can estimate the mechanical load on the glenohumeral joint, in terms of joint reaction forces. For long term ambulatory measurements, these 3D kinematics can be measured by means of Inertial Magnetic Measurement Systems. Recording of external forces under daily conditions is not feasible; estimations of joint loading should preferably be independent of this input. EMG signals reflect the musculoskeletal response and can easily be measured under daily conditions. This study presents the use of a neural network for the prediction of glenohumeral joint reaction forces based upon arm kinematics and shoulder muscle EMG. Several setups were examined for NN training, with varying combinations of type of input, type of motion, and handled weights. When joint reaction forces are predicted by a trained NN, for motion data independent of the training data, results show a high intraclass correlation (ICC up to 0.98) and relative SEM as low as 3%, compared to similar output of a musculoskeletal model. A convenient setup in which kinematics and only one channel of EMG were used as input for the NN׳s showed comparable predictive power as more complex setups. These results are promising and enable long term estimation of shoulder joint reaction forces outside the motion lab, independent of external forces. Copyright © 2015 Elsevier Ltd. All rights reserved.

  2. Glenohumeral joint reaction forces increase with critical shoulder angles representative of osteoarthritis-A biomechanical analysis.

    PubMed

    Viehöfer, Arnd F; Snedeker, Jess G; Baumgartner, Daniel; Gerber, Christian

    2016-06-01

    Osteoarthritis (OA) of the glenohumeral joint constitutes the most frequent indication for nontraumatic shoulder joint replacement. Recently, a small critical shoulder angle (CSA) was found to be associated with a high prevalence of OA. This study aims to verify the hypothesis that a small CSA leads to higher glenohumeral joint reaction forces during activities of daily living than a normal CSA. A shoulder simulator with simulated deltoid (DLT), supraspinatus (SSP), infraspinatus/teres minor (ISP/TM), and subscapularis (SSC) musculotendinous units was constructed. The DLT wrapping on the humerus was simulated using a pulley that could be horizontally adjusted to simulate the 28° CSA found in OA or the 33° CSA found in disease-free shoulders. Over a range of motion between 6° and 82° of thoracohumeral abduction joint forces were measured using a six-axis load cell. An OA-associated CSA yielded higher net joint reaction forces than a normal CSA over the entire range of motion. The maximum difference of 26.4 N (8.5%) was found at 55° of thoracohumeral abduction. Our model thus suggests that a CSA typical for OA predisposes the glenohumeral joint to higher joint reaction forces and could plausibly play a role in joint overloading and development of OA. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:1047-1052, 2016.

  3. Shoulder Joint For Protective Suit

    NASA Technical Reports Server (NTRS)

    Kosmo, Joseph J.; Smallcombe, Richard D.

    1994-01-01

    Shoulder joint allows full range of natural motion: wearer senses little or no resisting force or torque. Developed for space suit, joint offers advantages in protective garments for underwater work, firefighting, or cleanup of hazardous materials.

  4. Effect of lateralized design on muscle and joint reaction forces for reverse shoulder arthroplasty.

    PubMed

    Liou, William; Yang, Yang; Petersen-Fitts, Graysen R; Lombardo, Daniel J; Stine, Sasha; Sabesan, Vani J

    2017-04-01

    Manufacturers of reverse shoulder arthroplasty (RSA) implants have recently designed innovative implants to optimize performance in rotator cuff-deficient shoulders. These advancements are not without tradeoffs and can have negative biomechanical effects. The objective of this study was to develop an integrated finite element analysis-kinematic model to compare the muscle forces and joint reaction forces (JRFs) of 3 different RSA designs. A kinematic model of a normal shoulder joint was adapted from the Delft model and integrated with the well-validated OpenSim shoulder model. Static optimizations then allowed for calculation of the individual muscle forces, moment arms, and JRFs relative to net joint moments. Three-dimensional computer models of 3 RSA designs-humeral lateralized design (HLD), glenoid lateralized design, and Grammont design-were integrated, and parametric studies were performed. Overall, there were decreases in deltoid and rotator cuff muscle forces for all 3 RSA designs. These decreases were greatest in the middle deltoid of the HLD model for abduction and flexion and in the rotator cuff muscles under both internal rotation and external rotation. The JRFs in abduction and flexion decreased similarly for all RSA designs compared with the normal shoulder model, with the greatest decrease seen in the HLD model. These findings demonstrate that the design characteristics implicit in these modified RSA prostheses result in mechanical differences most prominently seen in the deltoid muscle and overall JRFs. Further research using this novel integrated model can help guide continued optimization of RSA design and clinical outcomes. Copyright © 2017 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

  5. Improper trunk rotation sequence is associated with increased maximal shoulder external rotation angle and shoulder joint force in high school baseball pitchers.

    PubMed

    Oyama, Sakiko; Yu, Bing; Blackburn, J Troy; Padua, Darin A; Li, Li; Myers, Joseph B

    2014-09-01

    In a properly coordinated throwing motion, peak pelvic rotation velocity is reached before peak upper torso rotation velocity, so that angular momentum can be transferred effectively from the proximal (pelvis) to distal (upper torso) segment. However, the effects of trunk rotation sequence on pitching biomechanics and performance have not been investigated. The aim of this study was to investigate the effects of trunk rotation sequence on ball speed and on upper extremity biomechanics that are linked to injuries in high school baseball pitchers. The hypothesis was that pitchers with improper trunk rotation sequence would demonstrate lower ball velocity and greater stress to the joint. Descriptive laboratory study. Three-dimensional pitching kinematics data were captured from 72 high school pitchers. Subjects were considered to have proper or improper trunk rotation sequences when the peak pelvic rotation velocity was reached either before or after the peak upper torso rotation velocity beyond the margin of error (±3.7% of the time from stride-foot contact to ball release). Maximal shoulder external rotation angle, elbow extension angle at ball release, peak shoulder proximal force, shoulder internal rotation moment, and elbow varus moment were compared between groups using independent t tests (α < 0.05). Pitchers with improper trunk rotation sequences (n = 33) demonstrated greater maximal shoulder external rotation angle (mean difference, 7.2° ± 2.9°, P = .016) and greater shoulder proximal force (mean difference, 9.2% ± 3.9% body weight, P = .021) compared with those with proper trunk rotation sequences (n = 22). No other variables differed significantly different between groups. High school baseball pitchers who demonstrated improper trunk rotation sequences demonstrated greater maximal shoulder external rotation angle and shoulder proximal force compared with pitchers with proper trunk rotation sequences. Improper sequencing of the trunk and torso alter

  6. The effect of glenosphere diameter in reverse shoulder arthroplasty on muscle force, joint load, and range of motion.

    PubMed

    Langohr, G Daniel G; Giles, Joshua W; Athwal, George S; Johnson, James A

    2015-06-01

    Little is known about the effects of glenosphere diameter on shoulder joint loads. The purpose of this biomechanical study was to investigate the effects of glenosphere diameter on joint load, load angle, and total deltoid force required for active abduction and range of motion in internal/external rotation and abduction. A custom, instrumented reverse shoulder arthroplasty implant system capable of measuring joint load and varying glenosphere diameter (38 and 42 mm) and glenoid offset (neutral and lateral) was implanted in 6 cadaveric shoulders to provide at least 80% power for all variables. A shoulder motion simulator was used to produce active glenohumeral and scapulothoracic motion. All implant configurations were tested with active and passive motion with joint kinematics, loads, and moments recorded. At neutral and lateralized glenosphere positions, increasing diameter significantly increased joint load (+12 ± 21 N and +6 ± 9 N; P < .01) and deltoid load required for active abduction (+9 ± 22 N and +11 ± 15 N; P < .02), whereas joint load angle was unaffected (P > .8). Passive internal rotation was reduced with increased diameter at both neutral and lateralized glenosphere positions (-6° ± 6° and -12° ± 6°; P < .002); however, external rotation was not affected (P > .05). At neutral glenosphere position, increasing diameter increased the maximum angles of both adduction (+1° ± 1°; P = .03) and abduction (+8° ± 9°; P < .05). Lateralization also increased abduction range of motion compared with neutral (P < .01). Although increasing glenosphere diameter significantly increased joint load and deltoid force, the clinical impact of these changes is presently unclear. Internal rotation, however, was reduced, which contradicts previous bone modeling studies, which we postulate is due to increased posterior capsular tension as it is forced to wrap around a larger 42 mm implant assembly. Copyright © 2015 Journal of

  7. Shoulder Joint Replacement

    MedlinePlus

    ... bones: your upper arm bone (humerus), your shoulder blade (scapula), and your collarbone (clavicle). The shoulder is ... fits into a shallow socket in your shoulder blade. This socket is called the glenoid. The surfaces ...

  8. 21 CFR 888.3690 - Shoulder joint humeral (hemi-shoulder) metallic uncemented prosthesis.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Shoulder joint humeral (hemi-shoulder) metallic... Shoulder joint humeral (hemi-shoulder) metallic uncemented prosthesis. (a) Identification. A shoulder joint humeral (hemi-shoulder) metallic uncemented prosthesis is a device made of alloys, such as...

  9. 21 CFR 888.3680 - Shoulder joint glenoid (hemi-shoulder) metallic cemented prosthesis.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Shoulder joint glenoid (hemi-shoulder) metallic... Shoulder joint glenoid (hemi-shoulder) metallic cemented prosthesis. (a) Identification. A shoulder joint glenoid (hemi-shoulder) metallic cemented prosthesis is a device that has a glenoid (socket)...

  10. Ultrasonography of the canine shoulder joint and its pathological changes.

    PubMed

    Piórek, A; Adamiak, Z

    2010-01-01

    The objective of this study was to present and discuss the available data on canine shoulder joint ultrasonography. The paper presents the method of ultrasonographic examination of the shoulder joint area, describes the normal structure of the shoulder joint in dogs, and discusses the most frequently encountered shoulder joint pathologies.

  11. Increased horizontal shoulder abduction is associated with an increase in shoulder joint load in baseball pitching.

    PubMed

    Takagi, Yohei; Oi, Takanori; Tanaka, Hiroshi; Inui, Hiroaki; Fujioka, Hiroyuki; Tanaka, Juichi; Yoshiya, Shinichi; Nobuhara, Katsuya

    2014-12-01

    Soft tissues of the shoulder undergoes substantial stresses due to humeral head movement, and this may contribute to throwing shoulder injuries in baseball pitchers. Prevention and management of throwing shoulder injuries critically rely on reduction of shear force at the shoulder joint. However, the amount and direction of the force applied to the shoulder during the throwing motion have not been clarified. The purpose of this study was to analyze forces applied to the shoulder during a baseball pitch. We performed biomechanical analysis of 213 baseball pitchers of various ages and skill levels. Throwing motion was analyzed with a 3-dimensional motion capture system. The Euler angle sequence was adopted to describe angular values of the upper arm relative to the trunk for shoulder rotation, and inverse dynamics was used to estimate the resultant joint forces at the shoulder. There was a significant relation between horizontal abduction/adduction angle and resultant anterior/posterior force at the point of maximum external rotation (MER) (r = -0.63, P < .01), whereby increased horizontal abduction was associated with increased resultant anterior force. There was a significant but weak correlation between abduction/adduction angle and superior/inferior force at MER (r = 0.24, P < .01). Comparison among the groups with variable ages and skill levels showed larger horizontal abduction and smaller external rotation angles at MER in the adult amateur player group, whereas normalized compression force and internal rotation torque values at MER were smaller in the junior high school- and elementary school-aged groups. These results suggest that excessive horizontal abduction at MER increases anterior shear force in the shoulder and may lead to shoulder injuries. Focusing on reducing horizontal abduction at MER in the throwing motion may be key to preventing and managing shoulder injuries in baseball pitchers. Copyright © 2014 Journal of Shoulder and Elbow

  12. Problems With Large Joints: Shoulder Conditions.

    PubMed

    Campbell, Michael

    2016-07-01

    The shoulder is the most mobile joint in the body. It requires an extensive support system to create mobility while providing stability. Although there are many etiologies of shoulder pain, weakness, and instability, most injuries in the shoulder are due to overuse. Rotator cuff tears, labral tears, calcific tendinopathy, and impingement often result from chronic overuse injuries. Acute injuries include dislocations that can cause labral tears or other complications. Frozen shoulder refers to a typically benign condition of restricted range of motion that may spontaneously resolve but can cause prolonged pain and discomfort. The history combined with specific shoulder examination techniques can help family physicians successfully diagnose shoulder conditions. X-ray imaging typically is sufficient to rule out more serious etiologies when evaluating patients with shoulder conditions. However, imaging with magnetic resonance imaging (MRI) study or ultrasonography for rotator cuff tears, and MRI study with intra-articular contrast for labral tears, is needed to confirm these diagnoses. Corticosteroid injections and physical therapy are first-line treatments for most shoulder conditions. Surgical options typically are reserved for patients for whom conservative treatments are ineffective, and typically are performed arthroscopically.

  13. 21 CFR 888.3690 - Shoulder joint humeral (hemi-shoulder) metallic uncemented prosthesis.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... uncemented prosthesis. 888.3690 Section 888.3690 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF... Shoulder joint humeral (hemi-shoulder) metallic uncemented prosthesis. (a) Identification. A shoulder joint humeral (hemi-shoulder) metallic uncemented prosthesis is a device made of alloys, such as...

  14. 21 CFR 888.3680 - Shoulder joint glenoid (hemi-shoulder) metallic cemented prosthesis.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... cemented prosthesis. 888.3680 Section 888.3680 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF... Shoulder joint glenoid (hemi-shoulder) metallic cemented prosthesis. (a) Identification. A shoulder joint glenoid (hemi-shoulder) metallic cemented prosthesis is a device that has a glenoid (socket)...

  15. 21 CFR 888.3690 - Shoulder joint humeral (hemi-shoulder) metallic uncemented prosthesis.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... uncemented prosthesis. 888.3690 Section 888.3690 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF... Shoulder joint humeral (hemi-shoulder) metallic uncemented prosthesis. (a) Identification. A shoulder joint humeral (hemi-shoulder) metallic uncemented prosthesis is a device made of alloys, such as...

  16. 21 CFR 888.3690 - Shoulder joint humeral (hemi-shoulder) metallic uncemented prosthesis.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... uncemented prosthesis. 888.3690 Section 888.3690 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF... Shoulder joint humeral (hemi-shoulder) metallic uncemented prosthesis. (a) Identification. A shoulder joint humeral (hemi-shoulder) metallic uncemented prosthesis is a device made of alloys, such as...

  17. 21 CFR 888.3690 - Shoulder joint humeral (hemi-shoulder) metallic uncemented prosthesis.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... uncemented prosthesis. 888.3690 Section 888.3690 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF... Shoulder joint humeral (hemi-shoulder) metallic uncemented prosthesis. (a) Identification. A shoulder joint humeral (hemi-shoulder) metallic uncemented prosthesis is a device made of alloys, such as...

  18. 21 CFR 888.3680 - Shoulder joint glenoid (hemi-shoulder) metallic cemented prosthesis.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... cemented prosthesis. 888.3680 Section 888.3680 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF... Shoulder joint glenoid (hemi-shoulder) metallic cemented prosthesis. (a) Identification. A shoulder joint glenoid (hemi-shoulder) metallic cemented prosthesis is a device that has a glenoid (socket)...

  19. Shoulder acromioclavicular joint reconstruction options and outcomes.

    PubMed

    Lee, Simon; Bedi, Asheesh

    2016-12-01

    Acromioclavicular joint separations are a common cause of shoulder pain in the young athletic population. In high-grade injuries, acromioclavicular joint reconstruction procedures may be indicated for functional improvement. There is currently no gold standard for the surgical management of these injuries. Multiple reconstructive options exist, including coracoclavicular screws, hook plates, endobutton coracoclavicular fixations, and anatomic ligament reconstructions with tendon grafts. This article aims to review pertinent acromioclavicular joint anatomy and biomechanics, radiographic evaluation, classification system, as well as reconstruction options, outcomes, and complications.

  20. Molecular biology of frozen shoulder-induced limitation of shoulder joint movements.

    PubMed

    Cui, Jiaming; Lu, Wei; He, Yong; Jiang, Luoyong; Li, Kuokuo; Zhu, Weimin; Wang, Daping

    2017-01-01

    Frozen shoulder is a chronic condition characterized by pain in the shoulder and restriction of movements in all directions. Some patients are left with long-term limitation of shoulder joint activity with various severities, which results in reduced quality of life. Currently, there is a paucity of literature on the molecular biology of frozen shoulder, and the molecular biological mechanism for periarthritis-induced limitation of shoulder joint movements remains unclear. Research in this field is focused on inflammation and cytokines associated with fibrosis. Repeated investigations confirmed alterations of specified inflammatory mediators and fibrosis-associated cytokines, which might be involved in the pathogenesis of frozen shoulder by causing structural changes of the shoulder joint and eventually the limitation of shoulder movements. The aim of this article is to review studies on molecular biology of frozen shoulder and provide a reference for subsequent research, treatment, and development of new drugs.

  1. 21 CFR 888.3680 - Shoulder joint glenoid (hemi-shoulder) metallic cemented prosthesis.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... made of alloys, such as cobalt-chromium-molybdenum, or alloys with ultra-high molecular weight... equivalent to a shoulder joint glenoid (hemi-shoulder) metallic cemented prosthesis that was in...

  2. 21 CFR 888.3680 - Shoulder joint glenoid (hemi-shoulder) metallic cemented prosthesis.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... made of alloys, such as cobalt-chromium-molybdenum, or alloys with ultra-high molecular weight... equivalent to a shoulder joint glenoid (hemi-shoulder) metallic cemented prosthesis that was in commercial...

  3. Objective Assessment of Joint Stiffness: A Clinically Oriented Hardware and Software Device with an Application to the Shoulder Joint.

    PubMed

    McQuade, Kevin; Price, Robert; Liu, Nelson; Ciol, Marcia A

    2012-08-30

    Examination of articular joints is largely based on subjective assessment of the "end-feel" of the joint in response to manually applied forces at different joint orientations. This technical report aims to describe the development of an objective method to examine joints in general, with specific application to the shoulder, and suitable for clinical use. We adapted existing hardware and developed laptop-based software to objectively record the force/displacement behavior of the glenohumeral joint during three common manual joint examination tests with the arm in six positions. An electromagnetic tracking system recorded three-dimensional positions of sensors attached to a clinician examiner and a patient. A hand-held force transducer recorded manually applied translational forces. The force and joint displacement were time-synchronized and the joint stiffness was calculated as a quantitative representation of the joint "end-feel." A methodology and specific system checks were developed to enhance clinical testing reproducibility and precision. The device and testing protocol were tested on 31 subjects (15 with healthy shoulders, and 16 with a variety of shoulder impairments). Results describe the stiffness responses, and demonstrate the feasibility of using the device and methods in clinical settings.

  4. An investigation of shoulder forces in active shoulder tackles in rugby union football.

    PubMed

    Usman, Juliana; McIntosh, Andrew S; Fréchède, Bertrand

    2011-11-01

    In rugby union football the tackle is the most frequently executed skill and one most associated with injury, including shoulder injury to the tackler. Despite the importance of the tackle, little is known about the magnitude of shoulder forces in the tackle and influencing factors. The objectives of the study were to measure the shoulder force in the tackle, as well as the effects of shoulder padding, skill level, side of body, player size, and experimental setting on shoulder force. Experiments were conducted in laboratory and field settings using a repeated measures design. Thirty-five participants were recruited to the laboratory and 98 to the field setting. All were male aged over 18 years with rugby experience. The maximum force applied to the shoulder in an active shoulder tackle was measured with a custom built forceplate incorporated into a 45 kg tackle bag. The overall average maximum shoulder force was 1660 N in the laboratory and 1997 N in the field. This difference was significant. The shoulder force for tackling without shoulder pads was 1684 N compared to 1635 N with shoulder pads. There was no difference between the shoulder forces on the dominant and non-dominant sides. Shoulder force reduced with tackle repetition. No relationship was observed between player skill level and size. A substantial force can be applied to the shoulder and to an opponent in the tackle. This force is within the shoulder's injury tolerance range and is unaffected by shoulder pads. Copyright © 2011 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

  5. Maternal Endogenous Forces and Shoulder Dystocia.

    PubMed

    Grimm, Michele J

    2016-12-01

    Childbirth is a complicated biomechanical process that many take for granted. However, the delivery forces generated by a mother (uterine contractions and maternal pushing) are strong and have a significant effect on the body and tissues of the fetus, especially during the second stage of labor. Although most infants are born without negative, force-related outcomes, in some infants the normal forces of labor cause an injury that can have either temporary or permanent sequelae. The biomechanical situation is further complicated when an infant's shoulder impacts the maternal pelvis, which provides increased resistance and creates added stresses within the neonatal body and tissues.

  6. Cases in Joint Force Development

    DTIC Science & Technology

    2001-10-01

    forces in the future. 15. SUBJECT TERMS Force Development; Joint Force Development; Air War College Curriculum; Force Planning; Military Planning; Joint...6 1. Class Participation .....................................................................................7 2. Term ...Paper Prospectus ..............................................................................7 3. Term Paper

  7. The effects of muscle fatigue on shoulder joint position sense.

    PubMed

    Carpenter, J E; Blasier, R B; Pellizzon, G G

    1998-01-01

    Proprioception, or joint position sense, probably plays an important role in shoulder joint function. In this study, we assessed the effect of muscle fatigue on shoulder proprioception in 20 volunteers with no shoulder abnormalities. Shoulder proprioception was measured as the threshold to first detection of humeral rotation with the joint at 90 degrees of abduction and 90 degrees of external rotation. Subjects were tested while rested, exercised on a isokinetic testing machine until fatigued, and then retested in an identical fashion. Both shoulders were tested, and the order of dominant and nondominant shoulder was randomized. Shoulder proprioception was analyzed for its dependence on arm dominance, direction of rotation, and muscle fatigue. Subjects detected external rotation after significantly less movement than they did internal rotation. Overall, before exercise, motion was detected after a mean of 0.92 degrees of rotation. After exercise, this threshold to detection of movement increased to 1.59 degrees, an increase of 73%. This significant increase occurred with both internal and external rotation. The decrease in proprioceptive sense with muscle fatigue may play a role in decreasing athletic performance and in fatigue-related shoulder dysfunction. It remains to be determined if training can lessen this loss in position sense.

  8. Detections of movements imposed on finger, elbow and shoulder joints.

    PubMed Central

    Hall, L A; McCloskey, D I

    1983-01-01

    The angular displacements necessary for 70% correct detection were determined in normal subjects at the shoulder and elbow joints and at the terminal joint of the middle finger. Angular velocities of displacement between 0.125 degrees and 160 degrees/s were tested. Each joint was tested in the mid-range of its normal excursion. The joints were carefully supported for testing and the muscles acting at the joints were relaxed. When assessed in terms of angular displacements and angular velocities, proprioceptive performance at the shoulder and elbow joints was superior to that at the finger joint. Optimal performance at the finger joint was attained over the range of angular velocities from 10 degrees to 80 degrees/s. Optimal performance at both more proximal joints was optimal over a wider range (2 degrees-80 degrees/s). Active pointing movements made without vision of the moving part were performed at each joint at velocities within the range of optimal proprioceptive performance. However, when detection levels and displacement velocities were expressed in terms of linear displacements and velocities at the finger tip for all three joints, the finger joint gave the best performance and the shoulder the worst. In practical terms, therefore, displacements of a given linear extent are best detected if they move distal joints and worst if they move proximal joints. For the elbow and finger joints the detection level and velocity data were expressed also in terms of proportional changes in the lengths of muscles operating at these joints, and as proportional changes in the distance between the points of attachment of the joint capsules. Analysis in terms of proportional changes of muscle length showed remarkably similar performance levels at both joints. This suggests that intramuscular receptors are important determinants of proprioceptive performance. Analysis in terms of joint capsular displacement did not unify the data: on this form of analysis proprioceptive

  9. The shoulder distraction force in cricket fast bowling.

    PubMed

    Stuelcken, Max C; Ferdinands, René E D; Ginn, Karen A; Sinclair, Peter J

    2010-08-01

    This preliminary study aimed to quantify the magnitude of the peak shoulder distraction force during the bowling action of female cricket fast bowlers. An eight camera Vicon motion analysis system operating at 120 Hz recorded the fast bowling actions of 18 Australian female fast bowlers. A three segment inverse solution model of the bowling arm was used to calculate the shoulder distraction force. A large peak shoulder distraction force was recorded during the early stages of the follow-through of the bowling action. When normalized for body weight, the distraction force was within the range of values reported for baseball and softball pitchers, who are considered to be at high risk of shoulder injury. Therefore, the relative importance of the peak shoulder distraction force in the fast bowling action for the development of shoulder pain in female cricket fast bowlers warrants further investigation.

  10. Contributions of the individual muscles of the shoulder to glenohumeral joint stability during abduction.

    PubMed

    Yanagawa, Takashi; Goodwin, Cheryl J; Shelburne, Kevin B; Giphart, J Erik; Torry, Michael R; Pandy, Marcus G

    2008-04-01

    The aim of this study was to determine the relative contributions of the deltoid and rotator cuff muscles to glenohumeral joint stability during arm abduction. A three-dimensional model of the upper limb was used to calculate the muscle and joint-contact forces at the shoulder for abduction in the scapular plane. The joints of the shoulder girdle-sternoclavicular joint, acromioclavicular joint, and glenohumeral joint-were each represented as an ideal three degree-of-freedom ball-and-socket joint. The articulation between the scapula and thorax was modeled using two kinematic constraints. Eighteen muscle bundles were used to represent the lines of action of 11 muscle groups spanning the glenohumeral joint. The three-dimensional positions of the clavicle, scapula, and humerus during abduction were measured using intracortical bone pins implanted into one subject. The measured bone positions were inputted into the model, and an optimization problem was solved to calculate the forces developed by the shoulder muscles for abduction in the scapular plane. The model calculations showed that the rotator cuff muscles (specifically, supraspinatus, subscapularis, and infraspinatus) by virtue of their lines of action are perfectly positioned to apply compressive load across the glenohumeral joint, and that these muscles contribute most significantly to shoulder joint stability during abduction. The middle deltoid provides most of the compressive force acting between the humeral head and the glenoid, but this muscle also creates most of the shear, and so its contribution to joint stability is less than that of any of the rotator cuff muscles.

  11. Echographic and kinetic changes in the shoulder joint after manual wheelchair propulsion under two different workload settings.

    PubMed

    Gil-Agudo, Ángel; Solís-Mozos, Marta; Crespo-Ruiz, Beatriz; Del-Ama Eng, Antonio J; Pérez-Rizo, Enrique; Segura-Fragoso, Antonio; Jiménez-Díaz, Fernando

    2014-01-01

    Manual wheelchair users with spinal cord injury (SCI) have a high prevalence of shoulder pain due to the use of the upper extremity for independent mobility, transfers, and other activities of daily living. Indeed, shoulder pain dramatically affects quality of life of these individuals. There is limited evidence obtained through radiographic techniques of a relationship between the forces acting on the shoulder during different propulsion conditions and shoulder pathologies. Today, ultrasound is widely accepted as a precise tool in diagnosis, displaying particularly effectiveness in screening the shoulder rotator cuff. Thus, we set out to perform an ultrasound-based study of the acute changes to the shoulder soft tissues after propelling a manual wheelchair in two workload settings. Shoulder joint kinetics was recorded from 14 manual wheelchair users with SCI while they performed high- and low-intensity wheelchair propulsion tests (constant and incremental). Shoulder joint forces and moments were obtained from inverse dynamic methods, and ultrasound screening of the shoulder was performed before and immediately after the test. Kinetic changes were more relevant after the most intensive task, showing the significance of high-intensity activity, yet no differences were found in ultrasound-related parameters before and after each propulsion task. It therefore appears that further studies will be needed to collect clinical data and correlate data regarding shoulder pain with both ultrasound images and data from shoulder kinetics.

  12. Echographic and Kinetic Changes in the Shoulder Joint after Manual Wheelchair Propulsion Under Two Different Workload Settings

    PubMed Central

    Gil-Agudo, Ángel; Solís-Mozos, Marta; Crespo-Ruiz, Beatriz; del-Ama Eng, Antonio J.; Pérez-Rizo, Enrique; Segura-Fragoso, Antonio; Jiménez-Díaz, Fernando

    2014-01-01

    Manual wheelchair users with spinal cord injury (SCI) have a high prevalence of shoulder pain due to the use of the upper extremity for independent mobility, transfers, and other activities of daily living. Indeed, shoulder pain dramatically affects quality of life of these individuals. There is limited evidence obtained through radiographic techniques of a relationship between the forces acting on the shoulder during different propulsion conditions and shoulder pathologies. Today, ultrasound is widely accepted as a precise tool in diagnosis, displaying particularly effectiveness in screening the shoulder rotator cuff. Thus, we set out to perform an ultrasound-based study of the acute changes to the shoulder soft tissues after propelling a manual wheelchair in two workload settings. Shoulder joint kinetics was recorded from 14 manual wheelchair users with SCI while they performed high- and low-intensity wheelchair propulsion tests (constant and incremental). Shoulder joint forces and moments were obtained from inverse dynamic methods, and ultrasound screening of the shoulder was performed before and immediately after the test. Kinetic changes were more relevant after the most intensive task, showing the significance of high-intensity activity, yet no differences were found in ultrasound-related parameters before and after each propulsion task. It therefore appears that further studies will be needed to collect clinical data and correlate data regarding shoulder pain with both ultrasound images and data from shoulder kinetics. PMID:25566539

  13. Shoulder muscle forces during driving: Sudden steering can load the rotator cuff beyond its repair limit.

    PubMed

    Pandis, Petros; Prinold, Joe A I; Bull, Anthony M J

    2015-10-01

    Driving is one of the most common everyday tasks and the rotator cuff muscles are the primary shoulder stabilisers. Muscle forces during driving are not currently known, yet knowledge of these would influence important clinical advice such as return to activities after surgery. The aim of this study is to quantify shoulder and rotator cuff muscle forces during driving in different postures. A musculoskeletal modelling approach is taken, using a modified driving simulator in combination with an upper limb musculoskeletal model (UK National Shoulder Model). Motion data and external force vectors were model inputs and upper limb muscle and joint forces were the outputs. Comparisons of the predicted glenohumeral joint forces were compared to in vivo literature values, with good agreement demonstrated (61 SD 8% body weight mean peak compared to 60 SD 1% body weight mean peak). High muscle activation was predicted in the rotator cuff muscles; particularly supraspinatus (mean 55% of the maximum and up to 164 SD 27 N). This level of loading is up to 72% of mean failure strength for supraspinatus repairs, and could therefore be dangerous for some cases. Statistically significant and large differences are shown to exist in the joint and muscle forces for different driving positions as well as steering with one or both hands (up to 46% body weight glenohumeral joint force). These conclusions should be a key consideration in rehabilitating the shoulder after surgery, preventing specific upper limb injuries and predicting return to driving recommendations. Copyright © 2015. Published by Elsevier Ltd.

  14. Joint Forces Capabilities

    DTIC Science & Technology

    2007-11-02

    for countering the proliferation of weapons of mass destruction (WMD) in space. The Space Operations Center ( SPOC ), USSPACECOM is the single point...of contact for assessing space capabilities. Combatant commanders, subordinate JFCs, and Services can access this information from the SPOC via the...special operations forces SPOC Space Operations Center SSBN fleet ballistic missile submarine SST space support team UJTL Universal Joint Task List UN

  15. Contact pressure of the coracoacromial arch in shoulders with joint contracture: A cadaveric study.

    PubMed

    Shiota, Yuki; Yamamoto, Nobuyuki; Kawakami, Jun; Nagamoto, Hideaki; Muraki, Takayuki; Kaneko, Kazuo; Itoi, Eiji

    2017-08-21

    There have been many reports describing that the capsular fibrosis of the shoulder joint is the main cause of frozen shoulder, whereas others reported the significance of subacromial impingement as an etiological factor. The purpose of this study was to investigate the contact pressure between the coracoacromial arch and the rotator cuff tendons to clarify the contact phenomenon in shoulders with joint contracture. Fourteen fresh-frozen cadaveric shoulders were used. Specimens were divided into two groups: normal group (8 shoulders, definition: more than 61° of flexion and abduction and more than 21° of external rotation) and joint contracture group (6 shoulders, definition: less than 60° of flexion and abduction and less than 20° of external rotation). Contact pressure and area beneath the coracoacromial arch were measured by a flexible force sensor during flexion, abduction, internal and external rotation in adduction and abduction, extension and horizontal extension motions. The peak contact pressure under the acromion was observed at 90° in flexion and abduction in the normal group, whereas that in the contracture group was observed at 30° in flexion (P = 0.037) and at 30° in abduction (P = 0.041). Contact pressure in the contracture group was significantly higher than that in the normal group at 20° and 30° of abduction (P = 0.043, P = 0.041, respectively). There were no significant differences of contact pressure during other motions. Although no significant differences of contact pressure beneath the coracoacromial ligament were observed, contact area significantly increased in extension and horizontal extension motion. The contact between the acromion and the rotator cuff was observed in lower angles of flexion and abduction in shoulders with contracture than in those without. When treating patients with shoulder contracture, we need to perform rehabilitation taking such an abnormal movement into consideration. Copyright © 2017 The

  16. 21 CFR 888.3650 - Shoulder joint metal/polymer non-constrained cemented prosthesis.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Shoulder joint metal/polymer non-constrained... Shoulder joint metal/polymer non-constrained cemented prosthesis. (a) Identification. A shoulder joint metal/polymer non-constrained cemented prosthesis is a device intended to be implanted to replace...

  17. 21 CFR 888.3650 - Shoulder joint metal/polymer non-constrained cemented prosthesis.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Shoulder joint metal/polymer non-constrained... Shoulder joint metal/polymer non-constrained cemented prosthesis. (a) Identification. A shoulder joint metal/polymer non-constrained cemented prosthesis is a device intended to be implanted to replace...

  18. 21 CFR 888.3660 - Shoulder joint metal/polymer semi-constrained cemented prosthesis.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Shoulder joint metal/polymer semi-constrained... Shoulder joint metal/polymer semi-constrained cemented prosthesis. (a) Identification. A shoulder joint metal/polymer semi-constrained cemented prosthesis is a device intended to be implanted to replace...

  19. 21 CFR 888.3660 - Shoulder joint metal/polymer semi-constrained cemented prosthesis.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Shoulder joint metal/polymer semi-constrained... Shoulder joint metal/polymer semi-constrained cemented prosthesis. (a) Identification. A shoulder joint metal/polymer semi-constrained cemented prosthesis is a device intended to be implanted to replace...

  20. Errors in Shoulder Joint Position Sense Mainly Come from the Glenohumeral Joint.

    PubMed

    Lin, Yin-Liang; Karduna, Andrew

    2017-02-01

    While synchronous movement of the glenohumeral and scapulothoracic joints has been emphasized in previous kinematics studies, most investigations of shoulder joint position sense have treated the shoulder complex as a single joint. The purposes of this study were to investigate the joint position sense errors of the humerothoracic, glenohumeral, and scapulothoracic joints at different elevation angles and to examine whether the errors of the glenohumeral and scapulothoracic joints contribute to the errors of the humerothoracic joint. Fifty-one subjects with healthy shoulders were recruited. Active joint position sense of the humerothoracic, glenohumeral, and scapulothoracic joints was measured at 50°, 70°, and 90° of humerothoracic elevation in the scapular plane. The results showed that while scapulothoracic joint position sense errors were not affected by target angles, there was an angle effect on humerothoracic and glenohumeral errors, with errors decreasing as the target angles approached 90° of elevation. The results of a multiple regression analysis revealed that glenohumeral errors explained most of the variance of the humerothoracic errors and that scapulothoracic errors had a weaker predictive relationship with humerothoracic errors. Therefore, it may be necessary to test scapular joint position sense separately in addition to the assessment of the overall shoulder joint position sense.

  1. Mathematical modelling as a tool to assessment of loads in volleyball player's shoulder joint during spike.

    PubMed

    Jurkojć, Jacek; Michnik, Robert; Czapla, Krzysztof

    2017-06-01

    This article deals with kinematic and kinetic conditions in volleyball attack and identifies loads in the shoulder joint. Joint angles and velocities of individual segments of upper limb were measured with the use of the motion capture system XSENS. Muscle forces and loads in skeletal system were calculated by means of mathematical model elaborated in AnyBody system. Spikes performed by players in the best and worst way were compared with each other. The relationships were found between reactions in shoulder joint and flexion/extension, abduction/adduction and rotation angles in the same joint and flexion/extension in the elbow joint. Reactions in shoulder joint varied from 591 N to 2001 N (in relation to body weight [BW] 83-328%). The analysis proved that hand velocity at the moment of the ball hit (which varied between 6.8 and 13.3 m s(-1)) influences on the value of reaction in joints, but positions of individual segments relative to each other are also crucial. It was also proved in objective way, that position of the upper limb during spike can be more or less harmful assuming that bigger reaction increases possibility of injury, what can be an indication for trainers and physiotherapists how to improve injury prevention.

  2. Shoulder joint kinetics of the elite wheelchair tennis serve

    PubMed Central

    Reid, Machar; Elliott, Bruce; Alderson, Jacque

    2007-01-01

    Background The shoulder is a key joint in wheelchair locomotion and commonly implicated in injury among virtually all wheelchair populations. In tennis, quantification of the shoulder joint kinetics that characterise the wheelchair serve could enhance injury prevention and rehabilitation practices as well as assist coaches evaluate the efficacy of their current technical instruction. Methods A 12‐camera, 250 Hz Vicon motion analysis system (Oxford Metrics Inc., UK) recorded the 3D flat (WFS) and kick serve (WKS) motions of two male top 30‐ranked international wheelchair players. Mechanical comparisons between wheelchair players, as well as to the previously captured data of 12 high‐performance able‐bodied players executing the same types of serves, were undertaken. Results Without the benefit of a propulsive leg action, wheelchair players developed lower peak absolute (∼32 m/s) and horizontal (∼28 m/s) pre‐impact racquet velocities than able‐bodied players (∼42 m/s, ∼38 m/s). Wheelchair serve tactics nevertheless necessitated that higher pre‐impact horizontal and right lateral racquet velocities characterised the WFS (∼29 m/s, WKS: ∼26 m/s) and WKS (∼4 m/s, WFS: ∼11 m/s) respectively. The shoulder joint kinetics that contributed to the differential racquet velocity profiles were mostly developed independent of wheelchair serve type, but varied with and were likely related to the level and severity of spinal cord injury of the individual players. Conclusions Compared with able‐bodied players, wheelchair players experienced matching pre‐ and post‐impact shoulder joint loads, such that wheelchair and able‐bodied playing populations appear subject to similar shoulder joint injury risk. PMID:17957009

  3. Kinesio Tape and Shoulder-Joint Position Sense.

    PubMed

    Aarseth, Lindsay M; Suprak, David N; Chalmers, Gordon R; Lyon, Lonnie; Dahlquist, Dylan T

    2015-08-01

    Joint position sense (JPS) is a key neuromuscular factor for developing and maintaining control of muscles around a joint. It is important when performing specialized tasks, especially at the shoulder. No researchers have studied how Kinesio Tape (KT) application affects JPS. To investigate the effects of KT application and no tape on shoulder JPS at increasing shoulder elevations in athletes. Cross-sectional study. University laboratory. A total of 27 healthy athletes who did not participate in overhead sports (age = 20.44 ± 1.05 years, height = 175.02 ± 11.67 cm, mass = 70.74 ± 9.65 kg) with no previous pathologic shoulder conditions volunteered for the study. All participants were from 1 university. Shoulder JPS was assessed at increasing elevations with and without KT application. Participants attempted to actively replicate 3 target positions with and without the KT and without visual guidance. We examined absolute and variable repositioning errors at increasing shoulder-elevation levels with and without KT application. Data revealed an interaction between tape and position for absolute error (F2,52 = 4.07, P = .02); simple effects revealed an increase in error, with KT demonstrating a 2.65° increase in error at 90° of elevation compared with no tape (t26 = 2.65, P = .01). The effect size was medium (ω(2) = .135). Variable error showed no interaction of tape and position (F2,52 = .709, P = .50). Further analysis of simple effects was not needed. However, we still calculated the effect size and observed small effect sizes for tape (ω(2) = .002), position (ω(2) = .072), and tape by position (ω(2) = .027). At 90° of elevation, shoulder JPS was impaired by the application of KT.

  4. Kinesio Tape and Shoulder-Joint Position Sense

    PubMed Central

    Aarseth, Lindsay M.; Suprak, David N.; Chalmers, Gordon R.; Lyon, Lonnie; Dahlquist, Dylan T.

    2015-01-01

    Context Joint position sense (JPS) is a key neuromuscular factor for developing and maintaining control of muscles around a joint. It is important when performing specialized tasks, especially at the shoulder. No researchers have studied how Kinesio Tape (KT) application affects JPS. Objective To investigate the effects of KT application and no tape on shoulder JPS at increasing shoulder elevations in athletes. Design Cross-sectional study. Setting University laboratory. Patients or Other Participants A total of 27 healthy athletes who did not participate in overhead sports (age = 20.44 ± 1.05 years, height = 175.02 ± 11.67 cm, mass = 70.74 ± 9.65 kg) with no previous pathologic shoulder conditions volunteered for the study. All participants were from 1 university. Intervention(s) Shoulder JPS was assessed at increasing elevations with and without KT application. Participants attempted to actively replicate 3 target positions with and without the KT and without visual guidance. Main Outcome Measure(s) We examined absolute and variable repositioning errors at increasing shoulder-elevation levels with and without KT application. Results Data revealed an interaction between tape and position for absolute error (F2,52 = 4.07, P = .02); simple effects revealed an increase in error, with KT demonstrating a 2.65° increase in error at 90° of elevation compared with no tape (t26 = 2.65, P = .01). The effect size was medium (ω2 = .135). Variable error showed no interaction of tape and position (F2,52 = .709, P = .50). Further analysis of simple effects was not needed. However, we still calculated the effect size and observed small effect sizes for tape (ω2 = .002), position (ω2 = .072), and tape by position (ω2 = .027). Conclusions At 90° of elevation, shoulder JPS was impaired by the application of KT. PMID:26090707

  5. The effect of an active vibration stimulus according to different shoulder joint angles on functional reach and stability of the shoulder joint

    PubMed Central

    Kim, Eun-Kyung; Kim, Seong-Gil

    2016-01-01

    [Purpose] The purpose of this study was to analyze the effect of an active vibration stimulus exercise according to shoulder joint angles on functional reach and stability of the shoulder joint. [Subjects and Methods] Thirty healthy male students participated in this study. Upper limb length of each subject was measured to obtain normalized measurement values. The exercise groups were as follows: group I (n=10, shoulder joint angle of 90°), group II (n=10, shoulder joint angle of 130°), and group III (n=10, shoulder joint angle of 180°). After warm-up, an active vibration stimulus was applied to the subjects with a Flexi-Bar. The Functional Reach Test and Y-balance test were conducted for measurement of shoulder stability. [Results] Analysis of covariance was conducted with values before the intervention as covariates to analyze the differences among the groups in the two tests. There were significant differences among the groups. According to Bonferroni post hoc comparison, group I showed greater improvement than group III in the Functional Reach Test, and group II showed greater improvement than group I and group III in the Y-balance test. [Conclusion] The effect of the exercise with different shoulder joint angles revealed that the shoulder joint has a certain effective joint angle for its functionality and stability. In addition, application of an active vibration stimulus with a Flexi-Bar can be a very effective tool for improvement of functionality and stability of the shoulder joint. PMID:27134352

  6. The shoulder and elbow joints and right and left sides demonstrate similar joint position sense.

    PubMed

    King, Jacqlyn; Harding, Elizabeth; Karduna, Andrew

    2013-01-01

    Proper orientation of the shoulder and elbow is necessary for accurate and precise positioning of the hand. The authors' goal was to compare these joints with an active joint position sense task, while also taking into account the effects of joint flexion angle and arm dominance. Fifteen healthy subjects were asked to replicate presented joint angles with a single degree of freedom active positioning protocol. There were no significant differences in angular joint position sense errors with respect to joint (shoulder vs. elbow) and side (left vs. right). However, when considering linear positioning, errors were lower for the elbow, due to a shorter lever arm. Also, as flexion angles increased toward 90°, there was a consistent pattern of lower errors for both joints.

  7. Clinical Effectiveness of Scapulothoracic Joint Control Training Exercises on Shoulder Joint Dysfunction.

    PubMed

    Zhang, Ming; Zhou, Jing-Jie; Zhang, Yu-Ming; Wang, Ji-Hong; Zhang, Qiu-Yang; Chen, Wei

    2015-05-01

    The objective of this study was to examine the clinical effectiveness of scapulothoracic joint control training exercises on shoulder joint dysfunction. Forty patients with traumatic shoulder pain and joint dysfunction were randomized into the treatment or control group. Standard rehabilitation interventions included glenohumeral joint mobilization techniques, ultrasound therapy, traditional Chinese medicine, interference current therapy, and other comprehensive interventions. Patients received scapulothoracic joint control training exercises, including active and passive motions of the scapulothoracic joints, peri-joint muscle exercise, and joint stability exercises for 1 month. Patient status was evaluated by Constant-Murley scales before and after the prescribed interventions. The pain conditions, daily activities, range of movement, strength tests and total scores were significantly improved compared to prior treatment. Moreover, improvements in pain, daily activities, scope of activities, and total scores for patients in the treatment group were statistically significant when compared to the control group (P < 0.05). However, there was no inter-group difference in strength testing. The combination of standard rehabilitation interventions and scapulothoracic joint control training exercises are an effective treatment of the shoulder joint dysfunction. Moreover, the pain outcomes, scope of activities, and total scores were better in the treatment group.

  8. A new shoulder model with a biologically inspired glenohumeral joint.

    PubMed

    Quental, C; Folgado, J; Ambrósio, J; Monteiro, J

    2016-09-01

    Kinematically unconstrained biomechanical models of the glenohumeral (GH) joint are needed to study the GH joint function, especially the mechanisms of joint stability. The purpose of this study is to develop a large-scale multibody model of the upper limb that simulates the 6 degrees of freedom (DOF) of the GH joint and to propose a novel inverse dynamics procedure that allows the evaluation of not only the muscle and joint reaction forces of the upper limb but also the GH joint translations. The biomechanical model developed is composed of 7 rigid bodies, constrained by 6 anatomical joints, and acted upon by 21 muscles. The GH joint is described as a spherical joint with clearance. Assuming that the GH joint translates according to the muscle load distribution, the redundant muscle load sharing problem is formulated considering as design variables the 3 translational coordinates associated with the GH joint translations, the joint reaction forces associated with the remaining kinematic constraints, and the muscle activations. For the abduction motion in the frontal plane analysed, the muscle and joint reaction forces estimated by the new biomechanical model proposed are similar to those estimated by a model in which the GH joint is modeled as an ideal spherical joint. Even though this result supports the assumption of an ideal GH joint to study the muscle load sharing problem, only a 6 DOF model of the GH joint, as the one proposed here, provides information regarding the joint translations. In this study, the biomechanical model developed predicts an initial upward and posterior migration of the humeral head, followed by an inferior and anterior movement, which is in good agreement with the literature.

  9. Shoulder sensorimotor control assessment by force platform: feasibility and reliability.

    PubMed

    Edouard, Pascal; Gasq, David; Calmels, Paul; Ducrot, Sarah; Degache, Francis

    2012-09-01

    Given the important role of the shoulder sensorimotor system in shoulder stability, its assessment appears of interest. Force platform monitoring of centre of pressure (CoP) in upper-limb weight-bearing positions is of interest as it allows integration of all aspects of shoulder sensorimotor control. This study aimed to determine the feasibility and reliability of shoulder sensorimotor control assessment by force platform. Forty-five healthy subjects performed two sessions of CoP measurement using Win-Posturo(®) Medicapteurs force platform in an upper-limb weight-bearing position with the lower limbs resting on a table to either the anterior superior iliac spines (P1) or upper patellar poles (P2). Four different conditions were tested in each position in random order: eyes open or eyes closed with trunk supported by both hands and eyes open with trunk supported on the dominant or non-dominant side. P1 reliability values were globally moderate to high for CoP length, CoP velocity and CoP standard deviation (SD), standard error of measurement ranged from 6·0% to 26·5%, except for CoP area. P2 reliability values were globally low and not clinically acceptable. Our results suggest that shoulder sensorimotor control assessment by force platform is feasible and has good reliability in upper-limb weight-bearing positions when the lower limbs are resting on a table to the anterior superior iliac spines. CoP length, CoP velocity and CoP SD velocity appear to be the most reliable variables.

  10. Towards computer-assisted surgery in shoulder joint replacement

    NASA Astrophysics Data System (ADS)

    Valstar, Edward R.; Botha, Charl P.; van der Glas, Marjolein; Rozing, Piet M.; van der Helm, Frans C. T.; Post, Frits H.; Vossepoel, Albert M.

    A research programme that aims to improve the state of the art in shoulder joint replacement surgery has been initiated at the Delft University of Technology. Development of improved endoprostheses for the upper extremities (DIPEX), as this effort is called, is a clinically driven multidisciplinary programme consisting of many contributory aspects. A part of this research programme focuses on the pre-operative planning and per-operative guidance issues. The ultimate goal of this part of the DIPEX project is to create a surgical support infrastructure that can be used to predict the optimal surgical protocol and can assist with the selection of the most suitable endoprosthesis for a particular patient. In the pre-operative planning phase, advanced biomechanical models of the endoprosthesis fixation and the musculo-skeletal system of the shoulder will be incorporated, which are adjusted to the individual's morphology. Subsequently, the support infrastructure must assist the surgeon during the operation in executing his surgical plan. In the per-operative phase, the chosen optimal position of the endoprosthesis can be realised using camera-assisted tools or mechanical guidance tools. In this article, the pathway towards the desired surgical support infrastructure is described. Furthermore, we discuss the pre-operative planning phase and the per-operative guidance phase, the initial work performed, and finally, possible approaches for improving prosthesis placement.

  11. Shoulder and hip joint for hard space suits

    NASA Technical Reports Server (NTRS)

    Vykukal, H. C.

    1986-01-01

    Shoulder and hip joints for hard space suits are disclosed which are comprised of three serially connected truncated spherical sections, the ends of which converge. Ball bearings between the sections permit relative rotation. The proximal end of the first section is connected to the torso covering by a ball bearing and the distal end of the outermost section is connected to the elbow or thigh covering by a ball bearing. The sections are equi-angular and this alleviates lockup, the condition where the distal end of the joint leaves the plane in which the user is attempting to flex. The axes of rotation of the bearings and the bearing mid planes are arranged to intersect in a particular manner that provides the joint with a minimum envelope. In one embodiment, the races of the bearing between the innermost section and the second section is partially within the inner race of the bearing between the torso and the innermost spherical section further to reduce bulk.

  12. 21 CFR 888.3640 - Shoulder joint metal/metal or metal/polymer constrained cemented prosthesis.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Shoulder joint metal/metal or metal/polymer... § 888.3640 Shoulder joint metal/metal or metal/polymer constrained cemented prosthesis. (a) Identification. A shoulder joint metal/metal or metal/polymer constrained cemented prosthesis is a...

  13. 21 CFR 888.3640 - Shoulder joint metal/metal or metal/polymer constrained cemented prosthesis.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Shoulder joint metal/metal or metal/polymer... § 888.3640 Shoulder joint metal/metal or metal/polymer constrained cemented prosthesis. (a) Identification. A shoulder joint metal/metal or metal/polymer constrained cemented prosthesis is a...

  14. 21 CFR 888.3640 - Shoulder joint metal/metal or metal/polymer constrained cemented prosthesis.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Shoulder joint metal/metal or metal/polymer... § 888.3640 Shoulder joint metal/metal or metal/polymer constrained cemented prosthesis. (a) Identification. A shoulder joint metal/metal or metal/polymer constrained cemented prosthesis is a...

  15. 21 CFR 888.3670 - Shoulder joint metal/polymer/metal nonconstrained or semi-constrained porous-coated uncemented...

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Shoulder joint metal/polymer/metal nonconstrained... ORTHOPEDIC DEVICES Prosthetic Devices § 888.3670 Shoulder joint metal/polymer/metal nonconstrained or semi-constrained porous-coated uncemented prosthesis. (a) Identification. A shoulder joint...

  16. 21 CFR 888.3640 - Shoulder joint metal/metal or metal/polymer constrained cemented prosthesis.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Shoulder joint metal/metal or metal/polymer... § 888.3640 Shoulder joint metal/metal or metal/polymer constrained cemented prosthesis. (a) Identification. A shoulder joint metal/metal or metal/polymer constrained cemented prosthesis is a...

  17. 21 CFR 888.3670 - Shoulder joint metal/polymer/metal nonconstrained or semi-constrained porous-coated uncemented...

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Shoulder joint metal/polymer/metal nonconstrained... ORTHOPEDIC DEVICES Prosthetic Devices § 888.3670 Shoulder joint metal/polymer/metal nonconstrained or semi-constrained porous-coated uncemented prosthesis. (a) Identification. A shoulder joint...

  18. 21 CFR 888.3640 - Shoulder joint metal/metal or metal/polymer constrained cemented prosthesis.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Shoulder joint metal/metal or metal/polymer... § 888.3640 Shoulder joint metal/metal or metal/polymer constrained cemented prosthesis. (a) Identification. A shoulder joint metal/metal or metal/polymer constrained cemented prosthesis is a...

  19. Role of Subscapularis Repair on Muscle Force Requirements with Reverse Shoulder Arthroplasty.

    PubMed

    Hansen, Matthew L; Nayak, Aniruddh; Narayanan, Madusudanan Sathia; Worhacz, Kellen; Stowell, Richard; Jacofsky, Marc C; Roche, Christopher P

    2015-12-01

    Concomitant repair of the subscapularis with reverse shoulder arthroplasty (rTSA) is controversial. To evaluate the biomechanical impact of subscapularis repair with rTSA, a cadaveric shoulder controller quantified the muscle forces required to elevate the arm during scapular abduction with the elbow flexed at 90°. The results of this study demonstrate that concomitant subscapularis repair with rTSA creates a biomechanically unfavorable condition during arm elevation. Specifically, repair of the subscapularis significantly increased the force required by the deltoid and posterior rotator cuff and also significantly increased the joint reaction force relative to when the subscapularis was not repaired. These results also demonstrated that both the 42 mm Grammont and 42 mm Equinoxe® rTSA prostheses significantly decreased the mean force required by the posterior rotator cuff and also significantly decreased the mean joint reaction force over the range of motion relative to the native joint with a rotator cuff tear (supraspinatus). As the posterior rotator cuff is often compromised in patients undergoing rTSA, patients may not be able to sustain these elevated forces in the infraspinatus and teres minor required to counteract the adduction and internal rotation moments generated by the subscapularis during activities of daily living. Similarly, the elevated posterior deltoid force and joint reaction loads could be deleterious to the long-term life of the prosthesis and can also increase the risk of loosening and fractures. For all these reasons, rTSA functional outcomes may be compromised if the subscapularis is repaired.

  20. ULTRASOUND MEASUREMENTS AND OBJECTIVE FORCES OF GLENOHUMERAL TRANSLATIONS DURING SHOULDER ACCESSORY PASSIVE MOTION TESTING IN HEALTHY INDIVIDUALS

    PubMed Central

    Worst, Haley; Decarreau, Ryan; Davies, George

    2016-01-01

    Background Clinical examination of caspuloligamentous structures of the glenohumeral joint has historically been subjective in nature, as demonstrated by limited intra-rater and inter-rater reproducibility. Musculoskeletal diagnostic ultrasound was utilized to develop a clinically objective measurement technique for glenohumeral inferior and posterolateral translation. Purpose The purpose of this study was to measure the accessory passive force required to achieve end range glenohumeral posterolateral and inferior accessory translation, as well as, to quantify the amount of translation of the glenohumeral joint caused by the applied force. Study Design Cross-sectional descriptive correlational study Methods Twenty-five asymptomatic subjects between the ages of 18 and 30 were recruited via convenience sampling. Posterolateral and inferior shoulder accessory passive translation was assessed and measured using a GE LOGIQe ultrasound, while concurrently using a hand held dynamometer to quantify the passive force applied during assessment. Normative values for force and translation were described as means and standard deviations. Results Mean values for posterolateral translation were 6.5 +/− 4.0 mm on the right shoulder and 6.3 +/− 3.5 mm on the left with an associated mean force of 127.1 +/− 55.6 N and 114.4 +/− 50.7 N, respectively. Mean values for inferior translation were 4.8 +/− 1.7 mm on the right shoulder and 5.4 +/− 1.8 mm on the left with an associated mean force of 84.5 +/− 30.5 N and 76.1 +/− 30.1 N, respectively. There was a significant association between inferior translation and inferior force (r = .51). No significant association was found between posterolateral translation and posterolateral force. Significant differences were found between dominant and non-dominant shoulders for posterolateral translation, posterolateral force to produce translation, and inferior translation values

  1. FIESTA: an MR arthrography celebration of shoulder joint anatomy, variants, and their mimics.

    PubMed

    Yu, D; Turmezei, T D; Kerslake, R W

    2013-03-01

    Magnetic resonance (MR) arthrography is currently the gold standard radiological investigation for shoulder joint instability. Not only does this investigation allow for identification of important disease processes, but the reduced slice thickness and increased in-plane resolution allowed by the latest imaging sequences also gives excellent demonstration of shoulder joint internal anatomy. This article describes the technique of MR arthrography of the shoulder practiced at our institution, briefly outlining features of the FIESTA (fast imaging employing steady state acquisition) MR sequence employed, including its advantages and limitations. A pictorial review of shoulder MR arthrography performed with this technique is presented, concentrating on normal shoulder joint internal anatomy and anatomical variants that may mimic pathology.

  2. Dislocated shoulder - aftercare

    MedlinePlus

    ... aftercare; Shoulder subluxation - aftercare; Shoulder reduction - aftercare; Glenohumeral joint dislocation ... that connect bone to bone) of the shoulder joint. All of these tissues help keep your arm ...

  3. Infected shoulder joint with loose Suture Anchor in the joint after Bankart’s Repair- A Case Report

    PubMed Central

    Kumar, Mukesh; Thilak, Jai

    2016-01-01

    Introduction: The glenoid labrum is frequently torn in traumatic glenohumeral dislocation; arthroscopic repair is the standard method of treatment. The complications associated with this repair are pulling out of metal suture anchors, chondrolysis and joint infection. The infection of joint after arthroscopy is less than 1%. Staphylococcus is most common organism and rarely followed by Pseudomonas aeruginosa. We report a case of infected shoulder with chondrolysis of the joint and pulled out metal suture anchor lying inside the joint after Bankart’s repair. Case Report: A 22-year-old gentleman came to us with complaints of shoulder joint pain & gross restriction of movements for one year, with history of intermittent fever and treatment in nearby hospital. He also gives past history of recurrent dislocation of shoulder with last episode 18 months back, which was diagnosed as Bankart’s lesion and arthroscopic Bankart’s repair was done 15 months back. He was evaluated at our institute and suspected to have infection of shoulder joint with pulled out metal suture anchor inside the joint. Arthroscopic removal of suture anchor and debridement of shoulder joint was done, Culture was obtained and culture specific antibiotics were given for six weeks, and significant improvement was observed with this line of treatment. At lyear follow up, the patient was able to perform his daily activities with terminal restriction of range of motion. Conclusions: Shoulder joint infection is rare after Bankart’s repair and required a high degree of suspicion. Any foreign materials inside the joint should be taken out & followed with aggressive treatment by debridement, irrigation and culture specific antibiotics. Suppression of joint infection with antibiotics should be avoided specially when there is foreign body inside the joint. PMID:27703928

  4. The accuracy of an external frame using ISB recommended rotation sequence to define shoulder joint angle.

    PubMed

    Xu, Xu; McGorry, Raymond W; Lin, Jia-hua

    2014-01-01

    When investigating shoulder kinematics, it may be necessary to limit shoulder joint angles at a specific level. Previous studies used external frames or external surfaces to assist the participant to reach the shoulder joint angles of interest. The accuracy of these methods, however, has not yet been investigated. In the current study, an external frame was designed to assist in maintaining specific shoulder postures in a wide range. The three degrees of freedom of rotation of the proposed frame were designed to be consistent with the description of shoulder joint angles recommended by the International Society of Biomechanics. Six participants used this frame to perform 118 different shoulder postures. The reference joint angles measured by a motion tracking system were compared with the frame-defined angles. The angle differences among all the participants ranged from 12.7° to 85.6°, with an average of 32.2° (SD 15.1°) across all postures. For the postures with elevation angles on or below horizontal, the average angle difference was 23.7° (SD 8.5°). Findings suggest that errors exist when using an external frame to assist in reaching specific shoulder postures. Error is minimized at elevation angles close to -30°, and the performance is poor for extreme shoulder postures. Copyright © 2013 The Authors. Published by Elsevier B.V. All rights reserved.

  5. Comparison of an EMG-based and a stress-based method to predict shoulder muscle forces.

    PubMed

    Engelhardt, Christoph; Malfroy Camine, Valérie; Ingram, David; Müllhaupt, Philippe; Farron, Alain; Pioletti, Dominique; Terrier, Alexandre

    2015-01-01

    The estimation of muscle forces in musculoskeletal shoulder models is still controversial. Two different methods are widely used to solve the indeterminacy of the system: electromyography (EMG)-based methods and stress-based methods. The goal of this work was to evaluate the influence of these two methods on the prediction of muscle forces, glenohumeral load and joint stability after total shoulder arthroplasty. An EMG-based and a stress-based method were implemented into the same musculoskeletal shoulder model. The model replicated the glenohumeral joint after total shoulder arthroplasty. It contained the scapula, the humerus, the joint prosthesis, the rotator cuff muscles supraspinatus, subscapularis and infraspinatus and the middle, anterior and posterior deltoid muscles. A movement of abduction was simulated in the plane of the scapula. The EMG-based method replicated muscular activity of experimentally measured EMG. The stress-based method minimised a cost function based on muscle stresses. We compared muscle forces, joint reaction force, articular contact pressure and translation of the humeral head. The stress-based method predicted a lower force of the rotator cuff muscles. This was partly counter-balanced by a higher force of the middle part of the deltoid muscle. As a consequence, the stress-based method predicted a lower joint load (16% reduced) and a higher superior-inferior translation of the humeral head (increased by 1.2 mm). The EMG-based method has the advantage of replicating the observed cocontraction of stabilising muscles of the rotator cuff. This method is, however, limited to available EMG measurements. The stress-based method has thus an advantage of flexibility, but may overestimate glenohumeral subluxation.

  6. Effect of joint conformity on glenoid component fixation in total shoulder arthroplasty.

    PubMed

    Oosterom, R; Rozing, P M; Verdonschot, N; Bersee, H E N

    2004-01-01

    Results of shoulder replacements are inferior and must be improved. Two of the major problems of total shoulder replacements are loosening of cemented glenoid components and wear of polyethylene inlays of uncemented, metal-backed glenoid components. The aim of this study is to investigate the influence of joint conformity on glenoid-component fixation. Keeled glenoid components, with radii of curvature of 24, 25, or 29 mm, were cemented in bone substitutes, placed in a force-controlled test set-up, articulating against a 24 mm humeral head. They were loaded by a constant joint compression force (725 +/- 10 N) and a superior subluxation force (shear force), cyclically varying between 0 and 350 +/- 1 N. After 200,000 load cycles, the upper and lower glenoid component rim-displacements were measured by custom-made displacement sensors. Additionally, the shear-out strength has been measured to investigate the residual strength. The glenoid component structures with radii of curvature of 24, 25, and 29 mm showed maximum superior rim-displacements of 0.163 (SD = 0.01), 0.299 (SD = 0.0306), and 0.350 (SD = 0.0197) mm respectively, which is a significant difference (p < 0.05). The maximum shear-out strength of glenoid components with radii of curvature of 24, 25, and 29 mm was 2707 (SD = 452), 2648 (SD = 299), and 2631 (SD = 312) N respectively, which is not a significant difference (p < 0.05). However, the results indicate that a conform articulation shows smaller glenoid rim-displacements, which might be beneficial for long-term component fixation.

  7. A regression model predicting isometric shoulder muscle activities from arm postures and shoulder joint moments.

    PubMed

    Xu, Xu; McGorry, Raymond W; Lin, Jia-Hua

    2014-06-01

    Tissue overloading is a major contributor to shoulder musculoskeletal injuries. Previous studies attempted to use regression-based methods to predict muscle activities from shoulder kinematics and shoulder kinetics. While a regression-based method can address co-contraction of the antagonist muscles as opposed to the optimization method, most of these regression models were based on limited shoulder postures. The purpose of this study was to develop a set of regression equations to predict the 10th percentile, the median, and the 90th percentile of normalized electromyography (nEMG) activities from shoulder postures and net shoulder moments. Forty participants generated various 3-D shoulder moments at 96 static postures. The nEMG of 16 shoulder muscles was measured and the 3-D net shoulder moment was calculated using a static biomechanical model. A stepwise regression was used to derive the regression equations. The results indicated the measured range of the 3-D shoulder moment in this study was similar to those observed during work requiring light physical capacity. The r(2) of all the regression equations ranged between 0.228 and 0.818. For the median of the nEMG, the average r(2) among all 16 muscles was 0.645, and the five muscles with the greatest r(2) were the three deltoids, supraspinatus, and infraspinatus. The results can be used by practitioners to estimate the range of the shoulder muscle activities given a specific arm posture and net shoulder moment. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

  8. Patients' experiences of telerehabilitation at home after shoulder joint replacement.

    PubMed

    Eriksson, Lisbeth; Lindström, Britta; Ekenberg, Lilly

    2011-01-01

    We investigated the experience of ten patients who received video-based physiotherapy at home for two months after a shoulder joint replacement. Videoconferencing took place via the patient's home broadband connection at a bandwidth of 256-768 kbit/s. Qualitative interviews were carried out, transcribed and analysed. Through qualitative content analysis six categories were identified: (1) a different reinforced communication; (2) pain-free exercising as an effective routine; (3) from a dependent patient to a strengthened person at home; (4) closeness at a distance; (5) facilitated daily living; and (6) continuous physiotherapy chain. The access to bodily knowledge, continuity, collaboration and being at home were all aspects that contributed to the patients' recovery. The patients described experiences of safety, and strengthening during their daily exercise routine at home. The frequent interplay with the patient during telerehabilitation made it possible for the physiotherapist to make an individual judgement about each patient; this could be one reason for the positive findings. Home video-based physiotherapy may be useful in other kinds of physiotherapy.

  9. Prevalence of shoulder pain in Swedish flatwater kayakers and its relation to range of motion and scapula stability of the shoulder joint.

    PubMed

    Johansson, Anette; Svantesson, Ulla; Tannerstedt, Jörgen; Alricsson, Marie

    2016-01-01

    Few studies have investigated the incidence of injuries in kayakers. The aim was to study the prevalence of shoulder pain in competitive flatwater kayakers and to evaluate any differences in range of motion or scapula stability of the shoulder joint among kayakers with or without the history of shoulder pain. Thirty-one kayakers were participated in the study, and a questionnaire including background data was used. Shoulder range of motion was measured with a goniometer, and the participants were observed for scapula dyskinesis in flexion and abduction. Of the participating kayakers, 54.8% (n = 17) had experienced shoulder pain. Kayakers who had experienced shoulder pain showed a significantly lower degree of internal rotational range of motion versus kayakers with no reported shoulder pain, with a mean degree of internal rotation in the right shoulder 49.3 vs. 60.0 (P = 0.017) and the left shoulder 51.9 vs. 66.0 (P = 0.000). Kayakers who had experienced shoulder pain were also observed with a scapular dyskinesis (n = 15 of 17 kayakers) to a significantly higher degree (P = 0.001) than kayakers with no reported shoulder pain. Findings suggest that screening for scapular dyskinesis and testing for rotational range of motion in the shoulder joint is essential in order to treat and maybe prevent shoulder pain in kayakers.

