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Scott W Wolfe - One of the best experts on this subject based on the ideXlab platform.
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Wrist kinematic coupling and performance during functional tasks: effects of constrained motion.
Journal of Hand Surgery (European Volume), 2014Co-Authors: Rohit Garg, Andrew P. Kraszewski, Holbrook H. Stoecklein, Grisha Syrkin, Sherry I. Backus, Mark L. Lenhoff, Aviva L. Wolff, Joseph J. Crisco, Howard J. Hillstrom, Scott W WolfeAbstract:Purpose To quantify the coupled motion of the wrist during selected functional tasks and to determine the effects of constraining this coupled motion using a radial-Ulnar Deviation blocking splint on performance of these tasks. Methods Ten healthy, right-handed men performed 15 trials during selected functional tasks with and without a splint, blocking radial and Ulnar Deviation. The following tasks were performed: dart throwing, hammering, basketball free-throw, overhand baseball and football throwing, clubbing, and pouring. Kinematic coupling parameters (coupling, kinematic path length, flexion-extension range of motion, radial-Ulnar Deviation range of motion, flexion-extension offset, and radial-Ulnar Deviation offset) and performance were determined for each functional task. A generalized estimation equation model was used to determine whether each kinematic coupling parameter was significantly different across tasks. A repeated-measures generalized estimation equation model was used to test for differences in performance and kinematic coupling parameters between the free and splinted conditions. Results Wrist motion exhibited linear coupling between flexion-extension and radial-Ulnar Deviation, demonstrated by R 2 values from 0.70 to 0.99. Average wrist coupling and kinematic path lengths were significantly different among tasks. Coupling means and kinematic path lengths were different between free and splinted conditions across all tasks other than pouring. Performance was different between wrist conditions for dart throwing, hammering, basketball shooting, and pouring. Conclusions Wrist kinematic coupling parameters are task specific in healthy individuals. Functional performance is decreased when wrist coupling is constrained by an external splint. Clinical relevance Surgical procedures that restrict wrist coupling may have a detrimental effect on functional performance as defined in the study. Patients may benefit from surgical reconstructive procedures and wrist rehabilitation protocols designed to restore kinematic coupling.
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in vivo kinematic behavior of the radio capitate joint during wrist flexion extension and radio Ulnar Deviation
Journal of Biomechanics, 2001Co-Authors: Joseph J. Crisco, Scott W WolfeAbstract:Abstract The capitate is often considered the “keystone” of the carpus, not simply because of its central and prominent position in the wrist, but also because of its mechanical interactions with neighboring bones. The purpose of this study was to determine in vivo three-dimensional capitate kinematics. Twenty uninjured wrists were investigated using a recently developed, non-invasive markerless bone registration (MBR) technique. Surface contours of the capitate, third metacarpal and radius were extracted from computed tomography images of seven wrist positions and the three-dimensional motions of the capitate and third metacarpal were calculated with respect to the radius in wrist flexion–extension and radio-Ulnar Deviation. We found that in vivo capitate motion does not simply occur about a single pivot point like a universal joint, as demonstrated by non-intersecting rotation axes for different capitate motions. The distance between flexion and Ulnar Deviation axes was 3.9±2.0 mm, and the distance between extension and Ulnar Deviation axes was 3.9±1.4 mm. Furthermore, capitate axes for males tended to be located more distally than axes for females. However, we believe that this result is related to subject size and not to gender. We also found that there is minimal relative motion between the capitate and third metacarpal during these in vivo wrist motions. These findings demonstrate the complexity of capitate kinematics, as well as the different mechanisms through which wrist flexion, extension, radial Deviation and Ulnar Deviation occur.
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In vivo kinematic behavior of the radio-capitate joint during wrist flexion–extension and radio-Ulnar Deviation
Journal of biomechanics, 2001Co-Authors: Corey P. Neu, Joseph J. Crisco, Scott W WolfeAbstract:Abstract The capitate is often considered the “keystone” of the carpus, not simply because of its central and prominent position in the wrist, but also because of its mechanical interactions with neighboring bones. The purpose of this study was to determine in vivo three-dimensional capitate kinematics. Twenty uninjured wrists were investigated using a recently developed, non-invasive markerless bone registration (MBR) technique. Surface contours of the capitate, third metacarpal and radius were extracted from computed tomography images of seven wrist positions and the three-dimensional motions of the capitate and third metacarpal were calculated with respect to the radius in wrist flexion–extension and radio-Ulnar Deviation. We found that in vivo capitate motion does not simply occur about a single pivot point like a universal joint, as demonstrated by non-intersecting rotation axes for different capitate motions. The distance between flexion and Ulnar Deviation axes was 3.9±2.0 mm, and the distance between extension and Ulnar Deviation axes was 3.9±1.4 mm. Furthermore, capitate axes for males tended to be located more distally than axes for females. However, we believe that this result is related to subject size and not to gender. We also found that there is minimal relative motion between the capitate and third metacarpal during these in vivo wrist motions. These findings demonstrate the complexity of capitate kinematics, as well as the different mechanisms through which wrist flexion, extension, radial Deviation and Ulnar Deviation occur.
Joseph J. Crisco - One of the best experts on this subject based on the ideXlab platform.
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Differences in the Rotation Axes of the Scapholunate Joint During Flexion-Extension and Radial-Ulnar Deviation Motions.
The Journal of hand surgery, 2019Co-Authors: Gordon M. Best, Joseph J. Crisco, David R Pichora, Zoe E. Mack, Robin N. Kamal, Michael J. RainbowAbstract:Purpose To determine the location of the rotation axis between the scaphoid and the lunate (SL-axis) during wrist flexion-extension (FE) and radial-Ulnar Deviation (RUD). Methods An established and publicly available digital database of wrist bone anatomy and carpal kinematics of 30 healthy volunteers (15 males and 15 females) in up to 8 different positions was used to study the SL-axis. Using the combinations of positions from wrist FE and RUD, the helical axis of motion of the scaphoid relative to the lunate was calculated for each trial in an anatomical coordinate system embedded in the lunate. The differences in location and orientation between each individual axis and the average axis were used to quantify variation in axis orientation. Variation in the axis location was computed as the distance from the closest point on the rotation axis to the centroid of the lunate. Results The variation in axis orientation of the rotation axis for wrist FE and RUD were 84.3° and 83.5°, respectively. The mean distances of each rotation axis from the centroid of the lunate for FE and RUD were 5.7 ± 3.2 mm, and 5.0 ± 3.6 mm, respectively. Conclusions Based on the evaluation of this dataset, we demonstrated that the rotation axis of the scaphoid relative to the lunate is highly variable across subjects and positions during both FE and RUD motions. The range of locations and variation in axis orientations in this data set of 30 wrists shows that there is very likely no single location for the SL-axis. Clinical relevance Scapholunate interosseous ligament reconstruction methods focused on re-creating a standard SL-axis may not restore what is more likely to be a variable anatomical axis and normal kinematics of the scaphoid and lunate.
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Wrist kinematic coupling and performance during functional tasks: effects of constrained motion.
Journal of Hand Surgery (European Volume), 2014Co-Authors: Rohit Garg, Andrew P. Kraszewski, Holbrook H. Stoecklein, Grisha Syrkin, Sherry I. Backus, Mark L. Lenhoff, Aviva L. Wolff, Joseph J. Crisco, Howard J. Hillstrom, Scott W WolfeAbstract:Purpose To quantify the coupled motion of the wrist during selected functional tasks and to determine the effects of constraining this coupled motion using a radial-Ulnar Deviation blocking splint on performance of these tasks. Methods Ten healthy, right-handed men performed 15 trials during selected functional tasks with and without a splint, blocking radial and Ulnar Deviation. The following tasks were performed: dart throwing, hammering, basketball free-throw, overhand baseball and football throwing, clubbing, and pouring. Kinematic coupling parameters (coupling, kinematic path length, flexion-extension range of motion, radial-Ulnar Deviation range of motion, flexion-extension offset, and radial-Ulnar Deviation offset) and performance were determined for each functional task. A generalized estimation equation model was used to determine whether each kinematic coupling parameter was significantly different across tasks. A repeated-measures generalized estimation equation model was used to test for differences in performance and kinematic coupling parameters between the free and splinted conditions. Results Wrist motion exhibited linear coupling between flexion-extension and radial-Ulnar Deviation, demonstrated by R 2 values from 0.70 to 0.99. Average wrist coupling and kinematic path lengths were significantly different among tasks. Coupling means and kinematic path lengths were different between free and splinted conditions across all tasks other than pouring. Performance was different between wrist conditions for dart throwing, hammering, basketball shooting, and pouring. Conclusions Wrist kinematic coupling parameters are task specific in healthy individuals. Functional performance is decreased when wrist coupling is constrained by an external splint. Clinical relevance Surgical procedures that restrict wrist coupling may have a detrimental effect on functional performance as defined in the study. Patients may benefit from surgical reconstructive procedures and wrist rehabilitation protocols designed to restore kinematic coupling.