  10. Effects of hand grip exercise on shoulder joint internal rotation and external rotation peak torque.

    PubMed

    Lee, Dong-Rour; Jong-Soon Kim, Laurentius

    2016-08-10

    The goal of this study is to analyze the effects of hand grip training on shoulder joint internal rotation (IR)/external rotation (ER) peak torque for healthy people. The research was conducted on 23 healthy adults in their 20 s-30 s who volunteered to participate in the experiment. Hand grip power test was performed on both hands of the research subjects before/after the test to study changes in hand grip power. Isokinetic machine was used to measure the concentric IRPT (internal rotation peak torque) and concentric ERPT (external rotation peak torque) at the velocity of 60°/sec, 90°/sec, and 180°/sec before/after the test. Hand grip training was performed daily on the subject's right hand only for four weeks according to exercise program. Finally, hand grip power of both hands and the maximum torque values of shoulder joint IR/ER were measured before/after the test and analyzed. There was a statistically significant difference in the hand grip power of the right hand, which was subject to hand grip training, after the experiment. Also, statistically significant difference for shoulder ERPT was found at 60°/sec. Hand grip training has a positive effect on shoulder joint IRPT/ERPT and therefore can help strengthen muscles around the shoulder without using weight on the shoulder. Consequently, hand grip training would help maintain strengthen the muscles around the shoulder in the early phase of rehabilitation process after shoulder surgery.

  11. Friction stir spot welded joints of 409L stainless steels fabricated by a convex shoulder tool

    NASA Astrophysics Data System (ADS)

    Hossain, Md. Abu Mowazzem; Hasan, Md. Tariqul; Hong, Sung-Tae; Miles, Michael; Cho, Hoon-Hwe; Han, Heung Nam

    2013-11-01

    Spot joints of ferritic 409L stainless steel are successfully fabricated by friction stir spot welding (FSSW) using a convex shoulder tool. The welding process, microstructure and failure of the FSSW joint are investigated experimentally. During the FSSW process, the Z-force history shows significant variations depending on the contact phenomena between the tool and the joined sheets, while the Z-torque history shows a rather steady increase without pronounced changes in the trend until the initiation of dwelling. Electron back-scatter diffraction suggests that both continuous dynamic recrystallization and recovery occurred in the stir zone during the FSSW process. Observation of the FSSW joint that failed under the given lap shear load shows that the cracks, which are the result of the interfaces between the upper and lower sheets, propagated into the weld along the interfacial surfaces, after which a necking/shear failure occurred. Finally, the rupture of the joint, which was initiated by the necking/shear failure, propagated along the circumference of the weld.

  12. VARIABILITY OF PEAK SHOULDER FORCE DURING WHEELCHAIR PROPULSION IN MANUAL WHEELCHAIR USERS WITH AND WITHOUT SHOULDER PAIN

    PubMed Central

    Moon, Y.; Chandrasekaran, J.; Hsu, I.M.K.; Rice, I.M.; Hsiao-Wecksler, E.T.; Sosnoff, J.J.

    2013-01-01

    Background Manual wheelchair users report a high prevalence of shoulder pain. Growing evidence shows that variability in forces applied to biological tissue is related to musculoskeletal pain. The purpose of this study was to examine the variability of forces acting on the shoulder during wheelchair propulsion as a function of shoulder pain. Methods Twenty-four manual wheelchair users (13 with pain, 11 without pain) participated in the investigation. Kinetic and kinematic data of wheelchair propulsion were recorded for three minutes maintaining a constant speed at three distinct propulsion speeds (fast speed of 1.1 m/s, a self-selected speed, and a slow speed of 0.7 m/s). Peak resultant shoulder forces in the push phase were calculated using inverse dynamics. Within individual variability was quantified as the coefficient of variation of cycle to cycle peak resultant forces. Findings There was no difference in mean peak shoulder resultant force between groups. The pain group had significantly smaller variability of peak resultant force than the no pain group (p < 0.01, η2 = 0.18). Interpretation The observations raise the possibility that propulsion variability could be a novel marker of upper limb pain in manual wheelchair users. PMID:24210512

  13. Maximum force levels in different positions of shoulder and elbow.

    PubMed

    Castro, C; De la Vega, E; Báez, G; Carrasco, F

    2012-01-01

    The number of occupational diseases in Mexico is alarming and clearly it is important to do studies with the purpose of improving the design of workstations. The objective of this research is to determine the maximum force levels in different positions of shoulder and elbow. An experiment was conducted with 16 subjects between 18 and 28 years old: 8 male and 8 female. We considered 16 different positions, working with the right and left arm to perform the tasks of pull and push. The tasks consisted of pushing or pulling a dynamometer for a period of 3 seconds as hard as possible. The results were presented in tables. The tables show the mean, standard deviation and range of force levels in different positions.

  14. Effects of hook plate on shoulder function after treatment of acromioclavicular joint dislocation

    PubMed Central

    Chen, Chang-Hong; Dong, Qi-Rong; Zhou, Rong-Kui; Zhen, Hua-Qing; Jiao, Ya-Jun

    2014-01-01

    Introduction: Internal fixation with hook plate has been used to treat acromioclavicular joint dislocation. This study aims to evaluate the effect of its use on shoulder function, to further analyze the contributing factors, and provide a basis for selection and design of improved internal fixation treatment of the acromioclavicular joint dislocation in the future. Methods: A retrospective analysis was performed on patients treated with a hook plate for acromioclavicular joint dislocation in our hospital from January 2010 to February 2013. There were 33 cases in total, including 25 males and 8 females, with mean age of 48.27 ± 8.7 years. There were 29 cases of Rockwood type III acromioclavicular dislocation, 4 cases of type V. The Constant-Murley shoulder function scoring system was used to evaluate the shoulder function recovery status after surgery. Anteroposterior shoulder X-ray was used to assess the position of the hook plate, status of acromioclavicular joint reduction and the occurrence of postoperative complications. Results: According to the Constant-Murley shoulder function scoring system, the average scores were 78 ± 6 points 8 to 12 months after the surgery and before the removal of the hook plate, the average scores were 89 ± 5 minutes two months after the removal of hook plate. Postoperative X-ray imaging showed osteolysis in 10 cases (30.3%), osteoarthritis in six cases (18.1%), osteolysis associated with osteoarthritis in four cases(12.1%), and steel hook broken in one case (3%). Conclusion: The use of hook plate on open reduction and internal fixation of the acromioclavicular joint dislocation had little adverse effect on shoulder function and is an effective method for the treatment of acromioclavicular joint dislocation. Osteoarthritis and osteolysis are the two common complications after hook plate use, which are associated with the impairment of shoulder function. Shoulder function will be improved after removal of the hook plate. PMID

  15. Effects of hook plate on shoulder function after treatment of acromioclavicular joint dislocation.

    PubMed

    Chen, Chang-Hong; Dong, Qi-Rong; Zhou, Rong-Kui; Zhen, Hua-Qing; Jiao, Ya-Jun

    2014-01-01

    Internal fixation with hook plate has been used to treat acromioclavicular joint dislocation. This study aims to evaluate the effect of its use on shoulder function, to further analyze the contributing factors, and provide a basis for selection and design of improved internal fixation treatment of the acromioclavicular joint dislocation in the future. A retrospective analysis was performed on patients treated with a hook plate for acromioclavicular joint dislocation in our hospital from January 2010 to February 2013. There were 33 cases in total, including 25 males and 8 females, with mean age of 48.27 ± 8.7 years. There were 29 cases of Rockwood type III acromioclavicular dislocation, 4 cases of type V. The Constant-Murley shoulder function scoring system was used to evaluate the shoulder function recovery status after surgery. Anteroposterior shoulder X-ray was used to assess the position of the hook plate, status of acromioclavicular joint reduction and the occurrence of postoperative complications. According to the Constant-Murley shoulder function scoring system, the average scores were 78 ± 6 points 8 to 12 months after the surgery and before the removal of the hook plate, the average scores were 89 ± 5 minutes two months after the removal of hook plate. Postoperative X-ray imaging showed osteolysis in 10 cases (30.3%), osteoarthritis in six cases (18.1%), osteolysis associated with osteoarthritis in four cases(12.1%), and steel hook broken in one case (3%). The use of hook plate on open reduction and internal fixation of the acromioclavicular joint dislocation had little adverse effect on shoulder function and is an effective method for the treatment of acromioclavicular joint dislocation. Osteoarthritis and osteolysis are the two common complications after hook plate use, which are associated with the impairment of shoulder function. Shoulder function will be improved after removal of the hook plate.

  16. Arm and shoulder conditions, active component, U.S. Armed Forces, 2003-2012.

    PubMed

    2013-06-01

    This analysis estimated the incidence and health care burden of acute and chronic conditions of the arm and shoulder among active component service members of the Armed Forces from 1 January 2003 through 31 December 2012. There were 196,789 diagnosed incident cases of acute arm and shoulder conditions for a rate of 13.7 cases per 1,000 person-years. The annual incidence rates of sprains, the most common acute condition, nearly doubled during the period. Diagnoses of chronic conditions (overall rate of 28.8 per 1,000 person-years) increased 25 percent during the period, mainly associated with a doubling of the incidence of diagnoses of joint pain. Incidence rates of chronic disorders were progressively higher among successively older age groups of service members. The health care burden of all arm and shoulder conditions together steadily increased during the period, as indicated by numbers of health care encounters, individuals affected, and lost work time. The most commonly documented causes associated with acute and chronic conditions are described.

  17. Shoulder joint loading in the high performance flat and kick tennis serves

    PubMed Central

    Reid, Machar; Elliott, Bruce; Alderson, Jacque

    2007-01-01

    Objective To quantify and compare the full body kinematics and shoulder joint kinetics during the high‐performance tennis flat (FS) and kick serves (KS). Methods A 12‐camera 250 Hz, Vicon motion analysis system recorded the three‐dimensional FS and KS of 12 high‐performance male players. A total of 22 paired Student's t tests, with an accompanying partial Bonferroni correction (p<0.01), determined statistically significant differences between the variables of interest in both serves. Results Higher peak horizontal, vertical and absolute racquet velocities were developed during the FS, while higher lateral velocities characterised the KS. Similar shoulder joint kinematics and kinetics punctuated both serves, but with some variation in trunk and lower limb mechanics. Conclusions Similar shoulder joint kinetics assisted the development of varying three‐dimensional racquet velocities in the FS and KS. The comparable shoulder joint loading conditions point to the repetitive, long‐term performance of either serve as relevant in shoulder joint injury pathologies. PMID:17513331

  18. Similarities in the neural control of the shoulder and elbow joints belie their structural differences.

    PubMed

    Karduna, Andrew R; Sainburg, Robert L

    2012-01-01

    Movement of the hand in three dimensional space is primarily controlled by the orientation of the shoulder and elbow complexes. Due to discrepancies in proprioceptive acuity, overlap in motor cortex representation and grossly different anatomies between these joints, we hypothesized that there would be differences in the accuracy of aimed movements between the two joints. Fifteen healthy young adults were tested under four conditions - shoulder motion with the elbow constrained and unconstrained, and elbow motion with the shoulder constrained and unconstrained. End point target locations for each joint were set to coincide with joint excursions of 10, 20 or 30 degrees of either the shoulder or elbow joint. Targets were presented in a virtual reality environment. For the constrained condition, there were no significant differences in angular errors between the two joints, suggesting that the central nervous system represents linked segment models of the limb in planning and controlling movements. For the unconstrained condition, although angle errors were higher, hand position errors remained the same as those of the constrained trials. These results support the idea that the CNS utilizes abundant degrees of freedom to compensate for the potentially different contributions to end-point errors introduced by each joint.

  19. In vivo three-dimensional motion analysis of the shoulder joint during internal and external rotation.

    PubMed

    Koishi, Hayato; Goto, Akira; Tanaka, Makoto; Omori, Yasushi; Futai, Kazuma; Yoshikawa, Hideki; Sugamoto, Kazuomi

    2011-10-01

    The purpose of this study was to assess accurately the three-dimensional movements of the scapula and humerus relative to the thorax during internal/external rotation motion with abduction of the shoulder joint. Ten right shoulders of ten healthy volunteers were examined using a wide-gantry open magnetic resonance imaging (MRI) system. MRI was performed every 30° from 90° external rotation to 90° internal rotation of the shoulder joint. The contribution ratio of the scapulothoracic joint was 12.5% about the long axis of the humerus during internal/external rotation motion. With arm position changes from 90° external rotation to 60° internal rotation, most movement was performed by the glenohumeral joint. Conversely, at internal rotation of ≥60°, the scapula began to markedly tilt in the anterior direction. At 90° internal rotation, the scapula was significantly tilted anteriorly (p < 0.05) when compared with the other positions. We clarified the existence of a specific scapulohumeral motion pattern, whereby the glenohumeral joint moves with internal rotation and the scapulothoracic joint moves with anterior tilt together with internal rotation motion of the shoulder joint.

  20. Influence of Combinations of Shoulder, Elbow and Trunk Orientation on Elbow Joint Loads in Youth Baseball Pitchers

    PubMed Central

    Tanaka, Hiroshi; Hayashi, Toyohiko; Inui, Hiroaki; Ninomiya, Hiroki; Muto, Tomoyuki; Nobuhara, Katsuya

    2016-01-01

    Objectives: Shoulder and elbow pain in youth baseball pitchers is a well-recognized phenomenon. Common problems in pitching mechanics that can lead to injury begin with stride foot contact. The purpose of this study was to address the relationships between the combinations of shoulder, elbow and trunk orientation at the instant of stride foot contact and elbow joint loads in youth baseball pitchers. Methods: A total of 143 Japanese male youth baseball pitchers participated in this study after providing written informed consents approved by the hospital’s institutional review board. The procedures to be performed were also explained to their parent(s) or legal guardian(s). Each participant was not currently injured or recovering from an injury at time of testing. For data collection of baseball pitching, a set of 14-mm spherical reflective markers was placed on the skin overlying 34 anatomical landmarks determined. Subsequently, a motion capture three-dimensional automatic digitizing system was used to collect 500-Hz from 7 charge-coupled-device synchronized cameras was set up around the regulation pitching mound in an indoor laboratory. After performing a preparation routine of stretching and warm-up pitching, each player pitch to 5 fastball pitches off the pitching mound to a catcher at the regulation distance of 16 m for youth pitchers. The best pitch thrown for a strike was chosen for kinematic and kinetic analysis. The local coordinate systems were used to calculate 3-dimesional rotation at the trunk, shoulder and elbow using the typical Eulerian sequence. Afterward, the standard inverse dynamic equation was used to estimate resultant joint forces and torques at throwing shoulder and elbow. In order to normalize data between subjects, forces and torques were expressed as percent using body weight and height. A multiple regression analysis was carried out to assess the combined effects of shoulder (external rotation, abduction and horizontal adduction), elbow

  1. The effects of fast bowling fatigue and adhesive taping on shoulder joint position sense in amateur cricket players in Victoria, Australia.

    PubMed

    Weerakkody, Nivan; Allen, Trevor

    2016-10-18

    The impact that muscle fatigue and taping have on proprioception in an applied sporting context remains unclear. The purpose of this study was to investigate disturbances in position sense at the shoulder joint, and asses the effectiveness of adhesive tape in preventing injury and improving performance, after a bout of cricket fast bowling. Among amateur cricket players (N = 14), shoulder position sense, maximum voluntary contraction (MVC) force and bowling accuracy was assessed before and immediately after a fatiguing exercise bout of fast bowling. Participants were tested with the shoulder taped and untapped. Shoulder extension MVC force dropped immediately and 30 min after the exercise (P < 0.05 and P < 0.05, respectively). Position sense errors increased immediately after exercise (P < 0.05), shifting in the direction of shoulder extension for all measurements. Taping had no effect on position errors before exercise, but did significantly reduce position errors after exercise at mid-range shoulder flexion angles (45° and 60°; P < 0.05 and P < 0.05, respectively). Taping had no significant effect on bowling accuracy. These findings may be explained by a body map shift towards a gravity neutral position. Added cutaneous input from the tape is proposed to contribute more to shoulder position sense when muscles are fatigued.

  2. Kinematics of the shoulder joint in tennis players.

    PubMed

    Lädermann, A; Chagué, S; Kolo, F C; Charbonnier, C

    2016-01-01

    Shoulder pain and injury are common in tennis players. The precise causes for such pain remain unclear. Impingement at critical tennis positions and glenohumeral instability have never been dynamically evaluated in vivo. The purpose of this study was to evaluate the different types of impingement and stability during tennis movements. Laboratory study. Type and frequency of impingement as well as percentage of subluxation were evaluated in 10 tennis players through a novel dedicated patient-specific measurement technique based on optical motion capture and Magnetic Resonance Imaging (MRI). All volunteers, nine male and one female, had a clinically functional rotator cuff. MRI revealed 11 rotator cuff lesions in six subjects and six labral lesions in five subjects. Lateral subacromial, anterior subacromial, internal anterosuperior, and internal posterosuperior impingements were observed in four, three, two and seven subjects, respectively. No instability could be demonstrated in this population. Tennis players presented frequent radiographic signs of structural lesions that could mainly be related to posterosuperior impingements due to repetitive abnormal motion contacts. This is the first study demonstrating that a dynamic and precise motion analysis of the entire kinematic chain of the shoulder is possible through a non-invasive method of investigation. This premier kinematic observation offers novel insights into the analysis of shoulder impingement and instability that could, with future studies, be generalized to other shoulder pathologies and sports. This original method may open new horizons leading to improvement in impingement comprehension. Copyright © 2014 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

  3. [Value of magnetic resonance imaging in the diagnosis of sequels of shoulder joint injuries].

    PubMed

    Murashina, I V; Egorova, E A

    2011-01-01

    The paper presents the results of examining 45 persons with sequels of shoulder joint injuries, by applying magnetic resonance imaging (MRI) (100%) and arthroscopy (95.6%). The data of arthroscopy were compared with those of MRI; thereafter the sensitivity, specificity, and accuracy of MRI were calculated. The findings suggested that there was no statistically significant difference in the capacities of the two comparable techniques MRI and arthroscopy to diagnose labral tears with degenerative changes, synovitis, bursitis and tendinitis (McNemar's test; p > 0.05). The capacities of MRI are greater than those of arthroscopy only to detect the structural disintegrity of the joint shoulder.

  4. Joint Kinetics to Assess the Influence of the Racket on a Tennis Player’s Shoulder

    PubMed Central

    Creveaux, Thomas; Dumas, Raphaël; Hautier, Christophe; Macé, Pierre; Chèze, Laurence; Rogowski, Isabelle

    2013-01-01

    This study aimed at investigating the influence of three rackets on shoulder net joint moments, power and muscle activity during the flat tennis serve under field- conditions. A 6-camera Eagle® motion analysis system, operating at 256 Hz, captured racket and dominant upper limb kinematics of the serve in five tennis players under three racket conditions (A: low mass, high balance and polar moment, B: low three moments of inertia, and C: high mass, swingweight and twistweight). The electromyographic activity of six trunk and arm muscles was simultaneously recorded. Shoulder net joint moments and power were computed by 3D inverse dynamics. The results showed that greater shoulder joint power and internal/external rotation peak moments were found to accelerate and decelerate racket A in comparison with the racket C. Moreover, serving with the racket A resulted in less activity in latissimus dorsi muscle during the acceleration phase, and biceps brachii muscle during the follow-through phase when compared with racket C. These initial findings encourage studying the biomechanical measurements to quantify the loads on the body during play in order to reduce them, and then prevent shoulder injuries. Racket specifications may be a critical point for coaches who train players suffering from shoulder pain and chronic upper limb injuries should be considered in relation to the racket specifications of the players. Key Points Light racket required more joint power than heavy one to achieve similar post impact ball velocity. Serving with a light racket resulted in higher shoulder internal and external rotation moments than using a heavy one for similar performance. Chronic shoulder pain should encourage coaches to check for potentially inappropriate racket specifications of their players. PMID:24149804

  5. Evaluation and management of adult shoulder pain: a focus on rotator cuff disorders, acromioclavicular joint arthritis, and glenohumeral arthritis.

    PubMed

    Armstrong, April

    2014-07-01

    Shoulder pain is a common reason for a patient to see their primary care physician. This article focuses on the evaluation and management of 3 common shoulder disorders; rotator cuff disorders, acromioclavicular joint arthritis, and glenohumeral joint arthritis. The typical history and physical examination findings for each of these entities are highlighted, in addition to treatment options.

  6. Development of an item list to assess the forgotten joint concept in shoulder patients.

    PubMed

    Giesinger, Johannes M; Kesterke, Nicolas; Hamilton, David F; Holzner, Bernhard; Jost, Bernhard; Giesinger, Karlmeinrad

    2015-03-24

    To generate an item list for the assessment of joint awareness in shoulder patients and to collect patient feedback on the comprehensibility of the items and the forgotten joint concept. Item content was generated on the basis of literature search and expert ratings following a stepwise refinement procedure, including final evaluation by an international expert board (n = 12) including members with various professional backgrounds. Items were translated from English to German and evaluated in 30 German-speaking shoulder patients in Switzerland and 30 shoulder patients in the UK. Literature search identified 45 questionnaires covering 805 issues potentially relevant for the assessment of joint awareness. Stepwise item selection resulted in 97 items to be evaluated by the international expert board leaving 70 items for collecting patient feedback. The majority of patients indicated that the introductory text explaining the forgotten joint concept was easy or very easy to understand (79.3%) and that the items were clear (91.4%). We developed a list of 70 questions for the assessment of joint awareness in shoulder patients and obtained positive patient feedback for these. In a next step, we will administer the items to a large international patient sample to obtain data for psychometric analysis and development of a measurement model, which is the basis for creation of computer-adaptive assessments or static short-forms.

  7. Development of an Arthroscopic Joint Capsule Injury Model in the Canine Shoulder

    PubMed Central

    Kovacevic, David; Baker, Andrew R.; Staugaitis, Susan M.; Kim, Myung-Sun; Ricchetti, Eric T.; Derwin, Kathleen A.

    2016-01-01

    Background The natural history of rotator cuff tears can be unfavorable as patients develop fatty infiltration and muscle atrophy that is often associated with a loss of muscle strength and shoulder function. To facilitate study of possible biologic mechanisms involved in early degenerative changes to rotator cuff muscle and tendon tissues, the objective of this study was to develop a joint capsule injury model in the canine shoulder using arthroscopy. Methods Arthroscopic surgical methods for performing a posterior joint capsulectomy in the canine shoulder were first defined in cadavers. Subsequently, one canine subject underwent bilateral shoulder joint capsulectomy using arthroscopy, arthroscopic surveillance at 2, 4 and 8 weeks, and gross and histologic examination of the joint at 10 weeks. Results The canine subject was weight-bearing within eight hours after index and follow-up surgeries and had no significant soft tissue swelling of the shoulder girdle or gross lameness. Chronic synovitis and macroscopic and microscopic evidence of pathologic changes to the rotator cuff bony insertions, tendons, myotendinous junctions and muscles were observed. Conclusions This study demonstrates feasibility and proof-of-concept for a joint capsule injury model in the canine shoulder. Future work is needed to define the observed pathologic changes and their role in the progression of rotator cuff disease. Ultimately, better understanding of the biologic mechanisms of early progression of rotator cuff disease may lead to clinical interventions to halt or slow this process and avoid the more advanced and often irreversible conditions of large tendon tears with muscle fatty atrophy. PMID:26808837

  8. Assessment of Correlation Between MRI and Arthroscopic Pathologic Findings in the Shoulder Joint

    PubMed Central

    Momenzadeh, Omid R; Gerami, Mohamad H; Sefidbakht, Sepideh; Dehghani, Sakineh

    2015-01-01

    Background: The objective of this study was to determine the diagnostic value of magnetic resonance imaging for shoulder joint pathologies and then compare the results with arthroscopy, the standard for joint diagnosis. Methods: In this cross-sectional study, 80 patients with shoulder joint disorders, who underwent final arthroscopy, were studied. Based on patients’ medical history and physical examinations, shoulder MRI was requested if paraclinical investigations were. If non-surgical therapies failed, arthroscopy of the affected shoulder was done and the same structures were inspected. Subsequently, sensitivity, specificity, and positive and negative predictive values (PPV) and (NPV) of MRI were determined by arthroscopy comparisons. Results: The highest sensitivity, specificity, PPV and NPV were found in MRI pathology reports that included: Hill-Sach lesion (0.910), infraspinatus tendon (0.985), supraspinatus tendon (0.930), and biceps tendon (0.954), respectively. Rotator interval (0.250), biceps labrum complex (0.805), subscapularis tendon (0.538) and anterior labrum lesions (0.604) had the lowest sensitivity, specificity, PPV and NPV, respectively. Conclusion: The results showed that MRI can be a useful tool in ruling out possible abnormalities in the shoulder and to give clues to the most probable diagnosis. Although knowing some practical skills in order to successfully perform the procedure and experience of the radiologist with suitable feedback by surgeon is necessary. PMID:26550595

  9. In vivo shoulder function after surgical repair of a torn rotator cuff: glenohumeral joint mechanics, shoulder strength, clinical outcomes, and their interaction.

    PubMed

    Bey, Michael J; Peltz, Cathryn D; Ciarelli, Kristin; Kline, Stephanie K; Divine, George W; van Holsbeeck, Marnix; Muh, Stephanie; Kolowich, Patricia A; Lock, Terrence R; Moutzouros, Vasilios

    2011-10-01

    Surgical repair of a torn rotator cuff is based on the belief that repairing the tear is necessary to restore normal glenohumeral joint (GHJ) mechanics and achieve a satisfactory clinical outcome. Dynamic joint function is not completely restored by rotator cuff repair, thus compromising shoulder function and potentially leading to long-term disability. Controlled laboratory study and Case series; Level of evidence, 4. Twenty-one rotator cuff patients and 35 control participants enrolled in the study. Biplane radiographic images were acquired bilaterally from each patient during coronal-plane abduction. Rotator cuff patients were tested at 3, 12, and 24 months after repair of a supraspinatus tendon tear. Control participants were tested once. Glenohumeral joint kinematics and joint contact patterns were accurately determined from the biplane radiographic images. Isometric shoulder strength and patient-reported outcomes were measured at each time point. Ultrasound imaging assessed rotator cuff integrity at 24 months after surgery. Twenty of 21 rotator cuff repairs appeared intact at 24 months after surgery. The humerus of the patients' repaired shoulder was positioned more superiorly on the glenoid than both the patients' contralateral shoulder and the dominant shoulder of control participants. Patient-reported outcomes improved significantly over time. Shoulder strength also increased over time, although strength deficits persisted at 24 months for most patients. Changes over time in GHJ mechanics were not detected for either the rotator cuff patients' repaired or contralateral shoulders. Clinical outcome was associated with shoulder strength but not GHJ mechanics. Surgical repair of an isolated supraspinatus tear may be sufficient to keep the torn rotator cuff intact and achieve satisfactory patient-reported outcomes, but GHJ mechanics and shoulder strength are not fully restored with current repair techniques. The study suggests that current surgical repair

  10. Effect of different hand positions on trunk and shoulder kinematics and reaction forces in sitting pivot transfer

    PubMed Central

    Kim, Sung Shin; Her, Jin Gan; Ko, Tae Sung

    2015-01-01

    [Purpose] The purpose of this study was to compare the changes in trunk and shoulder angles, and reaction forces under the two hands elicited by different hand base of support positions during sitting pivot transfer. [Subjects and Methods] Eighteen unimpaired subjects performed independent sitting pivot transfer. Subjects performed sitting pivot transfer between an initial seat to a target seat by only using their hands positioned at the same height as and lower than the seat position. Trunk and shoulder kinematics, and reaction forces on the trailing and leading hands were calculated. Mean peak joint angles and forces were compared between the hand positions using the pared t-test for the lift phase of the transfer. [Results] There were significant increases in the trunk angles of forward and lateral flexion, even though rotation decreased while transferring in the lower hand position. Increased shoulder flexion, anterior/posterior forces and reduced lateral forces were also shown. [Conclusion] Placing the hands of the supporting arms lower than the seat position during sitting pivot transfer was identified as having biomechanical advantages. Therefore, the lower hand position can be recommended as an effective and safe method for sitting pivot transfer by patients with spinal cord injury and can be utilized as a reference data for considering the appropriate height of aids for a wheelchair. PMID:26310994

  11. Effect of different hand positions on trunk and shoulder kinematics and reaction forces in sitting pivot transfer.

    PubMed

    Kim, Sung Shin; Her, Jin Gan; Ko, Tae Sung

    2015-07-01

    [Purpose] The purpose of this study was to compare the changes in trunk and shoulder angles, and reaction forces under the two hands elicited by different hand base of support positions during sitting pivot transfer. [Subjects and Methods] Eighteen unimpaired subjects performed independent sitting pivot transfer. Subjects performed sitting pivot transfer between an initial seat to a target seat by only using their hands positioned at the same height as and lower than the seat position. Trunk and shoulder kinematics, and reaction forces on the trailing and leading hands were calculated. Mean peak joint angles and forces were compared between the hand positions using the pared t-test for the lift phase of the transfer. [Results] There were significant increases in the trunk angles of forward and lateral flexion, even though rotation decreased while transferring in the lower hand position. Increased shoulder flexion, anterior/posterior forces and reduced lateral forces were also shown. [Conclusion] Placing the hands of the supporting arms lower than the seat position during sitting pivot transfer was identified as having biomechanical advantages. Therefore, the lower hand position can be recommended as an effective and safe method for sitting pivot transfer by patients with spinal cord injury and can be utilized as a reference data for considering the appropriate height of aids for a wheelchair.

  12. Differences in glenohumeral joint morphology between patients with anterior shoulder instability and healthy, uninjured volunteers.

    PubMed

    Peltz, Cathryn D; Zauel, Roger; Ramo, Nicole; Mehran, Nima; Moutzouros, Vasilios; Bey, Michael J

    2015-07-01

    Traumatic glenohumeral joint (GHJ) dislocations are common, resulting in significant shoulder disability and pain. Previous research indicates that bony morphology is associated with an increased risk of injury in other joints (eg, the knee), but the extent to which bony morphology is associated with traumatic GHJ dislocation is unknown. This study assessed GHJ morphology in patients with anterior GHJ instability and in a control population of healthy volunteers. Bilateral computed tomography scans were used to measure GHJ morphology in both shoulders of 11 patients with instability and 11 control subjects. Specific outcome measures included the glenoid radius of curvature (ROC) in the anterior/posterior (A/P) and superior/inferior (S/I) directions, humeral head ROC, A/P and S/I conformity index, and A/P and S/I stability angle. Compared with the control subjects, the glenoid of the instability the injured shoulder in patients with instability was flatter (ie, higher ROC) in the A/P (P = .001) and S/I (P = .01) directions and this finding was also true for uninjured, contralateral shoulder (A/P: P = .01, S/I: P = .03). No differences in GHJ morphology were detected between the instability patients' injured and contralateral shoulders (P > .07). Similarly, no differences in GHJ morphology were detected between the control subjects' dominant and nondominant shoulders (P > .51). There are significant differences in GHJ morphology between healthy control subjects and both shoulders (injured and uninjured, contralateral) of patients diagnosed with anterior instability after GHJ dislocation. These findings are important clinically because they suggest that glenoid morphology may influence the risk of GHJ dislocation. Copyright © 2015 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

  13. Comparison of 3-dimensional shoulder complex kinematics in individuals with and without shoulder pain, part 1: sternoclavicular, acromioclavicular, and scapulothoracic joints.

    PubMed

    Lawrence, Rebekah L; Braman, Jonathan P; Laprade, Robert F; Ludewig, Paula M

    2014-09-01

    Cross-sectional. To compare sternoclavicular, acromioclavicular, and scapulothoracic joint motion between symptomatic and asymptomatic individuals during shoulder motion performed in 3 planes of humerothoracic elevation. Differences in scapulothoracic kinematics are associated with shoulder pain. Several studies have measured these differences using surface sensors, but the results of this technique may be affected by skin-motion artifact. Furthermore, previous studies have not included the simultaneous measurement of sternoclavicular and acromioclavicular joint motion. Transcortical bone pins were inserted into the clavicle, scapula, and humerus of 12 asymptomatic and 10 symptomatic individuals for direct, bone-fixed tracking using electromagnetic sensors. Angular positions for the sternoclavicular, acromioclavicular, and scapulothoracic joints were measured during shoulder flexion, abduction, and scapular plane abduction. Differences between groups were found for sternoclavicular and scapulothoracic joint positions. Symptomatic individuals consistently demonstrated less sternoclavicular posterior rotation, regardless of angle, phase, or plane of shoulder motion. Symptomatic individuals also demonstrated less scapulothoracic upward rotation at 30° and 60° of humerothoracic elevation during shoulder abduction and scapular plane abduction. The results of this study show that differences in shoulder complex kinematics exist between symptomatic and asymptomatic individuals. However, the magnitude of these differences was small, and the resulting clinical implications are not yet fully understood. The biomechanical coupling of the sternoclavicular and acromioclavicular joints requires further research to better understand scapulothoracic movement deviations and to improve manual therapy and exercise-based physical therapy interventions.

  14. Comparison of 3-Dimensional Shoulder Complex Kinematics in Individuals With and Without Shoulder Pain, Part 1: Sternoclavicular, Acromioclavicular, and Scapulothoracic Joints

    PubMed Central

    LAWRENCE, REBEKAH L.; BRAMAN, JONATHAN P.; LAPRADE, ROBERT F.; LUDEWIG, PAULA M.

    2015-01-01

    STUDY DESIGN Cross-sectional. OBJECTIVES To compare sternoclavicular, acromioclavicular, and scapulothoracic joint motion between symptomatic and asymptomatic individuals during shoulder motion performed in 3 planes of humerothoracic elevation. BACKGROUND Differences in scapulothoracic kinematics are associated with shoulder pain. Several studies have measured these differences using surface sensors, but the results of this technique may be affected by skin-motion artifact. Furthermore, previous studies have not included the simultaneous measurement of sternoclavicular and acromioclavicular joint motion. METHODS Transcortical bone pins were inserted into the clavicle, scapula, and humerus of 12 asymptomatic and 10 symptomatic individuals for direct, bone-fixed tracking using electromagnetic sensors. Angular positions for the sternoclavicular, acromioclavicular, and scapulothoracic joints were measured during shoulder flexion, abduction, and scapular plane abduction. RESULTS Differences between groups were found for sternoclavicular and scapulothoracic joint positions. Symptomatic individuals consistently demonstrated less sternoclavicular posterior rotation, regardless of angle, phase, or plane of shoulder motion. Symptomatic individuals also demonstrated less scapulothoracic upward rotation at 30° and 60° of humerothoracic elevation during shoulder abduction and scapular plane abduction. CONCLUSION The results of this study show that differences in shoulder complex kinematics exist between symptomatic and asymptomatic individuals. However, the magnitude of these differences was small, and the resulting clinical implications are not yet fully understood. The biomechanical coupling of the sternoclavicular and acromioclavicular joints requires further research to better understand scapulothoracic movement deviations and to improve manual therapy and exercise-based physical therapy interventions. PMID:25103135

  15. [The biologic interaction of movements in the shoulder joint of cats and dogs].

    PubMed

    Roos, H; Rauscher, T; Brugger, S

    1993-08-01

    The shoulder joint is a free joint which enables the free forelimb to describe curves in space, in order to perform movements and for locomotion. The movements can be measured in three planes: flexion-extension, abduction-adduction and rotation. The extent of movement in the cat, the German Shepherd and the Dachshund are described and the efficacy for these species and breeds is discussed.

  16. New concepts in restoring shoulder elevation in a stiff and painful shoulder patient.

    PubMed

    Donatelli, Robert; Ruivo, R M; Thurner, Michael; Ibrahim, Mahmoud Ibrahim

    2014-02-01

    The treatment and evaluation of a stiff and painful shoulder, characteristic of adhesive capsulitis and "frozen" shoulders, is a dilemma for orthopedic rehabilitation specialists. A stiff and painful shoulder is all-inclusive of Adhesive capsulitis and Frozen Shoulder diagnoses. Adhesive capsulitis and frozen shoulder will be referred to as a stiff and painful shoulder, throughout this paper. Shoulder motion occurs in multiple planes of movement. Loss of shoulder mobility can result in significant functional impairment. The traditional treatment approach to restore shoulder mobility emphasizes mobilization of the shoulder overhead. Forced elevation in a stiff and painful shoulder can be painful and potentially destructive to the glenohumeral joint. This manuscript will introduce a new biomechanical approach to evaluate and treat patients with stiff and painful shoulders.

  17. Objective evaluation of the shoulder dystocia phenomenon: effect of maternal pelvic orientation on force reduction.

    PubMed

    Gonik, B; Allen, R; Sorab, J

    1989-07-01

    This report describes the use of maternal pelvic and fetal models, a tactile sensing glove, and a microcomputer data acquisition system to measure fetal shoulder extraction forces. Sixty-nine experiments were carried out in the laboratory setting to simulate vaginal delivery of the aftercoming fetal shoulders. The tests were conducted using a variety of fetal biclavicular diameters (10-13 cm) and maternal pelvic angle positions (McRoberts, 10 degrees; lithotomy, 25 degrees). When comparing lithotomy versus McRoberts positioning, there was a consistent reduction in force needed to extract the fetal shoulders with the latter maneuver. No simulated clavicles were fractured during shoulder delivery until a biclavicular diameter of 12.0 cm was reached. At this point, five of eight clavicles (63%) were fractured at 25 degrees and zero of seven (0%) were fractured at 10 degrees (P less than .025). For all 69 experiments, fetal neck extension readings were consistently lower than the total traction forces recorded by the tactile sensing glove. This suggests that, in addition to the axially oriented fetal neck forces, a component of flexion (lateral force) was also present. As the difficulty of shoulder delivery increased, the impact of these inadvertent flexion forces became most pronounced at the level of the brachial plexus. This is the first study to measure shoulder extraction forces reproducibly using a laboratory model for shoulder dystocia and to describe the pathophysiology of specific neonatal injuries from a force perspective. The results document objectively that McRoberts positioning reduces shoulder extraction forces, brachial plexus stretching, and the incidence of clavicular fracture.

  18. Restoration of anterior-posterior rotator cuff force balance improves shoulder function in a rat model of chronic massive tears.

    PubMed

    Hsu, Jason E; Reuther, Katherine E; Sarver, Joseph J; Lee, Chang Soo; Thomas, Stephen J; Glaser, David L; Soslowsky, Louis J

    2011-07-01

    The rotator cuff musculature imparts dynamic stability to the glenohumeral joint. In particular, the balance between the subscapularis anteriorly and the infraspinatus posteriorly, often referred to as the rotator cuff "force couple," is critical for concavity compression and concentric rotation of the humeral head. Restoration of this anterior-posterior force balance after chronic, massive rotator cuff tears may allow for deltoid compensation, but no in vivo studies have quantitatively demonstrated an improvement in shoulder function. Our goal was to determine if restoring this balance of forces improves shoulder function after two-tendon rotator cuff tears in a rat model. Forty-eight rats underwent detachment of the supraspinatus and infraspinatus. After four weeks, rats were randomly assigned to three groups: no repair, infraspinatus repair, and two-tendon repair. Quantitative ambulatory measures including medial/lateral forces, braking, propulsion, and step width were significantly different between the infraspinatus and no repair group and similar between the infraspinatus and two-tendon repair groups at almost all time points. These results suggest that repairing the infraspinatus back to its insertion site without repair of the supraspinatus can improve shoulder function to a level similar to repairing both the infraspinatus and supraspinatus tendons. Clinically, a partial repair of the posterior cuff after a two-tendon tear may be sufficient to restore adequate function. An in vivo model system for two-tendon repair of massive rotator cuff tears is presented. Copyright © 2011 Orthopaedic Research Society.

  19. Restoration of Anterior-Posterior Rotator Cuff Force Balance Improves Shoulder Function in a Rat Model of Chronic Massive Tears

    PubMed Central

    Hsu, Jason E.; Reuther, Katherine E.; Sarver, Joseph J.; Lee, Chang Soo; Thomas, Stephen J.; Glaser, David L.; Soslowsky, Louis J.

    2011-01-01

    The rotator cuff musculature imparts dynamic stability to the glenohumeral joint. In particular, the balance between the subscapularis anteriorly and the infraspinatus posteriorly, often referred to as the rotator cuff “force couple,” is critical for concavity compression and concentric rotation of the humeral head. Restoration of this anterior-posterior force balance after chronic, massive rotator cuff tears may allow for deltoid compensation, but no in vivo studies have quantitatively demonstrated an improvement in shoulder function. Our goal was to determine if restoring this balance of forces improves shoulder function after two-tendon rotator cuff tears in a rat model. Forty-eight rats underwent detachment of the supraspinatus and infraspinatus. After four weeks, rats were randomly assigned to three groups: no repair, infraspinatus repair, and two-tendon repair. Quantitative ambulatory measures including medial/lateral forces, braking, propulsion, and step width were significantly different between the infraspinatus and no repair group and similar between the infraspinatus and two-tendon repair groups at almost all time points. These results suggest that repairing the infraspinatus back to its insertion site without repair of the supraspinatus can improve shoulder function to a level similar to repairing both the infraspinatus and supraspinatus tendons. Clinically, a partial repair of the posterior cuff after a two tendon tear may be sufficient to restore adequate function. An in vivo model system for two-tendon repair of massive rotator cuff tears is presented. PMID:21308755

  20. Influence of anthropometry on meat-packing plant workers: an approach to the shoulder joint.

    PubMed

    Reis, Pedro Ferreira; Peres, Luis Sérgio; Tirloni, Adriana Seára; dos Reis, Diogo Cunha; Estrázulas, Jansen Atier; Rossato, Mateus; Moro, Antônio Renato Pereira

    2012-01-01

    This study was conducted with 90 poultry slaughterhouse workers, which perform the function of removing chicken parts from the conveyor belt, and sample was composed of 66 women (33.5 ± 6.5 years) and 24 men (35.7 ± 7.2 years), aiming to analyze the influence of anthropometry in the shoulder joint of these workers. Body discomfort was evaluated by a human body diagram, being applied at the end of the work shift. The anthropometric measurement of shoulder was performed by measuring the height of the acromion process, being compared with the height of the conveyor belt. Analysis of the results was performed by descriptive statistics, mean, standard deviation, percentage and percentiles 5%, 50% and 95%. It was found that the height of the conveyor belt was 1.74 meters, while the average shoulder height of workers was 1.38 meters for percentile 5%, 1.41 meters for percentile 50% and 1.65 meters for percentile 95%. The discomfort regions were shoulder 45%, neck 29%, column 26%, arms 23%, and wrists and hand 20%. The upper limb assessment was performed with percentile 5% through the Rapid Upper Limb Assessment method, resulting in a final score > 7, indicating the need for adjustments of the work organization. It was concluded that the workplace does not meet the workers' anthropometric characteristics, mainly affecting the shoulder joint, and correction ergonomics becomes necessary so that the workers involved in this study can perform their functions with health, comfort and safety.

  1. Evaluation of shoulder joint kinematics and muscle activity during geared and standard manual wheelchair mobility.

    PubMed

    Jahanian, Omid; Schnorenberg, Alyssa J; Slavens, Brooke A

    2016-08-01

    Manual wheelchairs often lead to reduced independent function and an increase in shoulder pain and injuries. Geared manual wheelchairs may be a promising alternative that reduces the biomechanical demands of the shoulder needed for tasks such as propulsion on ramps and carpeted floors, while maximizing function and participation. To investigate the effects of geared manual wheelchair mobility during demanding tasks such as ramp ascent, six able-bodied subjects were evaluated in this study. Subjects were asked to propel both standard and geared manual wheelchairs on a tiled level floor and on a wheelchair ADA ramp. Shoulder muscle activity and glenohumeral joint kinematics were investigated. The results indicated that using geared manual wheelchair wheels did not alter the shoulder joint kinematics, but notably affected peak and integrated shoulder muscle activity. Muscle activity results normalized by stroke distance, indicated that using geared manual wheelchairs could decrease anterior deltoid, pectoralis major and infraspinatus muscle activity during ramp ascending, but on level floor infraspinatus muscle activity may increase. These results could have clinical implications for determining the types of functional mobility tasks for which geared manual wheelchairs are beneficial.

  2. Program Calculates Forces in Bolted Structural Joints

    NASA Technical Reports Server (NTRS)

    Buder, Daniel A.

    2005-01-01

    FORTRAN 77 computer program calculates forces in bolts in the joints of structures. This program is used in conjunction with the NASTRAN finite-element structural-analysis program. A mathematical model of a structure is first created by approximating its load-bearing members with representative finite elements, then NASTRAN calculates the forces and moments that each finite element contributes to grid points located throughout the structure. The user selects the finite elements that correspond to structural members that contribute loads to the joints of interest, and identifies the grid point nearest to each such joint. This program reads the pertinent NASTRAN output, combines the forces and moments from the contributing elements to determine the resultant force and moment acting at each proximate grid point, then transforms the forces and moments from these grid points to the centroids of the affected joints. Then the program uses these joint loads to obtain the axial and shear forces in the individual bolts. The program identifies which bolts bear the greatest axial and/or shear loads. The program also performs a fail-safe analysis in which the foregoing calculations are repeated for a sequence of cases in which each fastener, in turn, is assumed not to transmit an axial force.

  3. Exercises focusing on rotator cuff and scapular muscles do not improve shoulder joint position sense in healthy subjects.

    PubMed

    Lin, Yin-Liang; Karduna, Andrew

    2016-10-01

    Proprioception is essential for shoulder neuromuscular control and shoulder stability. Exercise of the rotator cuff and scapulothoracic muscles is an important part of shoulder rehabilitation. The purpose of this study was to investigate the effect of rotator cuff and scapulothoracic muscle exercises on shoulder joint position sense. Thirty-six healthy subjects were recruited and randomly assigned into either a control or training group. The subjects in the training group received closed-chain and open-chain exercises focusing on rotator cuff and scapulothoracic muscles for four weeks. Shoulder joint position sense errors in elevation, including the humerothoracic, glenohumeral and scapulothoracic joints, was measured. After four weeks of exercise training, strength increased overall in the training group, which demonstrated the effect of exercise on the muscular system. However, the changes in shoulder joint position sense errors in any individual joint of the subjects in the training group were not different from those of the control subjects. Therefore, exercises specifically targeting individual muscles with low intensity may not be sufficient to improve shoulder joint position sense in healthy subjects. Future work is needed to further investigate which types of exercise are more effective in improving joint position sense, and the mechanisms associated with those changes. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. Functional Anatomy of the Shoulder

    PubMed Central

    Terry, Glenn C.; Chopp, Thomas M.

    2000-01-01

    Objective: Movements of the human shoulder represent the result of a complex dynamic interplay of structural bony anatomy and biomechanics, static ligamentous and tendinous restraints, and dynamic muscle forces. Injury to 1 or more of these components through overuse or acute trauma disrupts this complex interrelationship and places the shoulder at increased risk. A thorough understanding of the functional anatomy of the shoulder provides the clinician with a foundation for caring for athletes with shoulder injuries. Data Sources: We searched MEDLINE for the years 1980 to 1999, using the key words “shoulder,” “anatomy,” “glenohumeral joint,” “acromioclavicular joint,” “sternoclavicular joint,” “scapulothoracic joint,” and “rotator cuff.” Data Synthesis: We examine human shoulder movement by breaking it down into its structural static and dynamic components. Bony anatomy, including the humerus, scapula, and clavicle, is described, along with the associated articulations, providing the clinician with the structural foundation for understanding how the static ligamentous and dynamic muscle forces exert their effects. Commonly encountered athletic injuries are discussed from an anatomical standpoint. Conclusions/Recommendations: Shoulder injuries represent a significant proportion of athletic injuries seen by the medical provider. A functional understanding of the dynamic interplay of biomechanical forces around the shoulder girdle is necessary and allows for a more structured approach to the treatment of an athlete with a shoulder injury. PMID:16558636

  5. Joint Force Quarterly. Issue 37

    DTIC Science & Technology

    2005-04-01

    Cooperation: The First Step by Matthew F. Bogdanos 19 U.S. European Command and Transformation by Charles F. Wald 27 Transformation and the...JFCOM) found that “JIACG has gained universal acceptance.”1 Deputy Secretary of Defense Paul Wolfowitz then notified Deputy National Secu- rity... Wolfowitz , “Joint Interagency Coordination Groups (JIACG) Assessment,” memoran- dum for the Assistant to the President and Deputy National Security

  6. A proposal for a new definition of the axial rotation angle of the shoulder joint.

    PubMed

    Masuda, Tadashi; Ishida, Akimasa; Cao, Lili; Morita, Sadao

    2008-02-01

    The Euler/Cardan angles are commonly used to define the motions of the upper arm with respect to the trunk. This definition, however, has a problem in that the angles of both the horizontal flexion/extension and the axial rotation of the shoulder joint become unstable at the gimbal-lock positions. In this paper, a new definition of the axial rotation angle was proposed. The proposed angle was stable over the entire range of the shoulder motion. With the new definition, the neutral position of the axial rotation agreed with that in the conventional anatomy. The advantage of the new definition was demonstrated by measuring actual complex motions of the shoulder with a three-dimensional motion capture system.

  7. A survey of glenohumeral joint rotational range and non-specific shoulder pain in elite cricketers.

    PubMed

    Giles, Karen; Musa, Iris

    2008-08-01

    To determine if a glenohumeral joint internal rotation range of motion difference (IRD) and external rotation difference (ERD) exists between dominant and non-dominant shoulders of cricketers as demonstrated in other overhead sports, and, if present, to establish if differences exist between cricketers with and without a history of gradual onset non-specific shoulder pain. An observational study. Non-clinical, at national cricket indoor training venues. One hundred and nine elite male and female cricketers (11-35 years), representing 97% of the England and Wales national and West of England regional Under 13 teams, consented. The final number included for data analysis was 133. Data relating to playing position, cricket exposure, shoulder pain and demographic details collected using a questionnaire. Passive isolated glenohumeral rotation measured in 90 degrees shoulder abduction using an inclinometer. Cricketers who regularly bowl or throw overarm had significantly less internal (-7.9 degrees , p<0.001) and greater external (8.6 degrees , p<0.001) dominant to non-dominant glenohumeral rotation. Wicket-keepers had tendencies for smaller differences that were still statistically significant [mean IRD -5.9 degrees (p<0.001); ERD 5.0 degrees (p=0.002)]. Cricketers who experienced shoulder pain demonstrated a significantly greater IRD [mean 3.2 degrees (p=0.032)] than those who did not. The results of this study support measurement of passive glenohumeral joint rotation during musculoskeletal profiling and indicate that a possible link between increased IRD and non-specific shoulder pain warrants further investigation.

  8. The relationship between glenohumeral joint total rotational range of motion and the functional movement screen™ shoulder mobility test.

    PubMed

    Sprague, Peter A; Monique Mokha, G; Gatens, Dustin R; Rodriguez, Rudy

    2014-10-01

    Side to side asymmetry in glenohumeral joint rotation correlates with injury risk in overhead athletes. The purpose of the current study was to identify the relationship between side-to-side asymmetries in glenohumeral joint total rotational range of motion and shoulder mobility test scores from the Functional Movement Screen™ in collegiate overhead athletes. The authors hypothesized that asymmetries of > 10° in glenohumeral total rotation would not be associated with asymmetrical findings in the Functional Movement Screen™ (FMS) shoulder mobility test. Passive glenohumeral total rotational range of motion and the shoulder mobility test of the FMS were measured during pre-participation examinations in 121 NCAA male and female Division II collegiate overhead athletes from varied sports. Passive shoulder range of motion was measured in supine at 90° of abduction, with the humerus in the scapular plane using two measurers and a bubble goniometer. A Pearson Chi-square analysis, p<.05 was used to associate the presence of asymmetries in glenohumeral joint rotation and in the FMS shoulder mobility test in each subject. 40/114 (35.1%) athletes demonstrated asymmetries in total glenohumeral rotation. 45/114 (39.5%) athletes demonstrated asymmetries in the shoulder mobility test. Only 17 of the 45 subjects who demonstrated asymmetry on the shoulder mobility test also demonstrated glenohumeral joint rotation differences of > 10°. Athletes with asymmetries in rotation of > 10° were not any more likely to have asymmetries identified in the shoulder mobility test (95% CI=.555-2.658, P=.627). Glenohumeral joint range of motion is one of multiple contributors to performance on the FMS shoulder mobility test, and alone, did not appear to influence results. The FMS shoulder mobility test should not be used alone as a means of identifying clinically meaningful differences of shoulder mobility in the overhead athlete. Clinicians working with overhead athletes may consider

  9. Scapular Dyskinesis is Detrimental to Shoulder Tendon Properties and Joint Mechanics in a Rat Model

    PubMed Central

    Reuther, Katherine E.; Thomas, Stephen J.; Tucker, Jennica J.; Yannascoli, Sarah M.; Caro, Adam C.; Vafa, Rameen P.; Liu, Stephen S.; Gordon, Joshua A.; Bhatt, Pankti R.; Kuntz, Andrew F.; Soslowsky, Louis J.

    2015-01-01

    Shoulder tendon injuries are frequently seen in the presence of abnormal scapular motion, termed scapular dyskinesis. The cause and effect relationship between scapular dyskinesis and shoulder injury has not been directly defined. The objective of this study was to develop and use an animal model to examine the initiation and progression of pathological changes in the rotator cuff and biceps tendon. 60 male Sprague-Dawley rats were randomized into two groups: nerve transection (to induce scapular dyskinesis, SD) or sham nerve transection (control). The animals were sacrificed 4 and 8 weeks after surgery. Shoulder function and passive joint mechanics were evaluated over time. Tendon mechanical, histological, organizational, and compositional properties were evaluated at 4 and 8 weeks. Gross observation demonstrated alterations in scapular motion, consistent with scapular “winging”. Shoulder function, passive internal range of motion, and tendon mechanical properties were significantly altered. Histology results, consistent with tendon pathology (rounded cell shape and increased cell density), were observed and protein expression of collagen III and decorin was altered. This study presents a new model of scapular dyskinesis that can rigorously evaluate cause and effect relationships in a controlled manner. These results identify scapular dyskinesis as a causative mechanical mechanism for shoulder tendon pathology. PMID:25070580

  10. Magnetic resonance imaging abnormalities in the shoulder and wrist joints of asymptomatic elite athletes.

    PubMed

    Fredericson, Michael; Ho, Charles; Waite, Brandee; Jennings, Fabio; Peterson, Jeffrey; Williams, Christina; Mathesonn, Gordon O

    2009-02-01

    To characterize abnormalities on magnetic resonance images (MRI) in the shoulder and wrist joints of asymptomatic elite athletes to better define the range of "normal" findings in this population. Cohort study. Academic medical center. Division IA collegiate volleyball players (n=12), swimmers (n=6), and gymnasts (n=15) with no history of injury or pain and normal physical examination results. None. Grade of severity of MRI changes of the shoulder and wrist joints. A 3- to 4-year follow-up questionnaire was administered to determine the clinical significance of the asymptomatic findings. All athletes demonstrated at least mild imaging abnormalities in the joints evaluated. Shoulder: Volleyball players had moderate and severe changes primarily in the labrum (50% moderate, 8% severe), rotator cuff (25% moderate, 17% severe), bony structures (33% moderate), and tendon/muscle (25% moderate, 8% severe). Swimmers had moderate changes primarily in the labrum (83% moderate) and ligament (67% moderate). Wrist: All gymnasts had changes in the wrist ligaments (40% mild, 60% moderate), tendons (53% mild, 47% moderate), and cartilage (60% mild, 33% moderate, 7% severe). Most gymnasts exhibited bony changes (20% normal, 47% mild, 26% moderate, 7% severe), the presence of cysts/fluid collections (80%), and carpal tunnel changes (53%). Swimmers had no wrist abnormalities. At follow-up interview, only 1 swimmer and 1 volleyball player reported shoulder problems during the study. Additionally, only 1 gymnast reported a wrist injury during their career. Asymptomatic elite athletes demonstrate MRI changes of the shoulder (swimmers and volleyball players) and wrist (gymnasts) similar to those associated with abnormalities for which medical treatment and sometimes surgery are advised. Given the somewhat high frequency of these asymptomatic findings, care must be taken to correlate clinical history and physical examination with MRI findings in these patients with symptoms.

  11. Shoulder replacement

    MedlinePlus

    ... the opening at the end of the shoulder blade, called the socket. This type of joint allows ... head. The socket part (glenoid) of your shoulder blade will be replaced with a smooth plastic shell ( ...

  12. SOF: A Joint Force Integrator

    DTIC Science & Technology

    2007-04-05

    abilities to communicate, enhance efficiencies, and empower midlevel managers with strategic decisions within their domain. Take for example how pop...typically gains the upper hand, leaving the slower competitor on their heels, attempting to conduct damage control . Often in recent times , the United...the need for the use of force during the appropriate times , but also takes consideration for 29

  13. Defending the Joint Force: Lessons Learned from Joint Base Balad

    DTIC Science & Technology

    2011-01-01

    the enemy’s aerial power by destroying his nests and eggs on the ground than to hunt his flying birds in the air.”1 This concept is reflected in Air...in defending its own assets and those of the joint force.  1. Giulio Douhet, The Command of the Air, trans. Dino Ferrari (1942; new imprint

  14. Joint Force Quarterly. Number 13, Autumn 1996

    DTIC Science & Technology

    1996-10-01

    Autumn 1996 Chemical attack exercise at Camp LeJuene . U .S . M ar in e C or ps (C .D . C la rk ) enemy NBC use are absent from the rele- vant...combat operations conducted by the unified commands, and joint force development. The opinions, conclusions, and recommendations ex- pressed or implied...inefficient, even ineffective, in conducting joint operations. In 1980, despite considerable heroism, we failed to rescue the American hostages in Iran. We

  15. [The Throwing Shoulder].

    PubMed

    Wieser, Karl; Gerber, Christian; Meyer, Dominik C

    2016-02-03

    Repetitive top-performance of overhead athletes induces a tremendous stress for the throwing shoulder. Throwers reach rotational speed of their arm of more than 7000°/s with joint compression and distraction forces of more than 1000 N. This performance is tributary to adaption of the shoulder muscles and the joint itself. These adaptions may, however lead to two specific problems of the throwing shoulder: 1. The posterosuperior internal impingement of the rotator cuff and labrum between glenoid and humeral head during late cooking phase; 2. A decreased internal rotation of the glenohumeral joint (GIRD) with compensatory problems of the scapula-stabilizing muscles. Precise analysis of kinematics and pathomechanics aims to improve understanding and treatment of those specific problems of the throwing shoulder.

  16. Knee joint forces: prediction, measurement, and significance

    PubMed Central

    D’Lima, Darryl D.; Fregly, Benjamin J.; Patil, Shantanu; Steklov, Nikolai; Colwell, Clifford W.

    2011-01-01

    Knee forces are highly significant in osteoarthritis and in the survival and function of knee arthroplasty. A large number of studies have attempted to estimate forces around the knee during various activities. Several approaches have been used to relate knee kinematics and external forces to internal joint contact forces, the most popular being inverse dynamics, forward dynamics, and static body analyses. Knee forces have also been measured in vivo after knee arthroplasty, which serves as valuable validation of computational predictions. This review summarizes the results of published studies that measured knee forces for various activities. The efficacy of various methods to alter knee force distribution, such as gait modification, orthotics, walking aids, and custom treadmills are analyzed. Current gaps in our knowledge are identified and directions for future research in this area are outlined. PMID:22468461

  17. A Biomechanical Model of the Scapulothoracic Joint to Accurately Capture Scapular Kinematics during Shoulder Movements

    PubMed Central

    Seth, Ajay; Matias, Ricardo; Veloso, António P.; Delp, Scott L.

    2016-01-01

    The complexity of shoulder mechanics combined with the movement of skin relative to the scapula makes it difficult to measure shoulder kinematics with sufficient accuracy to distinguish between symptomatic and asymptomatic individuals. Multibody skeletal models can improve motion capture accuracy by reducing the space of possible joint movements, and models are used widely to improve measurement of lower limb kinematics. In this study, we developed a rigid-body model of a scapulothoracic joint to describe the kinematics of the scapula relative to the thorax. This model describes scapular kinematics with four degrees of freedom: 1) elevation and 2) abduction of the scapula on an ellipsoidal thoracic surface, 3) upward rotation of the scapula normal to the thoracic surface, and 4) internal rotation of the scapula to lift the medial border of the scapula off the surface of the thorax. The surface dimensions and joint axes can be customized to match an individual’s anthropometry. We compared the model to “gold standard” bone-pin kinematics collected during three shoulder tasks and found modeled scapular kinematics to be accurate to within 2mm root-mean-squared error for individual bone-pin markers across all markers and movement tasks. As an additional test, we added random and systematic noise to the bone-pin marker data and found that the model reduced kinematic variability due to noise by 65% compared to Euler angles computed without the model. Our scapulothoracic joint model can be used for inverse and forward dynamics analyses and to compute joint reaction loads. The computational performance of the scapulothoracic joint model is well suited for real-time applications; it is freely available for use with OpenSim 3.2, and is customizable and usable with other OpenSim models. PMID:26734761

  18. A Biomechanical Model of the Scapulothoracic Joint to Accurately Capture Scapular Kinematics during Shoulder Movements.

    PubMed

    Seth, Ajay; Matias, Ricardo; Veloso, António P; Delp, Scott L

    2016-01-01

    The complexity of shoulder mechanics combined with the movement of skin relative to the scapula makes it difficult to measure shoulder kinematics with sufficient accuracy to distinguish between symptomatic and asymptomatic individuals. Multibody skeletal models can improve motion capture accuracy by reducing the space of possible joint movements, and models are used widely to improve measurement of lower limb kinematics. In this study, we developed a rigid-body model of a scapulothoracic joint to describe the kinematics of the scapula relative to the thorax. This model describes scapular kinematics with four degrees of freedom: 1) elevation and 2) abduction of the scapula on an ellipsoidal thoracic surface, 3) upward rotation of the scapula normal to the thoracic surface, and 4) internal rotation of the scapula to lift the medial border of the scapula off the surface of the thorax. The surface dimensions and joint axes can be customized to match an individual's anthropometry. We compared the model to "gold standard" bone-pin kinematics collected during three shoulder tasks and found modeled scapular kinematics to be accurate to within 2 mm root-mean-squared error for individual bone-pin markers across all markers and movement tasks. As an additional test, we added random and systematic noise to the bone-pin marker data and found that the model reduced kinematic variability due to noise by 65% compared to Euler angles computed without the model. Our scapulothoracic joint model can be used for inverse and forward dynamics analyses and to compute joint reaction loads. The computational performance of the scapulothoracic joint model is well suited for real-time applications; it is freely available for use with OpenSim 3.2, and is customizable and usable with other OpenSim models.

  19. Effects of a compression garment on shoulder external rotation force outputs during isotonic contractions.

    PubMed

    Tsuruike, Masaaki; Ellenbecker, Todd S

    2013-02-01

    The use of compression garments (CGs) has been advocated for performance enhancement and recovery in athletes. The effect of a CG on humeral rotation motor control has not been previously tested. The purpose of this study was to examine the isotonic contraction of external rotation (ER) of the glenohumeral joint at different force outputs to determine the effect of wearing a long sleeve CG on muscular performance. Twelve male college tennis players and 12 male college soccer players were tested for ER of the dominant shoulder during both concentric and eccentric isotonic contractions. The subjects performed 5 consecutive repetitions of both concentric and eccentric ER at 20-30% and 40-50% of maximum voluntary isometric contraction (MVIC) intensities. All subjects were tested with and without CG as well as with and without ongoing visual feedback information (OVFI). The order of CG wearing and the presence of OVFI were randomly assigned across all subjects. The results indicated a significant 3-way interaction between CG wearing and OVFI across 2 loads. Specifically, significantly different mean value of the completion time was found between OVFI and no-OVFI without CG wearing at 40-50% of MVIC, whereas no difference in the completion time was found with and without OVFI with CG wearing. Taken together, with CG wearing, athletes may have ER at 40-50% of MVIC more readily maintained by peripheral feedback without visuomotor control imposed on force outputs as compared without CG wearing.

  20. Joint Force Quarterly. Issue 39

    DTIC Science & Technology

    2005-10-01

    Marine Expeditionary Unit/Keith A. Milks ); and F–16 taking off from Shaw Air Force Base, Operation Noble Eagle (20th Communications Squadron/Keri S...Wake of Destruction By D A V I D J . D O R S E T T D o r s e t t Russia, France, and Malaysia joined it. At this point JTF–536, as a sole U.S...Operations AUS Australia AUT Austria BGD Bangladesh DEU Germany FRA France GBR Great Britain IND India JPN Japan KOR South Korea MYS Malaysia NZL New

  1. Effects of a shoulder injury prevention strength training program on eccentric external rotator muscle strength and glenohumeral joint imbalance in female overhead activity athletes.

    PubMed

    Niederbracht, Yvonne; Shim, Andrew L; Sloniger, Mark A; Paternostro-Bayles, Madeline; Short, Thomas H

    2008-01-01

    Imbalance of the eccentrically-activated external rotator cuff muscles versus the concentrically-activated internal rotator cuff muscles is a primary risk factor for glenohumeral joint injuries in overhead activity athletes. Nonisokinetic dynamometer based strength training studies, however, have focused exclusively on resulting concentric instead of applicable eccentric strength gains of the external rotator cuff muscles. Furthermore, previous strength training studies did not result in a reduction in glenoumeral joint muscle imbalance, thereby suggesting that currently used shoulder strength training programs do not effectively reduce the risk of shoulder injury to the overhead activity athlete. Two collegiate women tennis teams, consisting of 12 women, participated in this study throughout their preseason training. One team (n = 6) participated in a 5-week, 4 times a week, external shoulder rotator muscle strength training program next to their preseason tennis training. The other team (n = 6) participated in a comparable preseason tennis training program, but did not conduct any upper body strength training. Effects of this strength training program were evaluated by comparing pre- and posttraining data of 5 maximal eccentric external immediately followed by concentric internal contractions on a Kin-Com isokinetic dynamometer (Chattecx Corp., Hixson, Tennessee). Overall, the shoulder strength training program significantly increased eccentric external total work without significant effects on concentric internal total work, concentric internal mean peak force, or eccentric external mean peak force. In conclusion, by increasing the eccentric external total exercise capacity without a subsequent increase in the concentric internal total exercise capacity, this strength training program potentially decreases shoulder rotator muscle imbalances and the risk for shoulder injuries to overhead activity athletes.

  2. The effect of rugby shoulder padding on peak impact force attenuation.

    PubMed

    Harris, D A; Spears, I R

    2010-02-01

    The introduction of shoulder pads has coincided with a rise in shoulder impact injuries in the game of rugby. In this study, the effect of shoulder pads on impact force attenuation was quantified. Four different commercially available shoulder pads were tested for material properties. Hard and soft objects were dropped from predetermined heights onto a force plate imparting peak impact forces of 500, 1000 and 1500 N. The pads were then placed on the plate and subjected to 10 repeated impacts for each pad and drop height. Institutional laboratory setting. Peak force attenuation, expressed as the percentage reduction of peak force when compared with the no-pad condition, was calculated. Time to peak impact, expressed as the percentage increase of time to peak impact when compared with the no-pad condition, was calculated. All pads were found to reduce peak impact force and increase time to peak impact. Results varied between 1% and 70%, depending on the drop height and properties of the impactor. The best performing pad was the thickest, and all pads were best able to attenuate force under hard-object impacts particularly for the lower loads. Although several limitations exist to laboratory-based studies such as these, the inconsistencies in force attenuation were nonetheless disappointing. The pads appear to ''bottom out'' under higher-impact loads and therefore offer little protection when the athlete may need it most.

  3. A 200-m All-out Front-crawl Swim Modifies Competitive Swimmers' Shoulder Joint Position Sense.

    PubMed

    Uematsu, A; Kurita, Y; Inoue, K; Okuno, K; Hortobágyi, T; Suzuki, S

    2015-11-01

    We tested the hypothesis that an all-out-effort 200-m front-crawl swim trial affects competitive swimmers' shoulder joint position sense. On Day 1, we measured shoulder joint position sense before and after the swim trial, and on Day 2 before and after 2 min of seated rest. On both days, shoulder joint position sense was measured in the seated position using electromagnetic movement sensors in a position-matching paradigm. An investigator abducted participants' left (reference) shoulder joint in the frontal plane to test angles of 90°, 135°, and 180°. Participants then actively abducted the right (indicator) shoulder joint to match the position of the left, reference arm. After the 200-m all-out front-crawl swim trial, the indicator relative to the reference angle differed by 4.4° toward adduction at the 180° (vertical) testing position (P<0.05). Variation in absolute matching error was 3.2° or 2.2 times greater after swim compared with the no-swim control trial. An all-out 200-m front-crawl swim trial can selectively increase competitive swimmers' shoulder joint position sense error and increase variation in matching error in horizontal arm position.

  4. Shoulder joint movement of the non-throwing arm during baseball pitch--comparison between skilled and unskilled pitchers.

    PubMed

    Murata, A

    2001-12-01

    The shoulder of a non-throwing arm during a baseball pitch must be in a constant position while the shoulder of the throwing arm moves in a nearly circular path around it. However, it has not been investigated whether a skilled pitch requires less shoulder-joint movement. It was hypothesized that pitchers with less shoulder movement of the non-throwing arm can be considered to have higher skill and to attain higher initial ball velocity. Nine baseball pitchers were used as subjects. The coach classified them into a skilled and an unskilled group. The pitching motions were recorded using two high-speed cameras. The time series of three-dimensional landmark coordinates of the shoulder joint of the non-throwing arm during the baseball pitch were calculated using the direct linear transformation method. The shoulder-joint movement (SJM) index, which expresses the movement (displacement) of the shoulder joint of the non-throwing arm quantitatively, was proposed to compare the SJM at different skill levels and investigate the relationship between SJM and initial ball velocity. The SJM of the skilled pitchers was smaller than that of the unskilled pitchers, and the smaller value of the SJM led to faster initial ball velocity. The data suggest that the less SJM of the non-throwing arm is required to attain a skilled pitch and higher initial ball velocity.

  5. Computational reverse shoulder prosthesis model: Experimental data and verification.

    PubMed

    Martins, A; Quental, C; Folgado, J; Ambrósio, J; Monteiro, J; Sarmento, M

    2015-09-18

    The reverse shoulder prosthesis aims to restore the stability and function of pathological shoulders, but the biomechanical aspects of the geometrical changes induced by the implant are yet to be fully understood. Considering a large-scale musculoskeletal model of the upper limb, the aim of this study is to evaluate how the Delta reverse shoulder prosthesis influences the biomechanical behavior of the shoulder joint. In this study, the kinematic data of an unloaded abduction in the frontal plane and an unloaded forward flexion in the sagittal plane were experimentally acquired through video-imaging for a control group, composed of 10 healthy shoulders, and a reverse shoulder group, composed of 3 reverse shoulders. Synchronously, the EMG data of 7 superficial muscles were also collected. The muscle force sharing problem was solved through the minimization of the metabolic energy consumption. The evaluation of the shoulder kinematics shows an increase in the lateral rotation of the scapula in the reverse shoulder group, and an increase in the contribution of the scapulothoracic joint to the shoulder joint. Regarding the muscle force sharing problem, the musculoskeletal model estimates an increased activity of the deltoid, teres minor, clavicular fibers of the pectoralis major, and coracobrachialis muscles in the reverse shoulder group. The comparison between the muscle forces predicted and the EMG data acquired revealed a good correlation, which provides further confidence in the model. Overall, the shoulder joint reaction force was lower in the reverse shoulder group than in the control group. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. [Analysis of the shoulder joint mobility in overhead sports before and after experimental treatment].

    PubMed

    Kaćanski, Ivana; Gava, Branka Protić; Soldatović, Srdan

    2011-01-01

    "Overhead" sports, characterized by predominant movements of the hands above the head, are associated with very dynamic, often acyclic movements and require strong muscles of humero-scapular regions with high mobility of the shoulder joint as well as flexibility and ability to relax these muscles. This study was aimed at analyzing the shoulder joint mobility before and after conducting kinesiology treatment for a period of 6 months. The research included two complex exercises. The study included 100 "overhead" sports male athletes, who were randomly divided into the experimental and control group, aged 14 to 18 years. The range of motion was measured in degrees by goniometer. We calculated the central and depression parameter. There was a statistically significant difference inflexion, extension, abduction, adduction, external and internal rotation at the final measure in favor of the experimental group at the level of significance p<0.001, and some positive effects of the applied exercises were observed. Kinesitherapy had positive effects on the elasticity of the connective tissue capsule, ligaments and tendons. Changes in the shoulder area f the "overhead" sports athletes can be reduced to the same extent and at the same time by stretching and strength exercises. The authors of this paper have given their modest contribution by suggesting a more appropriate planning of training and performance of players at training and matches. This paper tries to emphasize the importance of proper incorporation of the corrective exercises in training.

  7. Towards the development of a novel experimental shoulder simulator with rotating scapula and individually controlled muscle forces simulating the rotator cuff.

    PubMed

    Baumgartner, Daniel; Tomas, Daniel; Gossweiler, Lukas; Siegl, Walter; Osterhoff, Georg; Heinlein, Bernd

    2014-03-01

    A preclinical analysis of novel implants used in shoulder surgery requires biomechanical testing conditions close to physiology. Existing shoulder experiments may only partially apply multiple cycles to simulate postoperative, repetitive loading tasks. The aim of the present study was therefore the development of an experimental shoulder simulator with rotating scapula able to perform multiple humeral movement cycles by simulating individual muscles attached to the rotator cuff. A free-hanging, metallic humerus pivoted in a polyethylene glenoid is activated by tension forces of linear electroactuators to simulate muscles of the deltoideus (DELT), supraspinatus (SSP), infraspinatus/teres minor and subscapularis. The abductors DELT and SSP apply forces with a ratio of 3:1 up to an abduction angle of 85°. The rotating scapular part driven by a rotative electro actuator provides one-third to the overall arm abduction. Resulting joint forces and moments are measured by a 6-axis load cell. A linear increase in the DELT and SSP motors is shown up to a maximum of 150 and 50 N for the DELT and SSP, respectively. The force vector in the glenoid resulted in 253 N at the maximum abduction. The present investigation shows the contribution of individual muscle forces attached to the moving humerus to perform active abduction in order to reproducibly test shoulder implants.

  8. Shoulder joint and muscle characteristics in the recreational weight training population.

    PubMed

    Kolber, Morey J; Beekhuizen, Kristina S; Cheng, Ming-Shun S; Hellman, Madeleine A

    2009-01-01

    Shoulder disorders attributed to weight training are well documented in the literature; however, a paucity of evidence-based research exists to describe risk factors inherent to participation. Shoulder joint and muscle characteristics in the recreational weight training (RWT) population were investigated to determine specific risk-related adaptations that may occur from participation. Ninety participants, men between the ages of 19 and 47 (mean age 28.9), including 60 individuals who participated in upper-extremity RWT and 30 controls with no record of RWT participation, were recruited. Active range of motion (AROM), posterior shoulder tightness (PST), body weight-adjusted strength values, and agonist/antagonist strength ratios were compared between the RWT participants and the control group. Statistical analysis identified significant differences (p < 0.001) between the groups when analyzing shoulder mobility. The RWT participants had decreased mobility when compared with the control group for all AROM measurements except external rotation, which was greater. Strength ratios were significantly greater in the RWT group when compared with the control group (p shoulder disorders in the general and athletic population; thus, these imbalances may place RWT participants at risk for injury. Common training patterns are biased toward large muscle groups such as the pectorals and deltoids but neglect muscles responsible for stabilization such as the external rotators and lower trapezius. Exercise selection that mitigates strength and mobility imbalances may serve to prevent injury in this population. Clinicians and strength and conditioning professionals should consider the biomechanical stresses and adaptations associated

  9. Segmentation and measurement of collagen fibers for shoulder and joint therapy studies

    SciTech Connect

    Mascio, L.

    1994-11-15

    Various shoulder instabilities are debilitating, especially in individuals who perform overhead activities. Thermal modification of soft tissues in joints may allow precise alteration of these tissues` mechanical and/or structural properties to enhance joint function without inducing cell death or an inflammatory response. Several studies have evaluated laser energy for tissue welding. The collective findings are promising, and the next step is to identify the mechanisms responsible for laser-induced capsular tissue alternation, and the short- and long-term effects of non-ablative laser energy on joint capsular tissue. One step toward this goal is to compare the effect of three laser energy densities on the histologic properties of the tissue evaluating the architecture of the collagen (including density, fibril diameter distribution, and interfibrillar space) in sheep at various time intervals after surgery. The specific computer algorithms that are being used to make these measurements will be described.

  10. Surgical normalization of the shoulder joint in obstetric brachial plexus injury.

    PubMed

    Nath, Rahul K; Amrani, Abdelouahed; Melcher, Sonya E; Wentz, Melissa J; Paizi, Melia

    2010-10-01

    Obstetric brachial plexus injuries (OBPI) result in bony derangements that include posterior humeral head subluxation, glenoid retroversion, and joint incongruity. Often these deformities are accompanied by scapular hypoplasia, elevation, and rotation, which further exacerbate shoulder dysfunction. The purpose of the current study was to investigate the effects of triangle tilt surgery on glenohumeral joint anatomy in 100 OBPI patients. The triangle tilt surgery restores the distal acromioclavicular triangle from an abnormal superiorly angled position to a neutral position, thereby restoring normal glenohumeral anatomic relationships.Axial computed tomography and magnetic resonance images taken before and 12- to 38-months after surgery showed significant improvements in both posterior subluxation and glenoid version. Patients with complete posterior glenohumeral dislocation improved from 19% preoperatively, to 11% postoperatively. Glenoid shape was also improved, with 81% of patients classified as concave or flat after surgery compared with 53% before surgery.Triangle tilt surgery allows for both repositioning and remodeling of the glenohumeral joint. These anatomic improvements after triangle tilt surgery hold promise for improving shoulder function and quality of life for OBPI patients.

  11. Joint Force Quarterly. Number 19, Summer 1998

    DTIC Science & Technology

    1998-08-01

    Airborne outside Tuzla Air Base (U.S. Army/Larry Lane), issue 13 (Autumn 96). The front inside cover shows flight deck crew rigging barricade (U.S. Navy...From the Sea.” If tested synergism is the most compelling view since it draws on common ground which the services have developed through joint...prepare for the ar- rival of ground and ground - based air power. Once accomplished, according to this argu- ment, naval forces fight alongside the other

  12. Joint Force Quarterly. Number 32, Autumn 2002

    DTIC Science & Technology

    2002-12-01

    industrialization, technological revolution in land warfare, revolution in naval warfare Early 20th century World War I Combined-arms tactics and...the Field by Ian Roxborough 76 The Army and Land Warfare: Transforming the Legions by Andrew F. Krepinevich 83 Corporate Disasters: Some Lessons for...understanding of the integrated employment of land , sea, air, space, and special operations forces. The journal focuses on joint doctrine, coalition warfare

  13. Standing Down a Joint Task Force

    DTIC Science & Technology

    1995-01-01

    maintains a small American military presence in Hon- duras at a facility known as Soto Cano Air Base. Joint Task Force-Bravo (JTF–B), directly...medivac heli- copter capability, and assists Hon- duras in counterdrug actions.1 Since the United States has no base leasing agreement, its military...example, SOUTHCOM points out that JTF–B contributes millions of dollars annu- ally to the local economy of Comay- agua and that the departure of Amer

  14. Joint Force Quarterly. Number 1, Summer 1993

    DTIC Science & Technology

    1993-01-01

    conduct joint operations to only “higher” levels is a recipe for missed opportunities, longer and more difficult operations, riskier outcomes, greater...changed the face of Europe, Asia, and Africa. The passing of the Cold War now has map-makers scrambling for pens and fresh ink, while territorial squabbles...America’s future is best served by a force mix that does not place too many eggs in any one basket, but which in- stead draws on the synergy of

  15. Joint Task Force on Undergraduate Physics Programs

    NASA Astrophysics Data System (ADS)

    This session will focus on the guidelines and recommendations being developed by the APS/AAPT Joint Task Force on Undergraduate Physics Programs. J-TUPP is studying how undergraduate physics programs might better prepare physics majors for diverse careers. The guidelines and recommendations will focus on curricular content, flexible tracks, pedagogical methods, research experiences and internships, the development of professional skills, and enhanced advising and mentoring for all physics majors.

  16. Effect of brief daily resistance training on rapid force development in painful neck and shoulder muscles: randomized controlled trial

    PubMed Central

    Jay, Kenneth; schraefel, mc; Andersen, Christoffer H; Ebbesen, Frederik S; Christiansen, David H; Skotte, Jørgen; Zebis, Mette K; Andersen, Lars L

    2013-01-01

    Objective: To determine the effect of small daily amounts of progressive resistance training on rapid force development of painful neck/shoulder muscles. Methods: 198 generally healthy adults with frequent neck/shoulder muscle pain (mean: age 43·1 years, computer use 93% of work time, 88% women, duration of pain 186 day during the previous year) were randomly allocated to 2- or 12 min of daily progressive resistance training with elastic tubing or to a control group receiving weekly information on general health. A blinded assessor took measures at baseline and at 10-week follow-up; participants performed maximal voluntary contractions at a static 90-degree shoulder joint angle. Rapid force development was determined as the rate of torque development and maximal muscle strength was determined as the peak torque. Results: Compared with the control group, rate of torque development increased 31·0 Nm s−1 [95% confidence interval: (1·33–11·80)] in the 2-min group and 33·2 Nm s−1 (1·66–12·33) in the 12-min group from baseline to 10-week follow-up, corresponding to an increase of 16·0% and 18·2% for the two groups, respectively. The increase was significantly different compared to controls (P<0·05) for both training groups. Maximal muscle strength increased only ∼5–6% [mean and 95% confidence interval for 2- and 12-min groups to control, respectively: 2·5 Nm (0·05–0·73) and 2·2 Nm (0·01–0·70)]. No significant differences between the 2- and 12-min groups were evident. A weak but significant relationship existed between changes in rapid force development and pain (r = 0·27, P<0·01), but not between changes in maximal muscle strength and pain. Conclusion: Small daily amounts of progressive resistance training in adults with frequent neck/shoulder pain increases rapid force development and, to a less extent, maximal force capacity. PMID:23758661

  17. Physiotherapy at a distance: a controlled study of rehabilitation at home after a shoulder joint operation.

    PubMed

    Eriksson, Lisbeth; Lindström, Britta; Gard, Gunvor; Lysholm, Jack

    2009-01-01

    We explored the benefit of video communication in home rehabilitation after shoulder joint replacement and compared it to referral for physiotherapy in the conventional way. A total of 22 patients were included in the study. The intervention group (n = 10) had training at home under the supervision of a physiotherapist at the hospital using videoconferencing. The control group (n = 12) had physiotherapy training in a conventional way in their home town. All patients had the same postoperative, three-phase-programme for two months. The outcome measures were a Visual Analogue Scale (VAS) for pain, range of motion (ROM), shoulder function ability (Constant score and SRQ-S) and health-related quality of life (SF-36). Questions about areas of priority for improvement and general satisfaction with the shoulder were also included. The telemedicine group received a greater number of treatments compared to the control group. After the intervention, there were significant improvements in VAS-pain, Constant score and SRQ-S for both groups. The telemedicine group improved significantly more in all three measurements than the control group (P < 0.001 for all). When changes from baseline to follow-up were compared, the telemedicine group improved significantly more in terms of decrease in pain (P = 0.004) and vitality (P = 0.001) than the control group. Despite some limitations, there seem to be clear benefits from physiotherapy at a distance with a telemedicine technique that allows patients to obtain access to physiotherapy at home.

  18. Associations among shoulder strength, glenohumeral joint motion, and clinical outcome after rotator cuff repair.

    PubMed

    Peltz, Cathryn D; Haladik, Jeffrey A; Hoffman, Scott E; McDonald, Michael; Ramo, Nicole; Moutzouros, Vasilios; Bey, Michael J

    2014-05-01

    Rotator cuff tears are a common condition causing pain and disability, but the relationships among clinical measures of shoulder function and measures of glenohumeral joint (GHJ) function are not well known. In the study reported here, dynamic in vivo GHJ motion was measured during abduction from biplane radiographs in 22 rotator cuff repair (RCR) patients and 36 control subjects. Isometric shoulder strength was measured and clinical outcomes were assessed using the Western Ontario Rotator Cuff (WORC) Index. Associations among WORC, GHJ motion, and several shoulder strength ratios were assessed with linear regression. An association was detected between higher ER/ABD (external rotation/coronal-plane abduction) strength ratio and a humerus positioned more inferiorly relative to the glenoid in control subjects and RCR patients. Higher ER/ABD strength ratio was also associated with better clinical outcome in RCR patients. These findings suggest a relationship between ER/ABD strength ratio and a more centrally located average superior/inferior contact center in RCR patients and control subjects. The ER/ABD strength ratio can be easily measured in a clinical setting and therefore can be used in larger studies to investigate its relation to clinical outcomes over time or perhaps to predict superior migration of the humeral head.

  19. Comparison in the effect of linear polarized near-infrared light irradiation and light exercise on shoulder joint flexibility.

    PubMed

    Demura, Shinichi; Noguchi, Takanori; Matsuzawa, Jinzaburo

    2006-07-01

    This study aimed at comparing the effect of linear polarized near-infrared light irradiation (PL irradiation) and bicycle exercise with 50%HRreserve on the flexibility of the shoulder joint. Placebo-controlled trial. Twenty-four healthy young adults (10 males: mean+/-SD, age 20.9+/-3.1 y, height 171.0+/-3.9 cm, body mass 63.4+/-3.5 kg and 14 females: age 21.2+/-1.7 y, height 162.0+/-7.8 cm, body mass 56.2+/-7.2 kg). PL-irradiation (100%, 1800 mW), placebo-irradiation (10%,180 mW), and light exercise (50%HRreserve) for 10 minutes. OUTCOME MEASUREMENTS AND RESULTS: The shoulder joint angles were measured twice-before and after each intervention. We measured the angles when the right shoulder joint extended forward and flexed backward maximally without support, and analyzed these shoulder joints and range of motion. Trial-to-trial reliability (intraclass correlations) of each joint angle was very high, over 0.98. All joint angles showed significant changes, and values in post-PL-irradiation and postlight exercise were significantly greater than that in postplacebo-irradiation. Shoulder forward flexion and backward extension angles had significantly greater change rates in PL-irradiation and light exercise than placebo-irradiation, and their range of motion angle was in the order of PL-irradiation, light exercise, and placebo-irradiation. It is suggested that PL-irradiation produces almost the same effect on shoulder joint range of motion as light exercise.

  20. The effect of shoulder core exercises on isometric torque of glenohumeral joint movements in healthy young females.

    PubMed

    Moghadam, Afsun Nodehi; Mohammadi, Roghayeh; Arab, Amir Massoud; Kazamnajad, Anoshirvan

    2011-12-01

    Strength improvement of the shoulder muscles is a major goal in rehabilitation or athletic conditioning programs. The purpose of this study was to determine the effect of shoulder core exercises on the isometric torque of glenohumeral joint movements. A total of 36 healthy females with no history of shoulder injury enrolled in this study. Subjects were randomly assigned into the control group (n = 18, 22 ± 2.19 years of age) or experimental group (n = 18, 21 ± 2.05 years of age). Subjects in experimental group performed shoulder core exercises, using progressive resistance training, three times a week for six weeks. Subjects in control group performed no exercise. The isometric torque of shoulder movements were measured with Dynatorq device in isolated test positions of glenohumeral muscles at the beginning and after six weeks in both groups. shoulder core exercise training led to an increase in maximal isometric torques of shoulder scaption at 0° and 90° arm elevation, external and internal rotation, horizontal adduction and extension movements (p < 0.001 in all instances). No significant difference was found between initial scores and scores after six weeks in the control group (p > 0.05). These findings indicated that shoulder core exercise training leads to an increase in peak torque for all glenohumeral movements that can be considered in glenohumeral muscles strengthening programs.

  1. The Standing Joint Force Headquarters: A Planning Multiplier?

    DTIC Science & Technology

    2006-05-25

    a Standing Joint Task Force Headquarters through its’ European Plans and Operations Center ( EPOC ). The European Plans and Operations Center was...elements of the Joint Forces Command Standing Joint Force Headquarters with minor modifications to meet EUCOM’s unique requirements.120 The EPOC contains...about half of the EPOC are assigned to the Joint Operations Center and the remainder were added as critical personnel as exercise planners, 36 121 Ibid

  2. Effect of Bankart repair on the loss of range of motion and the instability of the shoulder joint for recurrent anterior shoulder dislocation.

    PubMed

    Shibano, Koji; Koishi, Hayato; Futai, Kazuma; Yoshikawa, Hideki; Sugamoto, Kazuomi

    2014-06-01

    Bankart repair postoperative complications include loss of shoulder motion and shoulder instability. The primary reason that postoperative complications develop may be excessive imbrication of the anterior band of the inferior glenohumeral ligament (AIGHL) or inadequate repair position. The purpose of this study was to quantitatively evaluate the influence of inadequate repair by computer simulation for a normal shoulder joint. Magnetic resonance images of 10 normal shoulder joints were acquired for 7 positions every 30° from the maximum internal rotation to the maximum external rotation with the arm abducted at 90°. The shortest 3-dimensional path of the AIGHL in each rotational orientation was calculated. We used computer simulations to anticipate the loss of motion and instability by changing the AIGHL length and insertion sites on the glenoid. The AIGHL length measured 50 ± 5 mm at the maximum external shoulder rotation. AIGHL shortening by 3, 6, and 9 mm made the angle of maximum external rotation 80°, 68°, and 54°, respectively. A superior deviation of 3, 6, and 9 mm on the glenoid insertion resulted in a maximum external rotation angle of 85°, 79°, and 77°. An inferior deviation of 3, 6, and 9 mm produced humeral head translation of 1.7, 2.9, and 3.6 mm. Simulation of both excessive imbrication and deviation of the insertion position led to quantitative prediction of the resulting loss of motion and instability. These findings will be useful for anticipating complications after Bankart repair. Basic science study, computer modeling, imaging. Copyright © 2014. Published by Mosby, Inc.

  3. 76 FR 1975 - Disestablishment of United States Joint Forces Command

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-11

    ... Memorandum of January 6, 2011--Disestablishment of United States Joint Forces Command #0; #0; #0... of United States Joint Forces Command Memorandum for the Secretary of Defense Pursuant to my... Secretary of Defense and Chairman of the Joint Chiefs of Staff and approve the disestablishment of...

  4. [Case-control study on shoulder pain caused by hook palte for the treatment of acromioclavicular joint dislocation].

    PubMed

    Yang, Ying-guo; Cai, Xiao-bing; Wang, Xiao-min; Zhu, Yong-gan; Pan, He-yong

    2015-06-01

    To explore causes of shoulder pain and propose prevention measures in treating acromioclavicular joint dislocation. From January 2005 to January 2013, 86 patients with acromioclavicular joint dislocation (Tossy III) were treated with hook plate fixation, and were divided into two groups. Bsaed on recovery of shoulder function mostly, the patients who suffered from rest pain, motion pain were named as shoulder pain group, while the patients without pain were named as painless group. In shoulder pain group, there were 21 cases including 15 males and and 6 females ranging the age from 22 to 62 years old with an average of (40.6±11.2) years old. There were 8 cases were on the left side and 13 cases were on the right side. In painless group, there were 65 cases including 36 males and and 29 females ranging the age from 19 to 65 years old with an average of (40.0±11.3) years old. There were 33 cases were on the left side and 32 cases were on the right side. The time from injury to operation ranged from 3 h to 8 d with an average of 34.6 h. Shoulder function of all patients were normal before injuried. Postoperative pain, activity of daily living (ADL), range of motion, deltoid muscle strength were compared. Anteflexion,rear protraction, abduction and upthrow of shoulder joint were also compared. Postoperative complications between two groups were observed and compared. All patients were followed up from 12 to 48 months with an average of 18.5 months. Constant-Murley score were used to evaluate clinical efficacy at the least following up, and 13 cases got an excellent results, 5 moderate, 2 good and 1 poor in shoulder pain group ; while 61 cases were obtained excellent results, 3 moderate and 1 good in painless group. There were significantly differences between two groups in Constant-Murley score and activity of shoulder joint (P<0.05). In shoulder pain group, 3 cases were disconnected, 1 case occurred stress fracture, 9 cases were subacromial impingement syndrome, 5

  5. Topography of mechanoreceptors in the shoulder joint region--a computer-aided 3D reconstruction in the laboratory mouse.

    PubMed

    Backenköhler, U; Strasmann, T J; Halata, Z

    1997-07-01

    We investigated the pattern of distribution of corpuscular sensory nerve endings in the shoulder region of the laboratory mouse in relation to their functional properties. Twelve adult female white NMRI-F2-mice were used. The topography of sensory nerve endings in the shoulder joint region was reconstructed by three-dimensional image processing by using serial silver-stained sections of paraffin-embedded samples. Semithin sections obtained from additional samples were used for light microscopy. Within the fibrous layer of the joint capsule, three types of mechanoreceptors were identified: small lamellated corpuscles of the Pacini type, Ruffini corpuscles, and Golgi tendon organs. Intracapsular small lamellated corpuscles of the Pacini type (in an average number of 29/joint) were found mainly in three areas: in the predominantly flaccid tissue of the axillary region, in the denser ventromedial parts of the capsule, close to the scapula, and in the tight texture of the fiber bundles near the glenoid labrum. Ruffini corpuscles were identified only in small numbers (2/joint) in the ventral aspect of the articular capsule of two animals. Golgi tendon organs (14 or 15 receptors/joint) were discovered predominantly in close vicinity to the joint capsule at the muscle tendon junction of the inserting rotator cuff muscles and in the biceps brachii and triceps brachii muscles. In view of their location in the shoulder joint capsule and the glenoid labrum, corpuscular mechanoreceptors evidently play an important role in joint control by inducing protective reflex actions in phases of extreme or abnormal movement. The density of sensory receptors in distinct areas of the shoulder joint capsule appears to be related to zones that are subjected to increased biomechanical stress during physical activity.

  6. Does passive mobilization of shoulder region joints provide additional benefit over advice and exercise alone for people who have shoulder pain and minimal movement restriction? A randomized controlled trial.

    PubMed

    Yiasemides, Ross; Halaki, Mark; Cathers, Ian; Ginn, Karen A

    2011-02-01

    Passive mobilization of shoulder region joints, often in conjunction with other treatment modalities, is used for the treatment of people with shoulder pain and minimal movement restriction. However, there is only limited evidence supporting the efficacy of this treatment modality. The purpose of this study was to determine whether passive mobilization of shoulder region joints adds treatment benefit over exercise and advice alone for people with shoulder pain and minimal movement restriction. This was a randomized controlled clinical trial with short-, medium- and longer-term follow-up. The study was conducted in a metropolitan teaching hospital. Ninety-eight patients with shoulder pain of local mechanical origin and minimal shoulder movement restriction were randomly allocated to either a control group (n=51) or an experimental group (n=47). Participants in both groups received advice and exercises designed to restore neuromuscular control at the shoulder. In addition, participants in the experimental group received passive mobilization specifically applied to shoulder region joints. Outcome measurements of shoulder pain and functional impairment, self-rated change in symptoms, and painful shoulder range of motion were obtained at 1, 3, and 6 months after entry into the trial. All data were analyzed using the intention-to-treat principle by repeated-measures analyses of covariance. No statistically significant differences were detected in any of the outcome measurements between the control and experimental groups at short-, medium-, or longer-term follow-up. Therapists and participants were not blinded to the treatment allocation. This randomized controlled clinical trial does not provide evidence that the addition of passive mobilization, applied to shoulder region joints, to exercise and advice is more effective than exercise and advice alone in the treatment of people with shoulder pain and minimal movement restriction.

  7. Using your shoulder after replacement surgery

    MedlinePlus

    Joint replacement surgery - using your shoulder; Shoulder replacement surgery - after ... You have had shoulder replacement surgery to replace the bones of your shoulder joint with artificial parts. The parts include a stem made of metal and a ...

  8. Virtual power based algorithm for decoupling large motions from infinitesimal strains: application to shoulder joint biomechanics.

    PubMed

    Büchler, P; Rakotomanana, L; Farron, A

    2002-12-01

    New trends of numerical models of human joints require more and more computation of both large amplitude joint motions and fine bone stress distribution. Together, these problems are difficult to solve and very CPU time consuming. The goal of this study is to develop a new method to diminish the calculation time for this kind of problems which include calculation of large amplitude motions and infinitesimal strains. Based on the Principle of Virtual Power, the present method decouples the problem into two parts. First, rigid body motion is calculated. The bone micro-deformations are then calculated in a second part by using the results of rigid body motions as boundary conditions. A finite element model of the shoulder was used to test this decoupling technique. The model was designed to determine the influence of humeral head shape on stress distribution in the scapula for different physiological motions of the joint. Two versions of the model were developed: a first version completely deformable and a second version based on the developed decoupling method. It was shown that biomechanical variables, as mean pressure and von Mises stress, calculated with the two versions were sensibly the same. On the other hand, CPU time needed for calculating with the new decoupled technique was more than 6 times less than with the completely deformable model.

  9. Shoulder and hip joints for hard space suits and the like

    NASA Technical Reports Server (NTRS)

    Vykukal, H. C.

    1986-01-01

    For use in hard space suits and the like, a joint between the torso covering and the upper arm covering (i.e., shoulder) or between the torso covering and upper leg covering (i.e., hip) is disclosed. Each joint has an outer covering and a inner covering. The outer covering has plural perferably truncated toroidal sections decreasing in size proceeding outwardly. In one embodiment at each joint there are two bearings, the first larger than the second. The outer race of the larger bearing is attached to the outer edge of the smaller end of each section and the inner race of the larger bearing is attached to the end wall. The inner race of the smaller bearing is attached to the end wall. The outer race of the smaller bearing is attached to the larger end of the next section. Each bearing hask appropriate seals. Between each section is a rubber ring for the comfort of the wearer. Such rubber rings have radial flanges attached to the inner races of two adjacent bearings. Matching semicircular grooves are formed in the abutting overlapping surfaces. Bellows-like inner walls are also provided for each section fixed at one end to an inner cylindrical flange and, at the opposite end, to an end wall. Each outer section may rotate 360 deg relative to the next outer section, whereas the bellows sections do not rotate, but rather expand or contract locally as the rigid sections rotate relative to each other.

  10. The effects of swimming fatigue on shoulder strength, range of motion, joint control, and performance in swimmers.

    PubMed

    Matthews, Martyn J; Green, Daniel; Matthews, Helen; Swanwick, Emma

    2017-01-01

    To investigate the effects of training induced fatigue on shoulder strength, ROM, joint position sense, and stroke length in elite competitive swimmers. Seventeen national level swimmers performed maximum isometric strength (internal and external rotation), ROM, and joint position sense tests before and after a fatiguing 8 × 100 m training set. Stroke length, heart rate, blood lactate and blood glucose levels were recorded throughout. Peak blood lactate, blood glucose levels, and heart rate increased significantly (P < 0.001) post-training confirming fatigue. Reductions were observed in stroke length of both arms (P < 0.001), external rotation range of motion (P < 0.001, -5.29°, Right shoulder; P = 0.04, -3.18°, Left shoulder) and joint position sense in their dominant (breathing side) arm (P = 0.03). This investigation revealed a reduction in stroke length across both arms and also an arm bias in swimming whereby a greater reduction in both external rotation range and joint position sense was observed in the dominant arm when fatigued. This has highlighted a relationship between fatigue and potential mechanism of shoulder pathology in swimmers. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. Effect of Welding Speed on Joint Features and Lap Shear Properties of Stationary Shoulder FSLWed Alclad 2024 Al Alloy

    NASA Astrophysics Data System (ADS)

    Xu, Zhiwu; Li, Zhengwei; Lv, Zan; Zhang, Liguo

    2017-03-01

    Using alclad 2024-T4 aluminum alloy as the research object, stationary shoulder technology was used in friction stir lap welding process to investigate its performance in this study. Joint features and mechanical properties of the lap joints were mainly investigated. Results show that lap joint with smooth surface, without shoulder marks and inner defects can be obtained using the stationary shoulder technology. With increasing the welding speed from 40 to 130 mm/min, effective sheet thickness (EST) at the advancing side (AS) shows rather stable values (from 1.17 to 1.31 mm), EST at the retreating side (RS) increases from 0.57 to 1.13 mm, and stir zone width decreases from 4.95 to 4.44 mm. Lap shear failure load of the SSFSLW joints firstly increases and then decreases with increasing the welding speed. Using 100 mm/min, the maximum failure loads of 15.85 and 9.01 kN were obtained when the RS and AS of the joint bear the main load during the lap shear test. Shear fracture mode and tensile fracture mode can be obtained during the lap shear test. All joints present ductile fracture mode.

  12. Effect of Welding Speed on Joint Features and Lap Shear Properties of Stationary Shoulder FSLWed Alclad 2024 Al Alloy

    NASA Astrophysics Data System (ADS)

    Xu, Zhiwu; Li, Zhengwei; Lv, Zan; Zhang, Liguo

    2017-02-01

    Using alclad 2024-T4 aluminum alloy as the research object, stationary shoulder technology was used in friction stir lap welding process to investigate its performance in this study. Joint features and mechanical properties of the lap joints were mainly investigated. Results show that lap joint with smooth surface, without shoulder marks and inner defects can be obtained using the stationary shoulder technology. With increasing the welding speed from 40 to 130 mm/min, effective sheet thickness (EST) at the advancing side (AS) shows rather stable values (from 1.17 to 1.31 mm), EST at the retreating side (RS) increases from 0.57 to 1.13 mm, and stir zone width decreases from 4.95 to 4.44 mm. Lap shear failure load of the SSFSLW joints firstly increases and then decreases with increasing the welding speed. Using 100 mm/min, the maximum failure loads of 15.85 and 9.01 kN were obtained when the RS and AS of the joint bear the main load during the lap shear test. Shear fracture mode and tensile fracture mode can be obtained during the lap shear test. All joints present ductile fracture mode.

  13. The friction coefficient of shoulder joints remains remarkably low over 24 h of loading.

    PubMed

    Jones, Brian K; Durney, Krista M; Hung, Clark T; Ateshian, Gerard A

    2015-11-05

    The frictional response of whole human joints over durations spanning activities of daily living has not been reported previously. This study measured the friction of human glenohumeral joints during 24 h of reciprocal loading in a pendulum testing device, at moderate (0.2 mm/s, 4320 cycles) and low (0.02 mm/s, 432 cycles) sliding speeds, under a 200 N load. The effect of joint congruence was also investigated by testing human humeral heads against significantly larger mature bovine glenoids. Eight human joints and six bovine joints were tested in four combinations: human joints tested at moderate (hHCMS, n=6) and low speed (hHCLS, n=3), human humeral heads tested against bovine glenoids at moderate speed (LCMS, n=3), and bovine joints tested at moderate speed (bHCMS, n=3). In the first half hour the mean±standard deviation of the friction coefficient was hHCMS: 0.0016±0.0011, hHCLS: 0.0012±0.0002, LCMS: 0.0008±0.0002 and bHCMS: 0.0024±0.0008; in the last four hours it was hHCMS: 0.0057±0.0025, hHCLS: 0.0047±0.0017, LCMS: 0.0012±0.0003 and bHCMS: 0.0056±0.0016. The initial value was lower than the final value (p<0.0001). The value in LCMS was significantly lower than in hHCMS and bHCMS (p<0.01). No visual damage was observed in any of the specimens. These are the first results to demonstrate that the friction coefficient of natural human shoulders remains remarkably low (averaging as little as 0.0015 and no greater than 0.006) for up to 24 h of continuous loading. The sustained low friction coefficients observed in incongruent joints (~0.001) likely represent rolling rather than sliding friction. Copyright © 2015. Published by Elsevier Ltd.

  14. Joint Force Quarterly. Issue 44, 1st Quarter 2007

    DTIC Science & Technology

    2007-01-01

    General Lance L. Smith, USAF, Commander, U.S. Joint Forces Command 44 The Success of Global Force Management and Joint Force Providing by Michael...S) Stephen J. Miller, USAF Air War College BG Mark E. O’Neill, USA U.S. Army Command and General Staff College Maj Gen Teresa N. Peterson, USAF...ndu.edu Farewell to the Editor Two years ago, the Chairman of the Joint Chiefs of Staff, General Richard Myers, transferred a colonel from his personal

  15. The Impact of Nationalism on Joint Force Planning

    DTIC Science & Technology

    1996-01-01

    Understanding the dynamics of nationalism will remain critical to re- gional security affairs and joint force planning . Planning Implications Tension results...assigned to the Office of National Security Issues at the Defense Intelligence Agency. The Impact of NATIONALISM ON JOINT FORCE PLANNING By G E O R G E...COVERED 00-00-1995 to 00-00-1996 4. TITLE AND SUBTITLE The Impact of Nationalism on Joint Force Planning 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c

  16. Joint Space Forces in Theater: Coordination is No Longer Sufficient

    DTIC Science & Technology

    2007-04-01

    any other service or joint body, the Air Force has pushed the development of space systems, doctrine, procedures, and education . As the Department...operations and staff assignments. His assignments include Chief of Standardization and Evaluation for the 6th Space Operations Squadron, Offutt AFB...Force, Vandenberg AFB; and Chief of Joint Exercise Development , Headquarters Air Force Space Command, Peterson AFB. He has served in Combined/Joint

  17. Orthopaedic manual physical therapy for shoulder pain and impaired movement in a patient with glenohumeral joint osteoarthritis: a case report.

    PubMed

    Crowell, Michael S; Tragord, Bradley S

    2015-06-01

    Case report. Comprehensive treatment strategies are needed for individuals with glenohumeral joint osteoarthritis (OA), especially when they are young and active. Prior dislocation, with or without subsequent shoulder stabilization surgery, complicates the clinical presentation and increases the risk of OA progression. The purpose of this case report was to describe an orthopaedic manual physical therapy approach used in a patient with glenohumeral joint OA who presented with shoulder pain and impaired movement. CASE DESCRIPTION A 38-year-old male military officer presented with left-shoulder pain of 2 months in duration that was unrelieved with a subacromial injection. He reported a history of anterior-inferior dislocation with subsequent stabilization surgery 15 years prior and arthroscopic subacromial decompression 2 years prior. Physical examination demonstrated painful limitations in shoulder elevation and internal/external rotation movements, stiffness with testing using accessory glides, and rotator cuff and scapular musculature weakness associated with pain. Treatment consisted of 5 sessions provided over 4 weeks. The plan of care included manual physical therapy, exercises, and progressive functional activities specifically tailored to the patient's clinical presentation. Shoulder Pain and Disability Index scores decreased from 43% to 17%, and the Patient-Specific Functional Scale average score improved from 3.0 to 7.3 out of 10. After 4 additional weeks of a home exercise program, the Shoulder Pain and Disability Index score was 4% and Patient-Specific Functional Scale average score was 9.0. Improvements in self-reported function were maintained at 6 months. Four "booster" treatment sessions were administered at 9 months, contributing to sustained outcomes through 1 year. In a young, active patient with glenohumeral joint OA, clinically meaningful short-term improvements in self-reported function and pain, maintained at 1 year, were observed with manual

  18. Shoulder biomechanics.

    PubMed

    Lugo, Roberto; Kung, Peter; Ma, C Benjamin

    2008-10-01

    The biomechanics of the glenohumeral joint depend on the interaction of both static and dynamic-stabilizing structures. Static stabilizers include the bony anatomy, negative intra-articular pressure, the glenoid labrum, and the glenohumeral ligaments along with the joint capsule. The dynamic-stabilizing structures include the rotator cuff muscles and the other muscular structures surrounding the shoulder joint. The combined effect of these stabilizers is to support the multiple degrees of motion within the glenohumeral joint. The goal of this article is to review how these structures interact to provide optimal stability and how failure of some of these mechanisms can lead to shoulder joint pathology.

  19. "Floating shoulder" injuries.

    PubMed

    Heng, Kenneth

    2016-12-01

    "Floating shoulder" is a rare injury complex resulting from high-energy blunt force trauma to the shoulder, resulting in scapulothoracic dissociation. It is commonly associated with catastrophic neurovascular injury. Two cases of motorcyclists with floating shoulder injuries are described.

  20. Strategic Joint Staff Force Posture and Readiness Process Analysis

    DTIC Science & Technology

    2014-03-31

    STRATEGIC JOINT STAFF FORCE POSTURE AND READINESS PROCESS ANALYSIS 31 March 2014 Dan Kennedy, Consultant for Alcea Technologies Inc... Posture and Readiness Process Analysis 1 Executive Summary 1. The purpose of this report is to examine the process used by the Strategic Joint...Staff to determine the Force Posture and Readiness (FP&R) of the Canadian Armed Forces. The CDS Directive for CAF Force Posture and Readiness 2013

  1. Effects of Gait Speed of Femoroacetabular Joint Forces

    PubMed Central

    Irmischer, Bobbie S.; Sievert, Zachary A.

    2017-01-01

    Alterations in hip joint loading have been associated with diseases such as arthritis and osteoporosis. Understanding the relationship between gait speed and hip joint loading in healthy hips may illuminate changes in gait mechanics as walking speed deviates from preferred. The purpose of this study was to quantify hip joint loading during the gait cycle and identify differences with varying speed using musculoskeletal modeling. Ten, healthy, physically active individuals performed walking trials at their preferred speed, 10% faster, and 10% slower. Kinematic, kinetic, and electromyographic data were collected and used to estimate hip joint force via a musculoskeletal model. Vertical ground reaction forces, hip joint force planar components, and the resultant hip joint force were compared between speeds. There were significant increases in vertical ground reaction forces and hip joint forces as walking speed increased. Furthermore, the musculoskeletal modeling approach employed yielded hip joint forces that were comparable to previous simulation studies and in vivo measurements and was able to detect changes in hip loading due to small deviations in gait speed. Applying this approach to pathological and aging populations could identify specific areas within the gait cycle where force discrepancies may occur which could help focus management of care. PMID:28260849

  2. 3 CFR - Disestablishment of United States Joint Forces Command

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 3 The President 1 2012-01-01 2012-01-01 false Disestablishment of United States Joint Forces Command Presidential Documents Other Presidential Documents Memorandum of January 6, 2011 Disestablishment of United States Joint Forces Command Memorandum for the Secretary of Defense Pursuant to my authority as Commander in Chief and under 10 U.S.C. 16...

  3. Battlefield Renewable Energy: A Key Joint Force Enabler

    DTIC Science & Technology

    2010-06-01

    Environment, Energy Security & Sustainability Symposium Jun 2010 Battlefield Renewable Energy A Key Joint Force Enabler Roy H. Adams III, LTC, USA...COVERED 00-00-2010 to 00-00-2010 4. TITLE AND SUBTITLE Battlefield Renewable Energy : A Key Joint Force Enabler 5a. CONTRACT NUMBER 5b. GRANT

  4. Effect of extracorporeal shock wave therapy on the shoulder joint functional status of patients with calcific tendinitis

    PubMed Central

    Kim, Eun-Kyung; Kwak, Kwang-Il

    2016-01-01

    [Purpose] This study aimed to analyze the effect of extracorporeal shock wave therapy on the shoulder function of patients with calcific tendinitis through a 12-week follow-up. [Subjects and Methods] A total of 34 patients with calcific tendinitis participated in this study. In the extracorporeal shock wave therapy group, 18 patients received 6-week extracorporeal shock wave therapy and 12-week follow-up. The Constant-Murley scale was used to evaluate shoulder joint function. [Results] Analysis of variance showed a significant difference between the measurement periods. The independent t-test showed significant differences between the groups at 2, 6, and 12 weeks. [Conclusion] Extracorporeal shock wave therapy can be an effective treatment method for calcific tendinitis that affects patients’ shoulder function. PMID:27799684

  5. Effect of extracorporeal shock wave therapy on the shoulder joint functional status of patients with calcific tendinitis.

    PubMed

    Kim, Eun-Kyung; Kwak, Kwang-Il

    2016-09-01

    [Purpose] This study aimed to analyze the effect of extracorporeal shock wave therapy on the shoulder function of patients with calcific tendinitis through a 12-week follow-up. [Subjects and Methods] A total of 34 patients with calcific tendinitis participated in this study. In the extracorporeal shock wave therapy group, 18 patients received 6-week extracorporeal shock wave therapy and 12-week follow-up. The Constant-Murley scale was used to evaluate shoulder joint function. [Results] Analysis of variance showed a significant difference between the measurement periods. The independent t-test showed significant differences between the groups at 2, 6, and 12 weeks. [Conclusion] Extracorporeal shock wave therapy can be an effective treatment method for calcific tendinitis that affects patients' shoulder function.

  6. [The use of fascial distorsion model (FDM) in patient with limited mobility in the shoulder joint - a case report].

    PubMed

    Maśliński, Patryk; Woldańska-Okońska, Marta

    2017-05-23

    FDM is the anatomical model in which clinical signs in conjunction with the patient's body language allow to diagnose one or more of the six specific distortions of the fascial system described by the creator of the concept of FDM and doctor-osteopath Stephen Typaldos. The aim of the study is to present the use of therapy Fascial Distorsion Model to patient with limited mobility in the shoulder joint. Here we report a 32 year old female patient with painful limitation of motion in the shoulder joint right continuing for three weeks. The patient is an office worker, three times a week swims. Pain appears periodicaly and only in certain ranges of motion of the right upper limb. In the functional study by FDM it is continuum distortion and triggerband distortion. Then the appropriate therapeutic techniques were used. The patient regained full range of motion in the shoulder joint after using FDM techniques without pain that prevented her making a move. During the test, the patient performed functional movements in the full range of movement without pain. Techniques of the FDM are an interesting complement workshop therapy which is treating limits in the range of motion and pain in the joints.

  7. The validation of a human force model to predict dynamic forces resulting from multi-joint motions

    NASA Technical Reports Server (NTRS)

    Pandya, Abhilash K.; Maida, James C.; Aldridge, Ann M.; Hasson, Scott M.; Woolford, Barbara J.

    1992-01-01

    The development and validation is examined of a dynamic strength model for humans. This model is based on empirical data. The shoulder, elbow, and wrist joints were characterized in terms of maximum isolated torque, or position and velocity, in all rotational planes. This data was reduced by a least squares regression technique into a table of single variable second degree polynomial equations determining torque as a function of position and velocity. The isolated joint torque equations were then used to compute forces resulting from a composite motion, in this case, a ratchet wrench push and pull operation. A comparison of the predicted results of the model with the actual measured values for the composite motion indicates that forces derived from a composite motion of joints (ratcheting) can be predicted from isolated joint measures. Calculated T values comparing model versus measured values for 14 subjects were well within the statistically acceptable limits and regression analysis revealed coefficient of variation between actual and measured to be within 0.72 and 0.80.

  8. Dynamic joint and muscle forces during knee isokinetic exercise.

    PubMed

    Wei, S H

    2000-10-01

    Isokinetic exercise has been commonly used in knee rehabilitation, conditioning and research in the past two decades. Although many investigators have used various experimental and theoretical approaches to study the muscle and joint force involved in isokinetic knee extension and flexion exercises, only a few of these studies have actually distinguished between the tibiofemoral joint forces and muscle forces. Therefore, the objective of this study was to specify, via an eletromyography(EMG)-driven muscle force model of the knee, the magnitude of the tibiofemoral joint and muscle forces acting during isokinetic knee extension and flexion exercises. Fifteen subjects ranging from 21 to 36 years of age volunteered to participate in this study. A Kin Com exercise machine (Chattecx Corporation, Chattanooga, TN, U.S.A.) was used as the loading device. An EMG-driven muscle force model was used to predict muscle forces, and a biomechanical model was used to analyze two knee joint constraint forces; compression and shear force. The methods used in this study were shown to be valid and reliable (r > 0.84 andp < 0.05). The effects on the tibiofemoral joint force during knee isokinetic exercises were compared with several functional activities that were investigated by earlier researchers. The muscle forces generated during knee isokinetic exercise were also obtained. Based on the findings obtained in this study, several therapeutic justifications for knee rehabilitation are proposed.

  9. Absolute reliability of shoulder joint horizontal adductor muscle strength measurements using a handheld dynamometer.

    PubMed

    Hirano, Masahiro; Katoh, Munenori

    2015-07-01

    [Purpose] The aim of this study was to verify the absolute reliability of shoulder joint horizontal adductor muscle strength measurements using a handheld dynamometer (HHD). [Subjects and Methods] The subjects were 33 healthy college students. The measurements were made three times with the HHD fixed using a belt (BFHHD) or with the examiner's hand (conventional method; HFHHD). The absolute reliability of measurements was verified using Bland-Altman analysis, both in the all subjects group and a group of subjects showing measurements less than a fixed limit of 30 kgf. [Results] In the <30 kgf group, a systematic bias was not observed, and BFHHD values were greater than HFHHD values. BFHHD values in the all subjects group showed a systematic bias; the 3rd measurement value was less than the maximum value obtained during the 1st and 2nd measurements. [Conclusion] For obtaining an acceptable value during clinical measurements of horizontal adductor muscle strength, single measurements obtained using an HFHHD in the case of a <30 kgf group and the maximum value of two measurements obtained using a BFHHD are reliable.

  10. Peak velocity of elbow joint during touching contra lateral shoulder activity for normal subject

    NASA Astrophysics Data System (ADS)

    Nan, Hasyatun Che; Rambely, Azmin Sham

    2017-04-01

    A better understanding of upper limb movements requires analysis of motion. Measurements of movement analysis through biomechanical studies are necessary to describe upper limb activities. Therefore this study intend to investigate peak velocity of elbow joint for different age groups during the "touching contra lateral shoulder" activity. Twenty healthy subjects age range 20 - 59 years old (n = 60) performed a complete cycle of hand lifting, resting and returning the hand to its initial position. This activity was analyzed using Vicon motion-analysis system, which consists of three infra-red and high speed cameras. Phase definitions were defined and descriptive kinematic variables were obtained from this activity. Movement times is found to increase in 50's age group. The difference of movement times is < 0.3s. Peak velocity for subject age 50s' also higher between all subjects. The difference of peak velocity is < 0.03m/s for all different phases. It was found that there were a significant difference in total movement time and no significance different between each age group for peak velocity parameter.

  11. Joint Tactics, Techniques, and Procedures for Joint Special Operations Task Force Operations

    DTIC Science & Technology

    2001-12-19

    military operations. It also provides an overview of joint special operations tenets and doctrinal principles . It includes guidance for organizing a JSOTF... principles and guidance also may apply when significant forces of one Service are attached to forces of another Service or when significant forces of...and the Principles of War ............................................................ I-4 • Characteristics of Special Operations Forces

  12. Managing Air Force Joint Expeditionary Taskings in an Uncertain Environment

    DTIC Science & Technology

    2011-01-01

    44 A.2. Process from URF to RFF Validation...state security posture URF unit request for forces USCENTCOM U.S. Central Command USJFCOM U.S. Joint Forces Command UTC unit type code 1 CHAPTER ONE...requirement, the field commander submits a unit request for forces ( URF ) to the COCOM staff, which determines whether the request can be filled with existing

  13. Redefining Joint Fires Service Functions to Better Support Joint Force Operations

    DTIC Science & Technology

    2012-06-01

    of tasks and systems that provide the collective and coordinated use of Army indirect fires, air and missile defense (AMD), and joint fires...effort. Operational fires can occur anywhere within the Joint Operating Area (JOA) and may be delivered via a variety of platforms, weapon systems ...freedom of maneuver for the joint force. They require defensive fires to protect the force. The JFC, using systems that allow rapid response to changes

  14. Effect of glenoid cementation on total shoulder arthroplasty for degenerative arthritis of the shoulder: a review of the New Zealand National Joint Registry.

    PubMed

    Clitherow, Harry D S; Frampton, Christopher M A; Astley, Timothy M

    2014-06-01

    Despite the lack of literature showing improved results compared with cemented designs, uncemented glenoid components are still commonly used in total shoulder arthroplasty (TSA). Most studies comparing cemented with uncemented glenoids involve small numbers or include patients with inflammatory arthritis. New Zealand National Joint Registry data was used to compare the outcomes of uncemented and cemented glenoids in TSA performed for degenerative arthritis. Measured variables were the revision rate and the Oxford Shoulder Score (OSS). Data were retrieved on 1596 patients, with a mean follow-up 3.5 years (range 2-10.7 years), 1065 of whom had a cemented glenoid. There were no significant differences in any preoperative factors between the 2 groups. The revision rate for uncemented glenoids was 4.4 times higher than for cemented glenoids (1.92 vs. 0.44 revisions per 100 component-years, P < .001). Age <55 years was an independent risk factor for revision (P < .001). The most common reason for revision was rotator cuff wear (35.5%) in the uncemented glenoids and loosening (36.3%) in the cemented glenoids. The difference in the mean OSS between the 2 groups was less than 1 point at 6 months (P = .109) and at 5 years (P = .377). Uncemented glenoids had a markedly higher revision rate. Patients aged <55 years have the highest revision rate regardless of glenoid fixation method. The higher revision rate in the uncemented glenoid group persisted when the effect of young age was corrected for. There was no clinically or statistically significant difference in the OSS results for clinical outcome between the two groups. Level III, retrospective cohort, treatment study. Copyright © 2014 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Mosby, Inc. All rights reserved.

  15. Implementing Joint Operational Access: From Concept to Joint Force Development

    DTIC Science & Technology

    2014-01-01

    multiple DOTMLPF-P gover - nance processes across the Department of Defense (DOD). Finally, pulling all of the various activities together related to JOA...eral Martin E . Dempsey signed the Joint Concept for Entry Operations (JCEO) on April 7, 2014. 5 Sustaining U.S. Global Leadership, 5. 6 JOAC, 33–36

  16. Change in the Distance From the Axillary Nerve to the Glenohumeral Joint With Shoulder External Rotation or Abduction Position.

    PubMed

    Simone, Juan Pablo; Streubel, Philipp N; Sanchez-Sotelo, Joaquin; Steinmann, Scott P; Adams, Julie E

    2017-07-01

    This study investigated whether axillary nerve (AN) distance to the inferior border of the humeral head and inferior glenoid would change while placing the glenohumeral joint in different degrees of external rotation and abduction. A standard deltopectoral approach was performed on 10 fresh-frozen cadaveric specimens. The distance between AN and the inferior border of the humeral head and inferior glenoid while placing the shoulder in 0°, 45°, and 90° of external rotation or abduction was measured. Continuous variables for changes in AN position were compared with paired 2-tailed Student t test. The mean distance between the AN and the humeral head with the shoulder in 0°, 45°, and 90° of external rotation and 0° of abduction was 13.77 mm (SD 4.31), 13.99 mm (SD 4.12), and 16.28 mm (SD 5.40), respectively. The mean distance between the AN and glenoid with the shoulder in 0°, 45°, and 90° of external rotation was 16.33 mm (SD 3.60), 15.60 mm (SD 4.19), and 16.43 (SD 5.35), respectively. The mean distance between the AN and the humeral head with the shoulder in 0°, 45°, and 90° of abduction and 0° of external rotation was 13.76 mm (SD 4.31), 10.68 mm (SD 4.19), and 3.81 mm (SD 3.08), respectively. The mean distance between the AN and glenoid with the shoulder in 0°, 45°, and 90° of abduction was 16.33 mm (SD 3.60), 17.66 mm (SD 5.80), and 12.44 mm (SD 5.57), respectively. The AN position relative to the inferior aspect of the glenohumeral joint does not significantly change despite position of external rotation. Increasing shoulder abduction over 45° decreases the distance from the glenohumeral joint to the AN and should be avoided.

  17. Joint Logistics Component Commander and the Mobility Air Forces

    DTIC Science & Technology

    2001-06-01

    ii AFIT/ GMO /ENS/01E-6 JOINT LOGISTICS COMPONENT COMMANDER AND THE MOBILITY AIR FORCES GRADUATE RESEARCH PAPER Presented...2001 APPROVED FOR PUBLIC RELEASE; DISTRIBUTION UNLIMITED iii AFIT/ GMO /ENS/01E-6 JOINT LOGISTICS COMPONENT COMMANDER...84 BIBLIOGRAPHY........................................................................................................... 85 viii AFIT/ GMO /ENS

  18. Joint Force Transformation to Fight the Global War on Terrorism

    DTIC Science & Technology

    2004-03-08

    JOINT FORCE TRANSFORMATION TO FIGHT THE GLOBAL WAR ON TERRORISM Capt Stephen Guse LTC Paul Disney...for the collection of information is estimated to average 1 hour per response , including the time for reviewing instructions, searching existing data...AND SUBTITLE Joint Force Transformation to Fight the Global War on Terrorism 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6

  19. Shoulder Impingement Treatment

    MedlinePlus

    ... imbalance in the rotator cuff or scapular muscles, postural abnormalities, shoulder joint instability, or improper training or ... with elastic tubing. Figure 2. Shoulder protraction exercise (balance with one arm on wobble board or deflated ...

  20. Muscle force and excursion requirements and moment arm analysis of a posterior-superior offset reverse total shoulder prosthesis.

    PubMed

    Onstot, Brian R; Jacofsky, Marc C; Hansen, Matthew L

    2013-01-01

    Current reverse total shoulder arthroplasty prosthesis designs do not permit offset of the humerus in the sagittal plane. Posteriorly shifting the humerus has the theoretical benefit of lengthening the infraspinatus and teres minor muscles and their external rotation moment arms, thereby improving the tension and efficiency of each external rotator and subsequently requiring each muscle to produce less force to rotate the arm. A cadaveric shoulder controller was used to quantify the impact of a novel posterior-superior offset reverse shoulder prosthesis on muscle length, moment arms, and muscle forces relative to a non-offset reverse shoulder design during two different motions: scapular plane abduction and internal/external rotation. The results of this study demonstrate that both the non-offset and offset reverse shoulder designs had similar force and excursion demands of the infraspinatus and teres minor muscles during both scapular abduction and internal and external rotation. Additionally, the offset reverse shoulder design was associated with significantly less over-tensioning of the middle and posterior deltoid and significantly more anatomic tensioning of the teres minor than the non-offset design. However, the offset reverse shoulder was observed to have more impingement than the non-offset design. These findings support the feasibility of this design: by restoring a more anatomic resting length to the deltoid and teres minor, the posterior-superior offset rTSA design may provide better teres minor function and rotational strength and may decrease the incidence of acromial stress fractures relative to the non-offset design. Clinical follow-up is required to confirm these findings.

  1. Limits of the manipulative-fixed method for measurement of shoulder joint horizontal adduction muscle strength using a handheld dynamometer.

    PubMed

    Hirano, Masahiro; Katoh, Munenori

    2015-01-01

    [Purpose] The aim of this study was to verify the limit of isometric muscle strength of shoulder joint horizontal adduction using handheld dynamometer (HHD) manipulated by hand (referred to as the manipulative-fixed method). [Subjects and Methods] The subjects were 33 healthy college students. The examiner was a healthy college student. Shoulder joint horizontal adductor muscle strength was measured using HHD with the subject in the supine position. The belt-fixed and manipulative-fixed methods were used to secure the HHD sensor unit. The limitations of the manipulative-fixed method were assessed by simple regression analysis, in which the participants were divided into 2 groups according to a branch point. The slope of the straight line of the graph was visualized. [Results] Single regression analysis of the <30 kgf group revealed significant results. The results of single regression of the >30 kgf group were not significant. [Conclusion] The manipulative-fixed method is simple to perform. However, there exists the possibility that the actual muscle strength is not measurable by this method. The measurement limit of the shoulder horizontal adduction strength with the manipulative-fixed method was 30 kgf in the case of the examiner in the present study. The fixed limit was also found to influence in the muscle strength of the upper limbs.

  2. Proprioception assessment in subjects with idiopathic loss of shoulder range of motion: joint position sense and a novel proprioceptive feedback index.

    PubMed

    Yang, Jing-Lan; Chen, Shiauyee; Jan, Mei-Hwa; Lin, Yeong-Fwu; Lin, Jiu-jenq

    2008-09-01

    We examined the effects of elevation range and plane on shoulder joint proprioception in subjects with idiopathic loss of shoulder range of motion (ROM). Joint position sense (JPS) and a novel proprioceptive feedback index (PFI), including difference magnitude and the similarity index, were used to assess proprioception. Twelve subjects (eight male, four female) with involved stiff shoulders and normal opposite shoulders were recruited from a university hospital. Subjects attempted to repeat six target positions. Target positions consisted of arm elevation in three planes (frontal, scapular, and sagittal planes) and two ranges (end/mid range). Six trials of each target position were used to determine acceptable trials for stabilization of the data, less than 5% of the cumulative mean values for at least three successive trials. The data stabilized at the sixth repetition. Compared to control shoulders, involved shoulders had enhanced proprioception during end range movements (p < 0.05). The magnitude of the repositioning error and difference magnitude decreased (1.6 degrees -3.5 degrees for repositioning error and 22.2 degrees -62.1 degrees for difference magnitude), whereas similarity index improved at end range movements compared to mid range movements (p < 0.05) in involved stiff shoulders. Results of JPS and PFI suggest that both capsuloligamentous and musculotendinous mechanoreceptors play an important role in proprioception feedback during active movements in subjects with idiopathic loss of shoulder ROM.

  3. The National Guard: Recommendations to Develop the Joint Future Force

    DTIC Science & Technology

    2010-03-01

    author of this paper, is a requirement to educate the military personnel on total force and joint concepts from the earliest stages. Aristotle once...8 Phillip S. Meilinger, American Airpower Biography : A Survey of the Field Air and Space Power (Maxwell Air Force Base, AL: Air University Press

  4. Determinants and magnitudes of manual force strengths and joint moments during two-handed standing maximal horizontal pushing and pulling.

    PubMed

    Chow, Amy Y; Dickerson, Clark R

    2016-04-01

    Pushing and pulling are common occupational exertions that are increasingly associated with musculoskeletal complaints. This study focuses on the sensitivity of shoulder capacity to gender, handle height, exertion type (push or pull) and handle orientation for these tasks. All factors except for handle orientation influenced unilateral and total manual force strength (p < 0.01), with exertion type being the most influential. Interaction effects also existed between handle height and exertion type. Additionally, joint moments at the shoulders and low back were influenced by all factors studied (p < 0.01), with exertion type again being most influential. Knowledge of the relative influence of multiple factors on shoulder capacity can provide guidance regarding these factors when designing or evaluating occupational pushing and pulling tasks for a diverse population. Practitioner Summary: pushing and pulling comprise nearly half of all manual materials handling tasks. Practitioners often assess, design or modify these tasks while incorporating constraints, including manual force direction and handle interface. This study provides guidance to aid design of pushing and pulling tasks in the context of shoulder physical capacity.

  5. Cyber Situational Awareness for Joint Force Commanders

    DTIC Science & Technology

    2012-02-15

    Officer assigned to the Air War College, Air University, Maxwell AFB, AL. Lt Col Payne is a graduate of Ohio University with a Bachelor of Science...manner. The central thesis being addressed is that military commanders need a common framework for cyber situation awareness in order to aid the force...The central thesis being addressed is that military commanders need a common framework for cyber SA in order to aid the force with building a

  6. Joint Force Quarterly. Number 31, Summer 2002

    DTIC Science & Technology

    2002-09-01

    Transformation 0131 Cov1 Only 1/29/04 1:05 PM Page 1 Report Documentation Page Form ApprovedOMB No. 0704-0188 Public reporting burden for the...Information Operations and Reports , 1215 Jefferson Davis Highway, Suite 1204, Arlington VA 22202-4302. Respondents should be aware that...currently valid OMB control number. 1. REPORT DATE 2002 2. REPORT TYPE 3. DATES COVERED 00-00-2002 to 00-00-2002 4. TITLE AND SUBTITLE Joint

  7. Joint Force Quarterly. Number 16, Summer 1997

    DTIC Science & Technology

    1997-08-01

    and deserves in the new century . JOHN M. SHALIKASHVILI Chairman of the Joint Chiefs of Staff implementing the recommendations in the QDR report will...innovations in the conduct of war, we approach the new century with possibilities that were once considered inconceivable. Few would deny these...warfighting and the ends we seek to achieve. In Creating a New Civilization, the Tofflers propose guidance for 21st century democracy. Alarmed over the

  8. Adaptive Joint Force Packaging (AJFP): A Critical Analysis

    DTIC Science & Technology

    1993-12-01

    threats and forces in mind, and will be coordinated sufficiently with the Pacific Command’s own force packaging initiatives. A great deal of the most...important critical analysis of the Adaptive Joint Force Packaging concept. As we enter this new and uncertain post-Cold War world, in which " threats " are less...largely from the end of the super-power stand-off, and domestic budgetary pressures. Without the Soviet threat , and in recognition of a national

  9. Assessing Posterior Shoulder Contracture: The Reliability and Validity of Measuring Glenohumeral Joint Horizontal Adduction

    PubMed Central

    Laudner, Kevin G; Stanek, Justin M; Meister, Keith

    2006-01-01

    Context: Increased contracture of the dominant posterior shoulder in throwing athletes has been associated with the development of altered shoulder rotational motion as well as several shoulder conditions. Clinicians must be able to accurately and reliably measure posterior shoulder contractures during the evaluation of such athletes in order to provide appropriate treatment. Objective: To evaluate the reliability and validity of assessing posterior shoulder contracture by measuring supine glenohumeral (GH) horizontal adduction. Design: Descriptive with repeated measures. Setting: The biomechanics laboratory at Illinois State University (Normal, IL) and the athletic training room in Surprise, AZ. Patients or Other Participants: Twenty-four shoulders were tested in 12 subjects (age = 21.9 ± 4.3 years, height = 175.0 ± 10.0 cm, mass = 82.4 ± 19.1 kg) for determination of reliability, and 46 shoulders were tested in 23 professional baseball pitchers (age = 21.25 ± 1.66 years, height = 190.0 ± 5.0 cm, mass = 88.45 ± 6.99 kg) for determination of validity. Main Outcome Measure(s): We examined intratester and intertester reliability over 3 testing sessions by having 2 examiners measure GH horizontal adduction with the subject in a supine position with the scapula stabilized. To determine the validity and clinical usefulness of this measurement, we examined the relationship between GH horizontal adduction motion and internal shoulder rotational motion among a group of baseball pitchers. Results: Intraclass correlation coefficients were high for intratester (0.93, SEM = 1.64°) and intertester (0.91, SEM = 1.71°) measurements. This measurement was also shown to have a moderate to good relationship with lost internal shoulder rotational motion ( r = .72, P = .001) of the dominant arm among the baseball pitchers. Conclusions: Based on the results of this study, we found that measuring GH horizontal adduction with the subject supine and the scapula stabilized is a

  10. Stress analysis of bolted joints under centrifugal force

    NASA Astrophysics Data System (ADS)

    Imura, Makoto; Iizuka, Motonobu; Nakae, Shigeki; Mori, Takeshi; Koyama, Takayuki

    2014-06-01

    Our objective is to develop a long-life rotary machine for synchronous generators and motors. To do this, it is necessary to design a high-strength bolted joint, which is responsible for fixing a salient pole on a rotor shaft. While the rotary machine is in operation, not only centrifugal force but also moment are loaded on a bolted joint, because a point of load is eccentric to a centre of a bolt. We tried to apply the theory proposed in VDI2230-Blatt1 to evaluate the bolted joint under eccentric force, estimate limited centrifugal force, which is the cause of partial separation between the pole and the rotor shaft, and then evaluate additional tension of a bolt after the partial separation has occurred. We analyzed the bolted joint by FEM, and defined load introduction factor in that case. Additionally, we investigated the effect of the variation of bolt preload on the partial separation. We did a full scale experiment with a prototype rotor to reveal the variation of bolt preload against tightening torque. After that, we verified limited centrifugal force and the strength of the bolted joint by the VDI2230-Blatt1 theory and FEM considering the variation of bolt preload. Finally, we could design a high-strength bolted joint verified by the theoretical study and FEM analysis.

  11. Milwaukee shoulder syndrome.

    PubMed

    Pandey, A; Das, S K; Kumar, P; Kumar, M; Meena, D; Garg, V

    2011-05-01

    Milwaukee shoulder syndrome or rapid destructive arthritis of the shoulder; is a particular form of arthritis which affects mainly elderly patients, predominantly women, with limited pain and sometimes neuropathic joints, rotator cuff tear, joint instability, mildly inflammatory or noninflammatory, blood-stained effusion, calcium apatite crystals, and marked joint and bone destruction. This is very uncommon condition and very sparsely reported and so far, there is no case report from India, hence, we report a case of Milwaukee shoulder syndrome from India.

  12. Service Culture and the Joint Force

    DTIC Science & Technology

    2011-03-18

    Joint Chiefs of Staff, 1990 to 2005 (Carlisle Barracks, PA: U.S. Army War College, April 2006), 23. 63 Richard M. Meinhart , “Vice Chairmen of the...reflect the official policy or position of the Department of the Army , Department of Defense, or the U.S. Government. U.S. Army War College...Carlisle Barracks, PA 17013-5050 USAWC CLASS OF 2011 The U.S. Army War College is accredited by the Commission on Higher Education of the Middle

  13. Automatic bone segmentation and bone-cartilage interface extraction for the shoulder joint from magnetic resonance images

    NASA Astrophysics Data System (ADS)

    Yang, Zhengyi; Fripp, Jurgen; Chandra, Shekhar S.; Neubert, Aleš; Xia, Ying; Strudwick, Mark; Paproki, Anthony; Engstrom, Craig; Crozier, Stuart

    2015-02-01

    We present a statistical shape model approach for automated segmentation of the proximal humerus and scapula with subsequent bone-cartilage interface (BCI) extraction from 3D magnetic resonance (MR) images of the shoulder region. Manual and automated bone segmentations from shoulder MR examinations from 25 healthy subjects acquired using steady-state free precession sequences were compared with the Dice similarity coefficient (DSC). The mean DSC scores between the manual and automated segmentations of the humerus and scapula bone volumes surrounding the BCI region were 0.926  ±  0.050 and 0.837  ±  0.059, respectively. The mean DSC values obtained for BCI extraction were 0.806  ±  0.133 for the humerus and 0.795  ±  0.117 for the scapula. The current model-based approach successfully provided automated bone segmentation and BCI extraction from MR images of the shoulder. In future work, this framework appears to provide a promising avenue for automated segmentation and quantitative analysis of cartilage in the glenohumeral joint.

  14. Automatic bone segmentation and bone-cartilage interface extraction for the shoulder joint from magnetic resonance images.

    PubMed

    Yang, Zhengyi; Fripp, Jurgen; Chandra, Shekhar S; Neubert, Aleš; Xia, Ying; Strudwick, Mark; Paproki, Anthony; Engstrom, Craig; Crozier, Stuart

    2015-02-21

    We present a statistical shape model approach for automated segmentation of the proximal humerus and scapula with subsequent bone-cartilage interface (BCI) extraction from 3D magnetic resonance (MR) images of the shoulder region. Manual and automated bone segmentations from shoulder MR examinations from 25 healthy subjects acquired using steady-state free precession sequences were compared with the Dice similarity coefficient (DSC). The mean DSC scores between the manual and automated segmentations of the humerus and scapula bone volumes surrounding the BCI region were 0.926  ±  0.050 and 0.837  ±  0.059, respectively. The mean DSC values obtained for BCI extraction were 0.806  ±  0.133 for the humerus and 0.795  ±  0.117 for the scapula. The current model-based approach successfully provided automated bone segmentation and BCI extraction from MR images of the shoulder. In future work, this framework appears to provide a promising avenue for automated segmentation and quantitative analysis of cartilage in the glenohumeral joint.

  15. Elastic Tape Improved Shoulder Joint Position Sense in Chronic Hemiparetic Subjects: A Randomized Sham-Controlled Crossover Study

    PubMed Central

    Souza, Matheus Bragança; Desloovere, Kaat; Russo, Thiago Luiz

    2017-01-01

    Background Elastic tape has been widely used in clinical practice in order to improve upper limb (UL) sensibility. However, there is little evidence that supports this type of intervention in stroke patients. Objective To verify the effect of elastic tape, applied to the paretic shoulder, on joint position sense (JPS) during abduction and flexion in subjects with chronic hemiparesis compared to sham tape (non-elastic tape). Furthermore, to verify if this potential effect is correlated to shoulder subluxation measurements and sensorimotor impairment. Methods A crossover and sham-controlled study was conducted with post-stroke patients who were randomly allocated into two groups: 1) those who received Sham Tape (ST) first and after one month they received Elastic Tape (ET); 2) those who received Elastic Tape (ET) first and after one month they received Sham Tape (ST). The JPS was evaluated using a dynamometer. The absolute error for shoulder abduction and flexion at 30° and 60° was calculated. Sensorimotor impairment was determined by Fugl-Meyer, and shoulder subluxation was measured using a caliper. Results Thirteen hemiparetic subjects (average time since stroke 75.23 months) participated in the study. At baseline (before interventions), the groups were not different for abduction at 30° (p = 0.805; p = 0.951), and 60° (p = 0.509; p = 0.799), or flexion at 30° (p = 0.872; p = 0.897) and 60° (p = 0.853; p = 0.970). For the ET group, differences between pre and post-elastic tape for abduction at 30° (p<0.010) and 60° (p<0.010), and flexion at 30° p<0.010) and 60° (p<0.010) were observed. For the ST group, differences were also observed between pre and post-elastic tape for abduction at 30° (p<0.010) and 60° (p<0.010), and flexion at 30° (p<0.010,) and 60° (p<0.010). Potential effects were only correlated with shoulder subluxation during abduction at 30° (p = 0.001, r = -0.92) and 60° (p = 0.020, r = -0.75). Conclusion Elastic tape improved shoulder

  16. Elastic Tape Improved Shoulder Joint Position Sense in Chronic Hemiparetic Subjects: A Randomized Sham-Controlled Crossover Study.

    PubMed

    Santos, Gabriela Lopes Dos; Souza, Matheus Bragança; Desloovere, Kaat; Russo, Thiago Luiz

    2017-01-01

    Elastic tape has been widely used in clinical practice in order to improve upper limb (UL) sensibility. However, there is little evidence that supports this type of intervention in stroke patients. To verify the effect of elastic tape, applied to the paretic shoulder, on joint position sense (JPS) during abduction and flexion in subjects with chronic hemiparesis compared to sham tape (non-elastic tape). Furthermore, to verify if this potential effect is correlated to shoulder subluxation measurements and sensorimotor impairment. A crossover and sham-controlled study was conducted with post-stroke patients who were randomly allocated into two groups: 1) those who received Sham Tape (ST) first and after one month they received Elastic Tape (ET); 2) those who received Elastic Tape (ET) first and after one month they received Sham Tape (ST). The JPS was evaluated using a dynamometer. The absolute error for shoulder abduction and flexion at 30° and 60° was calculated. Sensorimotor impairment was determined by Fugl-Meyer, and shoulder subluxation was measured using a caliper. Thirteen hemiparetic subjects (average time since stroke 75.23 months) participated in the study. At baseline (before interventions), the groups were not different for abduction at 30° (p = 0.805; p = 0.951), and 60° (p = 0.509; p = 0.799), or flexion at 30° (p = 0.872; p = 0.897) and 60° (p = 0.853; p = 0.970). For the ET group, differences between pre and post-elastic tape for abduction at 30° (p<0.010) and 60° (p<0.010), and flexion at 30° p<0.010) and 60° (p<0.010) were observed. For the ST group, differences were also observed between pre and post-elastic tape for abduction at 30° (p<0.010) and 60° (p<0.010), and flexion at 30° (p<0.010,) and 60° (p<0.010). Potential effects were only correlated with shoulder subluxation during abduction at 30° (p = 0.001, r = -0.92) and 60° (p = 0.020, r = -0.75). Elastic tape improved shoulder JPS of subjects with chronic hemiparesis

  17. Effect of increased pushoff during gait on hip joint forces

    PubMed Central

    Lewis, Cara L.; Garibay, Erin J.

    2014-01-01

    Anterior acetabular labral tears and anterior hip pain may result from high anteriorly directed forces from the femur on the acetabulum. While providing more pushoff is known to decrease sagittal plane hip moments, it is unknown if this gait modification also decreases hip joint forces. The purpose of this study was to determine if increasing pushoff decreases hip joint forces. Nine healthy subjects walked on an instrumented force treadmill at 1.25 m/s under two walking conditions. For the natural condition, subjects were instructed to walk as they normally would. For the increased pushoff condition, subjects were instructed to “push more with your foot when you walk”. We collected motion data of markers placed on the subjects’ trunk and lower extremities to capture trunk and leg kinematics and ground reaction force data to determine joint moments. Data were processed in Visual 3D to produce the inverse kinematics and model scaling files. In OpenSim, the generic gait model (Gait2392) was scaled to the subject, and hip joint forces were calculated for the femur on the acetabulum after computing the muscle activations necessary to reproduce the experimental data. The instruction to “push more with your foot when you walk” reduced the maximum hip flexion and extension moment compared to the natural condition. The average reduction in the hip joint forces was 12.5%, 3.2% and 9.6% in the anterior, superior and medial directions respectively and 2.3% for the net resultant force. Increasing pushoff may be an effective gait modification for people with anterior hip pain. PMID:25468661

  18. Effect of increased pushoff during gait on hip joint forces.

    PubMed

    Lewis, Cara L; Garibay, Erin J

    2015-01-02

    Anterior acetabular labral tears and anterior hip pain may result from high anteriorly directed forces from the femur on the acetabulum. While providing more pushoff is known to decrease sagittal plane hip moments, it is unknown if this gait modification also decreases hip joint forces. The purpose of this study was to determine if increasing pushoff decreases hip joint forces. Nine healthy subjects walked on an instrumented force treadmill at 1.25 m/s under two walking conditions. For the natural condition, subjects were instructed to walk as they normally would. For the increased pushoff condition, subjects were instructed to "push more with your foot when you walk". We collected motion data of markers placed on the subjects' trunk and lower extremities to capture trunk and leg kinematics and ground reaction force data to determine joint moments. Data were processed in Visual3D to produce the inverse kinematics and model scaling files. In OpenSim, the generic gait model (Gait2392) was scaled to the subject, and hip joint forces were calculated for the femur on the acetabulum after computing the muscle activations necessary to reproduce the experimental data. The instruction to "push more with your foot when you walk" reduced the maximum hip flexion and extension moment compared to the natural condition. The average reduction in the hip joint forces were 12.5%, 3.2% and 9.6% in the anterior, superior and medial directions respectively and 2.3% for the net resultant force. Increasing pushoff may be an effective gait modification for people with anterior hip pain.

  19. Subluxation of the shoulder joint in stroke patients and the influence of selected factors on the incidence of instability.

    PubMed

    Pop, Teresa

    2013-06-28

    The aim of the study was to evaluate the incidence of shoulder subluxation in stroke patients and the impact of rehabilitation and presence/absence of fluid in the subhumeral and subdeltoid bursae on the occurrence of instability. The study group was composed of 182 patients after stroke, with 108 men and 74 women. 156 of the patients had suffered an ischemic stroke whereas 26 had experienced a hemorrhagic stroke; 90 patients had right-sided paresis and 92 left-sided paresis. The study variables were evaluated by performing, on two occasions, an ultrasound examination of the shoulder and an assessment of upper limb functional capacity using the Brunnström scale. 182 patients of the study group participated in an exercise programme according tothe PNF concept. There was no subluxation of the shoulder on the healthy side, while on the paretic side, subluxation occurred in 25.3% of the patients. Bursal fluid was seen more frequently on the paretic side (12.6%). A statistically significant reduction of the subluxation and bursal fluid was achieved after the rehabilitation. Subluxation occurred more frequently in patients with a known presence of fluid in the bursae and in those with poorer functional capacity of the upper limb. 1. The clinical symptoms of stroke are the cause of subluxation in the shoulder joint. 2. Subluxation occurs more frequently in patients with a known presence of fluid in the subhumeral and subdeltoid bursae and in patients with reduced functional capacity. 3. The reduction of subluxation and bursal fluid was influenced by the exercise program and improved functional capacity.

  20. Joint Force Quarterly. Number 2, Autumn 1993

    DTIC Science & Technology

    1993-09-01

    Pacific (photo by Charles Kerlee cour- tesy of the Naval Historical Center). The front inside cover features ships of the U.S. Navy arriving in Sydney...purposes our pres- ence has political and military consequences. The United States has a clear humanitarian inter- est in preventing geno- cide and...to Somalia under UNOSOM I with the results of the U.S.-led coalition force deployed to Somalia as UNITAF, the Security Council de- cided to empower

  1. Joint Force Quarterly. Number 30, Spring 2002

    DTIC Science & Technology

    2002-05-01

    some leading analysts, including Michael O’Hanlon, Colin Gray, and Paul Van Riper , dispute the existence of a definitive RMA. Van Riper challenges the...sufficient to put our defense orientation, posture, and transformation activities on the right track. — Charles F. Hawkins Historical Evaluation and...Army Transformation Office RETHINKING SO/LIC To the Editor—I read “Special Operations Forces after Kosovo” by Charles J. Dunlap, Jr. (JFQ, Spring

  2. Joint Force Quarterly. Number 18, Spring 1998

    DTIC Science & Technology

    1998-06-01

    server” system. In this architecture, imagery and geospatial data will move from collection through exploitation and distribution (such as magnetic ...than cartographi - cally-displaced symbols. This accuracy will provide the precision required for the future battlespace where forces aided by...tributed in both CD–ROM or 8-mm magnetic tape versions. Planned paths to imagery, imagery intelligence, and geospatial information. Imagery and

  3. A nondestructive, reproducible method of measuring joint reaction force at the distal radioulnar joint.

    PubMed

    Canham, Colin D; Schreck, Michael J; Maqsoodi, Noorullah; Doolittle, Madison; Olles, Mark; Elfar, John C

    2015-06-01

    To develop a nondestructive method of measuring distal radioulnar joint (DRUJ) joint reaction force (JRF) that preserves all periarticular soft tissues and more accurately reflects in vivo conditions. Eight fresh-frozen human cadaveric limbs were obtained. A threaded Steinmann pin was placed in the middle of the lateral side of the distal radius transverse to the DRUJ. A second pin was placed into the middle of the medial side of the distal ulna colinear to the distal radial pin. Specimens were mounted onto a tensile testing machine using a custom fixture. A uniaxial distracting force was applied across the DRUJ while force and displacement were simultaneously measured. Force-displacement curves were generated and a best-fit polynomial was solved to determine JRF. All force-displacement curves demonstrated an initial high slope where relatively large forces were required to distract the joint. This ended with an inflection point followed by a linear area with a low slope, where small increases in force generated larger amounts of distraction. Each sample was measured 3 times and there was high reproducibility between repeated measurements. The average baseline DRUJ JRF was 7.5 N (n = 8). This study describes a reproducible method of measuring DRUJ reaction forces that preserves all periarticular stabilizing structures. This technique of JRF measurement may also be suited for applications in the small joints of the wrist and hand. Changes in JRF can alter native joint mechanics and lead to pathology. Reliable methods of measuring these forces are important for determining how pathology and surgical interventions affect joint biomechanics. Copyright © 2015 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.

  4. Instrumented Bolts Would Measure Shear Forces In Joints

    NASA Technical Reports Server (NTRS)

    Sawyer, James Wayne; Mcwithey, Robert R.

    1994-01-01

    Bolts instrumented with strain gauges used to measure shear forces. Bolts installed in multiple-bolt lap joints to obtain data on distribution of stresses and deformations in and around joints. Strain gauges indicate share of applied load borne by each individual bolt. In original application, bolted panels made of advanced refractory composite materials designed to withstand use at temperatures up to 4,000 degrees F. Also applicable to other joint materials and measurement of shear loads in other connections such as, shear loads on shafts in pulleys or gears.

  5. Instrumented Bolts Would Measure Shear Forces In Joints

    NASA Technical Reports Server (NTRS)

    Sawyer, James Wayne; Mcwithey, Robert R.

    1994-01-01

    Bolts instrumented with strain gauges used to measure shear forces. Bolts installed in multiple-bolt lap joints to obtain data on distribution of stresses and deformations in and around joints. Strain gauges indicate share of applied load borne by each individual bolt. In original application, bolted panels made of advanced refractory composite materials designed to withstand use at temperatures up to 4,000 degrees F. Also applicable to other joint materials and measurement of shear loads in other connections such as, shear loads on shafts in pulleys or gears.

  6. Modifying the shoulder joint position during shrugging and retraction exercises alters the activation of the medial scapular muscles.

    PubMed

    Castelein, Birgit; Cools, Ann; Parlevliet, Thierry; Cagnie, Barbara

    2016-02-01

    In patients with shoulder or neck pain, often an imbalance of the activation in the scapular upward and downward rotators is present which can cause abnormalities in coordinated scapular rotation. Shrug exercises are often recommended to activate muscles that produce upward rotation, but little information is available on the activity of the downward rotators during shrugging exercises. The position used for the shrug exercise may affect the relative participation of the medial scapular rotators. To compare muscle activity, using both surface and fine-wire electrodes, of the medial scapular muscles during different shoulder joint positions while performing shrug and retraction exercises. Controlled laboratory study. Twenty-six subjects performed 3 different exercises: shrug with the arms at the side while holding a weight ("Shrug"), shrug with arms overhead and retraction with arms overhead. EMG data with surface and fine wire electrodes was collected from the Upper Trapezius (UT), Levator Scapulae (LS), Middle Trapezius (MT), Rhomboid Major (RM) and Lower Trapezius (LT). The results showed that activity levels of the main medial scapular muscles depend upon the specific shoulder joint position when performing shrug and retraction exercises. High UT activity was found across all exercises, with no significant differences in UT activity between the exercises. The LS and RM activity was significantly lower during "ShrugOverhead" and the RM, MT and LT activity was significantly higher during "RetractionOverhead". This study has identified that all three exercises elicited similar UT activity. LS and RM activity is decreased with the "ShrugOverhead" exercise. The "RetractionOverhead" was the most effective exercise in activating the medial scapular muscles. Copyright © 2015 Elsevier Ltd. All rights reserved.

  7. In Vivo Evaluation of the Potential of High-Frequency Ultrasound for Arthroscopic Examination of the Shoulder Joint

    PubMed Central

    Puhakka, Jani; Afara, Isaac O.; Paatela, Teemu; Sormaala, Markus J.; Timonen, Matti A.; Virén, Tuomas; Jurvelin, Jukka S.; Töyräs, Juha; Kiviranta, Ilkka

    2015-01-01

    Objective Accurate arthroscopic evaluation of cartilage lesions could significantly improve the outcome of repair surgery. In this study, we investigated for the first time the potential of intra-articular ultrasound as an arthroscopic tool for grading cartilage defects in the human shoulder joint in vivo and compared the outcome to results from arthroscopic evaluation and magnetic resonance imaging findings. Design A total of 26 sites from 9 patients undergoing routine shoulder arthroscopy were quantitatively evaluated with a clinical intravascular (40MHz) ultrasound imaging system, using the regular arthroscopy portals. Reflection coefficient (R), integrated reflection coefficient (IRC), apparent integrated backscattering (AIB), and ultrasound roughness index (URI) were calculated, and high-resolution ultrasound images were obtained per site. Each site was visually graded according to the International Cartilage Repair Society (ICRS) system. “Ultrasound scores” corresponding to the ICRS system were determined from the ultrasound images. Magnetic resonance imaging was conducted and cartilage integrity at each site was classified into 5 grades (0 = normal, 4 = severely abnormal) by a radiologist. Results R and IRC were lower at sites with damaged cartilage surface (P = 0.033 and P = 0.043, respectively) and correlated with arthroscopic ICRS grades (rs = −0.444, P = 0.023 and rs = −0.426, P = 0.03, respectively). Arthroscopic ICRS grades and ultrasound scores were significantly correlated (rs = 0.472, P = 0.015), but no significant correlation was found between magnetic resonance imaging data and other parameters. Conclusion The results suggest that ultrasound arthroscopy could facilitate quantitative clinical appraisal of articular cartilage integrity in the shoulder joint and provide information on cartilage lesion depth and severity for quantitative diagnostics in surgery. PMID:27375840

  8. Does surgery for instability of the shoulder truly stabilize the glenohumeral joint?

    PubMed Central

    Lädermann, Alexandre; Denard, Patrick J.; Tirefort, Jérôme; Kolo, Frank C.; Chagué, Sylvain; Cunningham, Grégory; Charbonnier, Caecilia

    2016-01-01

    Abstract Despite the fact that surgery is commonly used to treat glenohumeral instability, there is no evidence that such treatment effectively corrects glenohumeral translation. The purpose of this prospective clinical study was to analyze the effect of surgical stabilization on glenohumeral translation. Glenohumeral translation was assessed in 11 patients preoperatively and 1 year postoperatively following surgical stabilization for anterior shoulder instability. Translation was measured using optical motion capture and computed tomography. Preoperatively, anterior translation of the affected shoulder was bigger in comparison to the normal contralateral side. Differences were significant for flexion and abduction movements (P < 0.001). Postoperatively, no patients demonstrated apprehension and all functional scores were improved. Despite absence of apprehension, postoperative anterior translation for the surgically stabilized shoulders was not significantly different from the preoperative values. While surgical treatment for anterior instability limits the chance of dislocation, it does not seem to restore glenohumeral translation during functional range of motion. Such persistent microinstability may explain residual pain, apprehension, inability to return to activity and even emergence of dislocation arthropathy that is seen in some patients. Further research is necessary to better understand the causes, effects, and treatment of residual microinstability following surgical stabilization of the shoulder. PMID:27495043

  9. Standing Joint Forces: Spearhead for Global Operational Maneuver

    DTIC Science & Technology

    2005-05-26

    Base 5, then directly to Central Intelligence Agency (CIA) Headquarters in Washington. Concurrent with the JTF mission , follow-on forces were...If America needs to spend a little more to accomplish its dual military missions - policing its virtual "empire" and deterring major-power...and under-equipped Pacific forces accomplished their mission through courage, ingenuity, and a reliance on joint/combined operations. While

  10. Knee joint forces during downhill walking with hiking poles.

    PubMed

    Schwameder, H; Roithner, R; Müller, E; Niessen, W; Raschner, C

    1999-12-01

    The aim of this study was to determine external and internal loads on the knee joint during downhill walking with and without hiking poles. Kinematic, kinetic and electromyographic data were collected from eight males during downhill walking on a ramp declined at 25 degrees. Planar knee joint moments and forces were calculated using a quasi-static knee model. The results were analysed for an entire pole-cycle as well as differentiated between single and double support phases and between each step of a pole-cycle. Significant differences between downhill walking with and without hiking poles were observed for peak and average magnitudes of ground reaction force, knee joint moment, and tibiofemoral compressive and shear forces (12-25%). Similar reductions were found in patellofemoral compressive force, the quadriceps tendon force and the activity of the vastus lateralis; however, because of a high variability, these differences were not significant. The reductions seen during downhill walking with hiking poles compared with unsupported downhill walking were caused primarily by the forces applied to the hiking poles and by a change in posture to a more forward leaning position of the upper body, with the effect of reducing the knee moment arm.

  11. A New Vector for Air Force Development of Joint Leaders

    DTIC Science & Technology

    2010-05-26

    HAROLD R . WINTON (Date) _______________________________________________ STEPHEN E. WRIGHT...2 Multiples sources, including: 1. Julian E. Barnes and Peter Spiegel , “Air Force’s Top Leaders Ousted,” Los Angeles Times, 6 June 2008...von Clausewitz, John Frederick Charles Fuller, Martin van Creveld, and James R Locher; essays from Joint Forces Quarterly (JFQ); and numerous

  12. Joint Force Interdependence for a Fiscally Constrained Future

    DTIC Science & Technology

    2013-03-01

    Army 5d. PROJECT NUMBER 5e. TASK NUMBER 5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) Dr. Richard Meinhart ...Joint Force Interdependence For A Fiscally Constrained Future by Colonel Daniel P. Ray United States Army ...United States Army War College Class of 2013 DISTRIBUTION STATEMENT: A Approved for Public Release Distribution is Unlimited

  13. Shoulder function, pain and health related quality of life in adults with joint hypermobility syndrome/Ehlers-Danlos syndrome-hypermobility type.

    PubMed

    Johannessen, Elise Christine; Reiten, Helle Sundnes; Løvaas, Helene; Maeland, Silje; Juul-Kristensen, Birgit

    2016-07-01

    Purpose To investigate shoulder function, pain and Health-Related Quality of life (HRQoL) among adults with joint hypermobility syndrome/Ehlers-Danlos syndrome-hypermobility type (JHS/EDS-HT), compared with the general population (controls). Method In a cross-sectional study using postal survey, 110 patients diagnosed with JHS/EDS-HT and 140 gender- and age-matched healthy controls from Statistics Norway participated. Shoulder function, pain and HRQol were registered by Western Ontario Shoulder Instability Index (WOSI), Numerical Rating Scale (NRS), pain drawings, 36-item Short Form (SF-36). Results Eighty-one individuals responded, with response rate 34% (JHS/EDS-HT: 53%, controls: 21%). JHS/EDS-HT had lower shoulder function (WOSI total: 49.9 versus 83.3; p < 0.001), lower HRQol on SF-36 Physical Component Scale (PCS: 28.1 versus 49.9; p < 0.001), and higher pain intensity (NRS: 6.4 versus 2.7; p < 0.001) than controls. Neck and shoulder joints were rated as primary painful areas in both groups, with significantly higher frequency in JHS/EDS-HT (neck: 90% versus 27%; shoulder: 80% versus 37%). Further, JHS/EDS-HT most often reported generalized pain (96%). Conclusions Adults with JHS/EDS-HT have impaired shoulder function, increased pain intensity, as well as reduced physical HRQoL compared with controls. Although neck and shoulder were most frequently rated as painful, significantly more JHS/EDS-HT also reported generalized pain compared to controls. Implications for Rehabilitation Adults with JHS/EDS-HT have impaired shoulder function, and most often painful areas in the neck and shoulder joints, which need to be targeted in the treatment strategy. Compared with the general population adults with JHS/EDS-HT have reduced physical HRQoL, supporting a physical approach for this group. Adults with JHS/EDS-HT may present with both specific painful joints and generalized pain.

  14. The effects of shoulder joint abduction angles on the muscle activity of the serratus anterior muscle and the upper trapezius muscle while vibrations are applied.

    PubMed

    Jung, Da-Eun; Moon, Dong-Chul

    2015-01-01

    [Purpose] The purpose of this study was to examine the ratio between the upper trapezius and the serratus anterior muscles during diverse shoulder abduction exercises applied with vibrations in order to determine the appropriate exercise methods for recovery of scapular muscle balance. [Subjects and Methods] Twenty-four subjects voluntarily participated in this study. The subjects performed shoulder abduction at various shoulder joint abduction angles (90°, 120°, 150°, 180°) with oscillation movements. [Results] At 120°, all the subjects showed significant increases in the muscle activity of the serratus anterior muscle in comparison with the upper trapezius muscle. However, no significant difference was found at angles other than 120°. [Conclusion] To selectively strengthen the serratus anterior, applying vibration stimuli at the 120° shoulder abduction position is considered to be appropriate.

  15. The influence of soft tissue movement on ground reaction forces, joint torques and joint reaction forces in drop landings.

    PubMed

    Pain, Matthew T G; Challis, John H

    2006-01-01

    The aim of this study was to determine the effects that soft tissue motion has on ground reaction forces, joint torques and joint reaction forces in drop landings. To this end a four body-segment wobbling mass model was developed to reproduce the vertical ground reaction force curve for the first 100 ms of landing. Particular attention was paid to the passive impact phase, while selecting most model parameters a priori, thus permitting examination of the rigid body assumption on system kinetics. A two-dimensional wobbling mass model was developed in DADS (version 9.00, CADSI) to simulate landing from a drop of 43 cm. Subject-specific inertia parameters were calculated for both the rigid links and the wobbling masses. The magnitude and frequency response of the soft tissue of the subject to impulsive loading was measured and used as a criterion for assessing the wobbling mass motion. The model successfully reproduced the vertical ground reaction force for the first 100 ms of the landing with a peak vertical ground reaction force error of 1.2% and root mean square errors of 5% for the first 15 ms and 12% for the first 40 ms. The resultant joint forces and torques were lower for the wobbling mass model compared with a rigid body model, up to nearly 50% lower, indicating the important contribution of the wobbling masses on reducing system loading.

  16. An age- and gender-related three-dimensional analysis of rotator cuff transverse force couple volume ratio in 304 shoulders.

    PubMed

    Espinosa-Uribe, Abraham Guadalupe; Negreros-Osuna, Adrian Antonio; Gutierréz-de la O, Jorge; Vílchez-Cavazos, Félix; Pinales-Razo, Ricardo; Quiroga-Garza, Alejandro; Elizondo-Riojas, Guillermo; Elizondo-Omaña, Rodrigo Enrique; Guzmán-López, Santos

    2017-02-01

    The rotator cuff transverse force couple (RCTFC) is fundamental in the shoulder biomechanics, as the balance of its muscle components (the subscapularis relative to the infraspinatus and teres minor) provides stability to the joint. The chronic progression of rotator cuff tears usually present alterations in muscle volume, along with atrophy and compensatory hypertrophy, which can be determined using imaging techniques. The aim of this study was to quantify RCTFC muscle volume in a large sample taking into account the age and gender of the participants involved. An observational, retrospective, cross-sectional, descriptive and comparative study was conducted, evaluating thoracic computed tomography scans from 152 patients (304 shoulders) of indistinct gender, with ages ranging between 18 and 85 years. The RCTFC muscle volume was quantified with an oblique/multiplanar segmentation technique. Measuring time was also documented. We observed that muscle volume decreases among the different age (p < 0.04) and gender (p < 0.001) groups. However, the RCTFC volume ratio remained constant at 1.02 ± 0.18 without significant differences throughout all age and gender groups evaluated (p > 0.298). The decrease in the RCTFC muscle volume is proportional during the different stages of life, maintaining a constant ratio between its components (physiological RCTFC muscle atrophy). The time-saving segmentation method and volume ratio formula proposed in this study contribute to the management and understanding of rotator cuff tear/pathology.

  17. Using the American alligator and a repeated-measures design to place constraints on in vivo shoulder joint range of motion in dinosaurs and other fossil archosaurs.

    PubMed

    Hutson, Joel D; Hutson, Kelda N

    2013-01-15

    Using the extant phylogenetic bracket of dinosaurs (crocodylians and birds), recent work has reported that elbow joint range of motion (ROM) studies of fossil dinosaur forearms may be providing conservative underestimates of fully fleshed in vivo ROM. As humeral ROM occupies a more central role in forelimb movements, the placement of quantitative constraints on shoulder joint ROM could improve fossil reconstructions. Here, we investigated whether soft tissues affect the more mobile shoulder joint in the same manner in which they affect elbow joint ROM in an extant archosaur. This test involved separately and repeatedly measuring humeral ROM in Alligator mississippiensis as soft tissues were dissected away in stages to bare bone. Our data show that the ROMs of humeral flexion and extension, as well as abduction and adduction, both show a statistically significant increase as flesh is removed, but then decrease when the bones must be physically articulated and moved until they separate from one another and/or visible joint surfaces. A similar ROM pattern is inferred for humeral pronation and supination. All final skeletonized ROMs were less than initial fully fleshed ROMs. These results are consistent with previously reported elbow joint ROM patterns from the extant phylogenetic bracket of dinosaurs. Thus, studies that avoid separation of complementary articular surfaces may be providing fossil shoulder joint ROMs that underestimate in vivo ROM in dinosaurs, as well as other fossil archosaurs.

  18. Intrarater reliabilities of shoulder joint horizontal adductor muscle strength measurements using a handheld dynamometer for geriatric and stroke patients.

    PubMed

    Hirano, Masahiro; Katoh, Munenori; Kawaguchi, Saori; Uemura, Tomomi

    2016-01-01

    [Purpose] This study aimed to verify the appropriate number of measurements and the intrarater reliabilities of shoulder joint horizontal adductor muscle strength measurements using a handheld dynamometer (HHD) for geriatric and stroke patients. [Subjects and Methods] The subjects were 40 inpatients, who were divided into two groups: 20 stroke patients in the stroke group (SG), and 20 geriatric patients in the no-stroke group (N-SG). Measurements were performed three times using an HHD with a belt. The reliability was verified using Bland-Altman analysis and the intraclass correlation coefficient (ICC). [Results] ICC (1, 1) was >0.9. A systematic bias was not observed between the first and second measurement values except for the right side in N-SG. A systematic bias between the maximum value obtained during the first and second measurements and third measurement value was observed on the left side in N-SG, and on the non-paralyzed side in SG: the third measurement values were small in both cases. [Conclusion] Intrarater reliabilities were high for shoulder horizontal adductor strength measurements using an HHD with a belt for geriatric and stroke patients. Taking the systematic bias into consideration, these findings suggest that the required number of measurements is two.

  19. Putting the shoulder to the wheel: a new biomechanical model for the shoulder girdle.

    PubMed

    Levin, S M

    1997-01-01

    The least successfully modeled joint complex has been the shoulder. In multi-segmented mathematical shoulder models rigid beams (the bones) act as a series of columns or levers to transmit forces or loads to the axial skeleton. Forces passing through the almost frictionless joints must, somehow, always be directed perfectly perpendicular to the joints as only loads directed at right angles to the surfaces could transfer across frictionless joints. Loads transmitted to the axial skeleton would have to pass through the moving ribs or the weak jointed clavicle and then through the ribs. A new model of the shoulder girdle, based on the tension icosahedron described by Buckminster Fuller, is proposed that permits the compression loads passing through the arm and shoulder to be transferred to the axial skeleton through its soft tissues. In this model the scapula 'floats' in the tension network of shoulder girdle muscles just as the hub of the wire wheel is suspended in its tension network of spokes. With this construct inefficient beams and levers are eliminated. A more energy efficient, load distributing, integrated, hierarchical system is created.

  20. Relaxin Receptor RXFP1 and RXFP2 Expression in Ligament, Tendon, and Shoulder Joint Capsule of Rats

    PubMed Central

    2016-01-01

    Numerous musculoskeletal disorders are caused by thickened ligament, tendon stiffness, or fibrosis of joint capsule. Relaxin, a peptide hormone, can exert collagenolytic effect on ligamentous and fibrotic tissues. We hypothesized that local injection of relaxin could be used to treat entrapment neuropathy and adhesive capsulitis. Because hormonal effect depends on the receptor of the hormone on the target cell, it is important to confirm the presence of such hormonal receptor at the target tissue before the hormone therapy is initiated. The aim of this study was to determine whether there were relaxin receptors in the ligament, tendon, and joint capsular tissues of rats and to identify the distribution of relaxin receptors in these tissues. Transverse carpal ligaments (TCLs), inguinal ligaments, anterior cruciate ligaments (ACLs), Achilles tendons, and shoulder joint capsules were obtained from male Wistar rats. Western blot analysis was used to identify relaxin receptor isoforms RXFP1 and RXFP2. The distribution of relaxin receptors was determined by immunohistochemical staining. The RXFP1 isoform was found in all tissues examined. The RXFP2 isoform was present in all tissues but the TCLs. Its expression in ACLs tissues was relatively weak compared to that in other tissues. Our results revealed that RXFP1 and RXFP2 were distributed in distinctly different patterns according to the type of tissue (vascular endothelial cells, fibroblast-like cells) they were identified. PMID:27247510

  1. The effects of prosthetic humeral head shape on glenohumeral joint kinematics during humeral axial rotation in total shoulder arthroplasty.

    PubMed

    Jun, Bong Jae; Lee, Thay Q; McGarry, Michelle H; Quigley, Ryan J; Shin, Sang Jin; Iannotti, Joseph P

    2016-07-01

    A non-spherical humeral head has been shown to influence kinematics and stability of the glenohumeral joint; yet, most prosthetic humeral head components are designed to be a perfect sphere. The effect of humeral head shape on prosthetic joint kinematics after total shoulder arthroplasty is not well understood. We hypothesized that prosthetic joint kinematics during humeral axial rotation is dependent on humeral head shape, regardless of joint conformity. Four prosthetic configurations were investigated using a spherical and a non-spherical prosthetic humeral head articulated with a conforming and a non-conforming glenoid component. Testing was performed in the coronal, scapular, and forward flexion plane at 0°, 30°, and 60° of abduction. Prosthetic joint kinematics was measured in 10° intervals during a 100° arc of humeral axial rotation. Glenohumeral translation patterns, net glenohumeral translation, and averaged glenohumeral translation were compared for each of 4 configurations. Non-spherical head configurations increased the net glenohumeral translation during humeral axial rotation in multiple test positions compared with spherical head configurations (P < .05). Spherical head configurations resulted in a relatively small amount of glenohumeral translation, less than 2 mm. The radius of curvature of the glenoid component alone did not affect the net glenohumeral translation within each of the 2 head groups (P > .05). During humeral axial rotation, the non-spherical humeral head shape contributes to increased glenohumeral translation during humeral axial rotation. However, the spherical head shape does not show significant glenohumeral translation during humeral axial rotation, regardless of glenoid conformity. Copyright © 2016. Published by Elsevier Inc.

  2. The influence of patellofemoral joint contact geometry on the modeling of three dimensional patellofemoral joint forces.

    PubMed

    Powers, Christopher M; Chen, Yu-Jen; Scher, Irving; Lee, Thay Q

    2006-01-01

    The purpose of this study was to determine the influence of patellofemoral joint contact geometry on the modeling of three-dimensional patellofemoral joint forces. To achieve this goal, patellofemoral joint reaction forces (PFJRFs) that were measured from an in-vitro cadaveric set-up were compared to PFJRFs estimated from a computer model that did not consider patellofemoral joint contact geometry. Ten cadaver knees were used in this study. Each was mounted on a custom jig that was fixed to an Instron frame. Quadriceps muscle loads were accomplished using a pulley system and weights. The force in the patellar ligament was obtained using a buckle transducer. To quantify the magnitude and direction of the PFJRF, a six-axis load cell was incorporated into the femoral fixation system so that a rigid body assumption could be made. PFJRF data were obtained at 0 degrees , 20 degrees , 40 degrees and 60 degrees of knee flexion. Following in vitro testing, SIMM modeling software was used to develop computational models based on the three-dimensional coordinates (Microscribe digitizer) of individual muscle and patellar ligament force vectors obtained from the cadaver knees. The overall magnitude of the PFJRF estimated from the computer generated models closely matched the direct measurements from the in vitro set-up (Pearson's correlation coefficient, R(2)=0.91, p<0.001). Although the computational model accurately estimated the posteriorly directed forces acting on the joint, some discrepancies were noted in the forces acting in the superior and lateral directions. These differences however, were relatively small when expressed as a total of the overall PFJRF magnitude.

  3. Quantifying plyometric intensity via rate of force development, knee joint, and ground reaction forces.

    PubMed

    Jensen, Randall L; Ebben, William P

    2007-08-01

    Because the intensity of plyometric exercises usually is based simply upon anecdotal recommendations rather than empirical evidence, this study sought to quantify a variety of these exercises based on forces placed upon the knee. Six National Collegiate Athletic Association Division I athletes who routinely trained with plyometric exercises performed depth jumps from 46 and 61 cm, a pike jump, tuck jump, single-leg jump, countermovement jump, squat jump, and a squat jump holding dumbbells equal to 30% of 1 repetition maximum (RM). Ground reaction forces obtained via an AMTI force plate and video analysis of markers placed on the left hip, knee, lateral malleolus, and fifth metatarsal were used to estimate rate of eccentric force development (E-RFD), peak ground reaction forces (GRF), ground reaction forces relative to body weight (GRF/BW), knee joint reaction forces (K-JRF), and knee joint reaction forces relative to body weight (K-JRF/BW) for each plyometric exercise. One-way repeated measures analysis of variance indicated that E-RFD, K-JRF, and K-JRF/BW were different across the conditions (p < 0.05), but peak GRF and GRF/BW were not (p > 0.05). Results indicate that there are quantitative differences between plyometric exercises in the rate of force development during landing and the forces placed on the knee, though peak GRF forces associated with landing may not differ.

  4. Joint Command and Control of Cyber Operations: The Joint Force Cyber Component Command (JFCCC)

    DTIC Science & Technology

    2012-05-04

    relies so heavily on complex command and control systems and interconnectivity in general, cyber warfare has become a serious topic of interest at the...defensive cyber warfare into current and future operations and plans. In particular, Joint Task Force (JTF) Commanders must develop an optimum method to

  5. Forced-Air Warming Discontinued: Periprosthetic Joint Infection Rates Drop.

    PubMed

    Augustine, Scott D

    2017-06-23

    Several studies have shown that the waste heat from forced-air warming (FAW) escapes near the floor and warms the contaminated air resident near the floor. The waste heat then forms into convection currents that rise up and contaminate the sterile field above the surgical table. It has been shown that a single airborne bacterium can cause a periprosthetic joint infection (PJI) following joint replacement surgery. We retrospectively compared PJI rates during a period of FAW to a period of air-free conductive fabric electric warming (CFW) at three hospitals. Surgical and antibiotic protocols were held constant. The pooled multicenter data showed a decreased PJI rate of 78% following the discontinuation of FAW and a switch to air-free CFW (n=2034; P=0.002). The 78% reduction in joint implant infections observed when FAW was discontinued suggests that there is a link between the waste FAW heat and PJIs.

  6. Shoulder injuries from attacking motion

    NASA Astrophysics Data System (ADS)

    Yanagi, Shigeru; Nishimura, Tetsu; Itoh, Masaru; Wada, Yuhei; Watanabe, Naoki

    1997-03-01

    Sports injuries have bothered professional players. Although many medical doctors try to treat injured players, to prevent sports injuries is more important. Hence, it is required to clear a kinematic mechanism of the sport injuries. A shoulder of volleyball attacker or baseball pitcher is often inured by playing motion. The injuries are mainly caused at the end of long head tendon, which is located in the upper side of scapula. Generally, a muscle and tendon have enough strength against tensile force, however, it seems that they are sometimes defeated by the lateral force. It is imagined that the effect of the lateral force has a possibility of injuring the tendon. If we find the influence of the lateral force on the injured portion, the mechanism of injuries must be cleared. In our research, volleyball attacking motion is taken by high speed video cameras. We analyze the motion as links system and obtain an acceleration of an arm and a shoulder from video image data. The generated force at a shoulder joint is calculated and resolved into the lateral and longitudinal forces. Our final goal is to discuss a possibility that the lateral force causes the injuries.

  7. Effect of core muscle thickness and static or dynamic balance on prone bridge exercise with sling by shoulder joint angle in healthy adults.

    PubMed

    Park, Mi Hwa; Yu, Jae Ho; Hong, Ji Heon; Kim, Jin Seop; Jung, Sang Woo; Lee, Dong Yeop

    2016-03-01

    [Purpose] To date, core muscle activity detected using ultrasonography during prone bridge exercises has not been reported. Here we investigated the effects of core muscle thickness and balance on sling exercise efficacy by shoulder joint angle in healthy individuals. [Subjects and Methods] Forty-three healthy university students were enrolled in this study. Ultrasonography thickness of external oblique, internal oblique, and transversus abdominis during sling workouts was investigated. Muscle thickness was measured on ultrasonography imaging before and after the experiment. Dynamic balance was tested using a functional reaching test. Static balance was tested using a Tetrax Interactive Balance System. [Results] Different muscle thicknesses were observed during the prone bridge exercise with the shoulder flexed at 60°, 90° or 120°. Shoulder flexion at 60° and 90° in the prone bridge exercise with a sling generated the greatest thickness of most transversus abdominis muscles. Shoulder flexion at 120° in the prone bridge exercise with a sling generated the greatest thickness of most external oblique muscles. [Conclusion] The results suggest that the prone bridge exercise with shoulder joint angle is an effective method of increasing global and local muscle strength.

  8. Effect of core muscle thickness and static or dynamic balance on prone bridge exercise with sling by shoulder joint angle in healthy adults

    PubMed Central

    Park, Mi Hwa; Yu, Jae Ho; Hong, Ji Heon; Kim, Jin Seop; Jung, Sang Woo; Lee, Dong Yeop

    2016-01-01

    [Purpose] To date, core muscle activity detected using ultrasonography during prone bridge exercises has not been reported. Here we investigated the effects of core muscle thickness and balance on sling exercise efficacy by shoulder joint angle in healthy individuals. [Subjects and Methods] Forty-three healthy university students were enrolled in this study. Ultrasonography thickness of external oblique, internal oblique, and transversus abdominis during sling workouts was investigated. Muscle thickness was measured on ultrasonography imaging before and after the experiment. Dynamic balance was tested using a functional reaching test. Static balance was tested using a Tetrax Interactive Balance System. [Results] Different muscle thicknesses were observed during the prone bridge exercise with the shoulder flexed at 60°, 90° or 120°. Shoulder flexion at 60° and 90° in the prone bridge exercise with a sling generated the greatest thickness of most transversus abdominis muscles. Shoulder flexion at 120° in the prone bridge exercise with a sling generated the greatest thickness of most external oblique muscles. [Conclusion] The results suggest that the prone bridge exercise with shoulder joint angle is an effective method of increasing global and local muscle strength. PMID:27134390

  9. Joint Force Quarterly. Issue 76, 1st Quarter 2015

    DTIC Science & Technology

    2015-01-01

    rather than “coercing” them with grades, tests , and onerous reading lists. The net effect is an educational experience that, while impressive in...Fridman is a Ph.D. Candidate at the University of Reading , United Kingdom. Soldier aims XM-25 weapon system, Aberdeen Test Center, Maryland (U.S...the Editor: As I read Rebecca Patterson and Jodi Vittori’s article titled “Why Military Offi- cers Should Study Political Economy” in Joint Force

  10. Joint Force Quarterly. Issue 63, 4th Quarter 2011

    DTIC Science & Technology

    2011-10-01

    is quoted from or based on its content. COMMUNICATIONS Please visit NDU Press and Joint Force Quarterly online at ndupress.ndu.edu for more on...His final arguments are directed at the noncommissioned officer (NCO) corps (not petty officers), so I would like to know if his data are based ...on his experiences across the Services, or mainly based on his observations and study within his own branch. Though observant of and an occasional

  11. Joint Force Quarterly. Issue 56, 1st Quarter, January 2010

    DTIC Science & Technology

    2010-01-01

    between single - and double-loop learning.17 The contrast pertains to knowledge about improving what one is already doing based on a given set of...how they should be developed, and why many recent attempts at theories are really shallow approaches based on a single governing idea, ignor...Quarterly should be acknowledged whenever material is quoted from or based on its content. COMMUNICATIONS Please visit NDU Press and Joint Force Quarterly

  12. Integration of Special Operations Forces into the Joint Targeting Process

    DTIC Science & Technology

    2003-01-01

    INTEGRATION OF SPECIAL OPERATIONS FORCES INTO THE JOINT TARGETING PROCESS A thesis presented to the Faculty of the U. S . Army Command and General...B. S ., Texas A&M University, College Station, Texas, 1991 Fort Leavenworth, Kansas 2003 Approved for public release; distribution is unlimited...CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR( S ) Hester, Johnny, L 5d. PROJECT NUMBER 5e. TASK NUMBER 5f. WORK UNIT NUMBER 7

  13. Expanding the MEU(SOC) Joint Task Force Enabler Concept

    DTIC Science & Technology

    1998-05-28

    concept. 2 The influential twentieth-century linguistic philosopher Ludwig Wittgenstein argued that real understanding rests on the precise use...of language and universally agreed upon meanings. Without clarity and common understanding, Wittgenstein observed, we can never really communicate... Wittgenstein anticipated when we don’t share a common understanding of what a term means. The Joint Task Force Enabler is potentially a critical concept, both

  14. Shoulder electromyography in multidirectional instability.

    PubMed

    Morris, Alfred D; Kemp, Graham J; Frostick, Simon P

    2004-01-01

    We studied shoulder muscle activity in multidirectional instability (MDI) and multidirectional laxity (MDL) of the shoulder, our hypothesis being that altered muscle activity plays a role in their pathogenesis. Six muscles (supraspinatus, infraspinatus, subscapularis, anterior deltoid, middle deltoid, and posterior deltoid) were investigated by use of intramuscular dual fine-wire electrodes in 7 normal shoulders, 5 MDL shoulders, and 6 MDI shoulders. Each subject performed 5 types of exercise (rotation in neutral, 45 degrees of abduction, 90 degrees of abduction, flexion/extension, and abduction/adduction) on an isokinetic muscle dynamometer at two rates, 90 degrees /s and 180 degrees /s. After filtering, rectification, and smoothing, the electromyography signal was normalized by using the peak voltage of the movement cycle. In subjects with MDI, compared with normal subjects, activity patterns of the anterior deltoid were different during rotation in neutral and 90 degrees of abduction, whereas those of the middle and posterior deltoid were different during rotation in 90 degrees of abduction. In subjects with MDL, the posterior deltoid showed increased activity compared with normal subjects during adduction. Activity patterns of the supraspinatus, infraspinatus, and subscapularis appeared similar in both groups. Dual fine-wire electromyography offers insight into the complex role of shoulder girdle muscle function in normal movement and in instability. Altered patterns of shoulder girdle muscle activity and imbalances in muscle forces support the theory that impaired coordination of shoulder girdle muscle activity and inefficiency of the dynamic stabilizers of the glenohumeral joint are involved in the etiology of MDI. Interestingly, the abnormalities are in the deltoid rather than the muscles of the rotator cuff.

  15. Impairment-Based 3-D Robotic Intervention Improves Upper Extremity Work Area in Chronic Stroke: Targeting Abnormal Joint Torque Coupling With Progressive Shoulder Abduction Loading

    PubMed Central

    Ellis, Michael D.; Sukal-Moulton, Theresa M.; Dewald, Julius P. A.

    2010-01-01

    The implementation of a robotic system (ACT3D) that allowed for a quantitative measurement of abnormal joint torque coupling in chronic stroke survivors and, most importantly, a quantitative means of initiating and progressing an impairment-based intervention, is described. Individuals with chronic moderate to severe stroke (n = 8) participated in this single-group pretest-posttest design study. Subjects were trained over eight weeks by progressively increasing the level of shoulder abduction loading experienced by the participant during reaching repetitions as performance improved. Reaching work area was evaluated pre- and postintervention for ten different shoulder abduction loading levels along with isometric single-joint strength and a qualitative clinical assessment of impairment. There was a significant effect of session (pre versus post) with an increase in reaching work area, despite no change in single-joint strength. This data suggests that specifically targeting the abnormal joint torque coupling impairment through progressive shoulder abduction loading is an effective strategy for improving reaching work area following hemiparetic stroke. Application of robotics, namely, the ACT3D, allowed for quantitative control of the exercise parameters needed to directly target the synergistic coupling impairment. The targeted reduction of abnormal joint torque coupling is likely the key factor explaining the improvements in reaching range of motion achieved with this intervention. PMID:20657711

  16. Influence of joint models on lower-limb musculo-tendon forces and three-dimensional joint reaction forces during gait.

    PubMed

    Dumas, Raphaël; Moissenet, Florent; Gasparutto, Xavier; Cheze, Laurence

    2012-02-01

    Several three-dimensional (3D) lower-limb musculo-skeletal models have been developed for gait analysis and different hip, knee and ankle joint models have been considered in the literature. Conversely to the influence of the musculo-tendon geometry, the influence of the joint models--i.e. number of degrees of freedom and passive joint moments--on the estimated musculo-tendon forces and 3D joint reaction forces has not been extensively examined. In this paper musculo-tendon forces and 3D joint reaction forces have been estimated for one subject and one gait cycle with nine variations of a musculoskeletal model and outputs have been compared to measured electromyographic signals and knee joint contact forces. The model outputs are generally in line with the measured signals. However, the 3D joint reaction forces were higher than published values and the contact forces measured for the subject. The results of this study show that, with more degrees of freedom in the model, the musculo-tendon forces and the 3D joint reaction forces tend to increase but with some redistribution between the muscles. In addition, when taking into account passive joint moments, the 3D joint reaction forces tend to decrease during the stance phase and increase during the swing phase. Although further investigations are needed, a five-degree-of-freedom lower-limb musculo-skeletal model with some angle-dependent joint coupling and stiffness seems to provide satisfactory musculo-tendon forces and 3D joint reaction forces.

  17. Differences Regarding Branded HA in Italy, Part 2: Data from Clinical Studies on Knee, Hip, Shoulder, Ankle, Temporomandibular Joint, Vertebral Facets, and Carpometacarpal Joint

    PubMed Central

    Migliore, A.; Bizzi, E.; De Lucia, O.; Delle Sedie, A.; Tropea, S.; Bentivegna, M.; Mahmoud, A.; Foti, C.

    2016-01-01

    OBJECTIVES The aim of the current study is to collect scientific data on all branded hyaluronic acid (HA) products in Italy that are in use for intra-articular (IA) injection in osteoarthritis (OA) compared with that reported in the leaflet. METHODS An extensive literature research was performed for all articles reporting data on the IA use of HA in OA. Selected studies were taken into consideration only if they are related to products based on HAs that are currently marketed in Italy with the specific joint indication for IA use in patients affected by OA. RESULTS Sixty-two HA products are marketed in Italy: 30 products are indicated for the knee but only 8 were proved with some efficacy; 9 products were effective for the hip but only 6 had hip indication; 7 products proved to be effective for the shoulder but only 3 had the indication; 5 products proved effective for the ankle but only one had the indication; 6 products were effective for the temporomandibular joint but only 2 had the indication; only 2 proved effective for vertebral facet joints but only 1 had the indication; and 5 products proved effective for the carpometacarpal joint but only 2 had the indication. CONCLUSIONS There are only a few products with some evidences, while the majority of products remain without proof. Clinicians and regulators should request postmarketing studies from pharmaceuticals to corroborate with that reported in the leaflet and to gather more data, allowing the clinicians to choose the adequate product for the patient. PMID:27279754

  18. Shoulder Osteoarthritis

    PubMed Central

    2013-01-01

    Osteoarthritis (OA) is the most frequent cause of disability in the USA, affecting up to 32.8% of patients over the age of sixty. Treatment of shoulder OA is often controversial and includes both nonoperative and surgical modalities. Nonoperative modalities should be utilized before operative treatment is considered, particularly for patients with mild-to-moderate OA or when pain and functional limitations are modest despite more advanced radiographic changes. If conservative options fail, surgical treatment should be considered. Although different surgical procedures are available, as in other joints affected by severe OA, the most effective treatment is joint arthroplasty. The aim of this work is to give an overview of the currently available treatments of shoulder OA. PMID:23365745

  19. [Orthopedic treatment of the shoulder joint impairment in patients with rheumatoid arthritis].

    PubMed

    Herasymenko, S I; Babko, A M; Poluliakh, M V; Huzhevs'kyĭ, I V; Herasymenko, A S

    2014-12-01

    Brachial joint affection in patients, suffering rheumatoid arthritis, occupies a third place after such of the elbow and the hand. Due to significant reduction of a freedom degree, caused by inflammation, the upper extremity looses function of active instrument for the items transposition. Volume of surgical treatment of such patients depends on stage of the process. On early stages arthroscopic synovectomy of brachial joint is performed and on the late--endoprosthesis. Late results of the treatment are mainly positive. Satisfactory results are based, predominantly, on raising of activity of general rheumatoid inflammation.

  20. Passive Joint Forces Are Tuned to Limb Use in Insects and Drive Movements without Motor Activity

    PubMed Central

    Ache, Jan M.; Matheson, Thomas

    2013-01-01

    Summary Background Limb movements are generally driven by active muscular contractions working with and against passive forces arising in muscles and other structures. In relatively heavy limbs, the effects of gravity and inertia predominate, whereas in lighter limbs, passive forces intrinsic to the limb are of greater consequence. The roles of passive forces generated by muscles and tendons are well understood, but there has been little recognition that forces originating within joints themselves may also be important, and less still that these joint forces may be adapted through evolution to complement active muscle forces acting at the same joint. Results We examined the roles of passive joint forces in insect legs with different arrangements of antagonist muscles. We first show that passive forces modify actively generated movements of a joint across its working range, and that they can be sufficiently strong to generate completely passive movements that are faster than active movements observed in natural behaviors. We further demonstrate that some of these forces originate within the joint itself. In legs of different species adapted to different uses (walking, jumping), these passive joint forces complement the balance of strength of the antagonist muscles acting on the joint. We show that passive joint forces are stronger where they assist the weaker of two antagonist muscles. Conclusions In limbs where the dictates of a key behavior produce asymmetry in muscle forces, passive joint forces can be coadapted to provide the balance needed for the effective generation of other behaviors. PMID:23871240

  1. Shoulder arthroplasty for chondrolysis.

    PubMed

    Schoch, Bradley; Werthel, Jean-David; Cofield, Robert; Sanchez-Sotelo, Joaquin; Sperling, John W

    2016-09-01

    Chondrolysis is a rare complication after shoulder arthroscopy leading to early joint destruction. Shoulder arthroplasty may be considered for end-stage chondrolysis, but concerns exist about implant survivorship, given the younger age of this population. This study aimed to assess pain relief, function, and survivorship of shoulder arthroplasty for chondrolysis and to assess risk factors for failure. Between January 2000 and January 2013, 26 consecutive shoulders with chondrolysis were treated at our institution with shoulder arthroplasty. All shoulders had a prior arthroscopic procedure that predated a phase of rapid joint destruction. Twenty-three shoulders were followed up for a minimum of 2 years or until reoperation (mean, 4.0 years; range, 0.7-8.6 years). The mean age of the patients was 40 years (range, 21-58 years). Outcome measures included pain, range of motion, postoperative modified Neer ratings, American Shoulder and Elbow Surgeons scores, complications, and reoperations. At most recent follow-up, only 14 of 23 shoulders had no or mild pain. Overall pain scores improved from 4.7 to 2.6 points. Abduction and external rotation improved significantly. Five shoulders required reoperation, 2 for glenoid loosening and 1 each for infection, instability, and stiffness. Subjectively, 8 patients rated their shoulder as much better, 7 as better, 4 the same, and 4 worse. Most recent American Shoulder and Elbow Surgeons scores averaged 64 points (range, 20-95 points). Shoulder arthroplasty for the treatment of chondrolysis improves pain and range of motion. However, patient satisfaction is variable. Early follow-up shows a higher than expected rate of reoperation (25%). Patients undergoing shoulder arthroplasty for chondrolysis should be counseled appropriately about expectations after surgery. Copyright © 2016 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

  2. The Joint Operating Environment (JOE): Challenges and Implications for the Future Joint Force

    DTIC Science & Technology

    2008-11-25

    be called on to protect our national interests. Merely sustaining the health of the Joint Force, never mind adapting and transforming, is far more...very powerful motives prevent us from doing so – security, honour, and self interest. And we were not the first to act in this way. Far from it.” 4...deep understanding of the enemy – his culture, history, geography, religious and ideological motivations , and particularly the huge differences in

  3. The Disestablishment of U.S. Joint Forces Command: A Step Backward in "Jointness"

    DTIC Science & Technology

    2011-06-01

    States Army ABSTRACT The Unified Command Plan established the United States Joint Forces Command (USJFCOM) as a separate and distinct...doctrine, training, tactics, and equipment.”3 One of the premier Army visionaries of the post-Vietnam era, Donn Starry, also recognized that “change is...files/College/F_Publications/occPapers/occ-paper_18-en.pdf (accessed 20 November 2010). 4 U.S. Army War College, Selected Readings, Volume II, Course

  4. Temporomandibular joint forces measured at the condyle of Macaca arctoides.

    PubMed

    Boyd, R L; Gibbs, C H; Mahan, P E; Richmond, A F; Laskin, J L

    1990-06-01

    Forces were measured at the articular surface of the temporomandibular joint (TMJ) condyle in two stump-tail monkeys (Macaca arctoides) during chewing, incisal biting, and drinking and also during aggressive behaviors. Force was measured with a thin piezoelectric foil transducer, which was cemented over the anterior and superior surfaces of the condyle. Wires from the upper and lower surfaces of the foil were insulated between two layers of Teflon tape and run subcutaneously to a telemetry unit, which was implanted in the upper back. Force applied across the foil by the condyle was detected by the telemetry unit and transmitted to an FM radio receiver outside the animal. The FM signals were received and demodulated, and a signal proportional to the force applied between the condyle and the TMJ fossa was displayed on a chart recorder. Data were collected over an 8-day period. The animals were not constrained. The TMJ was found to be load bearing. The greatest force of 39.0 lb (17.7 kg) was measured during feisty vocal aggression. Forces ranged as high as 34.5 lb (15.7 kg) during chewing and 28.5 lb (13.0 kg) during incisal biting. Forces were greater on the working (food) side than on the nonworking (balancing) side by average ratios of 1.4 to 2.6. A large unilateral interference at the most distal molar greatly disturbed chewing. It reduced TMJ forces by 50% or more, and the monkey refused to chew on the side opposite the interference.

  5. Revisiting the Force-Joint Angle Relationship After Eccentric Exercise.

    PubMed

    Welsh, Molly C; Allen, David L; Batliner, Matthew E; Byrnes, William C

    2015-12-01

    The purpose of this study was to evaluate force-angle curve fitting techniques pre-eccentric exercise, quantify changes in curve characteristics postexercise, and examine the relationship between curve changes and markers of muscle damage. Fourteen males unaccustomed to eccentric exercise performed 60 eccentric muscle actions of the elbow flexors. Maximal voluntary isometric force was measured throughout a range of angles pre- (Pre1 and Pre2), immediately post (IP), and 1, 2, 4, and 7 days postexercise. Force-angle curves for each visit were constructed using second-order polynomials. Changes in curve characteristics (optimal angle, peak force, curve height), range of motion, soreness, and creatine kinase activity were quantified. Optimal joint angle and force at optimal angle were significantly correlated from Pre1 to Pre2 (ICC = 0.821 and 0.979, respectively). Optimal angle was significantly right shifted (p = 0.035) by 10.4 ± 12.9° from Pre2 to IP and was restored by 1 day post exercise. Interestingly, the r value for curve fit was significantly decreased (p < 0.001) from Pre2 (r = 0.896) to IP (r = 0.802) and 1 day post exercise (r = 0.750). Curve height was significantly decreased (39%) IP and restored to pre-exercise height by 4 days postexercise. There was no correlation between optimal angle or curve height and other damage markers. In conclusion, force-angle relationships can be accurately described using second-order polynomials. After eccentric exercise, the force-angle curve is flattened and shifted (downward and rightward), but these changes are not correlated to other markers of muscle damage. Changes in the force-angle relationship are multifaceted, but determining the physiological significance of these changes requires further investigation.

  6. Adhesively-Bonded Structural Composite Joint Utilizing Shoulder-Centered Sleeves

    NASA Technical Reports Server (NTRS)

    Lukowski, Florian P., Jr. (Inventor)

    2015-01-01

    A composite joint includes a first member having a groove therein, a second member adjacent to the first member, and a connector member disposed between the second member and the first member. The connector member is received in the groove so as to bias a load path between the first member and the second member from a peripheral portion to a central portion of the connector member.

  7. Effect of Resistance Training Maintaining the Joint Angle-torque Profile Using a Haptic-based Machine on Shoulder Internal and External Rotation.

    PubMed

    Kim, Yeonghun; Lee, Kunwoo; Moon, Jeheon; Koo, Dohoon; Park, Jaewoo; Kim, Kyengnam; Hong, Daehie; Shin, Inshik

    2014-04-01

    [Purpose] The aim of this study was to present an individualized resistance training method to enable exercise while maintaining an exercise load that is set according to an individual's joint angle-torque using a haptic-based resistance training machine. [Methods] Five participants (machine group) performed individualized shoulder internal and external rotation training with a haptic resistance training machine, while another five participants performed general dumbbell-based shoulder internal and external rotation training for eight weeks. Internal and external rotation powers of subjects were measured using an isokinetic machine before and after training. [Results] The average powers of both shoulder internal and external rotation has been improved after training (25.72%, 13.62%). The improvement in power of external rotation in the machine group was significantly higher than that in the control group. [Conclusion] This study proposes a haptic-based individualized rotator cuff muscle training method. The training protocol maintaining the joint angle-torque profile showed better improvement of shoulder internal/external rotation than dumbbell training.

  8. Effect of Resistance Training Maintaining the Joint Angle-torque Profile Using a Haptic-based Machine on Shoulder Internal and External Rotation

    PubMed Central

    Kim, Yeonghun; Lee, Kunwoo; Moon, Jeheon; Koo, Dohoon; Park, Jaewoo; Kim, Kyengnam; Hong, Daehie; Shin, Inshik

    2014-01-01

    [Purpose] The aim of this study was to present an individualized resistance training method to enable exercise while maintaining an exercise load that is set according to an individual’s joint angle-torque using a haptic-based resistance training machine. [Methods] Five participants (machine group) performed individualized shoulder internal and external rotation training with a haptic resistance training machine, while another five participants performed general dumbbell-based shoulder internal and external rotation training for eight weeks. Internal and external rotation powers of subjects were measured using an isokinetic machine before and after training. [Results] The average powers of both shoulder internal and external rotation has been improved after training (25.72%, 13.62%). The improvement in power of external rotation in the machine group was significantly higher than that in the control group. [Conclusion] This study proposes a haptic-based individualized rotator cuff muscle training method. The training protocol maintaining the joint angle-torque profile showed better improvement of shoulder internal/external rotation than dumbbell training. PMID:24764626

  9. Individual muscle contributions to the axial knee joint contact force during normal walking.

    PubMed

    Sasaki, Kotaro; Neptune, Richard R

    2010-10-19

    Muscles are significant contributors to the high joint forces developed in the knee during human walking. Not only do muscles contribute to the knee joint forces by acting to compress the joint, but they also develop joint forces indirectly through their contributions to the ground reaction forces via dynamic coupling. Thus, muscles can have significant contributions to forces at joints they do not span. However, few studies have investigated how the major lower-limb muscles contribute to the knee joint contact forces during walking. The goal of this study was to use a muscle-actuated forward dynamics simulation of walking to identify how individual muscles contribute to the axial tibio-femoral joint force. The simulation results showed that the vastii muscles are the primary contributors to the axial joint force in early stance while the gastrocnemius is the primary contributor in late stance. The tibio-femoral joint force generated by these muscles was at times greater than the muscle forces themselves. Muscles that do not cross the knee joint (e.g., the gluteus maximus and soleus) also have significant contributions to the tibio-femoral joint force through their contributions to the ground reaction forces. Further, small changes in walking kinematics (e.g., knee flexion angle) can have a significant effect on the magnitude of the knee joint forces. Thus, altering walking mechanics and muscle coordination patterns to utilize muscle groups that perform the same biomechanical function, yet contribute less to the knee joint forces may be an effective way to reduce knee joint loading during walking.

  10. Individual Muscle Contributions to the Axial Knee Joint Contact Force during Normal Walking

    PubMed Central

    Sasaki, Kotaro; Neptune, Richard R.

    2010-01-01

    Muscles are significant contributors to the high joint forces developed in the knee during human walking. Not only do muscles contribute to the knee joint forces by acting to compress the joint, but they also develop joint forces indirectly through their contributions to the ground reaction forces via dynamic coupling. Thus, muscles can have significant contributions to forces at joints they do not span. However, few studies have investigated how the major lower-limb muscles contribute to the knee joint contact forces during walking. The goal of this study was to use a muscle-actuated forward dynamics simulation of walking to identify how individual muscles contribute to the axial tibio-femoral joint force. The simulation results showed that the vastii muscles are the primary contributors to the axial joint force in early stance while the gastrocnemius is the primary contributor in late stance. The tibio-femoral joint force generated by these muscles was at times greater than the muscle forces themselves. Muscles that do not cross the knee joint (e.g., the gluteus maximus and soleus) also have significant contributions to the tibio-femoral joint force through their contributions to the ground reaction forces. Further, small changes in walking kinematics (e.g., knee flexion angle) can have a significant effect on the magnitude of the knee joint forces. Thus, altering walking mechanics and muscle coordination patterns to utilize muscle groups that perform the same biomechanical function, yet contribute less to the knee joint forces may be an effective way to reduce knee joint loading during walking. PMID:20655046

  11. Immediate Effects of Angular Joint Mobilization (a New Concept of Joint Mobilization) on Pain, Range of Motion, and Disability in a Patient with Shoulder Adhesive Capsulitis: A Case Report

    PubMed Central

    Kim, Younghoon; Lee, GyuChang

    2017-01-01

    Patient: Female, 53 Final Diagnosis: Adhesive capsulitis Symptoms: Pain • limited range of motion Medication: None Clinical Procedure: Manual therapy (joint mobilization) Specialty: Physical Therapy Objective: Unusual or unexpected effect of treatment Background: Adhesive capsulitis is a common disabling condition, with reviews reporting up to 5.3% of the population being affected, the burden placed upon individuals and healthcare services may therefore be considered substantial. For recovering the normal extensibility of the capsule in individuals with adhesive capsulitis of the shoulder, passive stretching of the capsule through end-range mobilization has been suggested. Recently, the concept of joint mobilization into angular joint mobilization (AJM), which is rotational joint mobilization with joint axis shift, was proposed. This case report aimed to investigate the immediate effect of AJM on pain, range of motion (ROM), and disability in a patient with shoulder adhesive capsulitis. Case Report: The patient was a 53-year-old woman who was diagnosed with left shoulder adhesive capsulitis. Her left shoulder gradually stiffened, affecting functional activity. The patient attended 12 joint mobilization sessions over a period of six weeks (two times per week). The intervention consisted of rotary oscillations of the left shoulder, which were applied with overpressure and stops before the end of the pathological limit. After intervention, the patient reported 3/100 pain intensity on the visual analogue scale (VAS) (before versus after: 58 versus 3). Active ROM improved by 51° in flexion, 76.4° in abduction, 38.7° in external rotation, and 51.4° in active internal rotation. Passive ROM improved by 49° in flexion, 74.6° in abduction, 39.4° in external rotation, 51.4° in internal rotation. The total shoulder, pain and disability index (SPADI) score improved by 53.9%. Conclusions: The patient reacted positively to AJM, resulting in improved shoulder pain, ROM

  12. Investigating shoulder muscle loading and exerted forces during wall painting tasks: influence of gender, work height and paint tool design.

    PubMed

    Rosati, Patricia M; Chopp, Jaclyn N; Dickerson, Clark R

    2014-07-01

    The task of wall painting produces considerable risk to the workers, both male and female, primarily in the development of upper extremity musculoskeletal disorders. Insufficient information is currently available regarding the potential benefits of using different paint roller designs or the possible adverse effects of painting at different work heights. The aim of this study was to investigate the influence of gender, work height, and paint tool design on shoulder muscle activity and exerted forces during wall painting. Ten young adults, five male and five female, were recruited to perform simulated wall painting at three different work heights with three different paint roller designs while upper extremity muscle activity and horizontal push force were recorded. Results demonstrated that for female participants, significantly greater total average (p = 0.007) and integrated (p = 0.047) muscle activity was present while using the conventional and curly flex paint roller designs compared to the proposed design in which the load was distributed between both hands. Additionally, for both genders, the high working height imposed greater muscular demands compared to middle and low heights. These findings suggest that, if possible, avoid painting at extreme heights (low or high) and that for female painters, consider a roller that requires the use of two hands; this will reduce fatigue onset and subsequently mitigate potential musculoskeletal shoulder injury risks.

  13. Adaptation of the AnyBody™ Musculoskeletal Shoulder Model to the Nonconforming Total Shoulder Arthroplasty Context.

    PubMed

    Sins, Lauranne; Tétreault, Patrice; Hagemeister, Nicola; Nuño, Natalia

    2015-10-01

    Current musculoskeletal inverse dynamics shoulder models have two limitations to use in the context of nonconforming total shoulder arthroplasty (NC-TSA). First, the ball and socket glenohumeral (GH) joint simplification avoids any humeral head translations. Second, there is no contact at the GH joint to compute the contact area and the center of pressure (COP) between the two components of NC-TSA. In this paper, we adapted the AnyBody™ shoulder model by introducing humeral head translations and contact between the two components of an NC-TSA. Abduction in the scapular plane was considered. The main objective of this study was to adapt the AnyBody™ shoulder model to a NC-TSA context and to compare the results of our model (translations, COP, contact area, GH joint reaction forces (GH-JRFs), and muscular forces) with previous numerical, experimental, and clinical studies. Humeral head translations and contact were successfully introduced in our adapted shoulder model with strong support for our findings by previous studies.

  14. Separated Shoulder

    MedlinePlus

    Separated shoulder Overview By Mayo Clinic Staff A separated shoulder is an injury to the ligaments that hold your collarbone (clavicle) to your shoulder blade. In a mild separated shoulder, the ligaments ...

  15. Anteroposterior translation of the glenohumeral joint in various pathologies: differences between shoulder MRI in the adducted neutral rotation and abducted externally rotated positions.

    PubMed

    Kim, Kyung Cheon; Rhee, Yong Girl; Park, Jin Young; Shin, Hyun Dae; Cha, Soo Min; Park, Jun Yeong; Han, Sun Cheol; Yang, Jae Hoon

    2015-09-01

    The present study was performed to determine the translation of the glenohumeral joint in patients with and without shoulder lesions by comparing the magnetic resonance images obtained in the conventional adducted neutral rotation position with those obtained in the abducted externally rotated position. Two hundred and eighty-five consecutive shoulders without rotator cuff tears that had been subjected to magnetic resonance imaging (MRI) without arthrography in the abducted externally rotated position were reviewed retrospectively. Among them, 50 shoulders without pathology were selected at random to be compared with three shoulder pathology groups, comprising shoulders with superior labrum, anterior-to-posterior (SLAP) lesions without range of motion (ROM) limitation (group I, 47 shoulders), with massive rotator cuff tears without ROM limitation (group II, 20 shoulders), and with full-thickness subscapularis tendon tears without ROM limitation (group III, 20 shoulders). Glenohumeral translation in the anterior-to-posterior direction relative to the glenoid face was evaluated using a method based on the glenohumeral contact point (CP) and humeral head centre (HHC) in the adducted neutral rotation and abducted externally rotated views, which were measured by three orthopaedic surgeons. For each shoulder, the differences in translation for the glenohumeral CP and HHC between the adducted neutral rotation and abducted externally rotated views were calculated as relative posterior translation in millimetres. The differences in ΔCP and ΔHHC between group I and the normal control group were not statistically significant. The differences in ΔCP (P = 0.001) and ΔHHC (P = 0.001) between group II and the normal control group were statistically significant. Additionally, the differences in ΔCP and ΔHHC between group III and the normal control group were not statistically significant. The MRI in abducted externally rotated view in patients with SLAP lesions or full

  16. The effects of orientation of lumbar facet joints on the facet joint contact forces: an in vitro biomechanical study.

    PubMed

    Liu, Xiang; Huang, Zhiping; Zhou, Ruozhou; Zhu, Qingan; Ji, Wei; Long, Yaowu; Wang, Jixing

    2017-07-28

    A biomechanical human cadaveric study. The aim of this study was to measure L2-L3 facet joint contact forces in a flexibility test using thin film electroresistive sensors, and facet joint orientation on CT scan images, to examine the effects of orientation of lumbar facet joint on the facet joint contact forces. Biomechanically the bilateral facet joints play a critical role in maintaining stability of the lumbar spine by sharing load. The effect of orientation of lumbar facet joints on the contact forces remains unknown. Eight human cadaveric lumbar spine specimens (L2-L3) were tested by applying a pure moment of ± 7.5 Nm in 3 directions of loading(flexion-extension, lateral bending and axial rotation) with and without a follower preload of 300 N. The orientation of the lumbar facet joints at the L2-L3 was measured on axial CT scans. Bilateral facet contact forces were measured during flexibility tests using thin film electroresistive sensors (Tekscan 6900). The average total peak facet loads was 66 N in axial rotation, 27 N in extension and 20 N in lateral bending under a pure moment. Under a pure moment and with a follower preload of 300N, the average total peak facet loads was 53 N in axial rotation, 43 N in extension and 24 N in lateral bending. The facet joint forces were correlated positively and significantly with the orientation in all directions with and without a compressive follower preload (P < 0.05). In addition, the facet joint contact forces at neutral position with a follower preload were correlated positively with the orientation (rs = 0.759, P = 0.001). This study identified that the greater coronal orientation of lumbar facet joints are, the higher the facet joint contact forces are. 3.

  17. Multibody system of the upper limb including a reverse shoulder prosthesis.

    PubMed

    Quental, C; Folgado, J; Ambrósio, J; Monteiro, J

    2013-11-01

    The reverse shoulder replacement, recommended for the treatment of several shoulder pathologies such as cuff tear arthropathy and fractures in elderly people, changes the biomechanics of the shoulder when compared to the normal anatomy. Although several musculoskeletal models of the upper limb have been presented to study the shoulder joint, only a few of them focus on the biomechanics of the reverse shoulder. This work presents a biomechanical model of the upper limb, including a reverse shoulder prosthesis, to evaluate the impact of the variation of the joint geometry and position on the biomechanical function of the shoulder. The biomechanical model of the reverse shoulder is based on a musculoskeletal model of the upper limb, which is modified to account for the properties of the DELTA® reverse prosthesis. Considering two biomechanical models, which simulate the anatomical and reverse shoulder joints, the changes in muscle lengths, muscle moment arms, and muscle and joint reaction forces are evaluated. The muscle force sharing problem is solved for motions of unloaded abduction in the coronal plane and unloaded anterior flexion in the sagittal plane, acquired using video-imaging, through the minimization of an objective function related to muscle metabolic energy consumption. After the replacement of the shoulder joint, significant changes in the length of the pectoralis major, latissimus dorsi, deltoid, teres major, teres minor, coracobrachialis, and biceps brachii muscles are observed for a reference position considered for the upper limb. The shortening of the teres major and teres minor is the most critical since they become unable to produce active force in this position. Substantial changes of muscle moment arms are also observed, which are consistent with the literature. As expected, there is a significant increase of the deltoid moment arms and more fibers are able to elevate the arm. The solutions to the muscle force sharing problem support the

  18. Is it possible to reduce the knee joint compression force during level walking with hiking poles?

    PubMed

    Jensen, S B; Henriksen, M; Aaboe, J; Hansen, L; Simonsen, E B; Alkjaer, T

    2011-12-01

    Walking with hiking poles has become a popular way of exercising. Walking with poles is advocated as a physical activity that significantly reduces the loading of the hip, knee and ankle joints. We have previously observed that pole walking does not lead to a reduction of the load on the knee joint. However, it is unclear whether an increased force transmitted through the poles can reduce the load on the knee joint. Thus, the purpose of the present study was to investigate if an increased load transmitted through the arms to the poles could reduce the knee joint compression force during level walking with poles. We hypothesized that an increased pole force would result in a reduction of the knee joint compression force. Gait analyses from 10 healthy subjects walking with poles were obtained. The pole force was measured simultaneously during the gait analyses. The knee joint compression forces were estimated by using a biomechanical knee joint model. The results showed that the subjects were able to increase the pole force by 2.4 times the normal pole force. However, this did not lead to a reduction in the knee joint compressive force and we rejected our hypothesis. In conclusion, the use of poles during level walking does not seem to reduce knee joint compressive loads. However, it is possible that the use of poles in other populations (e.g. osteoarthritis patients) and in terrain would unload the knee joint. This should be investigated in the future.

  19. Milwaukee shoulder syndrome.

    PubMed

    Dewachter, L; Aerts, P; Crevits, I; De Man, R

    2012-01-01

    Milwaukee shoulder syndrome or rapid destructive arthropathy of the shoulder is a rare form of arthropathy that mainly affects elderly women. It is characterized by a rapid destruction of the glenohumeral joint and the rotator cuff and by an important noninflammatory joint effusion containing hydroxyapatite crystals. Radiography plays an important role in the evaluation of patients with articular disease. However, magnetic resonance imaging is the method of choice for assessing the full extent of osseous, chondral, and soft-tissue involvement.

  20. The Standing Joint Force Headquarters Plan-Does It Go Far Enough?

    DTIC Science & Technology

    2010-07-26

    humanitarian relief effort in Bangladesh following Cyclone Marian, the PACOM DJTFAC deployed in support of the III MEF. A successful relief operation...Putnam’s Sons, 2002. 67 Cole, Ronald H., “Grenada, Panama, and Haiti : Joint Operational Reform,” Joint Forces Quarterly, Autumn/Winter 1998-99...2002. Smith, Matthew , Major (USAF), “Successfully Developing Future Joint Leaders,” Norfolk, VA: Joint Forces Staff College, 2005. Stewart

  1. Shoulder proprioception in baseball pitchers.

    PubMed

    Safran, M R; Borsa, P A; Lephart, S M; Fu, F H; Warner, J J

    2001-01-01

    We examined proprioceptive differences between the dominant and nondominant shoulders of 21 collegiate baseball pitchers without a history of shoulder instability or surgery. A proprioceptive testing device was used to measure kinesthesia and joint position sense. Joint position sense was significantly (P =.05) more accurate in the nondominant shoulder than in the dominant shoulder when starting at 75% of maximal external rotation and moving into internal rotation. There were no significant differences for proprioception in the other measured positions or with kinesthesia testing. Six pitchers with recent shoulder pain had a significant (P =.04) kinesthetic deficit in the symptomatic dominant shoulder compared with the asymptomatic shoulder, as measured in neutral rotation moving into internal rotation. The net effect of training, exercise-induced laxity, and increased external rotation in baseball pitchers does not affect proprioception, although shoulder pain, possibly due to rotator cuff inflammation or tendinitis, is associated with reduced kinesthetic sensation.

  2. How well do the muscular synergies extracted via non-negative matrix factorisation explain the variation of torque at shoulder joint?

    PubMed

    Moghadam, M Nassajian; Aminian, K; Asghari, M; Parnianpour, M

    2013-01-01

    The way central nervous system manages the excess degrees of freedom to solve kinetic redundancy of musculoskeletal system remains an open question. In this study, we utilise the concept of synergy formation as a simplifying control strategy to find the muscle recruitment based on summation of identified muscle synergies to balance the biomechanical demands (biaxial external torque) during an isometric shoulder task. A numerical optimisation-based shoulder model was used to obtain muscle activation levels when a biaxial external isometric torque is imposed at the shoulder glenohumeral joint. In the numerical simulations, 12 different shoulder torque vectors in the transverse plane are considered. For each selected direction for the torque vector, the resulting muscle activation data are calculated. The predicted muscle activation data are used for grouping muscles in some fixed element synergies by the non-negative matrix factorisation method. Next, torque produced by these synergies are computed and projected in the 2D torque space to investigate the magnitude and direction of torques that each muscle synergy generated. The results confirmed our expectation that few dominant synergies are sufficient to reconstruct the torque vectors and each muscle contributed to more than one synergy. Decomposition of the concatenated data, combining the activation and external torque, provided functional muscle synergies that produced torques in the four principal directions. Four muscle synergies were able to account for more than 95% of variation of the original data.

  3. Relationship Between the Range of Motion and Isometric Strength of Elbow and Shoulder Joints and Ball Velocity in Women Team Handball Players.

    PubMed

    Schwesig, René; Hermassi, Souhail; Wagner, Herbert; Fischer, David; Fieseler, Georg; Molitor, Thomas; Delank, Karl-Stefan

    2016-12-01

    Schwesig, R, Hermassi, S, Wagner, H, Fischer, D, Fieseler, G, Molitor, T, and Delank, K-S. Relationship between the range of motion and isometric strength of elbow and shoulder joints and ball velocity in women team handball players. J Strength Cond Res 30(12): 3428-3435, 2016-The aims of this study were to investigate relationships between isometric strength and range of motion (ROM) of shoulder and elbow joints and compare 2 different team handball throwing techniques in women team handball. Twenty highly experienced women team handball players (age: 20.7 ± 2.9 years; body mass: 68.4 ± 6.0 kg; and height: 1.74 ± 0.06 m) participated in this study. The isometric strength (hand-held dynamometer) and ROM (goniometer) of shoulder and elbow joints were measured at the beginning of the preseasonal training. After clinical examination, the subjects performed 3 standing throws with run-up (10 m) and 3 jump throws over a hurdle (0.20 m). The mean ball velocity was calculated from 3 attempts and measured using a radar gun. The results showed that the ball velocity of the standing throw with run-up (vST) was significantly higher than that of the jump throw (vJT) (25.5 ± 1.56 vs. 23.2 ± 1.31 m·s; p < 0.001). Therefore, significant playing position effects (p = 0.021) were only found for ST. Goalkeepers (n = 2) had the lowest (22.6 ± 0.04 m·s) and backcourt players (n = 9), the highest (26.1 ± 1.36 m·s) vST. The retroversion strength in the shoulder was the only parameter with relevant correlations to both throws (vST: r = 0.52, and vJT: r = 0.43). Other relevant relationships to vJT were found for adduction strength shoulder (r = 0.55) and ROM flexion elbow (r = -0.54). The vST was only correlated to the glenohumeral internal rotation deficit. As a consequence, strength is more important than the ROM, and in addition to this, the shoulder, compared with the elbow, has a greater influence on the vST in highly experienced women team handball players.

  4. Shoulder joint dislocation as an unusual complication of defibrillation threshold testing following subcutaneous implantable cardioverter-defibrillator implantation.

    PubMed

    Noheria, Amit; Cha, Yong-Mei; Asirvatham, Samuel J; Friedman, Paul A

    2014-01-01

    A 53-year-old man underwent implantation of a totally subcutaneous ICD (S-ICD; Boston Scientific). He was positioned supine, with the left arm abducted, externally rotated (i.e. palm up) and strapped to the arm extender. The generator was placed in the left mid-axillary line along the 5th-6th intercostal spaces and the defibrillation coil was tunneled anterior to the sternum. Defibrillation threshold (DFT) testing with 65 Jcaused a forceful pectoralis twitch. The patient woke up with a painful anteriorly dislocated left shoulder. Glenohumeral dislocation due to DFT testing has not been previously reported. It is likely that this complication is specific to the S-ICD implantation, and is related to positioning with the arm abducted, externally rotated, and immobilized, and use of greater defibrillation energy with current pathway through the bulk of the pectoralis muscle.Precautions may include extending the arm palm down, strapping the arm loosely, and adduction of the arm for DFT testing.

  5. Functional Analysis of the Primate Shoulder

    PubMed Central

    Hohn, Bianca; Scherf, Heike; Schmidt, Manuela; Krause, Cornelia; Witzel, Ulrich

    2010-01-01

    Studies of the shoulder girdle are in most cases restricted to morphological comparisons and rarely aim at elucidating function in a strictly biomechanical sense. To fill this gap, we investigated the basic functional conditions that occur in the shoulder joint and shoulder girdle of primates by means of mechanics. Because most of nonhuman primate locomotion is essentially quadrupedal walking—although on very variable substrates—our analysis started with quadrupedal postures. We identified the mechanical situation at the beginning, middle, and end of the load-bearing stance phase by constructing force parallelograms in the shoulder joint and the scapulo-thoracal connection. The resulting postulates concerning muscle activities are in agreement with electromyographical data in the literature. We determined the magnitude and directions of the internal forces and explored mechanically optimal shapes of proximal humerus, scapula, and clavicula using the Finite Element Method. Next we considered mechanical functions other than quadrupedal walking, such as suspension and brachiation. Quadrupedal walking entails muscle activities and joint forces that require a long scapula, the cranial margin of which has about the same length as the axillary margin. Loading of the hand in positions above the head and suspensory behaviors lead to force flows along the axillary margin and so necessitate a scapula with an extended axillary and a shorter cranial margin. In all cases, the facies glenoidalis is nearly normal to the calculated joint forces. In anterior view, terrestrial monkeys chose a direction of the ground reaction force requiring (moderate) activity of the abductors of the shoulder joint, whereas more arboreal monkeys prefer postures that necessitate activity of the adductors of the forelimb even when walking along branches. The same adducting and retracting muscles are recruited in various forms of suspension. As a mechanical consequence, the scapula is in a more

  6. Functional Analysis of the Primate Shoulder.

    PubMed

    Preuschoft, Holger; Hohn, Bianca; Scherf, Heike; Schmidt, Manuela; Krause, Cornelia; Witzel, Ulrich

    2010-04-01

    Studies of the shoulder girdle are in most cases restricted to morphological comparisons and rarely aim at elucidating function in a strictly biomechanical sense. To fill this gap, we investigated the basic functional conditions that occur in the shoulder joint and shoulder girdle of primates by means of mechanics. Because most of nonhuman primate locomotion is essentially quadrupedal walking-although on very variable substrates-our analysis started with quadrupedal postures. We identified the mechanical situation at the beginning, middle, and end of the load-bearing stance phase by constructing force parallelograms in the shoulder joint and the scapulo-thoracal connection. The resulting postulates concerning muscle activities are in agreement with electromyographical data in the literature. We determined the magnitude and directions of the internal forces and explored mechanically optimal shapes of proximal humerus, scapula, and clavicula using the Finite Element Method. Next we considered mechanical functions other than quadrupedal walking, such as suspension and brachiation. Quadrupedal walking entails muscle activities and joint forces that require a long scapula, the cranial margin of which has about the same length as the axillary margin. Loading of the hand in positions above the head and suspensory behaviors lead to force flows along the axillary margin and so necessitate a scapula with an extended axillary and a shorter cranial margin. In all cases, the facies glenoidalis is nearly normal to the calculated joint forces. In anterior view, terrestrial monkeys chose a direction of the ground reaction force requiring (moderate) activity of the abductors of the shoulder joint, whereas more arboreal monkeys prefer postures that necessitate activity of the adductors of the forelimb even when walking along branches. The same adducting and retracting muscles are recruited in various forms of suspension. As a mechanical consequence, the scapula is in a more frontal

  7. Computational sensitivity analysis to identify muscles that can mechanically contribute to shoulder deformity following brachial plexus birth palsy.

    PubMed

    Crouch, Dustin L; Plate, Johannes F; Li, Zhongyu; Saul, Katherine R

    2014-02-01

    Two mechanisms, strength imbalance or impaired longitudinal muscle growth, potentially cause osseous and postural shoulder deformity in children with brachial plexus birth palsy. Our objective was to determine which muscles, via either deformity mechanism, were mechanically capable of producing forces that could promote shoulder deformity. In an upper limb computational musculoskeletal model, we simulated strength imbalance by allowing each muscle crossing the shoulder to produce 30% of its maximum force. To simulate impaired longitudinal muscle growth, the functional length of each muscle crossing the shoulder was reduced by 30%. We performed a sensitivity analysis to identify muscles that, through either simulated deformity mechanism, increased the posteriorly directed, compressive glenohumeral joint force consistent with osseous deformity or reduced the shoulder external rotation or abduction range of motion consistent with postural deformity. Most of the increase in the posterior glenohumeral joint force by the strength imbalance mechanism was caused by the subscapularis, latissimus dorsi, and infraspinatus. Posterior glenohumeral joint force increased the most owing to impaired growth of the infraspinatus, subscapularis, and long head of biceps. Through the strength imbalance mechanism, the subscapularis, anterior deltoid, and pectoralis major muscles reduced external shoulder rotation by 28°, 17°, and 10°, respectively. Shoulder motion was reduced by 40° to 56° owing to impaired growth of the anterior deltoid, subscapularis, and long head of triceps. The infraspinatus, subscapularis, latissimus dorsi, long head of biceps, anterior deltoid, pectoralis major, and long head of triceps were identified in this computational study as being the most capable of producing shoulder forces that may contribute to shoulder deformity following brachial plexus birth palsy. The muscles mechanically capable of producing deforming shoulder forces should be the focus of

  8. Avulsive axillary artery injury in reverse total shoulder arthroplasty.

    PubMed

    Wingert, Nathaniel C; Beck, John D; Harter, G Dean

    2014-01-01

    In addition to neurologic injuries such as peripheral nerve palsy, axillary vessel injury should be recognized as a possible complication of reverse total shoulder arthroplasty. Limb lengthening associated with Grammont-type reverse total shoulder arthroplasty places tension across the brachial plexus and axillary vessels and may contribute to observed injuries. The Grammont-type reverse total shoulder arthroplasty prosthesis reverses the shoulder ball and socket, shifts the shoulder center of rotation distal and medial, and lengthens the arm. This alteration of native anatomy converts shearing to compressive glenohumeral joint forces while augmenting and tensioning the deltoid lever arm. Joint stability is enhanced; shoulder elevation is enabled in the rotator cuff–deficient shoulder. Arm lengthening associated with reverse total shoulder arthroplasty places a longitudinal strain on the brachial plexus and axillary vessels. Peripheral nerve palsies and other neurologic complications of reverse total shoulder arthroplasty have been documented. The authors describe a patient with rotator cuff tear arthropathy and a history of radioulnar synostosis who underwent reverse total shoulder arthroplasty complicated by intraoperative injury to the axillary artery and postoperative radial, ulnar, and musculocutaneous nerve palsies. Following a seemingly unremarkable placement of reverse shoulder components, brisk arterial bleeding was encountered while approximating the incised subscapularis tendon in preparation for wound closure. Further exploration revealed an avulsive-type injury of the axillary artery. After an unsuccessful attempt at primary repair, a synthetic arterial bypass graft was placed. Reperfusion of the right upper extremity was achieved and has been maintained to date. Postoperative clinical examination and electromyographic studies confirmed ongoing radial, ulnar, and musculocutaneous neuropathies.

  9. Physical examination of the shoulder.

    PubMed

    King, Joseph J; Wright, Thomas W

    2014-10-01

    This article summarizes the overall assessment of the shoulder joint and seeks to help direct clinicians to diagnose shoulder pathology using standard and specific physical examinations. The history and standard examination can prompt the examiner to focus on specific tests to further evaluate the shoulder and limit the differential diagnoses. An appropriate and directed shoulder physical examination allows the clinician to focus on further diagnostic strategies and treatment options for the patient.

  10. Strategic Mobility 21: SM21 CONOPS Revised - Phase II, Joint Force Deployment and Distribution Support Platform: Joint Operational Concept

    DTIC Science & Technology

    2009-12-02

    vendor managed inventory ( VMI ) applications. 6.2 Strategic Mobility 21 – Joint Experimentation and Demonstration Campaign Phases The...United States Joint Force Command USMC US Marine Corps USTRANSCOM US Transportation Command VMI Vendor Managed Inventory WMS Warehouse Management ...fulfillment center for vendor - managed inventory and Business-to-Business (B to B) and Business to Customer (B to C) transactions.

  11. Soft tissue balance changes depending on joint distraction force in total knee arthroplasty.

    PubMed

    Nagai, Kanto; Muratsu, Hirotsugu; Matsumoto, Tomoyuki; Miya, Hidetoshi; Kuroda, Ryosuke; Kurosaka, Masahiro

    2014-03-01

    The influence of joint distraction force on intraoperative soft tissue balance was evaluated using Offset Repo-Tensor® for 78 knees that underwent primary posterior-stabilized total knee arthroplasty. The joint center gap and varus ligament balance were measured between osteotomized surfaces using 20, 40 and 60 lbs of joint distraction force. These values were significantly increased at extension and flexion as the distraction force increased. Furthermore, lateral compartment stiffness was significantly lower than medial compartment stiffness. Thus, larger joint distraction forces led to larger varus ligament balance and joint center gap, because of the difference in soft tissue stiffness between lateral and medial compartments. These findings indicate the importance of the strength of joint distraction force in the assessment of soft tissue balance, especially when using gap-balancing technique.

  12. Pathomechanics of the throwing shoulder.

    PubMed

    Kibler, W Ben; Thomas, Stephen J

    2012-03-01

    Many anatomic, physiological, and biomechanical alterations have been observed in overhead athletes who present with painful shoulders. This is probably due to the complex kinetic chain mechanics required in the overhead throwing or serving motion. Any alteration along the kinetic chain can result in deficits in force production or increase in joint loads in other parts of the chain. The "disabled throwing shoulder" (DTS) is a general term that describes the limitations in function that exist in symptomatic overhead athletes. DTS typically results from a "cascade to injury" with alterations in the kinetic chain. Evaluation of athletes with the DTS should include examination of the local and distant anatomic injuries and screening for physiological (muscle inflexibilities, weakness, or imbalances) or biomechanical (motions, positions) alterations.

  13. Bipolar Bone Loss of the Shoulder Joint due to Recurrent Instability: Use of Fresh Osteochondral Distal Tibia and Humeral Head Allografts.

    PubMed

    Haber, Daniel B; Sanchez, Anthony; Sanchez, George; Ferrari, Marcio B; Ferdousian, Sami; Provencher, Matthew T

    2017-06-01

    With increasing shoulder instability events, the likelihood of a bony lesion of the glenoid and/or humeral head rises. Although bone loss of either the glenoid or humeral head may result in recurrent instability, bipolar lesions have been shown, in particular, to result in a negative and additive effect on glenohumeral stability. In the case of a bipolar lesion comprising severe glenoid bone loss and an engaging, "off-track" Hill-Sachs lesion, the bony foundation of the glenohumeral joint is compromised and bony augmentation is necessary. We present our preferred technique, made up of the application of a distal tibia allograft to address the glenoid bone loss and humeral head allograft to address the Hill-Sachs lesion, for the treatment of a severe bipolar lesion in the setting of recurrent anterior shoulder instability after a failed Latarjet procedure.

  14. Motor control hierarchy in joint action that involves bimanual force production

    PubMed Central

    Masumoto, Junya

    2015-01-01

    The concept of hierarchical motor control has been viewed as a means of progressively decreasing the number of variables manipulated by each higher control level. We tested the hypothesis that turning an individual bimanual force-production task into a joint (two-participant) force-production task would lead to positive correlation between forces produced by the two hands of the individual participant (symmetric strategy) to enable negative correlation between forces produced by two participants (complementary strategy). The present study consisted of individual and joint tasks that involved both unimanual and bimanual conditions. In the joint task, 10 pairs of participants produced periodic isometric forces, such that the sum of forces that they produced matched a target force cycling between 5% and 10% of maximum voluntary contraction at 1 Hz. In the individual task, individuals attempted to match the same target force. In the joint bimanual condition, the two hands of each participant adopted a symmetric strategy of force, whereas the two participants adopted a complementary strategy of force, highlighting that the bimanual action behaved as a low level of a hierarchy, whereas the joint action behaved as an upper level. The complementary force production was greater interpersonally than intrapersonally. However, whereas the coherence was highest at 1 Hz in all conditions, the frequency synchrony was stronger intrapersonally than interpersonally. Moreover, whereas the bimanual action exhibited a smaller error and variability of force than the unimanual action, the joint action exhibited a less-variable interval and force than the individual action. PMID:25904710

  15. Motor control hierarchy in joint action that involves bimanual force production.

    PubMed

    Masumoto, Junya; Inui, Nobuyuki

    2015-06-01

    The concept of hierarchical motor control has been viewed as a means of progressively decreasing the number of variables manipulated by each higher control level. We tested the hypothesis that turning an individual bimanual force-production task into a joint (two-participant) force-production task would lead to positive correlation between forces produced by the two hands of the individual participant (symmetric strategy) to enable negative correlation between forces produced by two participants (complementary strategy). The present study consisted of individual and joint tasks that involved both unimanual and bimanual conditions. In the joint task, 10 pairs of participants produced periodic isometric forces, such that the sum of forces that they produced matched a target force cycling between 5% and 10% of maximum voluntary contraction at 1 Hz. In the individual task, individuals attempted to match the same target force. In the joint bimanual condition, the two hands of each participant adopted a symmetric strategy of force, whereas the two participants adopted a complementary strategy of force, highlighting that the bimanual action behaved as a low level of a hierarchy, whereas the joint action behaved as an upper level. The complementary force production was greater interpersonally than intrapersonally. However, whereas the coherence was highest at 1 Hz in all conditions, the frequency synchrony was stronger intrapersonally than interpersonally. Moreover, whereas the bimanual action exhibited a smaller error and variability of force than the unimanual action, the joint action exhibited a less-variable interval and force than the individual action.

  16. Patellofemoral joint compression forces in backward and forward running

    PubMed Central

    Roos, Paulien E.; Barton, Nick; van Deursen, Robert W.M.

    2012-01-01

    Patellofemoral pain (PFP) is a common injury and increased patellofemoral joint compression forces (PFJCF) may aggravate symptoms. Backward running (BR) has been suggested for exercise with reduced PFJCF. The aims of this study were to (1) investigate if BR had reduced peak PFJCF compared to forward running (FR) at the same speed, and (2) if PFJCF was reduced in BR, to investigate which biomechanical parameters explained this. It was hypothesized that (1) PFJCF would be lower in BR, and (2) that this would coincide with a reduced peak knee moment caused by altered ground reaction forces (GRFs). Twenty healthy subjects ran in forward and backward directions at consistent speed. Kinematic and ground reaction force data were collected; inverse dynamic and PFJCF analyses were performed. PFJCF were higher in FR than BR (4.5±1.5; 3.4±1.4BW; p<0.01). The majority of this difference (93.1%) was predicted by increased knee moments in FR compared to BR (157±54; 124±51 Nm; p<0.01). 54.8% of differences in knee moments could be predicted by the magnitude of the GRF (2.3±0.3; 2.4±0.2BW), knee flexion angle (44±6; 41±7) and center of pressure location on the foot (25±11; 12±6%) at time of peak knee moment. Results were not consistent in all subjects. It was concluded that BR had reduced PFJCF compared to FR. This was caused by an increased knee moment, due to differences in magnitude and location of the GRF vector relative to the knee. BR can therefore be used to exercise with decreased PFJCF. PMID:22503882

  17. Patellofemoral joint compression forces in backward and forward running.

    PubMed

    Roos, Paulien E; Barton, Nick; van Deursen, Robert W M

    2012-06-01

    Patellofemoral pain (PFP) is a common injury and increased patellofemoral joint compression forces (PFJCF) may aggravate symptoms. Backward running (BR) has been suggested for exercise with reduced PFJCF. The aims of this study were to (1) investigate if BR had reduced peak PFJCF compared to forward running (FR) at the same speed, and (2) if PFJCF was reduced in BR, to investigate which biomechanical parameters explained this. It was hypothesized that (1) PFJCF would be lower in BR, and (2) that this would coincide with a reduced peak knee moment caused by altered ground reaction forces (GRFs). Twenty healthy subjects ran in forward and backward directions at consistent speed. Kinematic and ground reaction force data were collected; inverse dynamic and PFJCF analyses were performed. PFJCF were higher in FR than BR (4.5±1.5; 3.4±1.4BW; p<0.01). The majority of this difference (93.1%) was predicted by increased knee moments in FR compared to BR (157±54; 124±51 Nm; p<0.01). 54.8% of differences in knee moments could be predicted by the magnitude of the GRF (2.3±0.3; 2.4±0.2BW), knee flexion angle (44±6; 41±7) and center of pressure location on the foot (25±11; 12±6%) at time of peak knee moment. Results were not consistent in all subjects. It was concluded that BR had reduced PFJCF compared to FR. This was caused by an increased knee moment, due to differences in magnitude and location of the GRF vector relative to the knee. BR can therefore be used to exercise with decreased PFJCF.

  18. Apportion Everything: A New Joint Force Organization and Employment Construct

    DTIC Science & Technology

    2007-11-02

    documents and concepts include An Evolving Joint Perspective: US Joint Warfare and Crisis Resolution In the 21st Century, Joint Operations Concepts...descriptive acronyms for the instruments of power include DIME-FIL or MIDLIFE which includes finance, intelligence, and substitutes legal for judicial. 16...Perspective: US Joint Warfare and Crisis Resolution In the 21st Century (Washington, DC: Joint Chiefs of Staff, Directorate of Management Printing

  19. Improving anterior deltoid activity in a musculoskeletal shoulder model - an analysis of the torque-feasible space at the sternoclavicular joint.

    PubMed

    Ingram, David; Engelhardt, Christoph; Farron, Alain; Terrier, Alexandre; Müllhaupt, Philippe

    2016-01-01

    Modelling the shoulder's musculature is challenging given its mechanical and geometric complexity. The use of the ideal fibre model to represent a muscle's line of action cannot always faithfully represent the mechanical effect of each muscle, leading to considerable differences between model-estimated and in vivo measured muscle activity. While the musculo-tendon force coordination problem has been extensively analysed in terms of the cost function, only few works have investigated the existence and sensitivity of solutions to fibre topology. The goal of this paper is to present an analysis of the solution set using the concepts of torque-feasible space (TFS) and wrench-feasible space (WFS) from cable-driven robotics. A shoulder model is presented and a simple musculo-tendon force coordination problem is defined. The ideal fibre model for representing muscles is reviewed and the TFS and WFS are defined, leading to the necessary and sufficient conditions for the existence of a solution. The shoulder model's TFS is analysed to explain the lack of anterior deltoid (DLTa) activity. Based on the analysis, a modification of the model's muscle fibre geometry is proposed. The performance with and without the modification is assessed by solving the musculo-tendon force coordination problem for quasi-static abduction in the scapular plane. After the proposed modification, the DLTa reaches 20% of activation.

  20. The effect of foot progression angle on knee joint compression force during walking.

    PubMed

    Koblauch, Henrik; Heilskov-Hansen, Thomas; Alkjær, Tine; Simonsen, Erik B; Henriksen, Marius

    2013-06-01

    It is unclear how rotations of the lower limb affect the knee joint compression forces during walking. Increases in the frontal plane knee moment have been reported when walking with internally rotated feet and a decrease when walking with externally rotated feet. The aim of this study was to investigate the knee joint compressive forces during walking with internal, external and normal foot rotation and to determine if the frontal plane knee joint moment is an adequate surrogate for the compression forces in the medial and lateral knee joint compartments under such gait modifications. Ten healthy males walked at a fixed speed of 4.5 km/h under three conditions: Normal walking, internally rotated and externally rotated. All gait trials were recorded by six infrared cameras. Net joint moments were calculated by 3D inverse dynamics. The results revealed that the medial knee joint compartment compression force increased during external foot rotation and the lateral knee joint compartment compression force increased during internal foot rotation. The increases in joint loads may be a result of increased knee flexion angles. Further, these data suggest that the frontal plane knee joint moment is not a valid surrogate measure for knee joint compression forces but rather indicates the medial- to-lateral load distribution.

  1. Lower limb joint forces during walking on the level and slopes at different inclinations.

    PubMed

    Alexander, Nathalie; Schwameder, Hermann

    2016-03-01

    Sloped walking is associated with an increase of lower extremity joint loading compared to level walking. Therefore, the aim of this study was to analyse lower limb joint compression forces as well as tibiofemoral joint shear forces during sloped walking at different inclinations. Eighteen healthy male participants (age: 27.0 ± 4.7 years, height: 1.80 ± 0.05 m, mass: 74.5 ± 8.2 kg) were asked to walk at a pre-set speed of 1.1m/s on a ramp (6 m × 1.5 m) at the slopes of -18°, -12°, -6°, 0°, 6°, 12° and 18°. Kinematic data were captured with a twelve-camera motion capture system (Vicon). Kinetic data were recorded with two force plates (AMTI) imbedded into a ramp. A musculoskeletal model (AnyBody) was used to compute lower limb joint forces. Results showed that downhill walking led to significantly increased hip, tibiofemoral and patellofemoral joint compression forces (p<0.05) and to significantly decreased ankle joint compression forces (p<0.05). Uphill walking significantly increased all lower limb joint compression forces with increasing inclination (p<0.05). Findings that downhill walking is a stressful task for the anterior cruciate ligament could not be supported in the current study, since anterior tibiofemoral joint shear forces did not increase with the gradient. Due to diverse tibiofemoral joint shear force patterns in the literature, results should be treated with caution in general. Finally, lower limb joint force analyses provided more insight in the structure loading conditions during sloped walking than joint moment analyses. Copyright © 2016 Elsevier B.V. All rights reserved.

  2. Bilateral Anterior Shoulder Dislocation

    PubMed Central

    Siu, Yuk Chuen; Lui, Tun Hing

    2014-01-01

    Introduction: Unilateral anterior shoulder dislocation is one of the most common problems encountered in orthopedic practice. However, simultaneous bilateral anterior dislocation of the shoulders is quite rare. Case Presentation: We report a case of a 75-year-old woman presented with simultaneous bilateral anterior shoulder dislocation following a trauma, complicated with a traction injury to the posterior cord of the brachial plexus. Conclusions: Bilateral anterior shoulder dislocation is very rare. The excessive traction force during closed reduction may lead to nerve palsy. Clear documentation of neurovascular status and adequate imaging before and after a reduction should be performed. PMID:25685749

  3. Frozen Shoulder

    MedlinePlus

    ... bones: your upper arm bone (humerus), your shoulder blade (scapula), and your collarbone (clavicle). The head of ... fits into a shallow socket in your shoulder blade. Strong connective tissue, called the shoulder capsule, surrounds ...

  4. Active AFO with ankle joint brake friction control using force observer.

    PubMed

    Yoshizawa, Nobuyuki

    2012-01-01

    Optimum friction control of the ankle joint brake is essential for realizing a stable gait when wearing an active ankle foot orthosis (AFO). An optimum friction control system using a force observer is designed and simulated. The brake friction is controlled in proportion to the observed human force of the lower limb without using force sensors. The simulated results show that the force observer performs well. The force-controlled orthosis is robust and practical because it uses no force sensors.

  5. Shoulder pain in primary care: diagnostic accuracy of clinical examination tests for non-traumatic acromioclavicular joint pain

    PubMed Central

    2013-01-01

    Background Despite numerous methodological flaws in previous study designs and the lack of validation in primary care populations, clinical tests for identifying acromioclavicular joint (ACJ) pain are widely utilised without concern for such issues. The aim of this study was to estimate the diagnostic accuracy of traditional ACJ tests and to compare their accuracy with other clinical examination features for identifying a predominant ACJ pain source in a primary care cohort. Methods Consecutive patients with shoulder pain were recruited prospectively from primary health care clinics. Following a standardised clinical examination and diagnostic injection into the subacromial bursa, all participants received a fluoroscopically guided diagnostic block of 1% lidocaine hydrochloride (XylocaineTM) into the ACJ. Diagnostic accuracy statistics including sensitivity, specificity, predictive values, positive and negative likelihood ratios (LR+ and LR-) were calculated for traditional ACJ tests (Active Compression/O’Brien’s test, cross-body adduction, localised ACJ tenderness and Hawkins-Kennedy test), and for individual and combinations of clinical examination variables that were associated with a positive anaesthetic response (PAR) (P≤0.05) defined as 80% or more reduction in post-injection pain intensity during provocative clinical tests. Results Twenty two of 153 participants (14%) reported an 80% PAR. None of the traditional ACJ tests were associated with an 80% PAR (P<0.05) and combinations of traditional tests were not able to discriminate between a PAR and a negative anaesthetic response (AUC 0.507; 95% CI: 0.366, 0.647; P>0.05). Five clinical examination variables (repetitive mechanism of pain onset, no referred pain below the elbow, thickened or swollen ACJ, no symptom provocation during passive glenohumeral abduction and external rotation) were associated with an 80% PAR (P<0.05) and demonstrated an ability to accurately discriminate between an PAR and NAR

  6. Bidirectional transfer between joint and individual actions in a task of discrete force production.

    PubMed

    Masumoto, Junya; Inui, Nobuyuki

    2017-07-01

    The present study examined bidirectional learning transfer between joint and individual actions involving discrete isometric force production with the right index finger. To examine the effects of practice of joint action on performance of the individual action, participants performed a pre-test (individual condition), practice blocks (joint condition), and a post-test (individual condition) (IJI task). To examine the effects of practice of the individual action on performance during the joint action, the participants performed a pre-test (joint condition), practice blocks (individual condition), and a post-test (joint condition) (JIJ task). Whereas one participant made pressing movements with a target peak force of 10% maximum voluntary contraction (MVC) in the individual condition, two participants produced the target force of the sum of 10% MVC produced by each of them in the joint condition. In both the IJI and JIJ tasks, absolute errors and standard deviations of peak force were smaller post-test than pre-test, indicating bidirectional transfer between individual and joint conditions for force accuracy and variability. Although the negative correlation between forces produced by two participants (complementary force production) became stronger with practice blocks in the IJI task, there was no difference between the pre- and post-tests for the negative correlation in the JIJ task. In the JIJ task, the decrease in force accuracy and variability during the individual action did not facilitate complementary force production during the joint action. This indicates that practice performed by two people is essential for complementary force production in joint action.

  7. Numerical modelling of the shoulder for clinical applications.

    PubMed

    Favre, Philippe; Snedeker, Jess G; Gerber, Christian

    2009-05-28

    Research activity involving numerical models of the shoulder is dramatically increasing, driven by growing rates of injury and the need to better understand shoulder joint pathologies to develop therapeutic strategies. Based on the type of clinical question they can address, existing models can be broadly categorized into three groups: (i) rigid body models that can simulate kinematics, collisions between entities or wrapping of the muscles over the bones, and which have been used to investigate joint kinematics and ergonomics, and are often coupled with (ii) muscle force estimation techniques, consisting mainly of optimization methods and electromyography-driven models, to simulate muscular action and joint reaction forces to address issues in joint stability, muscular rehabilitation or muscle transfer, and (iii) deformable models that account for stress-strain distributions in the component structures to study articular degeneration, implant failure or muscle/tendon/bone integrity. The state of the art in numerical modelling of the shoulder is reviewed, and the advantages, limitations and potential clinical applications of these modelling approaches are critically discussed. This review concentrates primarily on muscle force estimation modelling, with emphasis on a novel muscle recruitment paradigm, compared with traditionally applied optimization methods. Finally, the necessary benchmarks for validating shoulder models, the emerging technologies that will enable further advances and the future challenges in the field are described.

  8. Dual-Energy Computed Tomography Arthrography of the Shoulder Joint Using Virtual Monochromatic Spectral Imaging: Optimal Dose of Contrast Agent and Monochromatic Energy Level

    PubMed Central

    An, Chansik; Chun, Yong-Min; Kim, Sungjun; Lee, Young Han; Yun, Min Jeong; Suh, Jin-Suck

    2014-01-01

    Objective To optimize the dose of contrast agent and the level of energy for dual-energy computed tomography (DECT) arthrography of the shoulder joint and to evaluate the benefits of the optimized imaging protocol. Materials and Methods Dual-energy scans with monochromatic spectral imaging mode and conventional single energy scans were performed on a shoulder phantom with 10 concentrations from 0 to 210 mg/mL of iodinated contrast medium at intervals of 15 or 30 mg/mL. Image noise, tissue contrast, and beam hardening artifacts were assessed to determine the optimum dose of contrast agent and the level of monochromatic energy for DECT shoulder arthrography in terms of the lowest image noise and the least beam hardening artifacts while good tissue contrast was maintained. Material decomposition (MD) imaging for bone-iodine differentiation was qualitatively assessed. The optimized protocol was applied and evaluated in 23 patients. Results The optimal contrast dose and energy level were determined by the phantom study at 60 mg/mL and 72 keV, respectively. This optimized protocol for human study reduced the image noise and the beam-hardening artifacts by 35.9% and 44.5%, respectively. Bone-iodine differentiation by MD imaging was not affected by the iodine concentration or level of energy. Conclusion Dual-energy scan with monochromatic spectral imaging mode results in reduced image noise and beam hardening artifacts. PMID:25469086

  9. Intra-Articular Knee Contact Force Estimation During Walking Using Force-Reaction Elements and Subject-Specific Joint Model.

    PubMed

    Jung, Yihwan; Phan, Cong-Bo; Koo, Seungbum

    2016-02-01

    Joint contact forces measured with instrumented knee implants have not only revealed general patterns of joint loading but also showed individual variations that could be due to differences in anatomy and joint kinematics. Musculoskeletal human models for dynamic simulation have been utilized to understand body kinetics including joint moments, muscle tension, and knee contact forces. The objectives of this study were to develop a knee contact model which can predict knee contact forces using an inverse dynamics-based optimization solver and to investigate the effect of joint constraints on knee contact force prediction. A knee contact model was developed to include 32 reaction force elements on the surface of a tibial insert of a total knee replacement (TKR), which was embedded in a full-body musculoskeletal model. Various external measurements including motion data and external force data during walking trials of a subject with an instrumented knee implant were provided from the Sixth Grand Challenge Competition to Predict in vivo Knee Loads. Knee contact forces in the medial and lateral portions of the instrumented knee implant were also provided for the same walking trials. A knee contact model with a hinge joint and normal alignment could predict knee contact forces with root mean square errors (RMSEs) of 165 N and 288 N for the medial and lateral portions of the knee, respectively, and coefficients of determination (R2) of 0.70 and -0.63. When the degrees-of-freedom (DOF) of the knee and locations of leg markers were adjusted to account for the valgus lower-limb alignment of the subject, RMSE values improved to 144 N and 179 N, and R2 values improved to 0.77 and 0.37, respectively. The proposed knee contact model with subject-specific joint model could predict in vivo knee contact forces with reasonable accuracy. This model may contribute to the development and improvement of knee arthroplasty.

  10. Effect of Alpine ski boot cuff release on knee joint force during the backward fall.

    PubMed

    Benoit, D L; Lamontagne, M; Greaves, C; Liti, A; Cerulli, G

    2005-01-01

    The modern rigid alpine ski boot has been associated with an increase in severe knee joint injuries. A new design that allows the rear portion of the upper cuff of the boot (rear spoiler) to open when a posterior directed force is applied to it (similar to when a skier falls back on the ski) is investigated. Motion analysis was combined with kinetic measures to estimate the shear and compressive forces at the knee joint using a link-segment model while subjects fell backward to provoke ski boot cuff release. The rear spoiler opening was found to reduce anterior cruciate ligament directed shear force while increasing compressive force at the joint. We conclude that both compressive force and reduced anterior cruciate directed shear force have been associated with protective mechanisms at the knee joint. This occurred over a very brief period of time, however, and the influence this may have on knee injury prevention is discussed.

  11. Contributions of individual muscles to hip joint contact force in normal walking.

    PubMed

    Correa, Tomas A; Crossley, Kay M; Kim, Hyung J; Pandy, Marcus G

    2010-05-28

    The human hip joint withstands high contact forces during daily activity and is therefore susceptible to injury and structural deterioration over time. Knowledge of muscle-force contributions to hip joint loading may assist in the development of strategies to prevent and manage conditions such as osteoarthritis, femoro-acetabular impingement and fracture. The main aim of this study was to determine the contributions of individual muscles to hip contact force in normal walking. Muscle contributions to hip contact force were calculated based on a previously published dynamic optimization solution for normal walking, which provided the time histories of joint motion, ground reaction forces, and muscle forces during the stance and swing phases of gait. The force developed by each muscle plus its contribution to the ground reaction force were used to determine the muscle's contribution to hip contact force. Muscles were the major contributors to hip contact force, with gravitational and centrifugal forces combined contributing less than 5% of the total contact force. Four muscles that span the hip - gluteus medius, gluteus maximus, iliopsoas, and hamstrings - contributed most significantly to the three components of the hip contact force and hip contact impulse (integral of hip contact force over time). Three muscles that do not span the hip - vasti, soleus, and gastrocnemius - also contributed substantially to hip joint loading. These results provide additional insight into lower-limb muscle function during walking and may also be relevant to studies of cartilage degeneration and bone remodelling at the hip.

  12. Concentric and eccentric shoulder rehabilitation biomechanics.

    PubMed

    Kohles, S S; Gregorczyk, K N; Phillips, T C; Brody, L T; Orwin, I F; Vanderby, R

    2007-04-01

    The use of an impulse-momentum (IM) exercise technique was investigated for end-stage shoulder rehabilitation. The objectives of this study were to: (a) quantify the net shoulder joint forces and moments while using an IM system and (b) test the influence of gender and muscle loading type (concentric or eccentric) on kinetic and kinematic parameters. Fourteen healthy adults (eight males, six females) performed a repeated measures experiment on an instrumented device utilizing a cabled shuttle system. While maintaining 90 degrees of shoulder abduction and 90 degrees of elbow flexion, the subjects externally rotated their upper arm from 0 degrees to 90 degrees (concentric acceleration) and then internally rotated their upper arm back from 90 degrees to the 0 degrees position (eccentric deceleration). Shoulder joint forces and moments as well as rotational work and power were calculated using inverse dynamics (free-body forces and moments calculated at intersegmental joint centres). Overall concentric peak forces and moments were greater than eccentric peak forces and moments (P < 0.0001). Joint forces and moments reached a maximum during the initial phase of concentric loading (0 degrees to 45 degrees) compared with any other rotational position in the loading cycle (concentric 45 degrees to 90 degrees or eccentric 90 degrees to 0 degrees). The results also indicate that males experienced higher (P < 0.0001) average resultant peak joint forces (concentric 0 degrees to 45 degrees = 108.0 N and eccentric 90 degrees to 45 degrees = 87.2 N) than females (concentric 0 degrees to 45 degrees = 74.7 N and eccentric 45 degrees to 0 degrees = 56.0 N). In addition, males experienced higher (P < 0.0001) average resultant peak joint moments (concentric 0 degrees to 45 degrees = 30.4 N m and eccentric 45 degrees to 0 degrees = 21.0 N m) than females (concentric 0 degrees to 45 degrees = 19.7 N m and eccentric 45 degrees to 0 degrees = 12.8 N m).

  13. Techniques of Force and Pressure Measurement in the Small Joints of the Wrist.

    PubMed

    Schreck, Michael J; Kelly, Meghan; Canham, Colin D; Elfar, John C

    2017-02-01

    The alteration of forces across joints can result in instability and subsequent disability. Previous methods of force measurements such as pressure-sensitive films, load cells, and pressure-sensing transducers have been utilized to estimate biomechanical forces across joints and more recent studies have utilized a nondestructive method that allows for assessment of joint forces under ligamentous restraints. A comprehensive review of the literature was performed to explore the numerous biomechanical methods utilized to estimate intra-articular forces. Methods of biomechanical force measurements in joints are reviewed. Methods such as pressure-sensitive films, load cells, and pressure-sensing transducers require significant intra-articular disruption and thus may result in inaccurate measurements, especially in small joints such as those within the wrist and hand. Non-destructive methods of joint force measurements either utilizing distraction-based joint reaction force methods or finite element analysis may offer a more accurate assessment; however, given their recent inception, further studies are needed to improve and validate their use.

  14. Range of motion and isometric strength of shoulder joints of team handball athletes during the playing season, Part II: changes after midseason.

    PubMed

    Fieseler, Georg; Jungermann, Philipp; Koke, Alexander; Irlenbusch, Lars; Delank, Karl-Stefan; Schwesig, Rene

    2015-03-01

    Our objective was to investigate the influence of workload and consecutive changes on active range of motion and isometric strength of team handball athletes' throwing shoulders (TSs) because the available data are insufficient. In a longitudinal investigation, 31 professional male handball athletes underwent a clinical shoulder examination. Athletes were examined at the beginning (week 0), at the end (week 6) of the preseasonal training, and at the end of the half-season (week 22) on both shoulders to determine isometric rotational strength (hand held dynamometer) and active range of motion (goniometer). This analysis demonstrates the results subsequently from week 6 to week 22 and from week 0 to week 22. The glenohumeral internal rotation (IR) deficit (GIRD), external rotation (ER) gain, and ER at the TS increased significantly (P < .05, η(2) > 0.10, d > 0.30) in the first sequence (week 6 to week 22) but not significantly from week 0 to week 22. The total range of motion remained stable, and IR changed but not significantly. There was no influence on IR, ER, and total range of motion at the non-TS. The isometric strength of the TS and non-TS IR did not change. The isometric strength in ER significantly increased bilaterally during the investigation period. Our data verify changes and influences, such as an increasing GIRD, at the overhead TS joint in accordance with the workload during team handball season. ER gain did improve after the half-season period but did not fully compensate the GIRD at the TS. Copyright © 2015 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

  15. Shoulder Injuries in US Astronauts Related to EVA Suit Design

    NASA Technical Reports Server (NTRS)

    Scheuring, R. A.; McCulloch, P.; Van Baalen, Mary; Minard, Charles; Watson, Richard; Blatt, T.

    2011-01-01

    Introduction: For every one hour spent performing extravehicular activity (EVA) in space, astronauts in the US space program spend approximately six to ten hours training in the EVA spacesuit at NASA-Johnson Space Center's Neutral Buoyancy Lab (NBL). In 1997, NASA introduced the planar hard upper torso (HUT) EVA spacesuit which subsequently replaced the existing pivoted HUT. An extra joint in the pivoted shoulder allows increased mobility but also increased complexity. Over the next decade a number of astronauts developed shoulder problems requiring surgical intervention, many of whom performed EVA training in the NBL. This study investigated whether changing HUT designs led to shoulder injuries requiring surgical repair. Methods: US astronaut EVA training data and spacesuit design employed were analyzed from the NBL data. Shoulder surgery data was acquired from the medical record database, and causal mechanisms were obtained from personal interviews Analysis of the individual HUT designs was performed as it related to normal shoulder biomechanics. Results: To date, 23 US astronauts have required 25 shoulder surgeries. Approximately 48% (11/23) directly attributed their injury to training in the planar HUT, whereas none attributed their injury to training in the pivoted HUT. The planar HUT design limits shoulder abduction to 90 degrees compared to approximately 120 degrees in the pivoted HUT. The planar HUT also forces the shoulder into a forward flexed position requiring active retraction and extension to increase abduction beyond 90 degrees. Discussion: Multiple factors are associated with mechanisms leading to shoulder injury requiring surgical repair. Limitations to normal shoulder mechanics, suit fit, donning/doffing, body position, pre-existing injury, tool weight and configuration, age, in-suit activity, and HUT design have all been identified as potential sources of injury. Conclusion: Crewmembers with pre-existing or current shoulder injuries or certain

  16. Shoulder osteoarthritis: diagnosis and management.

    PubMed

    Millett, Peter J; Gobezie, Reuben; Boykin, Robert E

    2008-09-01

    Osteoarthritis of the shoulder is a gradual wearing of the articular cartilage that leads to pain and stiffness. As the joint surface degenerates, the subchondral bone remodels, losing its sphericity and congruity. The joint capsule also becomes thickened, leading to further loss of shoulder rotation. This painful condition is a growing problem in the aging population. In most cases, diagnosis of degenerative joint disease of the shoulder can be made with careful history, physical examination, and radiography. The symptoms and degree of shoulder arthritis visible on radiography determine the best treatment option. Mild degenerative joint disease can be treated with physical therapy and over-the-counter anti-inflammatory medications such as acetaminophen or nonsteroidal anti-inflammatory drugs. More advanced cases of osteoarthritis that are refractory to nonoperative management can be managed with corticosteroid injections. In severe cases, surgery is indicated. Surgical options include arthroscopic debridement, arthroscopic capsular release, and, in the most severe instances, hemiarthroplasty or total shoulder arthroplasty.

  17. Scapulohumeral rhythm in shoulders with reverse shoulder arthroplasty.

    PubMed

    Walker, David; Matsuki, Keisuke; Struk, Aimee M; Wright, Thomas W; Banks, Scott A

    2015-07-01

    Little is known about kinematic function of reverse total shoulder arthroplasty (RTSA). Scapulohumeral rhythm (SHR) is a common metric for assessing muscle function and shoulder joint motion. The purpose of this study was to compare SHR in shoulders with RTSA to normal shoulders. Twenty-eight subjects, more than 12 months after unilateral RTSA, were recruited for an Institutional Review Board-approved study. Subjects performed arm abduction in the coronal plane with and without a 1.4-kg hand-held weight. Three-dimensional model-image registration techniques were used to measure orientation and position for the humerus and scapula from fluoroscopic images. Analysis of variance and Tukey tests were used to assess groupwise and pairwise differences. SHR in RTSA shoulders (1.3:1) was significantly lower than in normal shoulders (3:1). Below 30° abduction, RTSA and normal shoulders show a wide range of SHR (1.3:1 to 17:1). Above 30° abduction, SHR in RTSA shoulders was 1.3:1 for unweighted abduction and 1.3:1 for weighted abduction. Maximum RTSA shoulder abduction in weighted trials was lower than in unweighted trials. SHR variability in RTSA shoulders decreased with increasing arm elevation. RTSA shoulders show kinematics that are significantly different from normal shoulders. SHR in RTSA shoulders was significantly lower than in normal shoulders, indicating that RTSA shoulders use more scapulothoracic motion and less glenohumeral motion to elevate the arm. With these observations, it may be possible to improve rehabilitation protocols, with particular attention to the periscapular muscles, and implant design or placement to optimize functional outcomes in shoulders with RTSA. Copyright © 2015 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

  18. Comparison of 3D turbo spin-echo SPACE sequences with conventional 2D MRI sequences to assess the shoulder joint.

    PubMed

    Kloth, Jost Karsten; Winterstein, Marianne; Akbar, Michael; Meyer, Esther; Paul, Dominik; Kauczor, Haus-Ulrich; Weber, Marc-André

    2014-10-01

    To determine the accuracy and reliability of three-dimensional (3D) T1- and proton density (PD)-weighted turbo spin-echo (TSE) sampling perfection with application-optimized contrasts using different flip-angle evolution (SPACE) compared with conventional 2D sequences in assessment of the shoulder-joint. Ninety-three subjects were examined on a 3-T MRI system with both conventional 2D-TSE sequences in T1-, T2- and PD-weighting and 3D SPACE sequences in T1- and PD-weighting. All examinations were assessed independently by two reviewers for common pathologies of the shoulder-joint. Agreement between 2D- and 3D-sequences and inter-observer-agreement was evaluated using kappa-statistics. Using conventional 2D TSE sequences as standard of reference, sensitivity, specificity, and accuracy values of 3D SPACE were 81.8%, 95.1%, and 93.5% for injuries of the supraspinatus-tendon (SSP), 81.3%, 93.5%, and 91.4% for the cartilage layer and 82.4%, 98.5%, and 97.5% for the long biceps tendon. Concordance between 2D and 3D was almost perfect for tendinopathies of the SSP (κ=0.85), osteoarthritis (κ=1), luxation of the biceps tendon (κ=1) and adjacent bone marrow (κ=0.92). Inter-observer-agreement was generally higher for conventional 2D TSE sequences (κ, 0.23-1.0), when compared to 3D SPACE sequences (κ, -0.33 to 1.0) except for disorders of the long biceps tendon and supraspinatus tendon rupture. Because of substantial and almost perfect concordance with conventional 2D TSE sequences for common shoulder pathologies, MRI examination-time can be reduced by nearly 40% (up to 11 min) using 3D-SPACE without loss of information. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  19. Shoulder muscle activity and function in common shoulder rehabilitation exercises.

    PubMed

    Escamilla, Rafael F; Yamashiro, Kyle; Paulos, Lonnie; Andrews, James R

    2009-01-01

    The rotator cuff performs multiple functions during shoulder exercises, including glenohumeral abduction, external rotation (ER) and internal rotation (IR). The rotator cuff also stabilizes the glenohumeral joint and controls humeral head translations. The infraspinatus and subscapularis have significant roles in scapular plane abduction (scaption), generating forces that are two to three times greater than supraspinatus force. However, the supraspinatus still remains a more effective shoulder abductor because of its more effective moment arm. Both the deltoids and rotator cuff provide significant abduction torque, with an estimated contribution up to 35-65% by the middle deltoid, 30% by the subscapularis, 25% by the supraspinatus, 10% by the infraspinatus and 2% by the anterior deltoid. During abduction, middle deltoid force has been estimated to be 434 N, followed by 323 N from the anterior deltoid, 283 N from the subscapularis, 205 N from the infraspinatus, and 117 N from the supraspinatus. These forces are generated not only to abduct the shoulder but also to stabilize the joint and neutralize the antagonistic effects of undesirable actions. Relatively high force from the rotator cuff not only helps abduct the shoulder but also neutralizes the superior directed force generated by the deltoids at lower abduction angles. Even though anterior deltoid force is relatively high, its ability to abduct the shoulder is low due to a very small moment arm, especially at low abduction angles. The deltoids are more effective abductors at higher abduction angles while the rotator cuff muscles are more effective abductors at lower abduction angles. During maximum humeral elevation the scapula normally upwardly rotates 45-55 degrees, posterior tilts 20-40 degrees and externally rotates 15-35 degrees. The scapular muscles are important during humeral elevation because they cause these motions, especially the serratus anterior, which contributes to scapular upward rotation

  20. Shoulder injuries in rugby players: mechanisms, examination, and rehabilitation.

    PubMed

    Helgeson, Kevin; Stoneman, Paul

    2014-11-01

    The sport of rugby is growing in popularity for players at the high school and collegiate levels. This article will provided the sports therapist with an introduction to the management of shoulder injuries in rugby players. Rugby matches results in frequent impacts and leveraging forces to the shoulder region during the tackling, scrums, rucks and maul components of the game. Rugby players frequently sustain contusion and impact injuries to the shoulder region, including injuries to the sternoclavicular, acromioclavicular (AC), and glenohumeral (GH) joints. Players assessed during practices and matches should be screened for signs of fracture, cervical spine and brachial plexus injuries. A three phase program will be proposed to rehabilitate players with shoulder instabilities using rugby specific stabilization, proprioception, and strengthening exercises. A plan for return to play will be addressed including position-specific activities. Copyright © 2014 Elsevier Ltd. All rights reserved.

  1. Residual force enhancement during multi-joint leg extensions at joint- angle configurations close to natural human motion.

    PubMed

    Paternoster, Florian Kurt; Seiberl, Wolfgang; Hahn, Daniel; Schwirtz, Ansgar

    2016-03-21

    The isometric steady-state forces following lengthening are greater than those produced at the same muscle length and activation level but without prior lengthening. Although residual force enhancement (RFE) has been investigated across a range of conditions, its relevance for daily human movement is still poorly understood. We aimed to study RFE in a setup imitating daily activity, i.e., submaximal activation of the lower extremity's muscles with slightly flexed knee joints comparable to human walking. A motor-driven leg press dynamometer was used for randomly arranged purely isometric and isometric-eccentric-isometric contractions. Thirteen subjects performed multi-joint leg extensions, which were feedback-controlled at 30% of maximum voluntary vastus lateralis activation. Isometric-eccentric-isometric contractions incorporated a stretch from 30° to 50° knee flexion, while isometric contractions were performed at 50° knee flexion. Isometric contractions following stretch and purely isometric reference contractions were performed at 50° knee flexion. Kinematics, forces, and muscular activity were measured using 3D optical motion tracking, force plates, and surface EMG of 9 lower limb muscles of the right leg and joint torques were calculated by inverse dynamics. Variables of standardization (EMG, joint angles) showed no differences between contraction conditions. Eight of 13 subjects showed RFE of up to 24.8±32.5% for external forces and joint torques. Because the remaining 5 non-responders failed to produce enhanced forces during the stretch, we believe that RFE is functionally relevant for muscle function comparable to everyday human motion but only if there is enhanced force during stretch that sufficiently triggers mechanisms underlying RFE.

  2. In vivo hip joint loads and pedal forces during ergometer cycling.

    PubMed

    Damm, P; Dymke, J; Bender, A; Duda, G; Bergmann, G

    2017-07-26

    The rising prevalence of osteoarthritis and an increase in total hip replacements calls for attention to potential therapeutic activities. Cycling is considered as a low impact exercise for the hip joint and hence recommended. However, there are limited data about hip joint loading to support this claim. The aim of this study was to measure synchronously the in vivo hip joint loads and pedal forces during cycling. The in vivo hip joint loads were measured in 5 patients with instrumented hip implants. Data were collected at several combinations of power and cadence, at two saddle heights. Joint loads and pedal forces showed strong linear correlation with power. So the relationship between the external pedal forces and internal joint forces was shown. While cycling at different cadences the minimum joint loads were acquired at 60RPM. The lower saddle height configuration results in an approximately 15% increase compared to normal saddle height. The results offered new insights into the actual effects of cycling on the hip joint and can serve as useful tools while developing an optimum cycling regimen for individuals with coxarthrosis or following total hip arthroplasty. Due to the relatively low contact forces, cycling at a moderate power level of 90W at a normal saddle height is suitable for patients. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. The relationship between lower neck shear force and facet joint kinematics during automotive rear impacts.

    PubMed

    Stemper, Brian D; Yoganandan, Narayan; Pintar, Frank A; Maiman, Dennis J

    2011-04-01

    A primary goal of biomechanical safety research is the definition of localized injury thresholds in terms of quantities that are repeatable and easily measureable during experimentation. Recent biomechanical experimentation using human cadavers has highlighted the role of lower cervical facet joints in the injury mechanism resulting from low-speed automotive rear impacts. The present study was conducted to correlate lower neck forces and moments with facet joint motions during simulated rear impacts in an effort to define facet joint injury tolerance thresholds that can be used to assess automobile safety. Four male and four female intact head-neck complexes were obtained from cadaveric specimens and subjected to simulated automotive rear impacts using a pendulum-minisled device. Cervical spine segmental angulations and localized facet joint kinematics were correlated to shear and axial forces, and bending moments at the cervico-thoracic junction using linear regression. R(2) coefficients indicated that spinal kinematics correlated well with lower neck shear force and bending moment. Correlation slope was steeper in female specimens, indicating greater facet joint motions for a given loading magnitude. This study demonstrated that lower neck loads can be used to predict lower cervical facet joint kinematics during automotive rear impacts. Higher correlation slope in female specimens corresponds to higher injury susceptibility in that population. Although lower neck shear force and bending moment demonstrated adequate correlation with lower cervical facet joint motions, shear force is likely the better predictor due to similarity in the timing of peak magnitudes with regard to maximum facet joint motions.

  4. Biomechanical Considerations in the Competitive Swimmer's Shoulder.

    PubMed

    Heinlein, Scott A; Cosgarea, Andrew J

    2010-11-01

    Competitive swimming has become an increasingly popular sport in the United States. In 2007, more than 250 000 competitive swimmers were registered with USA Swimming, the national governing body. The average competitive swimmer swims approximately 60 000 to 80 000 m per week. With a typical count of 8 to 10 strokes per 25-m lap, each shoulder performs 30 000 rotations each week. This places tremendous stress on the shoulder girdle musculature and glenohumeral joint, and it is why shoulder pain is the most frequent musculoskeletal complaint among competitive swimmers. Articles were obtained through a variety of medical search sources, including Medline, Google Scholar, and review articles from 1980 through January 2010. The most common cause of shoulder pain in swimmers is supraspinatus tendinopathy. Glenohumeral instability and labral tears have also been reported, but a paucity of information remains regarding prevalence and treatment in swimmers. Because of the great number of stroke repetitions and force generated through the upper extremity, the shoulder is uniquely vulnerable to injury in the competitive swimmer. Comprehensive evaluation should include the entire kinetic chain, including trunk strength and core stability.

  5. Measurement of finger joint angles and maximum finger forces during cylinder grip activity.

    PubMed

    Lee, J W; Rim, K

    1991-03-01

    Finger joint angles and finger forces during maximal cylindrical grasping were measured using multi-camera photogrammetry and pressure-sensitive sheets, respectively. The experimental data were collected from four healthy subjects gripping cylinders of five different sizes. For joint angles, an image analysis system was used to digitize slides showing markers. During the calibration of the camera system, both the nonlinear least square and the direct linear transform methods were applied and compared, the former providing the fewer errors; it was used to determine joint angles. Data were collected from the pressure-sensitive grip films by using the same image analysis system as used in the collection of the joint angle data. The method of using pressure-sensitive sheets provided an estimation of the weighted centre of the phalangeal forces. Results indicate that finger flexion angles at the metacarpophalangeal and proximal interphalangeal joints gradually increase as cylinder diameter decreases, but that at the distal interphalangeal joint the angle remains constant throughout all cylinder sizes. It was also found that most of the radio-ulnar deviation and the axial rotation angles at the finger joints deviate from zero, but the deviations are small. For the force measurement, it was found that total finger force increases as cylinder size decreases, and the phalangeal force centres are not located at the mid-points of the phalanges. The data obtained in this experiment would be useful for muscle force predictions and for the design of handles.

  6. Intraarticular pressure distribution in the talocrural joint is related to lower leg muscle forces.

    PubMed

    Potthast, Wolfgang; Lersch, Christian; Segesser, Bernhard; Koebke, Jürgen; Brüggemann, Gert-Peter

    2008-06-01

    It is of paramount importance to know the magnitude and the distribution of joint contact stress within the most heavily loaded structures of the human foot. In the talocrural joint role of external loading and loading applied by muscles on joint contact stress is not extensively studied. The purpose was to determine the distribution of joint contact stress of the talocrural joint with varying axial tibia loading and extrinsic tendon loading. Five cadaveric feet were studied in the intact condition and following transsection of ligaments under seventeen different loading conditions. Joint contact stress was determined from capacitive pressure sensors implanted in the talocrural joint when the specimens were loaded in a specially designed loading simulator. Different axial tibia and extrinsic tendon loads were applied. Motions of the bony structures were assessed by an optical motion analysis system. The anterior aspect of the joint is predominantly stressed in all loading conditions. The influence of muscle force on the internal joint contact stress distribution is higher than the axial shank loading. The biggest effect on joint contact stress was initiated by the tibialis posterior muscle. The flexor hallucis homogenizes the pressure distribution in intact joint conditions. Joint angles were not substantially changed by muscle force applications. The functions of the muscles of the lower leg are important for maintaining physiologic joint contact stress. Reducing the force potentials of certain muscle tendon units through surgeries, immobilization, fatigue or inappropriate footwear should change the joint contact stress. Such information is helpful to understand the physiological function of the foot. It might also explain the development and manifestation of certain foot pathologies.

  7. An instrumented fastener for shear force measurements in joints

    NASA Technical Reports Server (NTRS)

    Sawyer, James W.; Rothgeb, Timothy M.

    1992-01-01

    Results are presented of a preliminary investigation of instrumented fasteners for use as sensors to measure the shear loads transmitted by individual fasteners installed in double splice joints. Calibration and load verification tests were conducted for instrumented fasteners installed at three fastener torque levels. Calibration test results show that the shear strains obtained from the instrumented fasteners vary linearly with the applied load and that the instrumented fasteners can be effectively used to measure shear loads transmitted by individual fasteners installed in double splice joints. The load distribution between individual fasteners is found to be dependent on the location of the fastener in the joint and the fastener torque level.

  8. Joint force protection advanced security system (JFPASS) "the future of force protection: integrate and automate"

    NASA Astrophysics Data System (ADS)

    Lama, Carlos E.; Fagan, Joe E.

    2009-09-01

    The United States Department of Defense (DoD) defines 'force protection' as "preventive measures taken to mitigate hostile actions against DoD personnel (to include family members), resources, facilities, and critical information." Advanced technologies enable significant improvements in automating and distributing situation awareness, optimizing operator time, and improving sustainability, which enhance protection and lower costs. The JFPASS Joint Capability Technology Demonstration (JCTD) demonstrates a force protection environment that combines physical security and Chemical, Biological, Radiological, Nuclear, and Explosive (CBRNE) defense through the application of integrated command and control and data fusion. The JFPASS JCTD provides a layered approach to force protection by integrating traditional sensors used in physical security, such as video cameras, battlefield surveillance radars, unmanned and unattended ground sensors. The optimization of human participation and automation of processes is achieved by employment of unmanned ground vehicles, along with remotely operated lethal and less-than-lethal weapon systems. These capabilities are integrated via a tailorable, user-defined common operational picture display through a data fusion engine operating in the background. The combined systems automate the screening of alarms, manage the information displays, and provide assessment and response measures. The data fusion engine links disparate sensors and systems, and applies tailored logic to focus the assessment of events. It enables timely responses by providing the user with automated and semi-automated decision support tools. The JFPASS JCTD uses standard communication/data exchange protocols, which allow the system to incorporate future sensor technologies or communication networks, while maintaining the ability to communicate with legacy or existing systems.

  9. Integrating Special Operations Forces Operational Design and Joint Doctrine

    DTIC Science & Technology

    2014-12-04

    prescribed by Joint Publication 5-0, Joint Operation Planning, are evaluated using historical and conceptual theories relevant to limited war 3 or...war’s second grammar.”2 A comparison of USASOC’s elements of SOF Operational Design to these same conceptual theories will provide contextual support to... theories are common within the military profession. Current and former practitioners of military art and science regularly seek to apply lessons

  10. Acute spontaneous atraumatic bilateral anterior dislocation of the shoulder joint with Hill-Sach's lesions: A rare case.

    PubMed

    Sachit, Malhan; Shekhar, Agarwal; Shekhar, Srivastav; Joban, Singh Har

    2015-01-01

    Late diagnoses of orthopedic injuries after epileptic crisis are a matter of concern. The rarity of correlation between seizure and specific trauma incidences such as bilateral anterior shoulder dislocation, may lead to improper estimation of the patient's clinical state, wrong treatment and unpleasant complications. We report a rare case of bilateral anterior shoulder dislocation associated with coracoid processes fracture after a seizure episode, in a young lady of 29 years. This is a rare event, however as patient is often disoriented after seizures, frequently this can be missed diagnosis. So this article puts emphasis on possibilities of rare diagnosis, which if treated promptly can lead to early restoration of complete movement. Although it is not a common problem, but one should have a high degree of suspicion and should always opt for further radiological examination if there is any doubt.

  11. Sleep position and shoulder pain.

    PubMed

    Zenian, John

    2010-04-01

    The overuse theory for musculoskeletal joint pain cannot explain adequately the occurrence of shoulder pain in those who do not engage in activities that involve repeated and stressful use of the shoulder since the percentage of the painful right shoulders usually does not match the percentage of dominant right arms in such individuals. An alternative hypothesis is presented to propose that shoulder pain is caused by postural immobility in the decubitus or side position during sleep. Prolonged pressure on the shoulder caused by the weight of the thorax can produce enough damage to cause subsequent shoulder pain. In order to test this hypothesis, a preliminary study was carried out to compare the laterality of shoulder pain with the laterality of sleep position. The calculated laterality ratios for sleep position and shoulder pain were found to be strikingly similar, suggesting a causal relationship between the two phenomena. However, the prevalence of shoulder pain in the general population was found to be smaller than the percentage of the time people would spend sleeping in the decubitus position. This discrepancy could be explained by the idea that in order for shoulder pain to develop subjects may have to spend longer times in the same decubitus position before changing to another position than the average person would. Additional evidence from published clinical studies also supports the postural theory of shoulder pain. More studies can be done to test this hypothesis by focusing on the sleep habits of patients with shoulder pain. According to the present hypothesis shoulder pain should for the most part occur on the side that the patient preferred to sleep on before the onset of shoulder pain. The postural theory of shoulder pain provides the possibility for a new and noninvasive method to treat shoulder pain by the modification of posture during sleep.

  12. Achieving Cross-Domain Synergy: Overcoming Service Barriers to Joint Force 2020

    DTIC Science & Technology

    2014-06-13

    solution such as the cultural analysis performed during mergers, acquisitions, and joint ventures may be necessary to mitigate individual service...these barriers, it was discovered that a corporate solution such as the cultural analysis performed during mergers, acquisitions, and joint ventures...7 Lewins Force Field Analysis

  13. Kinematics of the Shoulder Girdle During Pointing: Coordination Between Joints and their Contribution to the Peri-Personal Workspace.

    PubMed

    Roby-Brami, Agnès; Robertson, Johanna V G; Roren, Alexandra; Lefèvre-Colau, Marie-Martine

    2016-08-19

    This study explored the coordination between the components of the shoulder girdle (clavicle, scapula and humerus), and how they contribute to hand movement in the peri-personal space. Shoulder girdle motion was recorded in 10 healthy subjects during pointing movements to 9 targets in the peri-personal space, using electromagnetic sensors fixed to the trunk, scapula and upper arm. Most of the 9 degrees of freedom (DoF) of the shoulder girdle were finely scaled to target position. Principle component analysis revealed that the 6 DoF of scapula-thoracic motion were coordinated in three elementary patterns (protraction, shrug and lateral rotation). The ratio of gleno-humeral to scapulo-thoracic global motion was close to 2:1. A direct kinematic procedure showed that if no scapular motion occurred, the workspace would be reduced by 15.8 cm laterally, 13.7 cm vertically and 4.8 cm anteriorly. Scapulo-thoracic motion should be taken into account when investigating the physiology of upper-limb movements.

  14. History of the Standing Joint Force Headquarters for Elimination (SJFHQ-E): No More Ad Hoc

    DTIC Science & Technology

    2014-05-22

    Approved for Public Release; Distribution is Unlimited THE HISTORY OF THE STANDING JOINT FORCE HEADQUARTERS FOR ELIMINATION (SJFHQ-E): “NO MORE AD... Elimination (SJFHQ-E): “No More Ad Hoc” Approved by: __________________________________, Monograph Director Daniel G. Cox, Ph.D...THE HISTORY OF THE STANDING JOINT FORCE HEADQUARTERS FOR ELIMINATION (SJFHQ-E): “NO MORE AD HOC,” by LTC Kristofer D. Hopkins, U.S. Army, 54 pages

  15. The Closure of U.S. Joint Forces Command - Mission Accomplished?

    DTIC Science & Technology

    2011-06-18

    importance of defending North Atlantic sea 1 Leo P. Hirrel with William R. McClintock ; United States...3 Hirrel with McClintock , xiii. 5 1999.4 To the casual observer very little change was apparent, but in the words of... McClintock , 53. 5 Ibid., 53. 6 U.S. Joint Forces Command, Command Overview Briefing, Norfolk, VA: Office of Public Affairs, U.S. Joint Forces Command

  16. Influence of clamp-up force on the strength of bolted composite joints

    NASA Astrophysics Data System (ADS)

    Horn, Walter J.; Schmitt, Ron R.

    1994-03-01

    Composite materials offer the potential for a reduction in the number of individual parts and joints in a structure because large one-piece components can replace multipart assemblies. Nevertheless, there are many situations where composite parts must be joined and often mechanical fasteners provide the only practical method of joining those parts. The long-term strength of mechanically fastened joints of composite members can be directly affected by the clamp-up force of the fastener and thus perhaps by the relaxation of this force due to the viscoelastic character of the composite materials of the joint. Methods for predicting the effect of bolt clamp-up force relaxation on the strength of mechanically fastened joints of thermoplastic composite materials were investigated during the present study. A test program, using two thermoplastic composite materials, was conducted to determine the influence of clamp-up force on joint strength, to measure the relaxation of the joint clamp-up force with time, and to measure the change of joint strength as a function of time.

  17. Heads, Shoulders, Elbows, Knees, and Toes: Modular Gdf5 Enhancers Control Different Joints in the Vertebrate Skeleton

    PubMed Central

    Schoor, Michael; Mortlock, Doug P.; Reddi, A. Hari; Kingsley, David M.

    2016-01-01

    Synovial joints are crucial for support and locomotion in vertebrates, and are the frequent site of serious skeletal defects and degenerative diseases in humans. Growth and differentiation factor 5 (Gdf5) is one of the earliest markers of joint formation, is required for normal joint development in both mice and humans, and has been genetically linked to risk of common osteoarthritis in Eurasian populations. Here, we systematically survey the mouse Gdf5 gene for regulatory elements controlling expression in synovial joints. We identify separate regions of the locus that control expression in axial tissues, in proximal versus distal joints in the limbs, and in remarkably specific sub-sets of composite joints like the elbow. Predicted transcription factor binding sites within Gdf5 regulatory enhancers are required for expression in particular joints. The multiple enhancers that control Gdf5 expression in different joints are distributed over a hundred kilobases of DNA, including regions both upstream and downstream of Gdf5 coding exons. Functional rescue tests in mice confirm that the large flanking regions are required to restore normal joint formation and patterning. Orthologs of these enhancers are located throughout the large genomic region previously associated with common osteoarthritis risk in humans. The large array of modular enhancers for Gdf5 provide a new foundation for studying the spatial specificity of joint patterning in vertebrates, as well as new candidates for regulatory regions that may also influence osteoarthritis risk in human populations. PMID:27902701

  18. Heads, Shoulders, Elbows, Knees, and Toes: Modular Gdf5 Enhancers Control Different Joints in the Vertebrate Skeleton.

    PubMed

    Chen, Hao; Capellini, Terence D; Schoor, Michael; Mortlock, Doug P; Reddi, A Hari; Kingsley, David M

    2016-11-01

    Synovial joints are crucial for support and locomotion in vertebrates, and are the frequent site of serious skeletal defects and degenerative diseases in humans. Growth and differentiation factor 5 (Gdf5) is one of the earliest markers of joint formation, is required for normal joint development in both mice and humans, and has been genetically linked to risk of common osteoarthritis in Eurasian populations. Here, we systematically survey the mouse Gdf5 gene for regulatory elements controlling expression in synovial joints. We identify separate regions of the locus that control expression in axial tissues, in proximal versus distal joints in the limbs, and in remarkably specific sub-sets of composite joints like the elbow. Predicted transcription factor binding sites within Gdf5 regulatory enhancers are required for expression in particular joints. The multiple enhancers that control Gdf5 expression in different joints are distributed over a hundred kilobases of DNA, including regions both upstream and downstream of Gdf5 coding exons. Functional rescue tests in mice confirm that the large flanking regions are required to restore normal joint formation and patterning. Orthologs of these enhancers are located throughout the large genomic region previously associated with common osteoarthritis risk in humans. The large array of modular enhancers for Gdf5 provide a new foundation for studying the spatial specificity of joint patterning in vertebrates, as well as new candidates for regulatory regions that may also influence osteoarthritis risk in human populations.

  19. Subject-specific knee joint geometry improves predictions of medial tibiofemoral contact forces

    PubMed Central

    Gerus, Pauline; Sartori, Massimo; Besier, Thor F.; Fregly, Benjamin J.; Delp, Scott L.; Banks, Scott A.; Pandy, Marcus G.; D’Lima, Darryl D.; Lloyd, David G.

    2013-01-01

    Estimating tibiofemoral joint contact forces is important for understanding the initiation and progression of knee osteoarthritis. However, tibiofemoral contact force predictions are influenced by many factors including muscle forces and anatomical representations of the knee joint. This study aimed to investigate the influence of subject-specific geometry and knee joint kinematics on the prediction of tibiofemoral contact forces using a calibrated EMG-driven neuromusculoskeletal model of the knee. One participant fitted with an instrumented total knee replacement walked at a self-selected speed while medial and lateral tibiofemoral contact forces, ground reaction forces, whole-body kinematics, and lower-limb muscle activity were simultaneously measured. The combination of generic and subject-specific knee joint geometry and kinematics resulted in four different OpenSim models used to estimate muscle-tendon lengths and moment arms. The subject-specific geometric model was created from CT scans and the subject-specific knee joint kinematics representing the translation of the tibia relative to the femur was obtained from fluoroscopy. The EMG-driven model was calibrated using one walking trial, but with three different cost functions that tracked the knee flexion/extension moments with and without constraint over the estimated joint contact forces. The calibrated models then predicted the medial and lateral tibiofemoral contact forces for five other different walking trials. The use of subject-specific models with minimization of the peak tibiofemoral contact forces improved the accuracy of medial contact forces by 47% and lateral contact forces by 7%, respectively compared with the use of generic musculoskeletal model. PMID:24074941

  20. Subject-specific knee joint geometry improves predictions of medial tibiofemoral contact forces.

    PubMed

    Gerus, Pauline; Sartori, Massimo; Besier, Thor F; Fregly, Benjamin J; Delp, Scott L; Banks, Scott A; Pandy, Marcus G; D'Lima, Darryl D; Lloyd, David G

    2013-11-15

    Estimating tibiofemoral joint contact forces is important for understanding the initiation and progression of knee osteoarthritis. However, tibiofemoral contact force predictions are influenced by many factors including muscle forces and anatomical representations of the knee joint. This study aimed to investigate the influence of subject-specific geometry and knee joint kinematics on the prediction of tibiofemoral contact forces using a calibrated EMG-driven neuromusculoskeletal model of the knee. One participant fitted with an instrumented total knee replacement walked at a self-selected speed while medial and lateral tibiofemoral contact forces, ground reaction forces, whole-body kinematics, and lower-limb muscle activity were simultaneously measured. The combination of generic and subject-specific knee joint geometry and kinematics resulted in four different OpenSim models used to estimate muscle-tendon lengths and moment arms. The subject-specific geometric model was created from CT scans and the subject-specific knee joint kinematics representing the translation of the tibia relative to the femur was obtained from fluoroscopy. The EMG-driven model was calibrated using one walking trial, but with three different cost functions that tracked the knee flexion/extension moments with and without constraint over the estimated joint contact forces. The calibrated models then predicted the medial and lateral tibiofemoral contact forces for five other different walking trials. The use of subject-specific models with minimization of the peak tibiofemoral contact forces improved the accuracy of medial contact forces by 47% and lateral contact forces by 7%, respectively compared with the use of generic musculoskeletal model. © 2013 Published by Elsevier Ltd.

  1. The effects of cycling cadence on the phases of joint power, crank power, force and force effectiveness.

    PubMed

    Ettema, Gertjan; Lorås, Håvard; Leirdal, Stig

    2009-04-01

    We examined the influence of cadence in cycling technique by quantifying phase relationships for a number of important variables at the crank and lower extremity joints. Any difference in the effect of cadence on force, effectiveness, and power phases would indicate an essential change in coordination pattern. Cycle kinetics was recorded for 10 male competitive cyclists at five cadences (60-100 rpm) at submaximal load (260 W). Joint powers were calculated using inverse dynamics methods. All data were expressed as a function of crank position. The phase of the crank mechanical profiles (total force, crank and joint power, and effectiveness) was calculated using four methods: crank angle of maximum (MA) and minimum (MI), fitting a sine wave (SI) and by cross-correlation (XC). These methods, apart from the MA method, showed the same relative phase. The variables, however, showed different phases being expressed as time lag: force effectiveness: 0.131 (+/-0.034)s; total force: 0.149 (+/-0.021)s; power: 0.098 (+/-0.027)s. The phases in joint powers hip 0.071 (+/-0.008), knee 0.082 (+/-0.009), and hip 0.077 (+/-0.012) were only well described by XC, and were somewhat lower than the crank power phase. These differences indicate the potential effect of inertia of the lower limb in phase shifts from joints to crank. Furthermore, the differences between the various crank variables indicate a change of technique with cadence.

  2. A leader-follower relationship in joint action on a discrete force production task.

    PubMed

    Masumoto, Junya; Inui, Nobuyuki

    2014-11-01

    The present study examined the development of a leader-follower relationship in joint action performed by participants with different skill levels. Two participants were instructed to produce discrete isometric forces such that the sum of the forces was the target force. The task did not prescribe the onset time or share of force each participant contributed to the target force. Although novices with low force variability did not produce an earlier force than those with high force variability in the novice-novice group, experienced participants produced an earlier force than novices in the novice-experienced group. While participants with low force variability always produced a stronger force than those with high force variability in both the groups, there was no significant difference in force distributions between participants with low and high force variabilities. Although a novice-experienced pair produced force more complementarily than a novice-novice pair in the first practice block, the difference between pairs vanished after the first practice block, suggesting that leader-follower relations were not always beneficial to task performance. In addition, practice of the joint action did not transfer to individual action.

  3. Little league shoulder.

    PubMed

    Osbahr, Daryl C; Kim, Han Jo; Dugas, Jeffrey R

    2010-02-01

    The present review aims to provide a synopsis of the current literature on little league shoulder, including etiology, diagnosis, prevention, and treatment. As management involving little league shoulder has not drastically changed over recent years, most current research evaluating youth throwing athletes with shoulder pain relates to biomechanics and prevention. Current literature on biomechanics indicates that the maximum shoulder external rotation and ball release phases of throwing provide the highest rotational torque and distraction forces, respectively, with the maximum external rotation phase being most likely related to the development of little league shoulder. In addition, targets for prevention have also been identified in youth throwing athletes, including current or prior history of shoulder pain, variability in mechanics, glenohumeral internal rotation deficit, and accordance with throwing guidelines, especially in at-risk baseball pitchers. Little league shoulder is most commonly seen in youth throwing athletes between 11 and 16 years of age. Clinical evaluation and radiographic imaging typically confirms the diagnosis. Management is most effectively performed through prevention. With the onset of little league shoulder, nonoperative treatment is typically successful, with a 3-month period of rest followed by a progressive throwing program with subsequent return to play.

  4. A History of Shoulder Surgery

    PubMed Central

    Iqbal, S; Jacobs, U; Akhtar, A; Macfarlane, R.J; Waseem, M

    2013-01-01

    Shoulder surgery has emerged from being a marginalised sub-speciality to being an area of much research and advancement within the last seventy years. This has been despite the complexity of the joint, and success majorly rests on parallel development of biomedical technology. This article looks at the past and present of shoulder surgery and discusses future directions in the speciality. PMID:24082968

  5. Knee Joint Loads and Surrounding Muscle Forces during Stair Ascent in Patients with Total Knee Replacement

    PubMed Central

    Rasnick, Robert; Standifird, Tyler; Reinbolt, Jeffrey A.; Cates, Harold E.

    2016-01-01

    Total knee replacement (TKR) is commonly used to correct end-stage knee osteoarthritis. Unfortunately, difficulty with stair climbing often persists and prolongs the challenges of TKR patents. Complete understanding of loading at the knee is of great interest in order to aid patient populations, implant manufacturers, rehabilitation, and future healthcare research. Musculoskeletal modeling and simulation approximates joint loading and corresponding muscle forces during a movement. The purpose of this study was to determine if knee joint loadings following TKR are recovered to the level of healthy individuals, and determine the differences in muscle forces causing those loadings. Data from five healthy and five TKR patients were selected for musculoskeletal simulation. Variables of interest included knee joint reaction forces (JRF) and the corresponding muscle forces. A paired samples t-test was used to detect differences between groups for each variable of interest (p<0.05). No differences were observed for peak joint compressive forces between groups. Some muscle force compensatory strategies appear to be present in both the loading and push-off phases. Evidence from knee extension moment and muscle forces during the loading response phase indicates the presence of deficits in TKR in quadriceps muscle force production during stair ascent. This result combined with greater flexor muscle forces resulted in similar compressive JRF during loading response between groups. PMID:27258086

  6. Effects of moving forward or backward on the saddle on knee joint forces during cycling.

    PubMed

    Bini, Rodrigo Rico; Hume, Patria Anne; Lanferdini, Fabio Junner; Vaz, Marco Aurélio

    2013-02-01

    To examine the effects of cycling at preferred, forward and backward saddle positions on patellofemoral compressive and tibiofemoral compressive and shear forces. Cross-sectional. An incremental cycling test to exhaustion determined cyclists' maximal aerobic workload and second ventilatory threshold. In a second session, 1-min cycling trial at maximal aerobic workload then three 2-min trials at second ventilatory threshold workload at preferred, forward and backward saddle positions. Right pedal force via instrumented pedals, lower limb joint kinematics via video and inverse dynamics were used to calculate knee joint forces. Twenty-one competitive cyclists (28 ± 7 years). Patellofemoral compressive, tibiofemoral compressive and shear forces, and knee flexion angle. Changes to forward/backward saddle positions did not substantially affect compressive forces for patellofemoral (1-4%) or tibiofemoral (1-3%) joints. Tibiofemoral shear force increased in backward compared with preferred (19%) or forward (26%) saddle positions. Knee flexion angle at 3 o'clock (22%) and 6 o'clock crank positions (36%) increased at the forward compared to the backward saddle position. Small increases in knee flexion angle (5-6°) explained trivial differences in patellofemoral and tibiofemoral compressive forces. Tibiofemoral shear force may be more sensitive to changes in knee joint angle compared to other knee force components. Copyright © 2012 Elsevier Ltd. All rights reserved.

  7. Knee Joint Loads and Surrounding Muscle Forces during Stair Ascent in Patients with Total Knee Replacement.

    PubMed

    Rasnick, Robert; Standifird, Tyler; Reinbolt, Jeffrey A; Cates, Harold E; Zhang, Songning

    2016-01-01

    Total knee replacement (TKR) is commonly used to correct end-stage knee osteoarthritis. Unfortunately, difficulty with stair climbing often persists and prolongs the challenges of TKR patents. Complete understanding of loading at the knee is of great interest in order to aid patient populations, implant manufacturers, rehabilitation, and future healthcare research. Musculoskeletal modeling and simulation approximates joint loading and corresponding muscle forces during a movement. The purpose of this study was to determine if knee joint loadings following TKR are recovered to the level of healthy individuals, and determine the differences in muscle forces causing those loadings. Data from five healthy and five TKR patients were selected for musculoskeletal simulation. Variables of interest included knee joint reaction forces (JRF) and the corresponding muscle forces. A paired samples t-test was used to detect differences between groups for each variable of interest (p<0.05). No differences were observed for peak joint compressive forces between groups. Some muscle force compensatory strategies appear to be present in both the loading and push-off phases. Evidence from knee extension moment and muscle forces during the loading response phase indicates the presence of deficits in TKR in quadriceps muscle force production during stair ascent. This result combined with greater flexor muscle forces resulted in similar compressive JRF during loading response between groups.

  8. Joint Force Quarterly. Number 27, Winter 2000-01

    DTIC Science & Technology

    2001-04-01

    rapidly overcome enemy port denial operations. Second, it took months to es- tablish an offensive capability in-theater. We need more rapid force...before Serbia agreed to pull its forces from Kosovo. The reasons for this deci- sion were more self -evident than real- ized at the time. The withdrawal...That a corps head- quarters with more than 500 officers, noncommissioned officers, and sol- diers was necessary to coordinate a 5,000-man task force

  9. Joint Force Quarterly. Issue 67, 4th Quarter, October 2012

    DTIC Science & Technology

    2012-10-01

    Burundi were the only two countries to contribute troops to AMISOM.10 For the Ugandans, this marked their first deploy- ment of a military force...provide forces to AMISOM. We work extensively with Uganda and Burundi since they provide the majority of forces to AMISOM. If our efforts are successful...Department–contracted trainers and continue to shape collective and individual training efforts at locations in Uganda and Burundi . Section 1206

  10. Biomechanical analysis of anterior bone graft augmentation with reversed shoulder arthroplasty in large combined glenoid defects compared with total bony joint line reconstruction (modified bony-increased-offset reversed shoulder arthroplasty).

    PubMed

    Königshausen, Matthias; Sverdlova, Nina; Mersmann, Corinna; Ehlert, Christoph; Jettkant, Birger; Dermietzel, Rolf; Schildhauer, Thomas Armin; Seybold, Dominik

    2017-10-01

    The aim of this biomechanical study was to compare 2 surgical techniques for the reconstruction of large, combined, uncontained glenoid defects with reversed shoulder arthroplasty (RSA). Three groups of scapulae with RSA were tested by the application of a physiological combination of compressive/shear loads in Sawbones (Pacific Research Laboratories, Inc., Vashon Island, WA, USA) and cadavers. Two of the groups (both Sawbones and cadaveric specimens) consisted of anterior combined defects (14 mm in depth), and the third group served as a control group (only Sawbones specimens). The first group with an anterior combined defect was reconstructed with anterior bone grafts to contain the defect and cancellous bone to fill the central defect before RSA with partial bony joint line reconstruction (p-BJR). In the second group with an anterior combined defect, the dorsal rim was reamed and the joint line was reconstructed with a bone disc fully covering the peg. This total BJR (t-BJR) corresponds to the technique of bony-increased-offset-RSA (BIO-RSA). At 150 µm of displacement, the loadings in the inferior-superior (IS) direction were significantly more stable than those in the anterior-to-posterior (AP) direction within both reconstructed defect groups (P ≤ .002). In contrast, no significant differences were found between the partial BJR and t-BJR group in either direction (Sawbones: AP: P = .29; IS: P = .44; cadavers: AP: P = .67; IS: P = .99). The control group revealed significantly higher values in all loadings of the IS direction and significantly higher loadings at 40 µm and 150 µm in the AP direction. Both techniques could be applied for such complex defects provided that there is sufficient medial bone stock for a t-BJR. Significantly greater stability was found in the IS direction than in the AP direction within each group, which could be explained by the longer screw anchoring within the superior and inferior columns. Both

  11. Frozen shoulder

    MedlinePlus

    ... cut) by bringing the shoulder through a full range of motion. Arthroscopic surgery can also be used to cut ... if you develop shoulder pain that limits your range of motion for an extended period. People who have diabetes ...

  12. Shoulder Arthroscopy

    MedlinePlus

    ... bones: your upper arm bone (humerus), your shoulder blade (scapula), and your collarbone (clavicle). Ball and socket. ... fits into a rounded socket in your shoulder blade. This socket is called the glenoid. A slippery ...

  13. Shoulder pain

    MedlinePlus

    ... the rotator cuff, give the shoulder its wide range of motion. Swelling, damage, or bone changes around the rotator ... you are recovering from tendinitis, continue to do range-of-motion exercises to avoid frozen shoulder . Practice good posture ...

  14. Joint line elevation in revision TKA leads to increased patellofemoral contact forces.

    PubMed

    König, Christian; Sharenkov, Alexey; Matziolis, Georg; Taylor, William R; Perka, Carsten; Duda, Georg N; Heller, Markus O

    2010-01-01

    One difficulty in revision total knee arthroplasty (TKA) is the management of distal femoral bone defects in which a joint line elevation (JLE) is likely to occur. Although JLE has been associated with inferior clinical results, the effect that an elevated joint line has on knee contact forces has not been investigated. To understand the clinical observations and elaborate the potential risk associated with a JLE, we performed a virtual TKA on the musculoskeletal models of four subjects. Tibio- and patellofemoral joint contact forces (JCF) were calculated for walking and stair climbing, varying the location of the joint line. An elevation of the joint line primarily affected the patellofemoral joint with JCF increases of as much as 60% of the patient's body weight (BW) at 10-mm JLE and 90% BW at 15-mm JLE, while the largest increase in tibiofemoral JCF was only 14% BW. This data demonstrates the importance of restoring the joint line, as it plays a critical role for the magnitudes of the JCFs, particularly for the patellofemoral joint. JLE caused by managing distal femoral defects with downsizing and proximalizing the femoral component could increase the patellofemoral contact forces, and may be a contributing factor to postoperative complications such as pain, polyethylene wear, and limited function.

  15. [Winter sports and shoulder arthroplasty].

    PubMed

    Kirchhoff, C; Imhoff, A B; Hinterwimmer, S

    2008-09-01

    Nowadays, a general negative evaluation of sportive activity regarding different kinds of sport following arthroplasty is at present no more scientifically supported. However, at present no valid guidelines regarding sportive activity of patients after implantation of shoulder joint arthroplasty exist. The question regarding the ability of performing winter sports activities of patients treated with shoulder joint endoprothesis has not been answered so far. Therefore the aim of the presented work was to identify winter sports-specific risks for patients treated with shoulder joint endoprothesis as well as to critically discuss the actual literature in refer to winter sport activities. Criteria for the education of patients with shoulder joint endoprothesis as well as consultation regarding winter sport activities will be provided for the orthopaedic surgeon.

  16. Evidence of rapid Cenozoic uplift of the shoulder escarpment of the Cenozoic West Antarctic rift system and a speculation on possible climate forcing

    USGS Publications Warehouse

    Behrendt, John C.; Cooper, A.

    1991-01-01

    The Cenozoic West Antarctic rift system, characterized by Cenozoic bimodal alkalic volcanic rocks, extends over a largely ice-covered area, from the Ross Sea nearly to the Bellingshausen Sea. Various lines of evidence lead to the following interpretation: the transantarctic Mountains part of the rift shoulder (and probably the entire shoulder) has been rising since about 60 Ma, at episodic rates of ~1 km/m.y., most recently since mid-Pliocene Time, rather than continuously at the mean rate of 100 m/m.y. Uplift rates vary along the scarp, which is cut by transverse faults. It is speculated that this uplift may have climatically forced the advance of the Antarctic ice sheet since the most recent warm period. A possible synergistic relation is suggested between episodic tectonism, mountain uplift, and volcanism in the Cenozoic West Antarctic rift system and waxing and waning of the Antarctic ice sheet beginning about earliest Oligocene time. 

  17. Joint Task Force National Capital Region Medical: Integration of Education, Training, and Research

    DTIC Science & Technology

    2009-05-01

    MEDICAL (NCR) NCR TRANSITION OIPT ADtFORa COMPONENT COMHAHD ARMY COMPONCHT COMMAND 1 1 AIR FORCE FACUJTKS ARHV FAdUTIES 1 NAVY FAciuncs NAW COMPONE NT...MILITARY MEDICINE, Vol. 174. May Z 453 Joint Task Force National Capital Region Medical 3. De Lorenzo RA: Future trends in military graduate medical educa

  18. American Indian Policy Review Commission Special Joint Task Force Report on Alaskan Native Issues.

    ERIC Educational Resources Information Center

    Congress of the U.S. Washington, DC. American Indian Policy Review Commission.

    Impact of the Alaskan Native Claims Settlement Act (ANCSA) on Alaskan Natives, particularly at village levels, is the focus of a joint task force report on Alaskan Native issues. Prepared for the American Indian Policy Review Commission, the report is the work of representatives from task forces on tribal government, federal, state, and tribal…

  19. Three-dimensional knee joint contact forces during walking in unilateral transtibial amputees.

    PubMed

    Silverman, Anne K; Neptune, Richard R

    2014-08-22

    Individuals with unilateral transtibial amputations have greater prevalence of osteoarthritis in the intact knee joint relative to the residual leg and non-amputees, but the cause of this greater prevalence is unclear. The purpose of this study was to compare knee joint contact forces and the muscles contributing to these forces between amputees and non-amputees during walking using forward dynamics simulations. We predicted that the intact knee contact forces would be higher than those of the residual leg and non-amputees. In the axial and mediolateral directions, the intact and non-amputee legs had greater peak tibio-femoral contact forces and impulses relative to the residual leg. The peak axial contact force was greater in the intact leg relative to the non-amputee leg, but the stance phase impulse was greater in the non-amputee leg. The vasti and hamstrings muscles in early stance and gastrocnemius in late stance were the largest contributors to the joint contact forces in the non-amputee and intact legs. Through dynamic coupling, the soleus and gluteus medius also had large contributions, even though they do not span the knee joint. In the residual leg, the prosthesis had large contributions to the joint forces, similar to the soleus in the intact and non-amputee legs. These results identify the muscles that contribute to knee joint contact forces during transtibial amputee walking and suggest that the peak knee contact forces may be more important than the knee contact impulses in explaining the high prevalence of intact leg osteoarthritis. Copyright © 2014 Elsevier Ltd. All rights reserved.

  20. [Measurement of the isometric dorsiflexion and plantar flexion force in the ankle joint].

    PubMed

    Göpfert, Beat; Valderrabano, Victor; Hintermann, Beat; Wirz, Dieter

    2005-09-01

    This article describes an easy to use test equipment for measuring the isometric force in the ankle joints in dorsiflexion and plantar flexion. The combination of the test equipment for measuring the voluntary maximal isometric muscle force in the ankle joint, the surface electromyograms and the motion analysis of the measured leg allow an objective comparison of the strength of the muscular force between the left and right leg. It might be also used as a control setup during rehabilitation after surgical treatment or injuries.

  1. Out of Joint: Independent Air Forces in Democratic Cultures

    DTIC Science & Technology

    2010-06-01

    that service. Instead, Instant Thunder, the air operation against Iraq, simply became a model for the future. Strategic airlift took second place...be extremely disingenuous to suggest that the organizational learning experienced by one of the three air forces was not immediately shared with the...inventory Also, many of the historical influences that most shaped their understanding were shared experiences. All three air forces participated

  2. Joint Force Quarterly. Issue 48, 1st Quarter 2008

    DTIC Science & Technology

    2008-01-01

    and family support to ensure these forces are ready to serve effectively over the long term and across the full spectrum of operations. n Provide...leverage existing forces, streamline organiza- tions, and make units leaner, smaller, and more effective . We must likewise ensure that the National Guard...interdependent, priori- tized Service modernization plans. n Develop implementation plans to ensure effective execution of pending Base Realign- ment and

  3. Milwaukee Shoulder Syndrome.

    PubMed

    Ersoy, Hale; Pomeranz, Stephen J

    Milwaukee shoulder syndrome (MSS) is a rare, rapidly destructive arthropathy associated with calcium hydroxyapatite crystal deposition. This condition is a combination of rotator cuff tear, osteoarthritic changes, noninflammatory joint effusion containing crystals, synovial hyperplasia, cartilage and subchondral bone destruction, and multiple osteochondral loose bodies. This article discusses pathophysiology, clinical presentation, differential considerations, and magnetic resonance imaging findings of MSS.

  4. Joint Force Quarterly. Number 3, Winter 1993-94

    DTIC Science & Technology

    1994-01-01

    impossibility. Sources: Map (above) American Embassy, Saigon. Map (left) Joel D. Meyerson, Images of a Lengthy War (Washington: Government Printing Office...as Crusader Defense Transportation Report Documentation Page Form ApprovedOMB No. 0704-0188 Public reporting burden for the collection of...T W O R L D 101 Doctrine, Education, and Documentation 108 A Quarterly Review of Joint Literature O F F T H E S H E L F 110 Vietnam as Military

  5. The Business of Bundling: Joining Forces on Joint Replacement.

    PubMed

    Kaldy, Joanne

    2016-03-01

    A mandated bundled-payment program for joint replacement is in place in several regions across the country, and practitioners such as pharmacists are still sorting out their roles in this federal initiative. To get involved, pharmacists need to establish connections with area hospitals and physician groups to promote and document their ability to manage medications, reduce and eliminate medication-related problems and rehospitalizations, and work with patients to maximize adherence and improve communication for those undergoing hip and knee replacement.

  6. Joint Task Force Command, Control, and Communications: Have We Improved

    DTIC Science & Technology

    1989-05-05

    DECLASSIFICATION / DOWNGRADING SC-iEDULE unlimited 4. PERFORMING ORGANIZATION REPORT NUMBER(S) 5 MONiTORING ORGANIZATION REPORT NUMBER(S) 6a. NAME OF...REPORT (Year, Month, Day). 11 PAGE COUNT Monograph IFROM _____TO ____ 89/ 5 / 5 55 16. SUPPLEMENTARY NOTATION 17. COSATI CODES , 18. SUBJECT TERMS (Continue...cited, the same joint C3 problems kept reappearing; 5 )the reappearing problems were not fixed because of the services refusal to accept substantial

  7. Joint Force Quarterly. Number 33, Winter 2002-03

    DTIC Science & Technology

    2003-04-01

    Jefferson Davis Highway, Suite 1204, Arlington VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law , no person...all elements of national power must be better integrated. Financial services, law en- forcement, diplomatic efforts, and commercial ac- tivities both...terrorism in ill-advised ways. They may seek to deploy them with other agencies, such as intel- ligence and law enforcement, to form joint inter- agency

  8. Is Lifelong Knee Joint Force from Work, Home, and Sport Related to Knee Osteoarthritis?

    PubMed Central

    Ratzlaff, Charles R.; Koehoorn, Mieke; Cibere, Jolanda; Kopec, Jacek A.

    2012-01-01

    Purpose. To investigate the association of cumulative lifetime knee joint force on the risk of self-reported medically-diagnosed knee osteoarthritis (OA). Methods. Exposure data on lifetime physical activity type (occupational, household, sport/recreation) and dose (frequency, intensity, duration) were collected from 4,269 Canadian men and women as part of the Physical Activity and Joint Heath cohort study. Subjects were ranked in terms of the “cumulative peak force index”, a measure of lifetime mechanical knee force. Multivariable logistic regression was conducted to obtain adjusted effects for mean lifetime knee force on the risk of knee OA. Results. High levels of total lifetime, occupational and household-related force were associated with an increased in risk of OA, with odds ratio's ranging from approximately 1.3 to 2. Joint injury, high BMI and older age were related to risk of knee OA, consistent with previous studies. Conclusions. A newly developed measure of lifetime mechanical knee force from physical activity was employed to estimate the risk of self-reported, medically-diagnosed knee OA. While there are limitations, this paper suggests that high levels of total lifetime force (all domains combined), and occupational force in men and household force in women were risk factors for knee OA. PMID:22848225

  9. Calculation of muscle loading and joint contact forces during the rock step in Irish dance.

    PubMed

    Shippen, James M; May, Barbara

    2010-01-01

    A biomechanical model for the analysis of dancers and their movements is described. The model consisted of 31 segments, 35 joints, and 539 muscles, and was animated using movement data obtained from a three-dimensional optical tracking system that recorded the motion of dancers. The model was used to calculate forces within the muscles and contact forces at the joints of the dancers in this study. Ground reaction forces were measured using force plates mounted in a sprung floor. The analysis procedure is generic and can be applied to any dance form. As an exemplar of the application process an Irish dance step, the rock, was analyzed. The maximum ground reaction force found was 4.5 times the dancer's body weight. The muscles connected to the Achilles tendon experienced a maximum force comparable to their maximal isometric strength. The contact force at the ankle joint was 14 times body weight, of which the majority of the force was due to muscle contraction. It is suggested that as the rock step produces high forces, and therefore the potential to cause injury, its use should be carefully monitored.

  10. Recent advances in shoulder research.

    PubMed

    Killian, Megan L; Cavinatto, Leonardo; Galatz, Leesa M; Thomopoulos, Stavros

    2012-06-15

    Shoulder pathology is a growing concern for the aging population, athletes, and laborers. Shoulder osteoarthritis and rotator cuff disease represent the two most common disorders of the shoulder leading to pain, disability, and degeneration. While research in cartilage regeneration has not yet been translated clinically, the field of shoulder arthroplasty has advanced to the point that joint replacement is an excellent and viable option for a number of pathologic conditions in the shoulder. Rotator cuff disease has been a significant focus of research activity in recent years, as clinicians face the challenge of poor tendon healing and irreversible changes associated with rotator cuff arthropathy. Future treatment modalities involving biologics and tissue engineering hold further promise to improve outcomes for patients suffering from shoulder pathologies.

  11. Recent advances in shoulder research

    PubMed Central

    2012-01-01

    Shoulder pathology is a growing concern for the aging population, athletes, and laborers. Shoulder osteoarthritis and rotator cuff disease represent the two most common disorders of the shoulder leading to pain, disability, and degeneration. While research in cartilage regeneration has not yet been translated clinically, the field of shoulder arthroplasty has advanced to the point that joint replacement is an excellent and viable option for a number of pathologic conditions in the shoulder. Rotator cuff disease has been a significant focus of research activity in recent years, as clinicians face the challenge of poor tendon healing and irreversible changes associated with rotator cuff arthropathy. Future treatment modalities involving biologics and tissue engineering hold further promise to improve outcomes for patients suffering from shoulder pathologies. PMID:22709417

  12. Joint Force Quarterly. Issue 60, 1st Quarter 2011

    DTIC Science & Technology

    2011-01-01

    PUBLISHER ADM Michael G. Mullen, USN PRESIdEnt, ndU VADM Ann E. Rondeau, USN AdvISoRy CommIttEE AMB Joyce A. Barr Industrial College of the Armed Forces...Greenwood, USMC (Ret.) Institute for Defense Analyses Alan L. Gropman Industrial College of the Armed Forces Douglas N. Hime Naval War College Mark H...mates and I operated under a “burn it if you’ve got it” mentality. We were not deliberately wasteful or reckless; we just held the conventional

  13. Predicting sagittal plane biomechanics that minimize the axial knee joint contact force during walking.

    PubMed

    Miller, Ross H; Brandon, Scott C E; Deluzio, Kevin J

    2013-01-01

    Both development and progression of knee osteoarthritis have been associated with the loading of the knee joint during walking. We are, therefore, interested in developing strategies for changing walking biomechanics to offload the knee joint without resorting to surgery. In this study, simulations of human walking were performed using a 2D bipedal forward dynamics model. A simulation generated by minimizing the metabolic cost of transport (CoT) resembled data measured from normal human walking. Three simulations targeted at minimizing the peak axial knee joint contact force instead of the CoT reduced the peak force by 12-25% and increased the CoT by 11-14%. The strategies used by the simulations were (1) reduction in gastrocnemius muscle force, (2) avoidance of knee flexion during stance, and (3) reduced stride length. Reduced gastrocnemius force resulted from a combination of changes in activation and changes in the gastrocnemius contractile component kinematics. The simulations that reduced the peak contact force avoided flexing the knee during stance when knee motion was unrestricted and adopted a shorter stride length when the simulated knee motion was penalized if it deviated from the measured human knee motion. A higher metabolic cost in an offloading gait would be detrimental for covering a long distance without fatigue but beneficial for exercise and weight loss. The predicted changes in the peak axial knee joint contact force from the simulations were consistent with estimates of the joint contact force in a human subject who emulated the predicted kinematics. The results demonstrate the potential of using muscle-actuated forward dynamics simulations to predict novel joint offloading interventions.

  14. Joint Force Quarterly. Issue 66, 3rd Quarter 2012

    DTIC Science & Technology

    2012-07-01

    he retired on August 1, 2007, after 34 years of service. ndupress .ndu.edu issue 66, 3 rd quarter 2012 / JFQ 5 officers capable of leading joint...Washington, DC: DOD, August 2010), 22–37; Jan Van Tol with Mark Gunzinger, Andrew Krepinev- ich, and Jim Thomas, AIRSEA Battle: A Point-of- Departure...control-system>. 37 U.S. Cyber Consequences Unit (US-CCU), special report, Overview by the US-CCU of the Cyber Campaign Against Georgia in August of

  15. Computational model of a primate arm: from hand position to joint angles, joint torques and muscle forces

    NASA Astrophysics Data System (ADS)

    Chan, Sherwin S.; Moran, Daniel W.

    2006-12-01

    Three-dimensional reaching by non-human primates is an important behavioral paradigm for investigating representations existing in motor control areas of the brain. Most studies to date have correlated neural activity to a few of the many arm motion parameters including: global hand position or velocity, joint angles, joint angular velocities, joint torques or muscle activations. So far, no single study has been able to incorporate all these parameters in a meaningful way that would allow separation of these often highly correlated variables. This paper introduces a three-dimensional, seven degree-of-freedom computational musculoskeletal model of the macaque arm that translates the coordinates of eight tracking markers placed on the arm into joint angles, joint torques, musculotendon lengths and finally into an optimized prediction of muscle forces. This paper uses this model to illustrate how the classic center-out reaching task used by many researchers over the last 20 years is not optimal in separating out intrinsic, extrinsic, kinematic and kinetic variables. However, by using the musculoskeletal model to design and test novel behavioral movement tasks, a priori, it is possible to disassociate the myriad of movement parameters in motor neurophysiological reaching studies.

  16. Personnel Security during Joint Operations with Foreign Military Forces

    DTIC Science & Technology

    2013-08-01

    this article. Princi- pally among these is the desire to keep one’s family together in a safe, stable home. A closer look at the perpetrators of...military personnel overseas, the US Air Force’s security forces are well suited to aid in de- veloping an advanced training module (fig. 6).25 Those

  17. USAF Combat Rescue Helicopter: Addressing Joint Force Capability Shortfalls

    DTIC Science & Technology

    2013-04-07

    Untapped Combat Power.” Master’s Thesis, Air War College, 2005. DiPaolo, Marc C., Lee DePalo, Michael Healy, Glenn Hecht , Mike Trumpfheller. “A...Defense (May 2012): 46-49. Peck, Michael . “Combat Rescue Units See Shift in Missions.” National Defense (May 2006). Rolfsen, Bruce. “Air Force

  18. Comparison of joint space versus task force load distribution optimization for a multiarm manipulator system

    NASA Technical Reports Server (NTRS)

    Soloway, Donald I.; Alberts, Thomas E.

    1989-01-01

    It is often proposed that the redundancy in choosing a force distribution for multiple arms grasping a single object should be handled by minimizing a quadratic performance index. The performance index may be formulated in terms of joint torques or in terms of the Cartesian space force/torque applied to the body by the grippers. The former seeks to minimize power consumption while the latter minimizes body stresses. Because the cost functions are related to each other by a joint angle dependent transformation on the weight matrix, it might be argued that either method tends to reduce power consumption, but clearly the joint space minimization is optimal. A comparison of these two options is presented with consideration given to computational cost and power consumption. Simulation results using a two arm robot system are presented to show the savings realized by employing the joint space optimization. These savings are offset by additional complexity, computation time and in some cases processor power consumption.

  19. Evaluation of knee joint forces during kneeling work with different kneepads.

    PubMed

    Xu, Hang; Jampala, Sree; Bloswick, Donald; Zhao, Jie; Merryweather, Andrew

    2017-01-01

    The main purpose of this study is to determine knee joint forces resulting from kneeling work with and without kneepads to quantify how different kneepads redistribute force. Eleven healthy males simulated a tile setting task to different locations during six kneepad states (five different kneepad types and without kneepad). Peak and average forces on the anatomical landmarks of both knees were obtained by custom force sensors. The results revealed that kneepad design can significantly modify the forces on the knee joint through redistribution. The Professional Gel design was preferred among the five tested kneepads which was confirmed with both force measurements and participants' responses. The extreme reaching locations induced significantly higher joint forces on left knee or right knee depending on task. The conclusion of this study is that a properly selected kneepad for specific tasks and a more neutral working posture can modify the force distribution on the knees and likely decrease the risk of knee disorders from kneeling work. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. Measurement of intraarticular wrist joint biomechanics with a force controlled system.

    PubMed

    Erhart, Stefanie; Lutz, Martin; Arora, Rohit; Schmoelz, Werner

    2012-09-01

    Pathologies of the wrist, such as fractures or instabilities, can lead to alterations in joint biomechanics. Accurate treatment of these pathologies is a frequent challenge for the surgeon. For biomechanical investigations, a test-setup that applies physiological loading of the wrist joint is necessary. A force controlled test-bench with agonistic and antagonistic muscle forces was built to move six fresh frozen human upper extremities through flexion and extension of the wrist joint. Tendon forces, range of motion, intraarticular contact area and contact pressure of the lunate and scaphoid facet as well as tendon excursion were investigated and compared with the current literature. During wrist motion the extensors exerted double the force of the flexors. Capsulotomy and sensor insertion decreased the range of motion from 63.4° (SD 14.1) to 45.9° (SD 23.7). The ratio of force transmitted through the radius and ulna was 77:23 and pressure distribution between the scaphoid and lunate facet showed a 70:30 relationship. The obtained data indicate a good agreement with the available literature. Therefore, the force controlled test-bench in combination with intraarticular radiocarpal measurements can be used to investigate the influence of wrist pathologies on joint biomechanics.

  1. Evidence of rapid Cenozoic uplift of the shoulder escarpment of the Cenozoic West Antarctic rift system and a speculation on possible climate forcing

    SciTech Connect

    Behrendt, J.C. ); Cooper, A. )

    1991-04-01

    The Cenzoic West Antarctic rift system, characterized by Cenozoic bimodal alkalic volcanic rocks, extends over a largely ice-covered area, from the Ross Sea nearly to the Bellingshausen Sea. It is bounded on one side by a spectacular 4-to 5-km-high rift-shoulder scarp (maximum bedrock relief 5 to 7 km) from northern Victoria Land-Queen Maud Mountains to the Ellsworth-Whitmore-Horlick Mountains. Jurassic tholeiites crop out with the late Cenozoic volcanic rocks along the section of the Transantarctic Mountains from northern Victoria Land to the Horlick Mountains. The Cenozoic rift shoulder diverges here from the Jurassic tholeiite trend, and the tholeiites are exposed discontinuously along the lower elevation (1-2 km) section of the Transantarctic Mountains to the Weddell Sea. Various lines of evidence, no one of which is independently conclusive, lead the authors (as others have also suggested) to interpret the following. The Transantarctic Mountains part of the rift shoulder (and probably the entire shoulder) has been rising since about 60 Ma, at episodic rates of {approximately}1 km/m.y., most recently since mid-Pliocene time, rather than continuously at the mean rate of 100m/m.y. Uplift rates vary along the scarp, which is cut by transverse faults. The authors speculate that this uplift may have climatically forced the advance of the Antarctic ice sheet since the most recent warm period. They suggest a possible synergistic relation between episodic tectonism, mountain uplift, and volcanism in the Cenozoic West Antarctic rift system and waxing and waning of the Antarctic ice sheet beginning about earliest Oligocene time.

  2. The Joint Force Air Component Commander and the Integration of Offensive Cyberspace Effects: Power Projection through Cyberspace

    DTIC Science & Technology

    2016-06-14

    support model USSTRATCOM - US Strategic Command USCYBERCOM - US Cyber Command Spring 2016 | 89 Views JFHQ-Cyber - Joint Force Headquarters–Cyberspace...coordination authority within the joint cyberspace center (direct support model ) or the joint force cyberspace compo- nent commander (OPCON model ) since...and intelligence, surveillance, and reconnaissance division. As long as the direct support model is in effect, liaisons from the joint cyberspace

  3. A Common Set of Core Values - The Foundation for a More Effective Joint Force

    DTIC Science & Technology

    2015-05-18

    the U.S. military needs a common foundation in a single set of core values. 15. SUBJECT TERMS Core Values, Joint Force, Military Ethic , Military... dilemma . According to military ethicist, Anthony Hartle, “the global scale of the conflicts the United States finds itself immersed in has generated new...to propose a joint military ethic nor will he attempt to describe the membership of the profession of arms. The scope of this paper will be limited

  4. Implementing Network-Centric Operations in Joint Task Forces: Changes in Joint Doctrine

    DTIC Science & Technology

    2006-06-16

    of Defense planning guidance and doctrine that date to July of 2001. The conclusions reached in this thesis are that size, structure , interdependence...and synchronization are key NCO organizational attributes dictating shifts in basic joint doctrine and JTF organizational architecture.

  5. Trunk muscle activation and associated lumbar spine joint shear forces under different levels of external forward force applied to the trunk.

    PubMed

    Kingma, Idsart; Staudenmann, Didier; van Dieën, Jaap H

    2007-02-01

    High anterior intervertebral shear loads could cause low back injuries and therefore the neuromuscular system may actively counteract these forces. This study investigated whether, under constant moment loading relative to L3L4, an increased externally applied forward force on the trunk results in a shift in muscle activation towards the use of muscles with more backward directed lines of action, thereby reducing the increase in total joint shear force. Twelve participants isometrically resisted forward forces, applied at several locations on the trunk, while moments were held constant relative to L3L4. Surface EMG and lumbar curvature were measured, and an EMG-driven muscle model was used to calculate compression and shear forces at all lumbar intervertebral joints. Larger externally applied forward forces resulted in a flattening of the lumbar lordosis and a slightly more backward directed muscle force. Furthermore, the overall muscle activation increased. At the T12L1 to L3L4 joint, resulting joint shear forces remained small (less than 200N) because the average muscle force pulled backward relative to those joints. However, at the L5S1 joint the average muscle force pulled the trunk forward so that the increase in muscle force with increasing externally applied forward force caused a further rise in shear force (by 102.1N, SD=104.0N), resulting in a joint shear force of 1080.1N (SD=150.4N) at 50Nm moment loading. It is concluded that the response of the neuromuscular system to shear force challenges tends to increase rather than reduce the shear loading at the lumbar joint that is subjected to the highest shear forces.

  6. The biomechanical effects of variation in the maximum forces exerted by trunk muscles on the joint forces and moments in the lumbar spine: a finite element analysis.

    PubMed

    Kim, K; Lee, S K; Kim, Y H

    2010-10-01

    The weakening of trunk muscles is known to be related to a reduction of the stabilization function provided by the muscles to the lumbar spine; therefore, strengthening deep muscles might reduce the possibility of injury and pain in the lumbar spine. In this study, the effect of variation in maximum forces of trunk muscles on the joint forces and moments in the lumbar spine was investigated. Accordingly, a three-dimensional finite element model of the lumbar spine that included the trunk muscles was used in this study. The variation in maximum forces of specific muscle groups was then modelled, and joint compressive and shear forces, as well as resultant joint moments, which were presumed to be related to spinal stabilization from a mechanical viewpoint, were analysed. The increase in resultant joint moments occurred owing to decrease in maximum forces of the multifidus, interspinales, intertransversarii, rotatores, iliocostalis, longissimus, psoas, and quadratus lumborum. In addition, joint shear forces and resultant joint moments were reduced as the maximum forces of deep muscles were increased. These results from finite element analysis indicate that the variation in maximum forces exerted by trunk muscles could affect the joint forces and joint moments in the lumbar spine.

  7. Effects of reinnervation of the biarticular shoulder-elbow muscles on joint kinematics and electromyographic patterns of the feline forelimb during downslope walking.

    PubMed

    Livingston, Beven P; Nichols, T Richard

    2014-01-01

    Full recovery of the forelimb kinematics during level and upslope walking following reinnervation of the biarticular elbow extensor suggests that the proprioceptive loss is compensated by other sensory sources or altered central drive, yet these findings have not been explored in downslope walking. Kinematics and muscle activity of the shoulder and elbow during downslope locomotion following reinnervation of the feline long head of the triceps brachii (TLo) and biceps brachii (Bi) were evaluated (1) during paralysis and (2) after the motor function was recovered but the proprioceptive feedback was permanently disrupted. The step cycle was examined in three walking conditions: level (0%), -25% grade (-14° downslope) and -50% grade (-26.6° downslope). Measurements were taken prior to and at three time points (2 weeks, and 1 and 12+ months) after transecting and suturing the radial and musculocutaneous nerves. There was an increase in the yield (increased flexion) at the elbow and less extensor activity duration of flexion during stance as the downslope grade increased. There were two notable periods of eccentric contractions (active lengthening) providing an apparent 'braking' action. Paralysis of the TLo and the Bi resulted in uncompensated alterations in shoulder-elbow kinematics and motor activity during the stance phase. However, unlike the case for the level and upslope conditions, during both paralysis and reinnervation, changes in interjoint coordination persisted for the downslope condition. The lack of complete recovery in the long term suggests that the autogenic reflexes contribute importantly to muscle and joint stiffness during active lengthening. © 2015 S. Karger AG, Basel.

  8. Joint Task Force -Guantanamo Bay, Cuba: Open or Close?

    DTIC Science & Technology

    2013-03-01

    combination cells for legal visits (not to house detainees). Camp Echo requires a guard force of approximately 40 personnel.24 Camp Iguana Camp new mission...in 2008 was to house detainees who have received court- ordered releases. Camp Iguana has the capacity to hold 22 detainees who live in a complete...open, minimum-security environment. The detainees at Camp Iguana have 24-hour access to a recreation area, sleeping berths, and a laundry facility

  9. Joint Force Quarterly. Issue 41, 2nd Quarter, April 2006

    DTIC Science & Technology

    2006-04-01

    article argues that an integrated civil-mili- tary combatant command is the model for the United States to deter and defeat adver - saries and engage...healthy and fit force (for example, vaccinations and dental readiness), prevention of casualties (such as medical intelligence reports and digitized...particular, is well suited to cause the adver - sary to react with fear. Initially, it is fear of an attack, whether a preemptive strike or a response to

  10. What It Takes. Air Force Command of Joint Operations

    DTIC Science & Technology

    2009-01-01

    ters staff. For the headquarters to reach full functionality, it needs to be augmented with additional staff from both the host service and the other...Operations Command Central SOCPAC Special Operations Command Pacific SOF special operations forces TAC CP tactical command post TACON tactical control ...defines control as 1. Authority that may be less than full command exercised by a commander over part of the activities of subordinate or other

  11. Joint Force Quarterly. Issue 53, 2nd Quarter 2009

    DTIC Science & Technology

    2009-04-01

    subsequently water treatment facilities required electricity to power pumping units. Above all, security was needed to protect the linear...be a crime to waste the precious resource of experience our mili- tary has gained while executing elements of foreign policy throughout the world...Intelligence College Col Thomas Greenwood, USMC (Ret.) Institute for Defense Analyses RADM Garry E. Hall, USN Industrial College of the Armed Forces LtCol Frank

  12. Joint Force Quarterly. Issue 54, 3rd Quarter 2009

    DTIC Science & Technology

    2009-07-01

    suddenly intrude. Thus, forming and molding relationships must start on day one. The key to strong and productive relationships is trust. It must be...made more difficult by the depri- vation of food and sleep. As the culminating trial of recruit training, the Crucible requires individuals to make...heading to or from a fight is clear, but what of the gray areas—selling food and medicine or giving monetary aid to hostile forces, or not

  13. General Roy S. Geiger, USMC: Marine Aviator, Joint Force Commander

    DTIC Science & Technology

    2007-06-01

    undersupplied, even with Japanese forces furiously working to retake the island.7 Despite the strategic importance of holding Henderson Field and the...to deliver a final “knockout blow” to the Marines, 90 Geiger and Vandegrift furiously prepared for the inevitable ground assault. It was during... happy about getting orders from a staff that had no combat experience, but it worked out fairly well. General Geiger and his staff came in November

  14. Joint Force Quarterly (Issue 71, 4th Quarter, October 2013)

    DTIC Science & Technology

    2013-01-01

    achieve tactical or operational surprise by making any spot in the world accessible and forcing an adversary to defend in all direc - tions. During the...which injected huge sums into procure- ment, thus reducing the percentage going towards O&M), O&M has steadily con- sumed an increasing share of...minimal higher headquarters and senior leadership command and control injections and direction. Scenarios must present a hybrid of challenges that

  15. Joint Force Quarterly. Issue 51, 4th Quarter, October 2008

    DTIC Science & Technology

    2008-10-01

    War mentality . Unfortu- nately, that is just about where we left it—back in the Cold War, strewn among the rubble of the Berlin Wall. Deterrence...nuclear forces contribute uniquely and funda- mentally to deterrence through their ability to impose costs and deny benefits to an adver- sary in...educational curriculums are already highly saturated? JFQ encourages you to submit manuscripts that speak to your unique professional strengths and

  16. Non-Lethal Weapons: Considerations for the Joint Force Commander

    DTIC Science & Technology

    2007-05-10

    686 Cushing Road Newport, RI 02841-1207 9. SPONSORING/MONITORING AGENCY NAME( S ) AND ADDRESS(ES) 10...Commander 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR( S ) 5d. PROJECT NUMBER Jeffrey W. Voetberg, Major...United States Air Force 5e. TASK NUMBER Paper Advisor (if Any): William Hartig, Colonel, USMC 5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME( S

  17. Enhanced Army Airborne Forces: A New Joint Operational Capability

    DTIC Science & Technology

    2014-01-01

    appropriate one, the next steps should include the following: • Refine the operational concepts associated with a new airborne light armored infantry...such as the SA-18, have seekers coated with lead sulfide and indium antimonide, which is sensitive to electromagnetic energy out to 5 micrometers. This...right for the airborne force. If this direction appears to be an appropriate one, the next steps should include the following: • Refine the

  18. Joint Force Quarterly. Issue 75, 4th Quarter, October 2014

    DTIC Science & Technology

    2014-10-01

    different types of activities. JFQ: A number of social issues have been affecting all the Services, such as repeal of the “Don’t Ask, Don’t Tell” policy...will oversee the rede - ployment of the bulk of the 47,000 troops currently in Afghanistan. The actual number of troops to remain in place is... social services and poverty reduction, as well as salaries for government employees (including security forces). This could in turn improve security

  19. The relation between the instantaneous center of rotation and facet joint forces - A finite element analysis.

    PubMed

    Schmidt, Hendrik; Heuer, Frank; Claes, Lutz; Wilke, Hans-Joachim

    2008-03-01

    The instantaneous center of rotation in a functional spinal unit is an indicator for mechanical disorders and is relevant for the development of motion preserving techniques. In addition to the intervertebral disc, the facet joints also play a major role for load transmission through the spine, providing stability to it. The relationship between the rotation center and facet joint forces is not fully understood, since previous studies have separated both; spinal motion and facet forces. A finite element model of a L4-5 lumbar spinal segment was exposed to an axial compression preload of 500 N. Pure unconstrained moments of 7.5 Nm were additionally applied in the three anatomical main planes. The instantaneous center of rotation and the facet joint forces were investigated. For small moments, the center of rotation was found to be almost in the center of the disc, no matter what motion direction. With an increasing flexion moment, the center of rotation moved anteriorly. The facet joints remained unloaded in flexion. With proceeding extension movement, the center of rotation moved posteriorly. The facet forces increased up to 50 N. In lateral bending, with increasing moment the center of rotation migrated posteriorly in the ipsilateral side of the disc. The forces in the facet joints rose to 36 N. In axial rotation, the center of rotation migrated towards the compressed facet joint with increasing moment. Axial rotation yielded the maximum facet forces with 105 N. The determination of the rotation center is highly sensible against measurement resolution obtained during in vivo and in vitro studies. This finite element method can be used to complement the knowledge of the rotation center location from former experimental findings.

  20. 21 CFR 888.3670 - Shoulder joint metal/polymer/metal nonconstrained or semi-constrained porous-coated uncemented...

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...-joint. This generic type of device includes prostheses that have a humeral component made of alloys such as cobalt-chromium-molybdenum (Co-Cr-Mo) and titanium-aluminum-vanadium (Ti-6Al-4V) alloys, and a... articulating ultra-high molecular weight bearing surface fixed in a metal shell made of alloys such as...

  1. 21 CFR 888.3670 - Shoulder joint metal/polymer/metal nonconstrained or semi-constrained porous-coated uncemented...

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...-joint. This generic type of device includes prostheses that have a humeral component made of alloys such as cobalt-chromium-molybdenum (Co-Cr-Mo) and titanium-aluminum-vanadium (Ti-6Al-4V) alloys, and a... articulating ultra-high molecular weight bearing surface fixed in a metal shell made of alloys such as...

  2. 21 CFR 888.3670 - Shoulder joint metal/polymer/metal nonconstrained or semi-constrained porous-coated uncemented...

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...-joint. This generic type of device includes prostheses that have a humeral component made of alloys such as cobalt-chromium-molybdenum (Co-Cr-Mo) and titanium-aluminum-vanadium (Ti-6Al-4V) alloys, and a... articulating ultra-high molecular weight bearing surface fixed in a metal shell made of alloys such as...

  3. Are Standing Joint Task Force Headquarters the First Step in Transforming Cold War Formations?

    DTIC Science & Technology

    2002-05-01

    leoorst. 129 Jetfetrson Oavn Suihw ty,lte 1204, ArlingtOn, V 222024302. and t0 the Otfice of Manaqemett and Buidget. PaierwoeK Reduci on PrOlec (0704...Progress." 18. 113 "JFC Forum - The Persian Gulf War. Ten Years After." (Joint Forces Quarterly. Winter 2000-01). 10. 114 James R . Helmly, "Future U.S... R . Stocker. Canadian Jointery, (Joint Forces Quarterly, Winter 95-96), 116. & James R . Heimly. "Future U.S. Military Strategy: The Need for a

  4. Neuromuscular adaptations associated with knee joint angle-specific force change.

    PubMed

    Noorkõiv, Marika; Nosaka, Kazunori; Blazevich, Anthony J

    2014-08-01

    Neuromuscular adaptations to joint angle-specific force increases after isometric training have not yet been fully elucidated. This study examined angle-specific neuromuscular adaptations in response to isometric knee extension training at short (SL, joint angle 38.1° ± 3.7°) versus long (LL, 87.5° ± 6.0°) muscle lengths. Sixteen men trained three times a week for 6 wk either at SL (n = 8) or LL (n = 8). Voluntary maximal isometric knee extensor (MVC) force, doublet twitch force, EMG amplitudes (EMG/Mmax), and voluntary activation during MVC force (VA%) were measured at eight knee joint angles (30°-100°) at weeks 0, 3, and 6. Muscle volume and cross-sectional area (CSA) were measured from magnetic resonance imaging scans, and fascicle length (Lf) was assessed using ultrasonography before and after training. Clear joint angle specificity of force increase was seen in SL but not in LL. The 13.4% ± 9.7% (P = 0.01) force increase around the training angle in SL was related to changes in vastus lateralis and vastus medialis EMG/Mmax around the training angle (r = 0.84-0.88, P < 0.05), without changes in the doublet twitch force-angle relation or muscle size. In LL, muscle volume and CSA increased and the changes in CSA at specific muscle regions were correlated with changes in MVC force. A 5.4% ± 4.9% (P = 0.001) increase in Lf found in both groups was not associated with angle-specific force changes. There were no angle-specific changes in VA%. The EMG/Mmax, although not VA%, results suggest that neural adaptations underpinned training-related changes at short quadriceps lengths, but hypertrophic changes predominated after training at long lengths. The findings of this study should contribute to the development of more effective and evidence-based rehabilitation and strength training protocols.

  5. Influence of Muscle-Tendon Wrapping on Calculations of Joint Reaction Forces in the Equine Distal Forelimb

    PubMed Central

    Merritt, Jonathan S.; Davies, Helen M. S.; Burvill, Colin; Pandy, Marcus G.

    2008-01-01

    The equine distal forelimb is a common location of injuries related to mechanical overload. In this study, a two-dimensional model of the musculoskeletal system of the region was developed and applied to kinematic and kinetic data from walking and trotting horses. The forces in major tendons and joint reaction forces were calculated. The components of the joint reaction forces caused by wrapping of tendons around sesamoid bones were found to be of similar magnitude to the reaction forces between the long bones at each joint. This finding highlighted the importance of taking into account muscle-tendon wrapping when evaluating joint loading in the equine distal forelimb. PMID:18509485

  6. Frozen shoulder.

    PubMed

    Wadsworth, C T

    1986-12-01

    Widespread use of the label "frozen shoulder" as a diagnosis for any stiff and painful shoulder condition has led to its becoming a rather meaningless, catchall term. In addition to confounding both the lay public and health care professionals, this indiscriminate labeling may prevent a patient from receiving appropriate treatment. In this article, I define frozen shoulder and review its pathologic and etiologic factors, epidemiology, natural history, and diagnosis. I present this information in correlation with an examination process to assist physical therapists in identifying suspected cases of frozen shoulder. I also present the current options for treatment, including physical therapy management with physical agents and exercise.

  7. A feasibility study for experimentally determining dynamic force distribution in a lap joint.

    SciTech Connect

    Mayes, Randall Lee

    2013-11-01

    Developing constitutive models of the physics in mechanical joints is currently stymied by inability to measure forces and displacements within the joint. The current state of the art estimates whole joint stiffness and energy loss per cycle from external measured force input and one or two acceleration responses. To validate constitutive models beyond this state requires a measurement of the distributed forces and displacements at the joint interface. Unfortunately, introducing measurement devices at the interface completely disrupts the desired physics. A feasibility study is presented for a non-intrusive method of solving for the interface dynamic forces from an inverse problem using full field measured responses. The responses come from the viewable surface of a beam. The noise levels associated with digital image correlation and continuous scanning laser Doppler velocimetry are evaluated from typical beam experiments. Two inverse problems are simulated. One utilizes the extended Sum of Weighted Accelerations Technique (SWAT). The second is a new approach dubbed the method of truncated orthogonal forces. These methods are much more robust if the contact patch geometry is well identified. Various approaches to identifying the contact patch are investigated, including ion marker tracking, Prussian blue and ultrasonic measurements. A typical experiment is conceived for a beam which has a lap joint at one end with a single bolt connecting it to another identical beam. In a virtual test using the beam finite element analysis, it appears that the SWAT inverse method requires evaluation of too many coefficients to adequately identify the force distribution to be viable. However, the method of truncated orthogonal forces appears viable with current digital image correlation (and probably other) imaging techniques.

  8. Robotic quantification of upper extremity loss of independent joint control or flexion synergy in individuals with hemiparetic stroke: a review of paradigms addressing the effects of shoulder abduction loading.

    PubMed

    Ellis, Michael D; Lan, Yiyun; Yao, Jun; Dewald, Julius P A

    2016-10-29

    Unsupported or "against-gravity" reaching and hand opening movements are greatly impaired in individuals with hemiparetic stroke. The reduction in reaching excursion and hand opening is thought to be primarily limited by abnormal muscle co-activation of shoulder abductors with distal limb flexors, known as flexion synergy, that results in a loss of independent joint control or joint individuation. Our laboratory employs several methods for quantifying this movement impairment, however the most documented techniques are sophisticated and laboratory-based. Here a series of robotic methods that vary in complexity from comprehensive (laboratory-based) to focused (clinically relevant) are outlined in detail in order to facilitate translation and make recommendations for utilization across the translational spectrum as part of Journal of NeuroEngineering and Rehabilitation thematic series, "Technically-advanced assessments in sensory motor rehabilitation." While these methods focus on our published work utilizing the device, ACT(3D), these methods can be duplicated using any mechatronic device with the appropriate characteristics. The common thread and most important aspect of the methods described is addressing the deleterious effects of abduction loading. Distal upper extremity joint performance is directly and monotonically modulated by proximal (shoulder abduction) joint demands. The employment of robotic metrics is the best tool for selectively manipulating shoulder abduction task requirements spanning the individual's full range of shoulder abduction strength. From the series of methods and the concluding recommendations, scientists and clinicians can determine the ideal robotic quantification method for the measurement of the impact of loss of independent joint control on reaching and hand function.

  9. Joint Task Force Commander’s Handbook for Peace Operations

    DTIC Science & Technology

    2007-11-02

    medicine personnel •• Legal personnel •• Chaplain ministry team I-11 Mission The Commander for the United Nations Transitional Authority in Cambodia was...VIII, “Public Affairs and Media,” of this Handbook. c. Legal. See Chapter IX, “Legal,” of this Handbook. d. Surgeon “Preventive medicine , veterinary...health of the force, it is important to note that UN accepts World Health Organization Standards for food, water, medicine and immunizations when US

  10. Quantitative Methods for Analysing Joint Questionnaire Data: Exploring the Role of Joint in Force Design

    DTIC Science & Technology

    2015-08-01

    mathematics and engineering. A theoretical or conceptual model of ‘Joint’ was developed based on three Latent Variables (LVs) or constructs that aligned with...one, not as a group, so that the survey design team could provide feedback and learn about any shortfalls. The survey was then conducted in two...Hierarchical Cluster Analysis (HAC) was also conducted on both Joint, and Single Service responses. HAC attempts to assign the data to clusters based on

  11. The effect of different surfaces on biomechanical loading of shoulder and lumbar spine during pushing and pulling of two-wheeled containers.

    PubMed

    Laursen, Bjarne; Schibye, Bente

    2002-03-01

    Seven waste collectors pushed and pulled a two-wheeled container on three different surfaces: flagstones, paving stones, grass. Net torques at the shoulder joint and the lumbar spine as well as the compression and shear forces in the lumbar spine at the L4/L5 level were calculated for the tilting, initial and sustained phases. The lumbar spine compression force was below 1800N and the shear force was below 200 N in all situations. The shoulder torque when pulling with one hand was up to 80 N m. The container weight affected the magnitude of the push/pull forces and the load on the shoulders but not the load on the lumbar spine. The type of surface affected the magnitude of the push/pull forces during initial and sustained phases, and affected the load on the shoulder in the sustained phase. However, it did not affect the compression in the lumbar spine.

  12. The Future of Indigenous Security Force Training: Considerations for the Joint Operational Commander

    DTIC Science & Technology

    2007-11-06

    in Iraq and Afghanistan may not be sustained as these conflicts wind down. Where the U.S. conducts regime change or in failed states, U.S. forces...requirements of the Joint Force as across the full range of military operations ( ROMO ). 29 A major part of the Army transformation adds high demand... ROMO . Specific enhancements in planning, communications, computers, intelligence, civil affairs, public affairs, fires and effects, air space

  13. A Joint Force Medical Command is Required to Fix Combat Casualty Care

    DTIC Science & Technology

    2017-10-05

    Care Introduction The United States Army and Air Force Medical Departments and the Navy Bureau of Medicine require a Joint Forces Medical Command...action chosen included the creation of the Uniformed Services University of Health Science School of Medicine as well as the Health Professions...successfully implemented if most of the 19 hospital team is not available. Fortunately, there is an alternative to PROFIS often referred to as

  14. A finite element musculoskeletal model of the shoulder mechanism.

    PubMed

    van der Helm, F C

    1994-05-01

    The finite element method described in this study provides an easy method to simulate the kinetics of multibody mechanisms. It is used in order to develop a musculoskeletal model of the shoulder mechanism. Each relevant morphological structure has been represented by an appropriate element. For the shoulder mechanism two special-purpose elements have been developed: a SURFACE element representing the scapulothoracic gliding plane and a CURVED-TRUSS element to represent muscles which are wrapped around bony contours. The model contains four bones, three joints, three extracapsular ligaments, the scapulothoracic gliding plane and 20 muscles and muscle parts. In the model, input variables are the positions of the shoulder girdle and humerus and the external load on the humerus. Output variables are muscles forces subject to an optimization procedure in which the mechanical stability of the glenohumeral joint is one of the constraints. Four different optimization criteria are compared. For 12 muscles, surface EMG is used to verify the model. Since the optimum muscle length and force-length relationship are unknown, and since maximal EMG amplitude is length dependent, verification is only possible in a qualitative sense. Nevertheless, it is concluded that a detailed model of the shoulder mechanism has been developed which provides good insight into the function of morphological structures.

  15. Minimum detectable change for knee joint contact force estimates using an EMG-driven model.

    PubMed

    Gardinier, Emily S; Manal, Kurt; Buchanan, Thomas S; Snyder-Mackler, Lynn

    2013-09-01

    Adequate test-retest reliability of model estimates is a necessary precursor to examining treatment effects or longitudinal changes in individuals. The purpose of this study was to establish thresholds for minimal detectable change (MDC) for joint contact forces obtained using a patient specific EMG-driven musculoskeletal model of the knee. A sample of young, active individuals was selected for this study, and subjects were tested on 2 separate days. Three-dimensional motion analysis with electromyography (EMG) was used to obtain data from each subject during gait for model input. An EMG-driven modeling approach was used to estimate joint contact forces at each session. MDC's for contact force variables ranged from 0.30 to 0.66 BW. The lowest MDC was for peak medial compartment force (0.30 BW) and the highest was for peak tibiofemoral contact force (0.66 BW). Test-retest reliability coefficients were also reported for comparison with previous work. Using the present model, changes in joint contact forces between baseline and subsequent measurements that are greater than these MDCs are greater than typical day-to-day variation and can be identified as real change. Copyright © 2013 Elsevier B.V. All rights reserved.

  16. Knee joint angle affects EMG-force relationship in the vastus intermedius muscle.

    PubMed

    Saito, Akira; Akima, Hiroshi

    2013-12-01

    It is not understood how the knee joint angle affects the relationship between electromyography (EMG) and force of four individual quadriceps femoris (QF) muscles. The purpose of this study was to examine the effect of the knee joint angle on the EMG-force relationship of the four individual QF muscles, particularly the vastus intermedius (VI), during isometric knee extensions. Eleven healthy men performed 20-100% of maximal voluntary contraction (MVC) at knee joint angles of 90°, 120° and 150°. Surface EMG of the four QF synergists was recorded and normalized by the root mean square during MVC. The normalized EMG of the four QF synergists at a knee joint angle of 150° was significantly lower than that at 90° and 120° (P < 0.05). Comparing the normalized EMG among the four QF synergists, a significantly lower normalized EMG was observed in the VI at 150° as compared with the other three QF muscles (P < 0.05). These results suggest that the EMG-force relationship of the four QF synergists shifted downward at an extended knee joint angle of 150°. Furthermore, the neuromuscular activation of the VI was the most sensitive to change in muscle length among the four QF synergistic muscles. Copyright © 2013 Elsevier Ltd. All rights reserved.

  17. Joint Communications in Support of Joint Task Force South during Operation Just Cause

    DTIC Science & Technology

    1991-01-01

    JACC/CP) to control initial actions by the paratroops and other forces on the grcund using single channel radio. Phase four was "stability force...Marines and paratroops tended to use stand-alone SB-3614As because they were small and fai.rly simple. SB-361 4/TT Telephone Switchboard 0 .. . ...0...t(M0704088) Washington OC 20503 1. AGENCY USE ONLY (Leave blank) 2. REPORT DATE 3. REPORT TYPE AND DATES COVERED 1 1991 Master’s inesis,8-19-90 to 6

  18. Frozen shoulder.

    PubMed Central

    Anton, H. A.

    1993-01-01

    The frozen shoulder is a common cause of shoulder pain and disability. Most patients slowly improve over 12 to 24 months. Some have prolonged loss of movement, pain, and associated disability. Treatments include physiotherapy, corticosteroid injections, and manipulation. Clinical trials of these treatments have produced conflicting results. PMID:8374364

  19. Bilateral ground reaction forces and joint moments for lateral sidestepping and crossover stepping tasks

    PubMed Central

    Kuntze, Gregor; Sellers, William I.; Mansfield, Neil

    2009-01-01

    Racquet sports have high levels of joint injuries suggesting the joint loads during play may be excessive. Sports such as badminton employ lateral sidestepping (SS) and crossover stepping (XS) movements which so far have not been described in terms of biomechanics. This study examined bilateral ground reaction forces and three dimensional joint kinetics for both these gaits in order to determine the demands of the movements on the leading and trailing limb and predict the contribution of these movements to the occurrence of overuse injury of the lower limbs. A force platform and motion-analysis system were used to record ground reaction forces and track marker trajectories of 9 experienced male badminton players performing lateral SS, XS and forward running tasks at a controlled speed of 3 m·s-1 using their normal technique. Ground reaction force and kinetic data for the hip, knee and ankle were analyzed, averaged across the group and the biomechanical variables compared. In all cases the ground reaction forces and joint moments were less than those experienced during moderate running suggesting that in normal play SS and XS gaits do not lead to high forces that could contribute to increased injury risk. Ground reaction forces during SS and XS do not appear to contribute to the development of overuse injury. The distinct roles of the leading and trailing limb, acting as a generator of vertical force and shock absorber respectively, during the SS and XS may however contribute to the development of muscular imbalances which may ultimately contribute to the development of overuse injury. However it is still possible that faulty use of these gaits might lead to high loads and this should be the subject of future work. Key pointsGround reaction forces and joint moments during lateral stepping are smaller in magnitude than those experienced during moderate running.Force exposure in SS and XS gaits in normal play does not appear to contribute to the development of

  20. Bilateral ground reaction forces and joint moments for lateral sidestepping and crossover stepping tasks.

    PubMed

    Kuntze, Gregor; Sellers, William I; Mansfield, Neil

    2009-01-01

    Racquet sports have high levels of joint injuries suggesting the joint loads during play may be excessive. Sports such as badminton employ lateral sidestepping (SS) and crossover stepping (XS) movements which so far have not been described in terms of biomechanics. This study examined bilateral ground reaction forces and three dimensional joint kinetics for both these gaits in order to determine the demands of the movements on the leading and trailing limb and predict the contribution of these movements to the occurrence of overuse injury of the lower limbs. A force platform and motion-analysis system were used to record ground reaction forces and track marker trajectories of 9 experienced male badminton players performing lateral SS, XS and forward running tasks at a controlled speed of 3 m·s(-1) using their normal technique. Ground reaction force and kinetic data for the hip, knee and ankle were analyzed, averaged across the group and the biomechanical variables compared. In all cases the ground reaction forces and joint moments were less than those experienced during moderate running suggesting that in normal play SS and XS gaits do not lead to high forces that could contribute to increased injury risk. Ground reaction forces during SS and XS do not appear to contribute to the development of overuse injury. The distinct roles of the leading and trailing limb, acting as a generator of vertical force and shock absorber respectively, during the SS and XS may however contribute to the development of muscular imbalances which may ultimately contribute to the development of overuse injury. However it is still possible that faulty use of these gaits might lead to high loads and this should be the subject of future work. Key pointsGround reaction forces and joint moments during lateral stepping are smaller in magnitude than those experienced during moderate running.Force exposure in SS and XS gaits in normal play does not appear to contribute to the development of

  1. The effect of shoulder position on inferior glenohumeral mobilization.

    PubMed

    Witt, Dexter W; Talbott, Nancy R

    2017-03-09

    Cross-sectional clinical measurement study. Inferior mobilizations are used to treat patients with shoulder dysfunctions. Common positions recommended for promoting an inferior glide include: (1) an open-packed position (OPP) in which the shoulder is in 55° of abduction, 30° of horizontal adduction, and no rotation; (2) neutral position (NP) of the shoulder; and (3) position of 90° of shoulder abduction (ABDP). Studies comparing the impact of position on inferior mobilization are lacking. To determine the effect of shoulder position on humeral movement and mobilization force during inferior mobilizations. Twenty-three subjects were tested bilaterally. Subjects were placed in the OPP, and an ultrasound transducer placed over the superior glenohumeral joint. As inferior mobilization forces were applied through a dynamometer, ultrasound images were taken at rest and during 3 grades of inferior mobilization. This process was repeated in the NP and the ABDP. In the NP, movements during grade 1, 2, and 3 mobilizations were 1.8, 3.8, and 4.5 mm, respectively. Movements measured in the OPP (1.0, 2.4, and 3.6 mm, respectively) and in the ABDP (1.0, 2.2, and 2.3 mm, respectively) were less. Forces were higher in the NP during grade 1, 2, and 3 mobilizations (51.8, 138.7, and 202.1 N, respectively) than in the OPP (37.2, 91.2, and 139.9 N, respectively) and the ABPD (42.5, 115.3, and 165.5 N, respectively). Mobilization position altered the movement and force during inferior mobilizations. Shoulder position should be considered when utilizing inferior mobilizations. NA. Copyright © 2017 Hanley & Belfus. Published by Elsevier Inc. All rights reserved.

  2. Video Analysis of Primary Shoulder Dislocations in Rugby Tackles

    PubMed Central

    Maki, Nobukazu; Kawasaki, Takayuki; Mochizuki, Tomoyuki; Ota, Chihiro; Yoneda, Takeshi; Urayama, Shingo; Kaneko, Kazuo

    2017-01-01

    Background: Characteristics of rugby tackles that lead to primary anterior shoulder dislocation remain unclear. Purpose: To clarify the characteristics of tackling that lead to shoulder dislocation and to assess the correlation between the mechanism of injury and morphological damage of the glenoid. Study Design: Case series; Level of evidence, 4. Methods: Eleven elite rugby players who sustained primary anterior shoulder dislocation due to one-on-one tackling between 2001 and 2014 were included. Using an assessment system, the tackler’s movement, posture, and shoulder and head position were evaluated in each phase of tackling. Based on 3-dimensional computed tomography, the glenoid of the affected shoulder was classified into 3 types: intact, erosion, and bone defect. Orientation of the glenoid defect and presence of Hill-Sachs lesion were also evaluated. Results: Eleven tackles that led to primary shoulder dislocation were divided into hand, arm, and shoulder tackle types based on the site at which the tackler contacted the ball carrier initially. In hand and arm tackles, the tackler’s shoulder joint was forcibly moved to horizontal abduction by the impact of his upper limb, which appeared to result from an inappropriate approach to the ball carrier. In shoulder tackles, the tackler’s head was lowered and was in front of the ball carrier at impact. There was no significant correlation between tackle types and the characteristics of bony lesions of the shoulder. Conclusion: Although the precise mechanism of primary anterior shoulder dislocation could not be estimated from this single-view analysis, failure of individual tackling leading to injury is not uniform and can be caused by 2 main factors: failure of approach followed by an extended arm position or inappropriate posture of the tackler at impact, such as a lowered head in front of the opponent. These findings indicate that injury mechanisms should be assessed for each type of tackle, as it is unknown

  3. Shoulder dystocia.

    PubMed

    Grobman, William

    2013-03-01

    The frequency of shoulder dystocia in different reports has varied, ranging 0.2-3% of all vaginal deliveries. Once a shoulder dystocia occurs, even if all actions are appropriately taken, there is an increased frequency of complications, including third- or fourth-degree perineal lacerations, postpartum hemorrhage, and neonatal brachial plexus palsies. Health care providers have a poor ability to predict shoulder dystocia for most patients and there remains no commonly accepted model to accurately predict this obstetric emergency. Consequently, optimal management of shoulder dystocia requires appropriate management at the time it occurs. Multiple investigators have attempted to enhance care of shoulder dystocia by utilizing protocols and simulation training. Copyright © 2013 Elsevier Inc. All rights reserved.

  4. Differences in knee joint kinematics and forces after posterior cruciate retaining and stabilized total knee arthroplasty.

    PubMed

    Wünschel, Markus; Leasure, Jeremi M; Dalheimer, Philipp; Kraft, Nicole; Wülker, Nikolaus; Müller, Otto

    2013-12-01

    Posterior cruciate ligament (PCL) retaining (CR) and -sacrificing (PS) total knee arthroplasties (TKA) are widely-used to treat osteoarthritis of the knee joint. The PS design substitutes the function of the PCL with a cam-spine mechanism which may produce adverse changes to joint kinematics and kinetics. CR- and PS-TKA were performed on 11 human knee specimens. Joint kinematics were measured with a dynamic knee simulator and motion tracking equipment. In-situ loads of the PCL and cam-spine were measured with a robotic force sensor system. Partial weight bearing flexions were simulated and external forces were applied. The PS-TKA rotated significantly less throughout the whole flexion range compared to the CR-TKA. Femoral roll back was greater in the PS-TKA; however, this was not correlated with lower quadriceps forces. Application of external loads produced significantly different in-situ force profiles between the TKA systems. Our data demonstrate that the PS-design significantly alters kinematics of the knee joint. Our data also suggest the cam-spine mechanism may have little influence on high flexion kinematics (such as femoral rollback) with most of the load burden shared by supporting implant and soft-tissue structures. Copyright © 2013 Elsevier B.V. All rights reserved.

  5. Preserving the Illustrated Text. Report of the Joint Task Force on Text and Image.

    ERIC Educational Resources Information Center

    Commission on Preservation and Access, Washington, DC.

    The mission of the Joint Task Force on Text and Image was to inquire into the problems, needs, and methods for preserving images in text that are important for scholarship in a wide range of disciplines and to draw from that exploration a set of principles, guidelines, and recommendations for a comprehensive national strategy for image…

  6. Joint Interagency Task Forces; the Right Model to Combat Transnational Organized Crime

    DTIC Science & Technology

    2015-05-18

    cybercrime to human trafficking and narcoterrorism. 15. SUBJECT TERMS Joint Interagency Task Force; JIATF; Whole-of-Government; Transnational...Organized Crime; Narco-terrorism; Cybercrime ; Trafficking in Persons; Crime-Terror Convergence. 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF...from drug trafficking and cybercrime to human trafficking and narcoterrorism. 1 “Our organizational construct is our strength. It fosters

  7. Mediolateral force distribution at the knee joint shifts across activities and is driven by tibiofemoral alignment.

    PubMed

    Kutzner, I; Bender, A; Dymke, J; Duda, G; von Roth, P; Bergmann, G

    2017-06-01

    Tibiofemoral alignment is important to determine the rate of progression of osteoarthritis and implant survival after total knee arthroplasty (TKA). Normally, surgeons aim for neutral tibiofemoral alignment following TKA, but this has been questioned in recent years. The aim of this study was to evaluate whether varus or valgus alignment indeed leads to increased medial or lateral tibiofemoral forces during static and dynamic weight-bearing activities. Tibiofemoral contact forces and moments were measured in nine patients with instrumented knee implants. Medial force ratios were analysed during nine daily activities, including activities with single-limb support (e.g. walking) and double-limb support (e.g. knee bend). Hip-knee-ankle angles in the frontal plane were analysed using full-leg coronal radiographs. The medial force ratio strongly correlated with the tibiofemoral alignment in the static condition of one-legged stance (R² = 0.88) and dynamic single-limb loading (R² = 0.59) with varus malalignment leading to increased medial force ratios of up to 88%. In contrast, the correlation between leg alignment and magnitude of medial compartment force was much less pronounced. A lateral shift of force occurred during activities with double-limb support and higher knee flexion angles. The medial force ratio depends on both the tibiofemoral alignment and the nature of the activity involved. It cannot be generalised to a single value. Higher medial ratios during single-limb loading are associated with varus malalignment in TKA. The current trend towards a 'constitutional varus' after joint replacement, in terms of overall tibiofemoral alignment, should be considered carefully with respect to the increased medial force ratio. Cite this article: Bone Joint J 2017;99-B:779-87. ©2017 The British Editorial Society of Bone & Joint Surgery.

  8. Shoulder Injuries in the Overhead Throwing Athlete.

    PubMed

    Mlynarek, Ryan A; Lee, Simon; Bedi, Asheesh

    2017-02-01

    The overhead pitching motion is a coordinated sequence of movements that subjects the shoulder to extreme forces. The ultimate goal of this complex, dynamic activity is to generate high ball velocity and accuracy. In doing so, repetitive throwing can cause adaptive and pathologic changes in the thrower's shoulder. This article reviews the relevant shoulder anatomy, the kinetic chain, and throwing mechanics, as well as common shoulder injuries and surgical options for the treating orthopedic surgeon.

  9. Management of acromioclavicular joint injuries.

    PubMed

    Li, Xinning; Ma, Richard; Bedi, Asheesh; Dines, David M; Altchek, David W; Dines, Joshua S

    2014-01-01

    Acromioclavicular joint injuries are among the most common shoulder girdle injuries in athletes and most commonly result from a direct force to the acromion with the arm in an adducted position. Acromioclavicular joint injuries often present with associated injuries to the glenohumeral joint, including an increased incidence of superior labrum anterior posterior (SLAP) tears that may warrant further evaluation and treatment. Anteroposterior stability of the acromioclavicular joint is conferred by the capsule and acromioclavicular ligaments, of which the posterior and superior ligaments are the strongest. Superior-inferior stability is maintained by the coracoclavicular (conoid and trapezoid) ligaments. Type-I or type-II acromioclavicular joint injuries have been treated with sling immobilization, early shoulder motion, and physical therapy, with favorable outcomes. Return to activity can occur when normal shoulder motion and strength are obtained and the shoulder is asymptomatic as compared with the contralateral normal extremity. The management of type-III injuries remains controversial and is individualized. While a return to the previous level of functional activity with nonsurgical treatment has been documented in a number of case series, surgical reduction and coracoclavicular ligament reconstruction has been associated with a favorable outcome and can be considered in patients who place high functional demands on their shoulders or in athletes who participate in overhead sports. Surgical management is indicated for high-grade (≥type IV) acromioclavicular joint injuries to achieve anatomic reduction of the acromioclavicular joint, reconstruction of the coracoclavicular ligaments, and repair of the deltotrapezial fascia. Outcomes after surgical reconstruction of the coracoclavicular ligaments have been satisfactory with regard to achieving pain relief and return to functional activities, but further improvements in the biomechanical strength of these

  10. Shoulder motor performance assessment in the sagittal plane in children with hemiplegia during single joint pointing tasks.

    PubMed

    Formica, Domenico; Petrarca, Maurizio; Rossi, Stefano; Zollo, Loredana; Guglielmelli, Eugenio; Cappa, Paolo

    2014-07-29

    Pointing is a motor task extensively used during daily life activities and it requires complex visuo-motor transformation to select the appropriate movement strategy. The study of invariant characteristics of human movements has led to several theories on how the brain solves the redundancy problem, but the application of these theories on children affected by hemiplegia is limited. This study aims at giving a quantitative assessment of the shoulder motor behaviour in children with hemiplegia during pointing tasks. Eight children with hemiplegia were involved in the study and were asked to perform movements on the sagittal plane with both arms, at low and high speed. Subject movements were recorded using an optoelectronic system; a 4-DOF model of children arm has been developed to calculate kinematic and dynamic variables. A set of evaluation indexes has been extracted in order to quantitatively assess whether and how children modify their motor control strategies when perform movements with the more affected or less affected arm. In low speed movements, no differences can be seen in terms of movement duration and peak velocity between the More Affected arm (MA) and the Less Affected arm (LA), as well as in the main characteristics of movement kinematics and dynamics. As regards fast movements, remarkable differences in terms of strategies of motor control can be observed: while movements with LA did not show any significant difference in Dimensionless Jerk Index (JI) and Dimensionless Torque-change Cost index (TC) between the elevation and lowering phases, suggesting that motor control optimization is similar for movements performed with or against gravity, movements with MA showed a statistically significant increase of both JI and TC during lowering phase. Results suggest the presence of a different control strategy for fast movements in particular during lowering phase. Results suggest that motor control is not able to optimize Jerk and Torque-change cost

  11. Modeling of Human Joint Structures.

    DTIC Science & Technology

    1982-09-01

    Radial Lateral " epicondyle Olecranon Radius Ulna Figure 3. Lateral aspect of the right elbow joint. -17- Annular Ligament This strong band encircles... elbow joint, knee joint, human joints, shoulder joint, ankle joint, joint models, hip joint, ligaments. 20. ABSTRACT (Continue on reverse side If...ligaments. -A rather extended discussion of the articulations and anatomical descriptions of the elbow , shoulder, hip, knee and ankle joints are

  12. Evaluation of Hand Forces During a Joint-Protection Strategy for Women With Hand Osteoarthritis.

    PubMed

    McGee, Corey; Mathiowetz, Virgil

    We evaluated whether a joint-protection strategy changes the mechanics of opening a sealed jar. Thirty-one adult women with hand osteoarthritis attempted to open a "sealed" jar instrument when using and not using nonskid material. Grip force, torque, success, and pain were recorded for each trial. Participants used less grip force when twisting with their left hand. The greatest torque and success, yet the least amount of grip force across time, and pain was noted when the left hand turned the lid, the jar was held vertically, the right hand supported the base, and nonskid material was used. Women with hand osteoarthritis should be educated to consider the hand they use and their approach when opening sealed jars. Use of nonskid material without additional reasoning may increase load on arthritic joints, pain, and dysfunction. Additional research on task kinematics and the kinetics of the stabilizing hand is needed.

  13. Biomechanics of reverse total shoulder arthroplasty.

    PubMed

    Berliner, Jonathan L; Regalado-Magdos, Ashton; Ma, C Benjamin; Feeley, Brian T

    2015-01-01

    Reverse total shoulder arthroplasty is an effective procedure for treatment of glenohumeral joint disease among patients with severe rotator cuff deficiency. Improvements in prosthetic design are the result of an evolved understanding of both shoulder and joint replacement biomechanics. Although modern generations of the reverse shoulder prosthesis vary in specific design details, they continue to adhere to Grammont's core principles demonstrated by his original Delta III prosthesis. This review article discusses the biomechanics of reverse total shoulder arthroplasty with a focus on elements of implant design and surgical technique that may affect stability, postoperative complications, and functional outcomes.

  14. Management of Shoulder Problems Following Obstetric Brachial Plexus Injury

    PubMed Central

    Nixon, Matthew; Trail, Ian

    2013-01-01

    Obstetric brachial plexus injuries are common, with an incidence of 0.42 per 1000 live births in the UK, and with 25% of patients being left with permanent disability without intervention. The shoulder is the most commonly affected joint and, as a result of the subsequent imbalance of musculature, the abnormal deforming forces cause dysplasia of the glenohumeral joint. In the growing child, this presents with changing pattern of pathology, which requires a multidisciplinary approach and a broad range of treatment modalities to optimize function. PMID:27582903

  15. Articular nodular fasciitis of the right shoulder joint: report of an unusual case with focus on immunohistochemical differential diagnosis.

    PubMed

    Tajima, Shogo; Zuki, Tomoyukisu; Koda, Kenji

    2015-01-01

    The mesenchymal lesion nodular fasciitis (NF) can affect various sites of the body but usually arises in subcutaneous tissue or occasionally skeletal muscle. NF is not commonly known to arise in joints, and articular NF is extremely rare. Herein, we present a case of a 54-year-old woman with articular NF. No sign of recurrence was observed after surgical piecemeal removal with a suspected positive surgical margin. In our case, a differential diagnosis of NF, desmoid-type fibromatosis, and low-grade myofibroblastic sarcoma was considered. Stromal hyalinization, a characteristic of articular NF, made the diagnosis somewhat difficult, although typical NF morphology was present. Immunohistochemical analysis of α-smooth muscle actin, desmin, β-catenin, and protein gene product 9.5 expression along with close morphological examination provided a reliable distinction.

  16. Hip joint contact forces in normal subjects and subjects with total hip prostheses: walking and stair and ramp negotiation.

    PubMed

    Stansfield, B W; Nicol, A C

    2002-02-01

    To calculate the hip joint contact force in normal subjects and subjects with total hip replacements. An observational study of age matched normal subjects and subjects with hip joint replacements. Hip joint contact forces have been calculated using musculo-skeletal models and measured in vivo using instrumented hip prostheses. There are few examples of studies performed on subjects in the 40-60 year age range. This study characterises the forces in both normal subjects and subjects with hip joint replacements for these 'young' subjects. Motion analysis and force plate data were used as input to a three-dimensional model of the leg. Five male and six female normal subjects and five male subjects with hip prostheses were studied. Each subject was observed walking and negotiating stairs and a ramp. Hip joint contact forces in both thigh and pelvic-based co-ordinate systems are presented. Subjects cadence, speed and stride length are given. In general subjects with hip replacements exhibited lower hip joint contact forces than age matched normal subjects. It is suggested that this was the results of the lower speeds, stride lengths and cadences adopted by the subjects with hip replacements. The characterisation of hip joint contact forces provides essential information for prosthetic joint design and testing. The comparison of hip joint contact forces in normal subjects with those in subjects with prosthetic joints provides evidence of, not only actual use of joints, but also of possible levels of force that might be applied to hip prostheses if subjects returned to normal use.

  17. Development of 1-DOF manipulator with variable rheological joint for instantaneous force

    NASA Astrophysics Data System (ADS)

    Majima, T.; Nagai, S.; Tomori, H.; Nakamura, T.

    2013-02-01

    Highly rigid actuators such as a geared motor or hydraulic actuator are widely used in industrial robots. To obtain high-speed motion, actuators need to increase the actuator output. However, to increase high-rigidity actuators output, it is necessary to make actuators larger. In contrast, humans perform motions with instantaneous force such as jumping or throwing by using muscles. These instantaneous forces are realized by accumulating potential energy to the muscles and the muscles releasing the energy in a short time. Therefore, in this study a 1-DOF manipulator with variable rheological joint for instantaneous force using an artificial muscle and a magnetorheological (MR) brake was developed. In this paper, the method of generating instantaneous force for this manipulator was proposed. Further, the experiment of the proposed method was also conducted. As a result, generating instantaneous force by proposed method was realized.

  18. Biomechanics of first ray hypermobility: an investigation on joint force during walking using finite element analysis.

    PubMed

    Wong, Duo Wai-Chi; Zhang, Ming; Yu, Jia; Leung, Aaron Kam-Lun

    2014-11-01

    Hypermobility of the first ray is suggested to contribute to hallux valgus. The investigation of first ray hypermobility focused on the mobility and range of motion that based on manual examination. The load transfer mechanism of the first ray is important to understand the development and pathomechanism of hallux valgus. In this study, we investigated the immediate effect of the joint hypermobility on the metatarsocuneiform and metatarsophalangeal joint loading through a reduction of the stiffness of the foot ligaments. A three-dimensional foot model was constructed from a female aged 28 via MRI. All foot and ankle bones, including two sesamoids and the encapsulated bulk tissue were modeled as 3D solid parts, linking with ligaments of shell elements and muscles connectors. The stance phase of walking was simulated by the boundary and loading conditions obtained from gait analysis of the same subject. Compared with the normal foot, the hypermobile foot had higher resultant metatarsocuneiform and metatarsophalangeal joint forces. The increases accounted for 18.6% and 3.9% body weight. There was also an abrupt change of metatarsocuneiform joint force in the medial-lateral direction. The predicted results represented possible risk of joint problems and metatarsus primus varus.

  19. Work status in patients with early rheumatoid arthritis: emphasis on shoulder function and mechanical exposure.

    PubMed

    Bilberg, A; Bremell, T; Balogh, I; Mannerkorpi, K

    2014-01-01

    The aim of this study was to investigate work status and associated factors in patients with early rheumatoid arthritis (RA), with the emphasis on shoulder function, work-related mechanical exposure, and activity limitations related to the shoulder-arm-hand. Patients with early RA were provided with self-report questionnaires quantifying work-related mechanical exposure and activity limitations. Shoulder function (i.e. isometric muscle strength, shoulder-arm movement, and shoulder pain), hand-grip force, and number of tender and swollen joints were assessed. The study comprised 135 patients (103 women and 32 men), with a mean age of 48 (SD 9.6) years, a mean disease duration of 21 (SD 9.6) months, and a mean Disease Activity Score using 28 joint counts (DAS28) of 3.7 (SD 1.4). The majority (75.6%) were working full- or part-time. Work hours correlated with work-related mechanical exposure (rs = -0.34, p < 0.001) and with physical work load (rs = 0.26, p = 0.0036). Work hours also correlated with shoulder function, that is shoulder-arm movement (rs = 0.34, p < 0.0001), shoulder strength (rs = 0.25, p = 0.0032), and activity-induced shoulder pain (rs = -0.45, p < 0.0001). Significant correlations were found between work hours and hand-grip force (rs = 0.45, p < 0.0001), activity limitations related to the shoulder-arm-hand (using the Disabilities of the Arm, Shoulder and Hand Questionnaire, DASH) (rs = -0.61, p < 0.0001), and DAS28 (rs = -0.43, p < 0.0001). DASH was found to be the only significant (p < 0.001) variable to independently explain the ability of working full-time [odds ratio (OR) 0.40, 95% confidence interval (CI) 0.29-0.55 per 10 increments, area under the receiver operating characteristic (ROC) curve (AUC) 0.81, 95% CI 0.74-0.89]. Work status in early RA is associated with shoulder function and activity limitations related to the shoulder-arm-hand accentuated by work-related mechanical exposure.

  20. Organizing for Effective Joint Warfare: A Deductive Analysis of U.S. Armed Forces Joint Doctrine

    DTIC Science & Technology

    1993-06-18

    years the military has modified the concept of control from that conceived by the classical management theorist, Henri Fayol . It has evolved from a...methodology used in Henry C. Bartlett’s, and 0. Paul Holman, Jr’s. "Strategy As a Guide to Force Planning", Naval War College Review, Vcl XLI, No. 4...8217 Unpublished SAMS Monogram, U.S. Army Command and (eneral Staff College, Fort Leavenworth, KS: 1988. Bartlett, Henry C. and Holman, 0. Paul Jr. "Strategy As

  1. Influence of the 3D inverse dynamic method on the joint forces and moments during gait.

    PubMed

    Dumas, R; Nicol, E; Chèze, L

    2007-10-01

    The joint forces and moments are commonly used in gait analysis. They can be computed by four different 3D inverse dynamic methods proposed in the literature, either based on vectors and Euler angles, wrenches and quaternions, homogeneous matrices, or generalized coordinates and forces. In order to analyze the influence of the inverse dynamic method, the joint forces and moments were computed during gait on nine healthy subjects. A ratio was computed between the relative dispersions (due to the method) and the absolute amplitudes of the gait curves. The influence of the inverse dynamic method was negligible at the ankle (2%) but major at the knee and the hip joints (40%). This influence seems to be due to the dynamic computation rather than the kinematic computation. Compared to the influence of the joint center location, the body segment inertial parameter estimation, and more, the influence of the inverse dynamic method is at least of equivalent importance. This point should be confirmed with other subjects, possibly pathologic, and other movements.

  2. Measurement of force sense reproduction in the knee joint: application of a new dynamometric device.

    PubMed

    Zavieh, Minoo Khalkhali; Amirshakeri, Bahram; Rezasoltani, Asghar; Talebi, Ghadam Ali; Kalantari, Khosro Khademi; Nedaey, Vahab; Baghban, Alireza Akbarzadeh

    2016-08-01

    [Purpose] The aim of this study was to determine the reliability of a newly designed dynamometric device for use in frequent force producing/reproducing tasks on the knee joint. [Subjects and Methods] In this cross-sectional study (Development & Reliability), 30 young healthy males and females (age 23.4 ± 2.48 years) were selected among students of Tabriz University of Medical Sciences by simple randomized selection. The study instrument was designed to measure any isometric contraction force exerted by the knee joint flexor/extensor muscles, known as the ipsilateral and contralateral methods. Participant knees were fixed in 60° flexion, and each participant completed the entire set of measurements twice, 72 hours apart. [Results] The findings showed a good intraclass correlation coefficient of 0.73 to 0.81 for all muscle groups. The standard error of measurement and smallest detectable difference for flexor muscle groups were 0.37 and 1.02, respectively, while the values increased to standard error of measurement=0.38 and smallest detectable difference=1.05 for extensor muscle groups. [Conclusion] The device designed could quantify the forces producing/reproducing tasks on the knee joint with a high rate of reliability, and can probably be applied for outcome measurements in proprioceptive assessment of the knee joint.

  3. Measurement of force sense reproduction in the knee joint: application of a new dynamometric device

    PubMed Central

    Zavieh,, Minoo Khalkhali; Amirshakeri,, Bahram; Rezasoltani,, Asghar; Talebi,, Ghadam Ali; Kalantari,, Khosro Khademi; Nedaey,, Vahab; Baghban,, Alireza Akbarzadeh

    2016-01-01

    [Purpose] The aim of this study was to determine the reliability of a newly designed dynamometric device for use in frequent force producing/reproducing tasks on the knee joint. [Subjects and Methods] In this cross-sectional study (Development & Reliability), 30 young healthy males and females (age 23.4 ± 2.48 years) were selected among students of Tabriz University of Medical Sciences by simple randomized selection. The study instrument was designed to measure any isometric contraction force exerted by the knee joint flexor/extensor muscles, known as the ipsilateral and contralateral methods. Participant knees were fixed in 60° flexion, and each participant completed the entire set of measurements twice, 72 hours apart. [Results] The findings showed a good intraclass correlation coefficient of 0.73 to 0.81 for all muscle groups. The standard error of measurement and smallest detectable difference for flexor muscle groups were 0.37 and 1.02, respectively, while the values increased to standard error of measurement=0.38 and smallest detectable difference=1.05 for extensor muscle groups. [Conclusion] The device designed could quantify the forces producing/reproducing tasks on the knee joint with a high rate of reliability, and can probably be applied for outcome measurements in proprioceptive assessment of the knee joint. PMID:27630421

  4. Is there an association between the individual anatomy of the scapula and the development of rotator cuff tears or osteoarthritis of the glenohumeral joint?: A radiological study of the critical shoulder angle.

    PubMed

    Moor, B K; Bouaicha, S; Rothenfluh, D A; Sukthankar, A; Gerber, C

    2013-07-01

    We hypothesised that a large acromial cover with an upwardly tilted glenoid fossa would be associated with degenerative rotator cuff tears (RCTs), and conversely, that a short acromion with an inferiorly inclined glenoid would be associated with glenohumeral osteoarthritis (OA). This hypothesis was tested using a new radiological parameter, the critical shoulder angle (CSA), which combines the measurements of inclination of the glenoid and the lateral extension of the acromion (the acromion index). The CSA was measured on standardised radiographs of three groups: 1) a control group of 94 asymptomatic shoulders with normal rotator cuffs and no OA; 2) a group of 102 shoulders with MRI-documented full-thickness RCTs without OA; and 3) a group of 102 shoulders with primary OA and no RCTs noted during total shoulder replacement. The mean CSA was 33.1° (26.8° to 38.6°) in the control group, 38.0° (29.5° to 43.5°) in the RCT group and 28.1° (18.6° to 35.8°) in the OA group. Of patients with a CSA > 35°, 84% were in the RCT group and of those with a CSA < 30°, 93% were in the OA group. We therefore concluded that primary glenohumeral OA is associated with significantly smaller degenerative RCTs with significantly larger CSAs than asymptomatic shoulders without these pathologies. These findings suggest that individual quantitative anatomy may imply biomechanics that are likely to induce specific types of degenerative joint disorders.

  5. SHOULDER DISORDERS AND OCCUPATION

    PubMed Central

    Linaker, CH; Walker-Bone, K

    2016-01-01

    Shoulder pain is very common and causes substantial morbidity. Standardised classification systems based upon presumed patho-anatomical origins have proved poorly reproducible and hampered epidemiological research. Despite this, there is evidence that exposure to combinations of physical workplace strains such as overhead working, heavy lifting and forceful work as well as working in an awkward posture increase the risk of shoulder disorders. Psychosocial risk factors are also associated. There is currently little evidence to suggest that either primary prevention or treatment strategies in the workplace are very effective and more research is required, particularly around the cost-effectiveness of different strategies. PMID:26612238

  6. Vaccination-related shoulder dysfunction.

    PubMed

    Bodor, Marko; Montalvo, Enoch

    2007-01-08

    We present two cases of shoulder pain and weakness following influenza and pneumococcal vaccine injections provided high into the deltoid muscle. Based on ultrasound measurements, we hypothesize that vaccine injected into the subdeltoid bursa caused a periarticular inflammatory response, subacromial bursitis, bicipital tendonitis and adhesive capsulitis. Resolution of symptoms followed corticosteroid injections to the subacromial space, bicipital tendon sheath and glenohumeral joint, followed by physical therapy. We conclude that the upper third of the deltoid muscle should not be used for vaccine injections, and the diagnosis of vaccination-related shoulder dysfunction should be considered in patients presenting with shoulder pain following a vaccination.

  7. Joint Campaign Design: Using a Decide-Detect-Attack (DDA) Methodology to Synchronize the Joint Force’s Capabilities Against Enemy Centers of Gravity

    DTIC Science & Technology

    1994-05-06

    of COG. USMC DOCTRINE Field Marine Force Manual (FMFM) 1, Warfifhtinf, contains the USMC’s keystone doctrine. An examination of this manual reveals...Joint Publication (JP) 3-0, Doctrine for Unified and Joint Onerations. JP 3-0 is the keystone manual that sets forth the doctrine to govern unified and...seaways, rails, lines of communication, pipelines , and numerous other facilities needed to support the fielded military forces.m’ The next most critical

  8. Forces in bolted joints: analysis methods and test results utilized for nuclear core applications (LWBR Development Program)

    SciTech Connect

    Crescimanno, P.J.; Keller, K.L.

    1981-03-01

    Analytical methods and test data employed in the core design of bolted joints for the LWBR core are presented. The effects of external working loads, thermal expansion, and material stress relaxation are considered in the formulation developed to analyze joint performance. Extensions of these methods are also provided for bolted joints having both axial and bending flexibilities, and for the effect of plastic deformation on internal forces developed in a bolted joint. Design applications are illustrated by examples.

  9. The influence of elbow joint angle on different phases of force development during maximal voluntary contraction.

    PubMed

    Jaskólski, A; Kisiel, K; Adach, Z; Jaskólska, A

    2000-12-01

    The first aim of the study was to find an elbow joint angle at which muscle can produce maximum voluntary force (Lo(MVC)) and to compare that angle with an angle at which the fastest rates of force development occur (Lo). The second aim of the study was to find if changes in MVC and force development speed at an angle smaller (Ls) and larger (Ll) than the optimal angle depend on whether Ls and Ll were compared to Lo or Ls and Ll to Lo(MVC). Twenty-four male physical education students were tested four times using the BIODYNA dynamometer to measure torque versus time at an optimal length, as well as at lengths that were shorter (Ls = optimal -30 degrees) and longer (Ll = optimal +50 degrees). The average values of optimal angles for force development indices (Lo) were similar to the angle at which maximum force was produced (Lo(MVC)); however, there was a small (5-10 degrees) difference between Lo and Lo(MVC) in the majority of subjects. The results showed that during elbow flexion with the forearm in the midrange position, the difference between Lo and Lo(MVC) was small and did not affect MVC; however, it had a significant effect on the relation between joint angle and force development speed.

  10. How critical are the tibiofemoral joint reaction forces during frequent squatting in Asian populations?

    PubMed

    Thambyah, Ashvin

    2008-08-01

    This study examines tibiofemoral joint moments and forces when performing a squat. The relevance of studying such an activity is to understand better the mechanical factors involved in the higher incidence of tibiofemoral osteoarthritis in Asian populations where squatting is a common daily activity. In this study, motion analysis data of walking versus squatting were compared, specifically looking at net external knee flexion moments, ground reaction forces and tibiofemoral contact forces. It was found that while squatting resulted in more than 2.5 times larger peak external moments compared with walking, tibiofemoral contact forces were not significantly different. This was due to reduced ground reaction forces recorded for the squatting phase compared to the larger dynamic effects of deceleration at heel strike during walking. The most significant finding of this study was that in squatting, there was a reversal in the tibiofemoral shear reaction force from posterior-directed to anterior-directed, occurring under full compressive load and within a fraction of a second. It is believed that repeated squatting results in many such reversals in shear reactions that may ultimately have significant implications to the long term mechanical function and structural integrity of the joint cartilage.

  11. Force-velocity Relationship of Muscles Performing Multi-joint Maximum Performance Tasks.

    PubMed

    Jaric, S

    2015-08-01

    Manipulation of external loads typically provides a range of force, velocity, and power data that allows for modeling muscle mechanical characteristics. While a typical force-velocity relationship obtained from either in vitro muscles or isolated muscle groups can be described by a hyperbolic equation, the present review paper reveals the evidence that the same relationship obtained from maximum-performance multi-joint movements could be approximately linear. As a consequence, this pattern also results in a relatively simple shape of the power-velocity relationship. The parameters of the linear force-velocity relationship reveal the maximum force, velocity and power. Recent studies conducted on various functional movement tasks reveal that these parameters could be reliable, on average moderately valid, and typically sensitive enough to detect differences among populations of different physical abilities. Therefore, the linear force-velocity relationship together with the associated parabolic power-velocity relationship could provide both a new and simplified approach to studies of the design and function of human muscular system and its modeling. Regarding the practical applications, the reviewed findings also suggest that the loaded multi-joint movements could be developed into relatively simple routine tests of the force-, velocity- and power-generating capacity of the neuromuscular system.

  12. Editorial Commentary: Shoulder Arthroscopy, Shoulder Hemiarthroplasty, and Total Shoulder Arthroplasty for Glenohumeral Osteoarthritis.

    PubMed

    Lubowitz, James H

    2015-06-01

    Shoulder arthroscopy offers a safe, effective, and less invasive alternative to arthroplasty in patients under 60 years of age with glenohumeral arthritis. However, indications include joint space of greater than 2 mm. For patients who do not meet arthroscopic indications, total shoulder arthroplasty is more effective than hemiarthroplasty. Performance and publication bias may effect generalizability of these findings. Biologic treatment options seem on the horizon.

  13. Shoulder Pain

    MedlinePlus

    ... familydoctor.org editorial staff Categories: Exercise and Fitness, Injury Rehabilitation, Prevention and WellnessTags: Exercise Prescription, pain relievers, Shoulder Problems, sports medicine Exercise and Fitness, Injury Rehabilitation, Prevention and ...

  14. Shoulder MRI

    MedlinePlus

    ... of the shoulder uses a powerful magnetic field, radio waves and a computer to produce detailed pictures of ... scans, MRI does not utilize ionizing radiation. Instead, radio waves redirect alignment of hydrogen atoms that naturally exist ...

  15. Navy Information Dominance, the Battle of Midway, and the Joint Force Commander: It Worked Then, It Needs to Work Now

    DTIC Science & Technology

    2013-05-19

    cyberspace, is putting increased emphasis on the need for the Joint Force Commander to employ his force to achieve Information Dominance . The information... Information Dominance is to assist in achieving Decision Superiority, Assured Command and Control, Battlespace Awareness, and Integrated Fires. Navy... Information Dominance aims to use information in cyberspace as a way and means in warfare -- as a battery in the Joint Force Commander’s arsenal. The

  16. Joint Disorders

    MedlinePlus

    A joint is where two or more bones come together, like the knee, hip, elbow, or shoulder. Joints can be damaged by many types of injuries or diseases, including Arthritis - inflammation of a joint. It causes pain, stiffness, and swelling. Over time, ...

  17. The effects of therapeutic exercise using PNF on the size of calcium deposits, pain self-awareness, and shoulder joint function in a calcific tendinitis patient: a case study.

    PubMed

    Oh, Dong-Gun; Yoo, Kyung-Tae

    2017-01-01

    [Purpose] The purpose of this case study was to identify the effects of independent and intensive therapeutic exercise using Proprioceptive neuromuscular facilitation on the size of calcium deposits, pain self-awareness, and shoulder joint function in a patient with calcific tendonitis. [Subject and Methods] The subject was a 42-year-old female patient with calcific tendonitis and acute pain who had difficulty with active movement and problems with general function. The independent and intensive Proprioceptive neuromuscular facilitation exercise was applied for 40 min twice a day five times a week for two weeks for a total of 20 times. An X-ray, the visual analog scale, a simple shoulder test, the Constant-Murley Scale, and passive range of motion was used to evaluate the patient's change. [Results] The size of the calcium deposit, the visual analog scale score, and the simple shoulder test score decreased. The Constant-Murley Scale score and the passive range of motion were increased. [Conclusion] The results of this study suggested that intensive and independent therapeutic short-term exercise without any other exercise reduced pain and produced positive effects in shoulder function in a patient with the calcific tendonitis, which could confirm the importance of therapeutic exercise in the treatment of calcific tendonitis.

  18. The effects of therapeutic exercise using PNF on the size of calcium deposits, pain self-awareness, and shoulder joint function in a calcific tendinitis patient: a case study

    PubMed Central

    Oh, Dong-Gun; Yoo, Kyung-Tae

    2017-01-01

    [Purpose] The purpose of this case study was to identify the effects of independent and intensive therapeutic exercise using Proprioceptive neuromuscular facilitation on the size of calcium deposits, pain self-awareness, and shoulder joint function in a patient with calcific tendonitis. [Subject and Methods] The subject was a 42-year-old female patient with calcific tendonitis and acute pain who had difficulty with active movement and problems with general function. The independent and intensive Proprioceptive neuromuscular facilitation exercise was applied for 40 min twice a day five times a week for two weeks for a total of 20 times. An X-ray, the visual analog scale, a simple shoulder test, the Constant-Murley Scale, and passive range of motion was used to evaluate the patient’s change. [Results] The size of the calcium deposit, the visual analog scale score, and the simple shoulder test score decreased. The Constant-Murley Scale score and the passive range of motion were increased. [Conclusion] The results of this study suggested that intensive and independent therapeutic short-term exercise without any other exercise reduced pain and produced positive effects in shoulder function in a patient with the calcific tendonitis, which could confirm the importance of therapeutic exercise in the treatment of calcific tendonitis. PMID:28210065

  19. Finnishing the Force: Achieving True Flexibility for the Joint Force Commander

    DTIC Science & Technology

    2014-06-01

    CREW) 2.1 vehicle-mounted jammer (up to 25,000 of which are on contract for purchase by the US Army). It uses a digitally controlled, 30-watt...out assigned tasks. We may no longer be able to afford the luxury of retaining our most sophisticated capabilities as or- ganic elements of a...joint force” (II-7). 2. “JCREW: ITT Wins Contracts for Land Mine Jammers,” Defense Industry Daily, 3 Octo- ber 2011, http://www.defenseindustrydaily.com

  20. Biomechanical Considerations in the Competitive Swimmer’s Shoulder

    PubMed Central

    Heinlein, Scott A.; Cosgarea, Andrew J.

    2010-01-01

    Context: Competitive swimming has become an increasingly popular sport in the United States. In 2007, more than 250 000 competitive swimmers were registered with USA Swimming, the national governing body. The average competitive swimmer swims approximately 60 000 to 80 000 m per week. With a typical count of 8 to 10 strokes per 25-m lap, each shoulder performs 30 000 rotations each week. This places tremendous stress on the shoulder girdle musculature and glenohumeral joint, and it is why shoulder pain is the most frequent musculoskeletal complaint among competitive swimmers. Evidence Acquisition: Articles were obtained through a variety of medical search sources, including Medline, Google Scholar, and review articles from 1980 through January 2010. Results: The most common cause of shoulder pain in swimmers is supraspinatus tendinopathy. Glenohumeral instability and labral tears have also been reported, but a paucity of information remains regarding prevalence and treatment in swimmers. Conclusion: Because of the great number of stroke repetitions and force generated through the upper extremity, the shoulder is uniquely vulnerable to injury in the competitive swimmer. Comprehensive evaluation should include the entire kinetic chain, including trunk strength and core stability. PMID:23015983

  1. In vivo pediatric shoulder muscle volumes and their relationship to 3D strength.

    PubMed

    Im, Hyun Soo; Alter, Katharine E; Brochard, Sylvain; Pons, Christelle; Sheehan, Frances T

    2014-08-22

    In the pediatric shoulder, injury and pathology can disrupt the muscle force balance, resulting in severe functional losses. As little data exists pertaining to in vivo pediatric shoulder muscle function, musculoskeletal data are crucially needed to advance the treatment of pediatric shoulder pathology/injury. Therefore, the purpose of this study was to develop a pediatric database of in vivo volumes for the major shoulder muscles and correlate these volumes with maximum isometric flexion/extension, internal/external rotation, and abduction/adduction joint moments. A methodology was developed to derive 3D shoulder muscle volumes and to divide the deltoid into sub-units with unique torque producing capabilities, based on segmentation of three-dimensional magnetic resonance images. Eleven typically developing children/adolescents (4F/7M, 12.0 ± 3.2 years, 150.8 ± 16.7 cm, 49.2 ± 16.4 kg) participated. Correlation and regression analyses were used to evaluate the relationship between volume and maximum, voluntary, isometric joint torques. The deltoid demonstrated the largest (30.4 ± 1.2%) and the supraspinatus the smallest (4.8 ± 0.5%) percent of the total summed volume of all six muscles evaluated. The anterior and posterior deltoid sections were 43.4 ± 3.9% and 56.6 ± 3.9% of the total deltoid volume. The percent volumes were highly consistent across subjects. Individual muscle volumes demonstrated moderate-high correlations with torque values (0.70-0.94, p<0.001). This study presents a comprehensive database documenting normative pediatric shoulder muscle volume. Using these data a clear relationship between shoulder volume and the torques they produce was established in all three rotational degrees-of-freedom. This study furthers the understanding of shoulder muscle function and serves as a foundation for evaluating shoulder injury/pathology in the pediatric/adolescent population.

  2. In Vivo Pediatric Shoulder Muscle Volumes and Their Relationship to 3D Strength

    PubMed Central

    Im, Hyun Soo; Alter, Katharine E.; Brochard, Sylvain; Pons, Christelle; Sheehan, Frances T.

    2017-01-01

    In the pediatric shoulder, injury and pathology can disrupt the muscle force balance, resulting in severe functional losses. As little data exists pertaining to in vivo pediatric shoulder muscle function, musculoskeletal data are crucially needed to advance the treatment of pediatric shoulder pathology/injury. Therefore, the purpose of this study was to develop a pediatric database of in vivo volumes for the major shoulder muscles and correlate these volumes to maximum isometric flexion/extension, internal/external rotation, and abduction/adduction joint moments. A methodology was developed to derive 3D shoulder muscle volumes and to divide the deltoid into sub-units with unique torque producing capabilities, based on segmentation of three-dimensional magnetic resonance images. Eleven typically developing children/adolescents (4F/7M, 12.0±3.2years, 150.8±16.7cm, 49.2±16.4kg) participated. Correlation and regression analyses were used to evaluate the relationship between volume and maximum, voluntary, isometric joint torques. The deltoid demonstrated the largest (30.4 ±1.2%) and the supraspinatus the smallest (4.8 ± 0.5%) percent of the total summed volume of all six muscles evaluated. The anterior and posterior deltoid sections were 43.4±3.9% and 56.6±3.9% of the total deltoid volume. The percent volumes were highly consistent across subjects. Individual muscle volumes demonstrated moderate-high correlations with torque values (0.70–0.94, p<0.001). This study presents a comprehensive database documenting normative pediatric shoulder muscle volume. Using these data a clear relationship between shoulder volume and the torques they produce was established in all three rotational degrees-of-freedom. This study furthers the understanding of shoulder muscle function and serves as a foundation for evaluating shoulder injury/pathology in the pediatric/adolescent population. PMID:24925254

  3. Age and gender differences in the control of vertical ground reaction force by the hip, knee and ankle joints.

    PubMed

    Toda, Haruki; Nagano, Akinori; Luo, Zhiwei

    2015-06-01

    [Purpose] This study examined the relationships between joint moment and the control of the vertical ground reaction force during walking in the elderly and young male and female individuals. [Subjects and Methods] Forty elderly people, 65 years old or older (20 males and 20 females), and 40 young people, 20 to 29 years old (20 males and 20 females), participated in this study. Joint moment and vertical ground reaction force during walking were obtained using a 3D motion analysis system and force plates. Stepwise linear regression analysis determined the joint moments that predict the amplitude of the vertical ground reaction force. [Results] Knee extension moment was related to the vertical ground reaction force in the young males and females. On the other hand, in the elderly females, hip, ankle, and knee joint moments were related to the first peak and second peak forces, and the minimum value of vertical ground reaction force, respectively. [Conclusion] Our results suggest that the young males and females make use of the knee joint moment to control of the vertical ground reaction force. There were differences between the elderly and the young females with regard to the joints used for the control of the vertical ground reaction force.

  4. Evalution of Mulligan's technique for adhesive capsulitis of the shoulder.

    PubMed

    Doner, Gokhan; Guven, Zeynep; Atalay, Ayçe; Celiker, Reyhan

    2013-01-01

    To evaluate Mulligan's technique for relieving pain and improving functional capacity of the shoulder in patients with adhesive capsulitis in the stiffness phase. Randomized controlled study. A total of 40 subjects were randomly allocated into 2 groups: (i) group 1 (n = 20) were treated with hot pack, transcutaneous electrical nerve stimulation, and passive stretching exercises; (ii) group 2 (n = 20) were treated with hot pack, transcutaneous electrical nerve stimulation and Mulligan's technique. Mulligan's technique combines the sustained application of a manual "gliding" force to a joint, with the aim of repositioning bone positional faults while enabling concurrent physiological (osteo-kinematic) motion of the joint. All cases were evaluated using visual analogue scales for pain, passive and active range of motion, Constant score, Shoulder Disability Questionnaire, and patient and therapist satisfaction at baseline, after completion of treatment sessions and at the end of 3 months of follow-up. Marked improvement was noted in both groups after completion of treatment sessions and at the third month of follow-up compared with baseline. The improvements in outcome measures, namely pain, range of motion, shoulder scores, and patient and physiotherapist satisfaction, were significantly greater in subjects in group 2, who were treated with Mulligan's technique. Mulligan's technique and passive stretching exercises are both effective in reducing pain, and restoring range of motion and function. However, compared with stretching exercises, Mulligan's technique led to better improvements in terms of pain, range of motion, shoulder scores, and patient and physiotherapist satisfaction.

  5. A musculoskeletal shoulder model based on pseudo-inverse and null-space optimization.

    PubMed

    Terrier, Alexandre; Aeberhard, Martin; Michellod, Yvan; Mullhaupt, Philippe; Gillet, Denis; Farron, Alain; Pioletti, Dominique P

    2010-11-01

    The goal of the present work was assess the feasibility of using a pseudo-inverse and null-space optimization approach in the modeling of the shoulder biomechanics. The method was applied to a simplified musculoskeletal shoulder model. The mechanical system consisted in the arm, and the external forces were the arm weight, 6 scapulo-humeral muscles and the reaction at the glenohumeral joint, which was considered as a spherical joint. The muscle wrapping was considered around the humeral head assumed spherical. The dynamical equations were solved in a Lagrangian approach. The mathematical redundancy of the mechanical system was solved in two steps: a pseudo-inverse optimization to minimize the square of the muscle stress and a null-space optimization to restrict the muscle force to physiological limits. Several movements were simulated. The mathematical and numerical aspects of the constrained redundancy problem were efficiently solved by the proposed method. The prediction of muscle moment arms was consistent with cadaveric measurements and the joint reaction force was consistent with in vivo measurements. This preliminary work demonstrated that the developed algorithm has a great potential for more complex musculoskeletal modeling of the shoulder joint. In particular it could be further applied to a non-spherical joint model, allowing for the natural translation of the humeral head in the glenoid fossa.

  6. Inter-individual similarities and variations in muscle forces acting on the ankle joint during gait.

    PubMed

    Błażkiewicz, Michalina; Wiszomirska, Ida; Kaczmarczyk, Katarzyna; Naemi, Roozbeh; Wit, Andrzej

    2017-07-29

    Muscle forces acting over the ankle joint play an important role in the forward progression of the body during gait. Yet despite the importance of ankle muscle forces, direct in-vivo measurements are neither possible nor practical. This makes musculoskeletal simulation useful as an indirect technique to quantify the muscle forces at work during locomotion. The purpose of this study was to: 1) identify the maximum peaks of individual ankle muscle forces during gait; 2) investigate the order over which the muscles are sorted based on their maximum peak force. Three-dimensional kinematics and ground reaction forces were measured during the gait of 10 healthy subjects, and the data so obtained were input into the musculoskeletal model distributed with the OpenSim software. In all 10 individuals we observed that the soleus muscle generated the greatest strength both in dynamic (1856.1N) and isometric (3549N) conditions, followed by the gastrocnemius in dynamic conditions (1232.5N). For all other muscles, however, the sequence looks different across subjects, so the k-means clustering method was used to obtain one main order over which the muscles' peak-forces are sorted. The results indicate a common theme, with some variations in the maximum peaks of ankle muscle force across subjects. Copyright © 2017. Published by Elsevier B.V.

  7. Supraspinatus tendon load during abduction is dependent on the size of the critical shoulder angle: A biomechanical analysis.

    PubMed

    Gerber, Christian; Snedeker, Jess G; Baumgartner, Daniel; Viehöfer, Arnd F

    2014-07-01

    Shoulders with supraspinatus (SSP) tears are associated with significantly larger critical shoulder angles (CSA) compared to disease-free shoulders. We hypothesized that larger CSAs increase the ratio of joint shear to joint compression forces (defined as "instability ratio"), requiring substantially increased compensatory supraspinatus loads. A shoulder simulator with simulated deltoid, supraspinatus, infraspinatus/teres minor, and subscapularis musculotendinous units was constructed. The model was configured to represent either a normal CSA of 33° or a CSA characteristic of shoulders with rotator cuff tears (38°), and the components of the joint forces were measured. The instability ratio increased for the 38° CSA compared with the control CSA (33°) for a range of motion between 6° to 61° of thoracohumeral abduction with the largest differences in instability observed between 33° and 37° of elevation. In this range, SSP force had to be increased by 13-33% (15-23 N) to stabilize the arm in space. Our results support the concept that a high CSA can induce SSP overload particularly at low degrees of active abduction.

  8. Environmental Assessment for the Joint Red Flag 󈧉 ADA Activities Nellis Air Force Base

    DTIC Science & Technology

    2005-03-01

    Prescribed by ANSI Std Z39-18 DECISION RECORD AND FINDING OF NO SIGNIFICANT IMPACT (DR/FONSI) JOINT RED FLAG –’05 ADA ACTIVITIES 1 Decision: I have...1500–1508]); Department of the Army Environmental Analysis of Army Actions (32 CFR 651); Department of the Air Force Environmental Impact Analysis...Standard Operating Procedures (SOP’s) and monitoring requirements to minimize potential environmental impacts . The project will be constructed under the

  9. Joint Strike Fighter, the Right Choice for the Future Norwegian Air Force

    DTIC Science & Technology

    2009-02-20

    Joint Strike Fighter, the right choice for the future Norwegian Air Force LtCdr Engen, Stein Presented to Major Aaron A...Fighter, the right choice for the future 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER 5e. TASK...According to official figures released to the press, the forty-eight JSFs will come at a cost of approximately eighteen billion Norwegian kroner ( NOK

  10. Honing the Dagger: The formation of a Standing Joint Special Operations Task Force Headquarters

    DTIC Science & Technology

    2005-05-26

    has greatly hindered the ability of SOF to prosecute the war on terrorism with the necessary efficiency, flexibility and agility . When a Joint Task...Operations, Ubiquitous Access, Regional Expertise, C4ISR Dominance, Agile and Unconventional Logistics, and Force Protection and Survivability.6 SOF’s...flexibility and agility of the organization. For example, if the need for the SJSOTF to expand into a JTF should arise, the Director of the Center for

  11. Utilization of the JANAF (Joint Army Navy Air Force) database for chemical thermodynamic calculations

    NASA Astrophysics Data System (ADS)

    Bafi, A. S.

    1987-12-01

    A computer code is presented here that calculates the standard-state free energy change and the equilibrium constant for a specified reaction aA + bB = cC + dD. In computing these values, this code utilizes the Joint Army Navy Air Force (JANAF) thermochemical data file. If desired, certain additional thermodynamic values for the individual reactants and products can also be included in the output of this code.

  12. Airpower in Hybrid War: Ethical Implications for the Joint Force Commander

    DTIC Science & Technology

    2014-05-15

    an ever enticing means to achieve the nation’s political objectives. Applying airpower to hybrid war raises unique ethical considerations for the...Airpower 3 Hierarchical Ethics in Applying Airpower to Hybrid War 5 Double Intent—A Consideration in Proportionality 8...hybrid war raises unique ethical considerations for the Joint Force Commander (JFC). In this essay, the author introduces the nuances of hybrid war, the

  13. Regional Engagement from Phase 0: A Joint Interagency Task Force for the Trans-Sahel

    DTIC Science & Technology

    2006-05-16

    are woven throughout the NSS. For most of Africa, the Commander, United States European Command (EUCOM), executes those NSS tasks which fall under ...hinges critically on reaching favorable agreements with those entities. New, and key to this construct, is a DoS Trans- Sahel officer. The State ...FINAL 3. DATES COVERED (From - To) Regional Engagement from Phase 0: A Joint Interagency Task Force for the Trans- Sahel 5a

  14. Advance Force Operations: The Middleweight Force’s Essential Role in the Joint Operations

    DTIC Science & Technology

    2013-04-18

    Force” concept ; however, changes regarding Advance Force Operations have increased the risk of the Marine Corps not meeting its obligation as the...finding through a detailed discussion of “the sea, air and climate , land types, native populations, economic conditions, and the enemy”20 to support this...was further refined based on the extensive experience gained by both the Navy and Marine Corps reconnaissance elements. Doctrinal changes captured

  15. Distal Radioulnar Joint Reaction Force Following Ulnar Shortening: Diaphyseal Osteotomy Versus Wafer Resection.

    PubMed

    Canham, Colin D; Schreck, Michael J; Maqsoodi, Noorullah; Messing, Susan; Olles, Mark; Elfar, John C

    2015-11-01

    To compare how ulnar diaphyseal shortening and wafer resection affect distal radioulnar joint (DRUJ) joint reaction force (JRF) using a nondestructive method of measurement. Our hypothesis was that ulnar shortening osteotomy would increase DRUJ JRF more than wafer resection. Eight fresh-frozen human cadaveric upper limbs were obtained. Under fluoroscopic guidance, a threaded pin was inserted into the lateral radius orthogonal to the DRUJ and a second pin was placed in the medial ulna coaxial to the radial pin. Each limb was mounted onto a mechanical tensile testing machine and a distracting force was applied across the DRUJ while force and displacement were simultaneously measured. Data sets were entered into a computer and a polynomial was generated and solved to determine the JRF. This process was repeated after ulnar diaphyseal osteotomy, ulnar re-lengthening, and ulnar wafer resection. The JRF was compared among the 4 conditions. Average baseline DRUJ JRF for the 8 arms increased significantly after diaphyseal ulnar shortening osteotomy (7.2 vs 10.3 N). Average JRF after re-lengthening the ulna and wafer resection was 6.9 and 6.7 N, respectively. There were no differences in JRF among baseline, re-lengthened, and wafer resection conditions. Distal radioulnar joint JRF increased significantly after ulnar diaphyseal shortening osteotomy and did not increase after ulnar wafer resection. Diaphyseal ulnar shortening osteotomy increases DRUJ JRF, which may lead to DRUJ arthrosis. Copyright © 2015 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.

  16. Sound side joint contact forces in below knee amputee gait with an ESAR prosthetic foot.

    PubMed

    Karimi, Mohammad Taghi; Salami, Firooz; Esrafilian, Amir; Heitzmann, Daniel W W; Alimusaj, Merkur; Putz, Cornelia; Wolf, Sebastian I

    2017-08-08

    The incidence of knee and hip joint osteoarthritis in subjects with below knee amputation (BK) appears significantly higher compared to unimpaired subjects, especially in the intact side. However, it is controversial if constant higher loads on the sound side are one of the major factors for an increased osteoarthritis (OA) incidence in subjects with BK, beside other risk factors, e.g. with respect to metabolism. The aim wasto investigate joint contact forces (JCF) calculated by a musculoskeletal model in the intact side and to compare it with those of unimpaired subjects and to further elucidate in how far increased knee JCF are associated with increased frontal plane knee moments. A group of seven subjects with BK amputation and a group of ten unimpaired subjects were recruited for this study. Gait data were measured by 3D motion capture and force plates. OpenSim software was applied to calculate JCF. Maximum joint angles, ground reaction forces, and moments as well as time distance parameters were determined and compared between groups showing no significant differences, with some JCF components of knee and hip even being slightly smaller in subjects with BK compared to the reference group. This positive finding may be due to the selected ESAR foot. However, other beneficial factors may also have influenced this positive result such as the general good health status of the subjects or the thorough and proper fitting and alignment of the prosthesis. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. Joint mobilization forces and therapist reliability in subjects with knee osteoarthritis

    PubMed Central

    Tragord, Bradley S; Gill, Norman W; Silvernail, Jason L; Teyhen, Deydre S; Allison, Stephen C

    2013-01-01

    Objectives: This study determined biomechanical force parameters and reliability among clinicians performing knee joint mobilizations. Methods: Sixteen subjects with knee osteoarthritis and six therapists participated in the study. Forces were recorded using a capacitive-based pressure mat for three techniques at two grades of mobilization, each with two trials of 15 seconds. Dosage (force–time integral), amplitude, and frequency were also calculated. Analysis of variance was used to analyze grade differences, intraclass correlation coefficients determined reliability, and correlations assessed force associations with subject and rater variables. Results: Grade IV mobilizations produced higher mean forces (P<0.001) and higher dosage (P<0.001), while grade III produced higher maximum forces (P = 0.001). Grade III forces (Newtons) by technique (mean, maximum) were: extension 48, 81; flexion 41, 68; and medial glide 21, 34. Grade IV forces (Newtons) by technique (mean, maximum) were: extension 58, 78; flexion 44, 60; and medial glide 22, 30. Frequency (Hertz) ranged between 0.9–1.1 (grade III) and 1.4–1.6 (grade IV). Intra-clinician reliability was excellent (>0.90). Inter-clinician reliability was moderate for force and dosage, and poor for amplitude and frequency. Discussion: Force measurements were consistent with previously reported ranges and clinical constructs. Grade III and grade IV mobilizations can be distinguished from each other with differences for force and frequency being small, and dosage and amplitude being large. Intra-clinician reliability was excellent for all biomechanical parameters and inter-clinician reliability for dosage, the main variable of clinical interest, was moderate. This study quantified the applied forces among multiple clinicians, which may help determine optimal dosage and standardize care. PMID:24421632

  18. Effect of power-assisted hand-rim wheelchair propulsion on shoulder load in experienced wheelchair users: A pilot study with an instrumented wheelchair.

    PubMed

    Kloosterman, Marieke G M; Buurke, Jaap H; de Vries, Wiebe; Van der Woude, Lucas H V; Rietman, Johan S

    2015-10-01

    This study aims to compare hand-rim and power-assisted hand-rim propulsion on potential risk factors for shoulder overuse injuries: intensity and repetition of shoulder loading and force generation in the extremes of shoulder motion. Eleven experienced hand-rim wheelchair users propelled an instrumented wheelchair on a treadmill while upper-extremity kinematic, kinetic and surface electromyographical data was collected during propulsion with and without power-assist. As a result during power-assisted propulsion the peak resultant force exerted at the hand-rim decreased and was performed with significantly less abduction and internal rotation at the shoulder. At shoulder level the anterior directed force and internal rotation and flexion moments decreased significantly. In addition, posterior and the minimal inferior directed forces and the external rotation moment significantly increased. The stroke angle decreased significantly, as did maximum shoulder flexion, extension, abduction and internal rotation. Stroke-frequency significantly increased. Muscle activation in the anterior deltoid and pectoralis major also decreased significantly. In conclusion, compared to hand-rim propulsion power-assisted propulsion seems effective in reducing potential risk factors of overuse injuries with the highest gain on decreased range of motion of the shoulder joint, lower peak propulsion force on the rim and reduced muscle activity.

  19. Relationship Between Hand Contact Angle and Shoulder Loading During Manual Wheelchair Propulsion by Individuals with Paraplegia

    PubMed Central

    Mulroy, Sara J.; Ruparel, Puja; Hatchett, Patricia E.; Haubert, Lisa Lighthall; Eberly, Valerie J.; Gronley, JoAnne K.

    2015-01-01

    Background: Shoulder loading during manual wheelchair propulsion (WCP) contributes to the development of shoulder pain in individuals with spinal cord injury (SCI). Objective: To use regression analysis to investigate the relationships between the hand contact angle (location of the hand on the pushrim at initial contact and release during the push phase of the WCP cycle) with propulsion characteristics, pushrim forces, and shoulder kinetics during WCP in individuals with paraplegia. Methods: Biomechanical data were collected from 222 individuals (198 men and 24 women) with paraplegia from SCI during WCP on a stationary ergometer at a self-selected speed. The average age of participants was 34.7 years (±9.3), mean time since SCI was 9.3 years (±6.1), and average body weight was 74.4 kg (±15.9). The majority (n = 127; 56%) of participants had lower level paraplegia (T8 to L5) and 95 (42%) had high paraplegia (T2 to T7). Results: Increased push arc (mean = 75.3°) was associated with greater velocity (R = 0.384, P < .001) and cycle distance (R = 0.658, P < .001) and reduced cadence (R = -0.419, P < .001). Initial contact angle and hand release angles were equally associated with cycle distance and cadence, whereas a more anterior release angle was associated with greater velocity (R = 0.372, P < .001). When controlling for body weight, a more posterior initial contact angle was associated with greater posterior shoulder net joint force (R = 0.229, P = .001) and greater flexor net joint moment (R = 0.204, P = .002), whereas a more anterior hand release angle was significantly associated with increased vertical (R = 0.270, P < .001) and greater lateral (R = .293, P < .001) pushrim forces; greater shoulder net joint forces in all 3 planes — posterior (R = 0.164, P = .015), superior (R = 0.176, P = .009), and medial (R = 0.284, P < .001); and greater external rotator (R = 0.176, P = .009) and adductor (R = 0.259, P = .001) net joint moments. Conclusions: Current

  20. Relationship Between Hand Contact Angle and Shoulder Loading During Manual Wheelchair Propulsion by Individuals with Paraplegia.

    PubMed

    Requejo, Philip Santos; Mulroy, Sara J; Ruparel, Puja; Hatchett, Patricia E; Haubert, Lisa Lighthall; Eberly, Valerie J; Gronley, JoAnne K

    2015-01-01

    Shoulder loading during manual wheelchair propulsion (WCP) contributes to the development of shoulder pain in individuals with spinal cord injury (SCI). To use regression analysis to investigate the relationships between the hand contact angle (location of the hand on the pushrim at initial contact and release during the push phase of the WCP cycle) with propulsion characteristics, pushrim forces, and shoulder kinetics during WCP in individuals with paraplegia. Biomechanical data were collected from 222 individuals (198 men and 24 women) with paraplegia from SCI during WCP on a stationary ergometer at a self-selected speed. The average age of participants was 34.7 years (±9.3), mean time since SCI was 9.3 years (±6.1), and average body weight was 74.4 kg (±15.9). The majority (n = 127; 56%) of participants had lower level paraplegia (T8 to L5) and 95 (42%) had high paraplegia (T2 to T7). Increased push arc (mean = 75.3°) was associated with greater velocity (R = 0.384, P < .001) and cycle distance (R = 0.658, P < .001) and reduced cadence (R = -0.419, P <.001). Initial contact angle and hand release angles were equally associated with cycle distance and cadence, whereas a more anterior release angle was associated with greater velocity (R = 0.372, P < .001). When controlling for body weight, a more posterior initial contact angle was associated with greater posterior shoulder net joint force (R = 0.229, P = .001) and greater flexor net joint moment (R = 0.204, P = .002), whereas a more anterior hand release angle was significantly associated with increased vertical (R = 0.270, P < .001) and greater lateral (R = .293, P < .001) pushrim forces; greater shoulder net joint forces in all 3 planes - posterior (R = 0.164, P = .015), superior (R = 0.176, P = .009), and medial (R = 0.284, P < .001); and greater external rotator (R = 0.176, P = .009) and adductor (R = 0.259, P = .001) net joint moments. Current clinical practice guidelines recommend using long, smooth

  1. Shoulder biomechanics during the push phase of wheelchair propulsion: a multisite study of persons with paraplegia.

    PubMed

    Collinger, Jennifer L; Boninger, Michael L; Koontz, Alicia M; Price, Robert; Sisto, Sue Ann; Tolerico, Michelle L; Cooper, Rory A

    2008-04-01

    To present a descriptive analysis and comparison of shoulder kinetics and kinematics during wheelchair propulsion at multiple speeds (self-selected and steady-state target speeds) for a large group of manual wheelchair users with paraplegia while also investigating the effect of pain and subject demographics on propulsion. Case series. Three biomechanics laboratories at research institutions. Volunteer sample of 61 persons with paraplegia who use a manual wheelchair for mobility. Subjects propelled their own wheelchairs on a dynamometer at 3 speeds (self-selected, 0.9m/s, 1.8m/s) while kinetic and kinematic data were recorded. Differences in demographics between sites, correlations between subject characteristics, comparison of demographics and biomechanics between persons with and without pain, linear regression using subject characteristics to predict shoulder biomechanics, comparison of biomechanics between speed conditions. Significant increases in shoulder joint loading with increased propulsion velocity were observed. Resultant force increased from 54.4+/-13.5N during the 0.9m/s trial to 75.7+/-20.7N at 1.8m/s (P<.001). Body weight was the primary demographic variable that affected shoulder forces, whereas pain did not affect biomechanics. Peak shoulder joint loading occurs when the arm is extended and internally rotated, which may leave the shoulder at risk for injury. Body-weight maintenance, as well as other interventions designed to reduce the force required to propel a wheelchair, should be implemented to reduce the prevalence of shoulder pain and injury among manual wheelchair users.

  2. Hip Joint Contact Force in the Emu (Dromaius novaehollandiae) during Normal Level Walking

    PubMed Central

    Goetz, Jessica E.; Derrick, Timothy R.; Pedersen, Douglas R.; Robinson, Duane A.; Conzemius, Michael G.; Baer, Thomas E.; Brown, Thomas D.

    2008-01-01

    The emu is a large, (bipedal) flightless bird that potentially can be used to study various orthopaedic disorders in which load protection of the experimental limb is a limitation of quadrupedal models. An anatomy-based analysis of normal emu walking gait was undertaken to determine hip contact forces for comparison with human data. Kinematic and kinetic data captured for two laboratory-habituated emus were used to drive the model. Muscle attachment data were obtained by dissection, and bony geometries were obtained by CT scan. Inverse dynamics calculations at all major lower-limb joints were used in conjunction with optimization of muscle forces to determine hip contact forces. Like human walking gait, emu ground reaction forces showed a bimodal distribution over the course of the stance phase. Two-bird averaged maximum hip contact force was approximately 5.5 times body weight, directed nominally axially along the femur. This value is only modestly larger than optimization-based hip contact forces reported in literature for humans. The interspecies similarity in hip contact forces makes the emu a biomechanically attractive animal in which to model loading-dependent human orthopaedic hip disorders. PMID:18206892

  3. A Biomechanical Model Correlating Shoulder Kinetics to Pain in Young Baseball Pitchers

    PubMed Central

    Keeley, David W.; Oliver, Gretchen D.; Dougherty, Christopher P.

    2012-01-01

    Previous work has postulated that shoulder pain may be associated with increases in both peak shoulder anterior force and peak shoulder proximal force. Unfortunately these relationships have yet to be quantified. Thus, the purpose of this study was to associate these kinetic values with reported shoulder pain in youth baseball pitchers. Nineteen healthy baseball pitchers participated in this study. Segment based reference systems and established calculations were utilized to identify peak shoulder anterior force and peak shoulder proximal force. A medical history questionnaire was utilized to identify shoulder pain. Following collection of these data, the strength of the relationships between both peak shoulder anterior force and peak shoulder proximal force and shoulder pain were analyzed. Although peak anterior force was not significantly correlated to shoulder pain, peak proximal force was. These results lead to the development of a single variable logistic regression model able to accurately predict 84.2% of all cases and 71.4% of shoulder pain cases. This model indicated that for every 1 N increase in peak proximal force, there was a corresponding 4.6% increase in the likelihood of shoulder pain. The magnitude of peak proximal force is both correlated to reported shoulder pain and capable of being used to accurately predict the likelihood of experiencing shoulder pain. It appears that those pitchers exhibiting high magnitudes of peak proximal force are significantly more likely to report experiencing shoulder pain than those who generate lower magnitudes of peak proximal force. PMID:23486209

  4. A biomechanical model correlating shoulder kinetics to pain in young baseball pitchers.

    PubMed

    Keeley, David W; Oliver, Gretchen D; Dougherty, Christopher P

    2012-10-01

    Previous work has postulated that shoulder pain may be associated with increases in both peak shoulder anterior force and peak shoulder proximal force. Unfortunately these relationships have yet to be quantified. Thus, the purpose of this study was to associate these kinetic values with reported shoulder pain in youth baseball pitchers. Nineteen healthy baseball pitchers participated in this study. Segment based reference systems and established calculations were utilized to identify peak shoulder anterior force and peak shoulder proximal force. A medical history questionnaire was utilized to identify shoulder pain. Following collection of these data, the strength of the relationships between both peak shoulder anterior force and peak shoulder proximal force and shoulder pain were analyzed. Although peak anterior force was not significantly correlated to shoulder pain, peak proximal force was. These results lead to the development of a single variable logistic regression model able to accurately predict 84.2% of all cases and 71.4% of shoulder pain cases. This model indicated that for every 1 N increase in peak proximal force, there was a corresponding 4.6% increase in the likelihood of shoulder pain. The magnitude of peak proximal force is both correlated to reported shoulder pain and capable of being used to accurately predict the likelihood of experiencing shoulder pain. It appears that those pitchers exhibiting high magnitudes of peak proximal force are significantly more likely to report experiencing shoulder pain than those who generate lower magnitudes of peak proximal force.

  5. Strength training and shoulder proprioception.

    PubMed

    Salles, José Inácio; Velasques, Bruna; Cossich, Victor; Nicoliche, Eduardo; Ribeiro, Pedro; Amaral, Marcus Vinicius; Motta, Geraldo

    2015-03-01

    Proprioception is essential to motor control and joint stability during daily and sport activities. Recent studies demonstrated that athletes have better joint position sense (JPS) when compared with controls matched for age, suggesting that physical training could have an effect on proprioception. To evaluate the result of an 8-week strength-training program on shoulder JPS and to verify whether using training intensities that are the same or divergent for the shoulder's dynamic-stabilizer muscles promote different effects on JPS. Randomized controlled clinical trial. We evaluated JPS in a research laboratory and conducted training in a gymnasium. A total of 90 men, right handed and asymptomatic, with no history of any type of injury or shoulder instability. For 8 weeks, the participants performed the strength-training program 3 sessions per week. We used 4 exercises (bench press, lat pull down, shoulder press, and seated row), with 2 sets each. We measured shoulder JPS acuity by calculating the absolute error. We found an interaction between group and time. To examine the interaction, we conducted two 1-way analyses of variance comparing groups at each time. The groups did not differ at pretraining; however, a difference among groups was noted posttraining. Strength training using exercises at the same intensity produced an improvement in JPS compared with exercises of varying intensity, suggesting that the former resulted in improvements in the sensitivity of muscle spindles and, hence, better neuromuscular control in the shoulder.

  6. Avoiding Shoulder Injury from Resistance Training.

    ERIC Educational Resources Information Center

    Durall, Chris J.; Manske, Robert C.; Davies, George J.

    2001-01-01

    Identifies shoulder exercises commonly performed in fitness centers that may contribute to or exacerbate glenohumeral joint (shoulder) injury, describing alternative exercises that may be substituted and a offering rationale for the variations. The article focuses on anterior and posterior glenohumeral instability, subacromial impingement (primary…

  7. Avoiding Shoulder Injury from Resistance Training.

    ERIC Educational Resources Information Center

    Durall, Chris J.; Manske, Robert C.; Davies, George J.

    2001-01-01

    Identifies shoulder exercises commonly performed in fitness centers that may contribute to or exacerbate glenohumeral joint (shoulder) injury, describing alternative exercises that may be substituted and a offering rationale for the variations. The article focuses on anterior and posterior glenohumeral instability, subacromial impingement (primary…

  8. Comparison of Upper Limb Joint Forces During Straight Line and Turning Wheelchair Maneuvers

    DTIC Science & Technology

    2007-11-02

    maneuvers. A high incidence of musculoskeletal injuries has been reported due to the overuse and high repetitive motion of wrist, elbow and shoulder...propulsion, upper extremities are the major source of power. Owing to the overuse and high repetitive motion of the wrist, elbow and shoulder, high...environment, turning motion is frequently performed. This repetitive movement could generate unwanted stresses at the wrist, elbow and shoulder

  9. Correlation of Shoulder and Elbow Kinetics With Ball Velocity in Collegiate Baseball Pitchers.

    PubMed

    Post, Eric G; Laudner, Kevin G; McLoda, Todd A; Wong, Regan; Meister, Keith

    2015-06-01

    Throwing a baseball is a dynamic and violent act that places large magnitudes of stress on the shoulder and elbow. Specific injuries at the elbow and glenohumeral joints have been linked to several kinetic variables throughout the throwing motion. However, very little research has directly examined the relationship between these kinetic variables and ball velocity. To examine the correlation of peak ball velocity with elbow-valgus torque, shoulder external-rotation torque, and shoulder-distraction force in a group of collegiate baseball pitchers. Cross-sectional study. Motion-analysis laboratory. Sixty-seven asymptomatic National Collegiate Athletic Association Division I baseball pitchers (age = 19.5 ± 1.2 years, height = 186.2 ± 5.7 cm, mass = 86.7 ± 7.0 kg; 48 right handed, 19 left handed). We measured peak ball velocity using a radar gun and shoulder and elbow kinetics of the throwing arm using 8 electronically synchronized, high-speed digital cameras. We placed 26 reflective markers on anatomical landmarks of each participant to track 3-dimensional coordinate data. The average data from the 3 highest-velocity fastballs thrown for strikes were used for data analysis. We calculated a Pearson correlation coefficient to determine the associations between ball velocity and peak elbow-valgus torque, shoulder-distraction force, and shoulder external-rotation torque (P < .05). A weak positive correlation was found between ball velocity and shoulder-distraction force (r = 0.257; 95% confidence interval [CI] = 0.02, 0.47; r(2) = 0.066; P = .018). However, no significant correlations were noted between ball velocity and elbow-valgus torque (r = 0.199; 95% CI = -0.043, 0.419; r(2) = 0.040; P = .053) or shoulder external-rotation torque (r = 0.097; 95% CI = -0.147, 0.329; r(2) = 0.009; P = .217). Although a weak positive correlation was present between ball velocity and shoulder-distraction force, no significant association was seen between ball velocity and elbow

  10. Correlation of Shoulder and Elbow Kinetics With Ball Velocity in Collegiate Baseball Pitchers

    PubMed Central

    Post, Eric G.; Laudner, Kevin G.; McLoda, Todd A.; Wong, Regan; Meister, Keith

    2015-01-01

    Context Throwing a baseball is a dynamic and violent act that places large magnitudes of stress on the shoulder and elbow. Specific injuries at the elbow and glenohumeral joints have been linked to several kinetic variables throughout the throwing motion. However, very little research has directly examined the relationship between these kinetic variables and ball velocity. Objective To examine the correlation of peak ball velocity with elbow-valgus torque, shoulder external-rotation torque, and shoulder-distraction force in a group of collegiate baseball pitchers. Design Cross-sectional study. Setting Motion-analysis laboratory. Patients or Other Participants Sixty-seven asymptomatic National Collegiate Athletic Association Division I baseball pitchers (age = 19.5 ± 1.2 years, height = 186.2 ± 5.7 cm, mass = 86.7 ± 7.0 kg; 48 right handed, 19 left handed). Main Outcome Measure(s) We measured peak ball velocity using a radar gun and shoulder and elbow kinetics of the throwing arm using 8 electronically synchronized, high-speed digital cameras. We placed 26 reflective markers on anatomical landmarks of each participant to track 3-dimensional coordinate data. The average data from the 3 highest-velocity fastballs thrown for strikes were used for data analysis. We calculated a Pearson correlation coefficient to determine the associations between ball velocity and peak elbow-valgus torque, shoulder-distraction force, and shoulder external-rotation torque (P < .05). Results A weak positive correlation was found between ball velocity and shoulder-distraction force (r = 0.257; 95% confidence interval [CI] = 0.02, 0.47; r2 = 0.066; P = .018). However, no significant correlations were noted between ball velocity and elbow-valgus torque (r = 0.199; 95% CI = −0.043, 0.419; r2 = 0.040; P = .053) or shoulder external-rotation torque (r = 0.097; 95% CI = −0.147, 0.329; r2 = 0.009; P = .217). Conclusions Although a weak positive correlation was present between ball velocity

  11. Analysis of applied forces and electromyography of back and shoulders muscles when performing a simulated hand scaling task.

    PubMed

    Porter, William; Gallagher, Sean; Torma-Krajewski, Janet

    2010-05-01

    Hand scaling is a physically demanding task responsible for numerous overexertion injuries in underground mining. Scaling requires the miner to use a long pry bar to remove loose rock, reducing the likelihood of rock fall injuries. The experiments described in this article simulated "rib" scaling (scaling a mine wall) from an elevated bucket to examine force generation and electromyographic responses using two types of scaling bars (steel and fiberglass-reinforced aluminum) at five target heights ranging from floor level to 176 cm. Ten male and six female subjects were tested in separate experiments. Peak and average force applied at the scaling bar tip and normalized electromyography (EMG) of the left and right pairs of the deltoid and erectores spinae muscles were obtained. Work height significantly affected peak prying force during scaling activities with highest force capacity at the lower levels. Bar type did not affect force generation. However, use of the lighter fiberglass bar required significantly more muscle activity to achieve the same force. Results of these studies suggest that miners scale points on the rock face that are below their knees, and reposition the bucket as often as necessary to do so.

  12. Practical approach to subject-specific estimation of knee joint contact force.

    PubMed

    Knarr, Brian A; Higginson, Jill S

    2015-08-20

    Compressive forces experienced at the knee can significantly contribute to cartilage degeneration. Musculoskeletal models enable predictions of the internal forces experienced at the knee, but validation is often not possible, as experimental data detailing loading at the knee joint is limited. Recently available data reporting compressive knee force through direct measurement using instrumented total knee replacements offer a unique opportunity to evaluate the accuracy of models. Previous studies have highlighted the importance of subject-specificity in increasing the accuracy of model predictions; however, these techniques may be unrealistic outside of a research setting. Therefore, the goal of our work was to identify a practical approach for accurate prediction of tibiofemoral knee contact force (KCF). Four methods for prediction of knee contact force were compared: (1) standard static optimization, (2) uniform muscle coordination weighting, (3) subject-specific muscle coordination weighting and (4) subject-specific strength adjustments. Walking trials for three subjects with instrumented knee replacements were used to evaluate the accuracy of model predictions. Predictions utilizing subject-specific muscle coordination weighting yielded the best agreement with experimental data; however this method required in vivo data for weighting factor calibration. Including subject-specific strength adjustments improved models' predictions compared to standard static optimization, with errors in peak KCF less than 0.5 body weight for all subjects. Overall, combining clinical assessments of muscle strength with standard tools available in the OpenSim software package, such as inverse kinematics and static optimization, appears to be a practical method for predicting joint contact force that can be implemented for many applications. Copyright © 2015 Elsevier Ltd. All rights reserved.

  13. [Current concepts in perinatal brachial plexus palsy. Part 2: late phase. Shoulder deformities].

    PubMed

    Dogliotti, Andrés Alejandro

    2011-10-01

    The incidence of obstetric brachial palsy is high and their sequelaes are frequent. Physiotherapy, microsurgical nerve reconstruction and secondary corrections are used together to improve the shoulder function. The most common posture is shoulder in internal rotation and adduction, because of the antagonist weakness. The muscle forces imbalance over the osteoarticular system, will result in a progressive glenohumeral joint deformity which can be recognized with a magnetic resonance image. Tendon transfers of the internal rotators towards the external abductor/rotator muscles, has good results, but has to be combined with antero-inferior soft-tissue releases, if passive range of motion is limited.

  14. Subject-specific hip geometry affects predicted hip joint contact forces during gait.

    PubMed

    Lenaerts, G; De Groote, F; Demeulenaere, B; Mulier, M; Van der Perre, G; Spaepen, A; Jonkers, I

    2008-01-01

    Hip loading affects bone remodeling and implant fixation. In this study, we have analyzed the effect of subject-specific modeling of hip geometry on muscle activation patterns and hip contact forces during gait, using musculoskeletal modeling, inverse dynamic analysis and static optimization. We first used sensitivity analysis to analyze the effect of isolated changes in femoral neck-length (NL) and neck-shaft angle (NSA) on calculated muscle activations and hip contact force during the stance phase of gait. A deformable generic musculoskeletal model was adjusted incrementally to adopt a physiological range of NL and NSA. In a second similar analysis, we adjusted hip geometry to the measurements from digitized radiographs of 20 subjects with primary hip osteoarthrosis. Finally, we studied the effect of hip abductor weakness on muscle activation patterns and hip contact force. This analysis showed that differences in NL (41-74 mm) and NSA (113-140 degrees ) affect the muscle activation of the hip abductors during stance phase and hence hip contact force by up to three times body weight. In conclusion, the results from both the sensitivity and subject-specific analysis showed that at the moment of peak contact force, altered NSA has only a minor effect on the loading configuration of the hip. Increased NL, however, results in an increase of the three hip contact-force components and a reduced vertical loading. The results of these analyses are essential to understand modified hip joint loading, and for planning hip surgery for patients with osteoarthrosis.

  15. Draft: Joint Federal/State Task Force on Evaluation Comprehensive Evaluation System--Current Status and Development Requirements.

    ERIC Educational Resources Information Center

    Scientific Educational Systems, Inc., Silver Spring, MD.

    The Joint Federal/State Task Force on Evaluation (the Belmont Group) is currently developing a Joint Comprehensive Evaluation System (JCES) for the federally funded programs under the federal acts listed above. It is planned that JCES will replace the multiplicity of evaluation systems (and paper work) under the separate existing programs. This…

  16. [Muscle efficiency in total shoulder prosthesis implantation: dependence on position of the humeral head and rotator cuff function].

    PubMed

    Klages, A; Hurschler, C; Wülker, N; Windhagen, H

    2001-09-01

    Modern shoulder prostheses permit an anatomic reconstruction of the joint, although the biomechanical advantages are not proven. The goal of this study was to investigate the relationship between position of the humeral head and function of the shoulder prosthesis (muscle efficiency). Shoulder elevation-motion and rotator cuff defects were simulated in vitro in a robot-assisted shoulder simulator. The EPOCA Custom Offset shoulder prosthesis (Argomedical AG, Cham, CH) was implanted in seven normal shoulders (77 +/- 20 kg, 55 +/- 14 years). Active elevation was simulated by hydraulic cylinders, and scapulothoratic motion by a specially programmed industrial robot. Muscle efficiency (elevation-angle/muscle-force of the deltoid muscle) was measured in anatomic (ANA), medialised (MED) and lateralised (LAT) positions of the humeral head, with or without rotator cuff muscle deficiency. Medialisation increased efficiency by 0.03 +/- 0.04 deg/N (p = 0.022), lateralisation decreased it by 0.04 +/- 0.06 deg/N (p = 0.009). Supraspinatus muscle deficiency increased the deltoid force required to elevate the arm, and thus decreased efficiency (ANA p = 0.091, MED p = 0.018, LAT p = 0.028). The data confirm that the position of the humeral head affects the mechanics of total shoulder arthroplasty. Medialisation increases efficiency of the deltoid muscle and may prove useful in compensating isolated supraspinatus muscle deficiency. Lateralisation, in contrast, leads to an unfavorable situation.

  17. A review on frozen shoulder.

    PubMed

    Wong, P L; Tan, H C

    2010-09-01

    Of all the joints in the human body, the shoulder has the greatest range of motion. This allows complex movements and functions to be carried out, and is of vital importance to the activities of daily living and work. Any restriction or pain that involves the joint puts a huge amount of strain on patients, especially those who are in their most productive years of life. Frozen shoulder, a frequently encountered disorder of the shoulder, has been well recognised since the early 1900s. Although benign, it has great impact on the quality of life of patients. This article aims to provide an overview of the nature and the widely accepted management of this condition based on other studies.

  18. A Cervico-Thoraco-Lumbar Multibody Dynamic Model for the Estimation of Joint Loads and Muscle Forces.

    PubMed

    Khurelbaatar, Tsolmonbaatar; Kim, Kyungsoo; Hyuk Kim, Yoon

    2015-11-01

    Computational musculoskeletal models have been developed to predict mechanical joint loads on the human spine, such as the forces and moments applied to vertebral and facet joints and the forces that act on ligaments and muscles because of difficulties in the direct measurement of joint loads. However, many whole-spine models lack certain elements. For example, the detailed facet joints in the cervical region or the whole spine region may not be implemented. In this study, a detailed cervico-thoraco-lumbar multibody musculoskeletal model with all major ligaments, separated structures of facet contact and intervertebral disk joints, and the rib cage was developed. The model was validated by comparing the intersegmental rotations, ligament tensile forces, facet joint contact forces, compressive and shear forces on disks, and muscle forces were to those reported in previous experimental and computational studies both by region (cervical, thoracic, or lumbar regions) and for the whole model. The comparisons demonstrated that our whole spine model is consistent with in vitro and in vivo experimental studies and with computational studies. The model developed in this study can be used in further studies to better understand spine structures and injury mechanisms of spinal disorders.

  19. A novel cadaveric model for anterior-inferior shoulder dislocation using forcible apprehension positioning.

    PubMed

    McMahon, Patrick J; Chow, Stephen; Sciaroni, Laura; Yang, Bruce Y; Lee, Thay Q

    2003-01-01

    A novel cadaveric model for anterior-inferior shoulder dislocation using forcible apprehension positioning is presented. This model simulates an in vivo mechanism and yields capsulolabral lesions. The scapulae of 14 cadaveric entire upper limbs (82 +/- 9 years, mean +/- standard deviation) were each rigidly fixed to a custom shoulder-testing device. A pneumatic system was used with pulleys and cables to simulate the rotator cuff and the deltoid muscles (anterior and middle portions). The glenohumeral joint was then positioned in the apprehension position of abduction, external rotation, and horizontal abduction. A 6-degree-of-freedom load cell (Assurance Technologies, Garner, North Carolina) measured the joint reaction force that was then resolved into three orthogonal components of compression force, anteriorly directed force, and superiorly directed force. With the use of a thrust bearing, the humerus was moved along a rail with a servomotor-controlled system at 50 mm/s that resulted in horizontal abduction. Force that developed passively in the pectoralis major muscle was recorded with an independent uniaxial load cell. Each of the glenohumeral joints dislocated anterior-inferior, six with avulsion of the capsulolabrum from the anterior-inferior glenoid bone and eight with capsulolabral stretching. Pectoralis major muscle force as well as the joint reaction force increased with horizontal abduction until dislocation. At dislocation, the magnitude of the pectoralis major muscle force, 609.6 N +/- 65.2 N was similar to the compression force, 569.6 N +/- 37.8 N. A cadaveric model yielded an anterior dislocation with a mechanism of forcible apprehension positioning when the appropriate shoulder muscles were simulated and a passive pectoralis major muscle was included. Capsulolabral lesions resulted, similar to those observed in vivo.

  20. Elbow joint stability in relation to forced external rotation: An experimental study of the osseous constraint.

    PubMed

    Deutch, Søren R; Jensen, Steen L; Olsen, Bo S; Sneppen, Otto

    2003-01-01

    The objective of this study was to evaluate the osseous constraint related to forced forearm external rotation as the initial stage in a posterior elbow dislocation. Six joint specimens without soft tissues were examined in a joint analysis system developed for simulation of dislocation. The osseous stability, expressed as the maximal torque needed for pathologic external forearm rotation, increased from varus to valgus stress (P =.0001) and from 10 degrees to 90 degrees of elbow flexion (P =.012) and also tended to increase from forearm supination to pronation. The work of pathologic external forearm rotation until the point of maximal torque decreased from a maximum in full extension to a minimum at 30 degrees of elbow flexion (P =.03). The elbow in a slightly flexed position, varus stress, and forearm external rotation trauma might be the important biomechanical factors in the posterior elbow dislocation, and they might serve as guidelines during clinical investigation for posterolateral instability.

  1. Posterior Shoulder Instability.

    PubMed

    Brelin, Alaina; Dickens, Jonathan F

    2017-09-01

    Posterior shoulder instability is a relatively uncommon condition, occurring in ∼10% of those with shoulder instability. Because of the rarity of the condition and the lack of knowledge in treatment, it is often misdiagnosed or patients experience a delay in diagnosis. Posterior instability typically affects athletes participating in contact or overhead sports and is usually the result of repetitive microtrauma or blunt force with the shoulder in the provocative position of flexion, adduction, and internal rotation, leading to recurrent subluxation events. Acute traumatic posterior dislocations are rare injuries with an incidence rate of 1.1 per 100,000 person years. This rate is ∼20 times lower than that of anterior shoulder dislocations. Risk factors for recurrent instability are: (1) age below 40 at time of first instability; (2) dislocation during a seizure; (3) a large reverse Hill-Sachs lesion; and (4) glenoid retroversion. A firm understanding of the pathoanatomy, along with pertinent clinical and diagnostic modalities is required to accurately diagnosis and manage this condition.

  2. "In vivo" determination of hip joint separation and the forces generated due to impact loading conditions.

    PubMed

    Dennis, D A; Komistek, R D; Northcut, E J; Ochoa, J A; Ritchie, A

    2001-05-01

    Numerous supporting structures assist in the retention of the femoral head within the acetabulum of the normal hip joint including the capsule, labrum, and ligament of the femoral head (LHF). During total hip arthroplasty (THA), the LHF is often disrupted or degenerative and is surgically removed. In addition, a portion of the remaining supporting structures is transected or resected to facilitate surgical exposure. The present study analyzes the effects of LHF absence and surgical dissection in THA patients. Twenty subjects (5 normal hip joints, 10 nonconstrained THA, and 5 constrained THA) were evaluated using fluoroscopy while performing active hip abduction. All THA subjects were considered clinically successful. Fluoroscopic videos of the normal hips were analyzed using digitization, while those with THA were assessed using a computerized interactive model-fitting technique. The distance between the femoral head and acetabulum was measured to determine if femoral head separation occurred. Error analysis revealed measurements to be accurate within 0.75mm. No separation was observed in normal hips or those subjects implanted with constrained THA, while all 10 (100%) with unconstrained THA demonstrated femoral head separation, averaging 3.3mm (range 1.9-5.2mm). This study has shown that separation of the prosthetic femoral head from the acetabular component can occur. The normal hip joint has surrounding capsuloligamentous structures and a ligament attaching the femoral head to the acetabulum. We hypothesize that these soft tissue supports create a passive, resistant force at the hip, preventing femoral head separation. The absence of these supporting structures after THA may allow increased hip joint forces, which may play a role in premature polyethylene wear or prosthetic loosening.

  3. Biomechanics of complex shoulder instability.

    PubMed

    Degen, Ryan M; Giles, Joshua W; Thompson, Stephen R; Litchfield, Robert B; Athwal, George S

    2013-10-01

    Identification and treatment of the osseous lesions associated with complex shoulder instability remains challenging. Further biomechanical testing is required to delineate critical defect values and determine which treatments provide improved glenohumeral joint stability for the various defect sizes, while minimizing the associated complications.

  4. AAPM/SNMMI Joint Task Force: report on the current state of nuclear medicine physics training.

    PubMed

    Harkness, Beth A; Allison, Jerry D; Clements, Jessica B; Coffey, Charles W; Fahey, Frederic H; Gress, Dustin A; Kinahan, Paul E; Nickoloff, Edward L; Mawlawi, Osama R; MacDougall, Robert D; Pizzutiello, Robert J

    2015-09-08

    The American Association of Physicists in Medicine (AAPM) and the Society of Nuclear Medicine and Molecular Imaging (SNMMI) recognized the need for a review of the current state of nuclear  medicine physics training and the need to explore pathways for improving nuclear medicine physics training opportunities. For these reasons, the two organizations formed a joint AAPM/SNMMI Ad Hoc Task Force on Nuclear Medicine Physics  Training. The mission of this task force was to assemble a representative group of stakeholders to:• Estimate the demand for board-certified nuclear medicine physicists in the next 5-10 years,• Identify the critical issues related to supplying an adequate number of physicists who have received the appropriate level of training in nuclear medicine physics, and• Identify approaches that may be considered to facilitate the training of nuclear medicine physicists.As a result, a task force was appointed and chaired by an active member of both organizations that included representation from the AAPM, SNMMI, the American Board of Radiology (ABR), the American Board of Science in Nuclear Medicine (ABSNM), and the Commission for the Accreditation of Medical Physics Educational Programs (CAMPEP). The Task Force first met at the AAPM Annual Meeting in Charlotte in July 2012 and has met regularly face-to-face, online, and by conference calls. This manuscript reports the findings of the Task Force, as well as recommendations to achieve the stated mission.

  5. AAPM/SNMMI Joint Task Force: report on the current state of nuclear medicine physics training.

    PubMed

    Harkness, Beth A; Allison, Jerry D; Clements, Jessica B; Coffey, Charles W; Fahey, Frederic H; Gress, Dustin A; Kinahan, Paul E; Nickoloff, Edward L; Mawlawi, Osama R; MacDougall, Robert D; Pizzuitello, Robert J

    2015-09-01

    The American Association of Physicists in Medicine (AAPM) and the Society of Nuclear Medicine and Molecular Imaging (SNMMI) recognized the need for a review of the current state of nuclear medicine physics training and the need to explore pathways for improving nuclear medicine physics training opportunities. For these reasons, the two organizations formed a joint AAPM/SNMMI Ad Hoc Task Force on Nuclear Medicine Physics Training. The mission of this task force was to assemble a representative group of stakeholders to: Estimate the demand for board-certified nuclear medicine physicists in the next 5-10 years, Identify the critical issues related to supplying an adequate number of physicists who have received the appropriate level of training in nuclear medicine physics, and Identify approaches that may be considered to facilitate the training of nuclear medicine physicists. As a result, a task force was appointed and chaired by an active member of both organizations that included representation from the AAPM, SNMMI, the American Board of Radiology (ABR), the American Board of Science in Nuclear Medicine (ABSNM), and the Commission for the Accreditation of Medical Physics Educational Programs (CAMPEP). The Task Force first met at the AAPM Annual Meeting in Charlotte in July 2012 and has met regularly face-to-face, online, and by conference calls. This manuscript reports the findings of the Task Force, as well as recommendations to achieve the stated mission. PACS number: 01.40.G.

  6. The Sum of Their Fears: The Relationship Between the Joint Targeting Coordination Board and the Joint Force Commander.

    DTIC Science & Technology

    1994-06-01

    established the Joint Target Group (JTG) on August 2, 1944. The JCS organized the JTG because, "Duplication of effort and lack of integration between the...field.ŗ The JCS tasked the Joint Target Group to provide continuing target analysis and assure a high degree of integration and coordination between...Memorandum, JCS 1020, subject: Joint Target Group , 24 August 1944, USAFHRA No K142.6601-1, 4. 3 Ibid. 2. 9 made it clear that the "Joint Targeting

  7. Ultrasound of the shoulder.

    PubMed

    Petranova, Tzvetanka; Vlad, Violeta; Porta, Francesco; Radunovic, Goran; Micu, Mihaela C; Nestorova, Rodina; Iagnocco, Annamaria

    2012-06-01

    Ultrasonography (US) is a helpful imaging tool in the evaluation of the musculoskeletal system. It has some advantages over the other imaging techniques, such as plain radiography, computed tomography and magnetic resonance imaging, represented by the non-invasiveness and multiplanar imaging capability, repeatability, lack of radiation burden, good patient acceptance, and relatively limited costs. US offers an excellent resolution and a possibility for real-time dynamic examination of the joints and surrounding soft tissues, as well as enables monitoring of therapeutic response. The most common clinical indications for US examination of the shoulder are rotator cuff and biceps tendon pathology (tenosynovitis, tendinosis, complete and partial tears, and impingement) and disorders of other soft-tissue structures (joint recesses, bursae, muscles, suprascapular and axillary nerves) as well as bony cortex abnormalities. US is very useful for US-guided procedures (biopsy, joint and bursae aspirations and injections, aspiration and dissolution of calcific tendinosis). The aim of this article is to analyze the current literature about US of the shoulder and to describe both normal and pathological findings.

  8. SHOULDER DEMANDS IN MANUAL WHEELCHAIR USERS ACROSS A SPECTRUM OF ACTIVITIES

    PubMed Central

    Morrow, Melissa M. B.; Hurd, Wendy J.; Kaufman, Kenton R.; An, Kai-Nan

    2009-01-01

    Objective Investigate shoulder joint kinetics over a range of daily activity and mobility tasks associated with manual wheelchair propulsion to characterize demands placed on the shoulder during the daily activity of manual wheelchair users. Design Case series. Subjects Twelve individuals who were experienced manual wheelchair users. Methods Upper extremity kinematics and handrim wheelchair kinetics were measured over level propulsion, ramp propulsion, start and stop over level terrain, and a weight relief maneuver. Shoulder intersegmental forces and moments were calculated from inverse dynamics for all conditions. Results Weight relief resulted in significantly higher forces and ramp propulsion resulted in significantly higher moments than the other conditions. Surprisingly, the start condition resulted in large intersegmental moments about the shoulder equivalent with that of the ramp propulsion, while the demand imparted by the stop condition was shown to be equivalent to level propulsion across all forces and moments. Conclusions This study provides characterization of daily living and mobility activities associated with manual wheelchair propulsion not previously reported and identifies activities that result in higher shoulder kinetics when compared to standard level propulsion. PMID:19269194

  9. Software Technology for Adaptable Reliable Systems (STARS) Joint Task Force Report.

    DTIC Science & Technology

    1983-03-15

    34 NCASIFE 4 * ~~SIN 6162 -0618 -ŝ SCCUOUT? LASS8FlCAT@IO0 THIS PASShII . 0 am * SOFTWARE TECHNOLOGY FOR ADAPTABLE, RELIABLE SYSTEMS (STARS) JOINT TASK...Following the workshop, the Task Force concentrated on producing the final set of documents (see Section 4 ! 0 for a complete list). Revisions were...Lafayette, LA. 7(504’ Jack C. Wileden Univ. of Mass. 115 Pelham Road Amherst, MA. 01002 9 4 ° /, * -.. r*• 4 0 DOCUMENTS PRODUCED The following documents are

  10. One Size Does Not Fit All: How Acquisition Fails the Joint Force Commander

    DTIC Science & Technology

    2010-04-02

    acquisition programs, such as the F-35, is worth the risk it presents to the nation by putting all ― eggs in one basket.‖ According to Joint Pub 1...Staff Procurement Backup Book: FY 2010 Budget Estimates, Research, Development, Test and Evaluation (RDT&E), Descriptive Summaries,‖ Vol. 3, May 2009...superiority fighter. This political climate caused the Air Force to recast the aircraft as a multi-role fighter and to scramble to add some air-to-ground

  11. The influence of the spine on the shoulder in the throwing athlete.

    PubMed

    Young, J L; Herring, S A; Press, J M; Casazza, B A

    1996-01-01

    Analysis of shoulder dysfunction in throwing and overhead athletes can no longer be restricted to evaluation of the glenohumeral joint alone. The isolated shoulder is incapable of generating the force necessary to hurl a baseball at velocities of 90-100 miles per hour or serve a tennis ball in excess of 120 miles per hour. The purpose of this paper is to provide a literature based theoretical framework for the role of the spine during these activities. The spine is a pivotal component of the kinematic chain which functions as a transfer link between the lower and upper limbs, a force generator capable of accelerating the arm, and a force attenuator which dampens shear forces at the glenohumeral joint during the deceleration phase of the pitching motion. Side bending and rotation of the cervical spine facilitates visual acquisition of the intended target. Inflexibility of the hip musculature and weakness of the muscles which attach to the thoracolumbar fascia have profound effects upon spine function which secondarily places greater stress upon the glenohumeral joint and rotator cuff. Shoulder rehabilitation and injury prevention programs should include evaluation of and exercise regimens for the lumbar, thoracic and cervical spine.

  12. Mechanisms of traumatic shoulder injury in elite rugby players

    PubMed Central

    Crichton, James; Jones, Doug R; Funk, Lennard

    2012-01-01

    Background Shoulder injuries in rugby players are common, but the mechanisms of injury are less well understood. This study aims to elucidate common mechanisms of injury and identify the patterns of injury they produce. Materials and methods Twenty-four elite rugby players, referred to the senior author for diagnosis and management of shoulder injuries, were selected. Videos of the injuries were independently reviewed by rugby-medical experts to describe the mechanisms of injury. The mechanisms reported were collated and analysed to determine the level of agreement between reviewers and conclude an overall description of injury mechanisms. Results The authors identified three mechanisms of shoulder injury from the video analysis. These are the ‘Try-Scorer’, characterised by hyperflexion of the outstretched arm such as when scoring a try; the ‘Tackler’, extension of the abducted arm behind the player while tackling; and the ‘Direct Impact’, a direct blow to the arm or shoulder when held by the side in neutral or slight adduction. The Try Scorer and Tackler mechanisms both involve a levering force on the glenohumeral joint (GHJ). These mechanisms predominantly cause GHJ dislocation, with Bankart, reverse Bankart and superior labrum anterior–posterior tears. The Try-Scorer Mechanism also caused the majority (83%) of rotator cuff tears. The Direct Hit mechanism resulted in GHJ dislocation and labral injury in 37.5% of players and was most likely to cause acromioclavicular joint dislocation and scapula fractures, injuries that were not seen with the other mechanisms. Conclusion Greater understanding of the mechanisms involved in rugby shoulder injury is useful in understanding the pathological injuries, guiding treatment and rehabilitation and aiding the development of injury-prevention methods. PMID:22510645

  13. Modeling of muscle forces in humans with and without temporomandibular joint disorders

    PubMed Central

    Iwasaki, LR; Liu, H; Gonzalez, YM; Marx, DB; Nickel, JC

    2015-01-01

    Objectives Subjects with/without temporomandibular joint disorders (TMJD) were tested for differences in muscle forces. Setting and Sample Population School of Dental Medicine, University at Buffalo. Ninety-one subjects were classified in 4 groups based on presence/absence (+/-) of chronic myofascial and/or TMJ pain (P) and bilateral disc displacement (DD). Material & Methods Validated numerical models employed an organizational objective and subjects’ anatomy to calculate masticatory muscle forces during static biting. ANOVA and Holm step-down procedure post-hoc tests assessed group differences. Theoretical geometries, representing the range of subjects’ muscle orientations, were surveyed via numerical models to identify key combinations resulting in high muscle forces. Effect-size (Cohen’s d) and ANOVA/post-hoc tests assessed group differences in key muscle orientations. Results +P-DD subjects had significantly higher muscle forces, especially for lateral pterygoid muscles, compared to the other groups (P<0.01) for bite-forces that were directed posteromedially or posterolaterally on mandibular molars and posteriorly and slightly medially on mandibular incisors. Key muscle orientations for peak lateral pterygoid muscle forces were identified and group comparisons showed mean orientation in +P-DD compared to other diagnostic groups was ≥5° more upright for masseter and ≥3° more posteriorly-directed for temporalis muscles (all Cohen’s d ≥0.8). Conclusion Predicted lateral pterygoid muscle forces were significantly higher in +P-DD compared to other groups for specific biting conditions and were attributable, in part, to differences in masseter and temporalis muscle orientations. PMID:25865546

  14. The senses of force and heaviness at the human elbow joint.

    PubMed

    Brooks, Jack; Allen, Trevor J; Proske, Uwe

    2013-05-01

    The present-day view of the neural basis for the senses of muscle force and heaviness is that they are generated centrally, within the brain, from copies of motor commands. A corollary of the motor discharge generates a sense of effort which underlies these sensations. In recent experiments on force and heaviness sensations using thumb flexor muscles, a rather different explanation has been invoked: Subjects were proposed to rely predominantly on inputs of a peripheral origin, in particular, the signals of muscle spindles. The present experiments have been carried out at the elbow joint to determine whether these new ideas apply more widely. The effects of fatigue of elbow flexor muscles have been studied in force and heaviness matching tasks using three exercise regimes, a sustained maximum voluntary contraction (MVC), a maintained contraction of 35 % MVC, and a maintained contraction of 35 % MVC combined with muscle vibration at 80 Hz. In force-matching experiments, subjects were required to contract both arms and while the reference arm generated the target force under visual control, it was matched by the indicator arm without visual feedback. During the 100 % MVC exercise, force in the exercising reference arm fell rapidly to almost a half of its original value over 90 s while force in the indicator did not fall, leading to a significant overestimation of the reference force. During the 35 % MVC exercise, subjects also overestimated the reference force and this persisted at 5 and 10 min after the exercise. When 35 % MVC was combined with vibration, the amount by which the indicator arm overestimated the reference force was significantly reduced. In heaviness matching experiments, subjects could move their arms through a small range. The reference arm was loaded with a weight, and weights were added or removed from the indicator until heaviness felt the same in the two arms. There was a small, but significant fall in the matching weight used after 100 % MVC

  15. Ability of sagittal kinematic variables to estimate ground reaction forces and joint kinetics in running.

    PubMed

    Wille, Christa M; Lenhart, Rachel L; Wang, Sijian; Thelen, Darryl G; Heiderscheit, Bryan C

    2014-10-01

    Controlled laboratory study, cross-sectional design. To determine if sagittal kinematic variables can be used to estimate select running kinetics. Excessive loading during running has been implicated in a variety of injuries, yet this information is typically not assessed during a standard clinical examination. Developing a clinically feasible strategy to estimate ground reaction forces and joint kinetics may improve the ability to identify those at an increased risk of injury. Three-dimensional kinematics and ground reaction forces of 45 participants were recorded during treadmill running at self-selected speed. Kinematic variables used to estimate specific kinetic metrics included vertical excursion of the center of mass, foot inclination angle at initial contact, horizontal distance between the center of mass and heel at initial contact, knee flexion angle at initial contact, and peak knee flexion angle during stance. Linear mixed-effects models were fitted to explore the association between the kinetic and kinematic measures, including step rate and sex, with final models created using backward variable selection. Models were developed to estimate peak knee extensor moment (R(2) = 0.43), energy absorbed at the knee during loading response (R(2) = 0.58), peak patellofemoral joint reaction force (R(2) = 0.55), peak vertical ground reaction force (R(2) = 0.48), braking impulse (R(2) = 0.50), and average vertical loading rate (R(2) = 0.04). Our findings suggest that insights into important running kinetics can be obtained from a subset of sagittal plane kinematics common to a clinical running analysis. Of note, the limb posture at initial contact influenced subsequent loading patterns in stance.

  16. Neurohistological examination of the inferior glenohumeral ligament of the shoulder.

    PubMed

    Steinbeck, Jörn; Brüntrup, Jens; Greshake, Oliver; Pötzl, Wolfgang; Filler, Timm; Liljenqvist, Ulf

    2003-03-01

    The neural histology of the anterior band of the inferior glenohumeral ligament (IGHL) was studied in 11 fresh shoulder specimen using a special silver impregnation technique. Between the collagen fibers small myelinated and unmyelinated dendrites could be detected. The appearance of neurovascular structures in the adjacent synovial layer clearly exceeded the typical supply to soft tissues. Analysing about 11,000 sections Ruffini mechanoreceptors that are known to be slow adapting were found on the humeral insertion of the band. The sections containing these neural end organs were identified by means of transillumination and reflection-contrast microscopy and reconstructed using three-dimensional image processing. The presence of neural structures including Ruffini corpuscles in these most important passive stabilizers of the shoulder joint shows that these ligaments function also as an active safety device. There slow adaption is a prerequisite for muscular reflexes counteracting the tensile stresses to which the passive stabilizing structures of the shoulder are exposed. A disruption of the continuity of these structures by mechanical forces or surgery can reduce the biofeedback and proprioceptive quality and thus lead to a decrease of shoulder function and/or stability. These observations should be taken into account when planning surgical interventions involving the IGHL. Procedures like capsule shifts or plications may affect mechanoreceptor orientation and concentrations, thereby affecting the interaction between these structures and the synergistic muscles. When possible, these intervention should avoid receptor-dense regions while attempting to restore normal anatomical orientation and tissue tension.

  17. Muscle optimization techniques impact the magnitude of calculated hip joint contact forces.

    PubMed

    Wesseling, Mariska; Derikx, Loes C; de Groote, Friedl; Bartels, Ward; Meyer, Christophe; Verdonschot, Nico; Jonkers, Ilse

    2015-03-01

    In musculoskeletal modelling, several optimization techniques are used to calculate muscle forces, which strongly influence resultant hip contact forces (HCF). The goal of this study was to calculate muscle forces using four different optimization techniques, i.e., two different static optimization techniques, computed muscle control (CMC) and the physiological inverse approach (PIA). We investigated their subsequent effects on HCFs during gait and sit to stand and found that at the first peak in gait at 15-20% of the gait cycle, CMC calculated the highest HCFs (median 3.9 times peak GRF (pGRF)). When comparing calculated HCFs to experimental HCFs reported in literature, the former were up to 238% larger. Both static optimization techniques produced lower HCFs (median 3.0 and 3.1 pGRF), while PIA included muscle dynamics without an excessive increase in HCF (median 3.2 pGRF). The increased HCFs in CMC were potentially caused by higher muscle forces resulting from co-contraction of agonists and antagonists around the hip. Alternatively, these higher HCFs may be caused by the slightly poorer tracking of the net joint moment by the muscle moments calculated by CMC. We conclude that the use of different optimization techniques affects calculated HCFs, and static optimization approached experimental values best.

  18. Joint strength measurements of individual fiber-fiber bonds: An atomic force microscopy based method

    NASA Astrophysics Data System (ADS)

    Schmied, Franz J.; Teichert, Christian; Kappel, Lisbeth; Hirn, Ulrich; Schennach, Robert

    2012-07-01

    We are introducing a method to measure tensile strength of individual fiber-fiber bonds within a breaking force range of 0.01 mN-1 mN as well as the energy consumed during breaking. Until now, such a method was not available. Using a conventional atomic force microscope and a specifically designed sample holder, the desired force and the breaking behavior can be analyzed by two different approaches. First, dynamic loading can be applied, where force-versus-distance curves are employed to determine the proportions of elastic energy and energy dissipated in the bond. Second, static loading is utilized to study viscoelastic behavior and calculate viscoelastic energy contributions. To demonstrate the capability of the proposed method, we are presenting results for breaking strength of kraft pulp fiber-fiber bonds in tensile opening mode. The procedure is by no means restricted to cellulose fibers, it has the potential to quantify joint strength of micrometer-sized fibers in general.

  19. The effect of an iliotibial tenodesis on intraarticular graft forces and knee joint motion.

    PubMed

    Engebretsen, L; Lew, W D; Lewis, J L; Hunter, R E

    1990-01-01

    Lateral extraarticular reconstructions are used as isolated procedures in knees with moderate rotatory instability and as "backups" in knees requiring primary repair or intraarticular reconstruction for major rotatory instability. We used an experimental knee testing system to analyze the immediate postoperative mechanical effect of an iliotibial band tenodesis on an intraarticular reconstruction of the ACL in fresh cadaver knees using a composite graft consisting of a bone-patellar tendonbone segment augmented with the Kennedy Ligament Augmentation Device (LAD, 3M Co., St. Paul, MN). The intraarticular graft was standardized by using a forcesetting technique. Ligament and graft forces were measured using buckle transducers, and joint motion was measured using an instrumented spatial linkage as 90 N anteriorly directed tibial loads were applied to seven fresh knee specimens at 0 degrees, 30 degrees, 60 degrees, and 90 degrees of flexion. The following knee states were tested in each specimen: intact ACL, excised ACL, intraarticular reconstruction, intraarticular reconstruction with the tenodesis added, and tenodesis with the intraarticular reconstruction added. Adding the iliotibial band tenodesis to an existing standardized intraarticular reconstruction significantly decreased the force in the ACL composite graft by an average of 43%. When the standardized intraarticular reconstruction was added to an existing tenodesis, the graft forces were an average of 15% below the level of when the reconstruction was performed alone. The force in the tenodesis was significantly less than the composite graft force at extension; however, the differences between the tenodesis and total graft force were not significant from 30 degrees to 90 degrees of flexion.(ABSTRACT TRUNCATED AT 250 WORDS)

  20. Effect of a pathological scapular tilt after total shoulder arthroplasty.

    PubMed

    Röthlisberger, Marion; Pioletti, Dominique P; Farron, Alain; Terrier, Alexandre

    2013-01-01

    Total shoulder arthroplasty (TSA) is an accepted and most successfully used treatment for different shoulder pathologies. Different risk factors for the failure of the prosthesis are known. A pathological scapular orientation, observed in elderly people or in patients suffering from neuromuscular diseases, could be a cause of failure, which has not been investigated yet. To test this hypothesis, a numerical musculoskeletal model of the glenohumeral joint was used to compare two TSA cases: a reference normal case and a case with a pathological anterior tilt of the scapula. An active abduction of 150° was simulated. Joint force, contact pattern, polyethylene and cement stress were evaluated for both cases. The pathological tilt slightly increased the joint force and the contact pressure, but also shifted the contact pattern. This eccentric contact increased the stress level within the polyethylene of the glenoid component and within the surrounding cement layer. This adverse effect occurred mainly during the first 60° of abduction. Therefore, a pathological orientation of the scapula may increase the risk of a failure of the cement layer around the glenoid component. These preliminary numerical results should be confirmed by a clinical study.