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in vivo kinematic behavior of the radio capitate joint during wrist flexion extension and radio Ulnar Deviation
Journal of Biomechanics, 2001Co-Authors: Joseph J. Crisco, Scott W WolfeAbstract:Abstract The capitate is often considered the “keystone” of the carpus, not simply because of its central and prominent position in the wrist, but also because of its mechanical interactions with neighboring bones. The purpose of this study was to determine in vivo three-dimensional capitate kinematics. Twenty uninjured wrists were investigated using a recently developed, non-invasive markerless bone registration (MBR) technique. Surface contours of the capitate, third metacarpal and radius were extracted from computed tomography images of seven wrist positions and the three-dimensional motions of the capitate and third metacarpal were calculated with respect to the radius in wrist flexion–extension and radio-Ulnar Deviation. We found that in vivo capitate motion does not simply occur about a single pivot point like a universal joint, as demonstrated by non-intersecting rotation axes for different capitate motions. The distance between flexion and Ulnar Deviation axes was 3.9±2.0 mm, and the distance between extension and Ulnar Deviation axes was 3.9±1.4 mm. Furthermore, capitate axes for males tended to be located more distally than axes for females. However, we believe that this result is related to subject size and not to gender. We also found that there is minimal relative motion between the capitate and third metacarpal during these in vivo wrist motions. These findings demonstrate the complexity of capitate kinematics, as well as the different mechanisms through which wrist flexion, extension, radial Deviation and Ulnar Deviation occur.
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In vivo kinematic behavior of the radio-capitate joint during wrist flexion–extension and radio-Ulnar Deviation
Journal of biomechanics, 2001Co-Authors: Corey P. Neu, Joseph J. Crisco, Scott W WolfeAbstract:Abstract The capitate is often considered the “keystone” of the carpus, not simply because of its central and prominent position in the wrist, but also because of its mechanical interactions with neighboring bones. The purpose of this study was to determine in vivo three-dimensional capitate kinematics. Twenty uninjured wrists were investigated using a recently developed, non-invasive markerless bone registration (MBR) technique. Surface contours of the capitate, third metacarpal and radius were extracted from computed tomography images of seven wrist positions and the three-dimensional motions of the capitate and third metacarpal were calculated with respect to the radius in wrist flexion–extension and radio-Ulnar Deviation. We found that in vivo capitate motion does not simply occur about a single pivot point like a universal joint, as demonstrated by non-intersecting rotation axes for different capitate motions. The distance between flexion and Ulnar Deviation axes was 3.9±2.0 mm, and the distance between extension and Ulnar Deviation axes was 3.9±1.4 mm. Furthermore, capitate axes for males tended to be located more distally than axes for females. However, we believe that this result is related to subject size and not to gender. We also found that there is minimal relative motion between the capitate and third metacarpal during these in vivo wrist motions. These findings demonstrate the complexity of capitate kinematics, as well as the different mechanisms through which wrist flexion, extension, radial Deviation and Ulnar Deviation occur.
Jin Bo Tang - One of the best experts on this subject based on the ideXlab platform.
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In Vivo Contact Characteristics of Distal RadioUlnar Joint With Malunited Distal Radius During Wrist Motion.
The Journal of hand surgery, 2015Co-Authors: Shuguo Xing, Ren Guo Xie, Yan Rong Chen, Jin Bo TangAbstract:Purpose To determine whether distal radioUlnar joint (DRUJ) contact characteristics were altered in patients with malunited distal radius fractures. Methods We obtained computed tomography scans at 5 positions of both wrists of 6 patients who had unilateral malunited distal radius fractures with dorsal angulation from 10° to 20° and Ulnar variance less than 3 mm. We reconstructed 3-dimensional images and mapped contact regions of DRUJ by calculating the shortest distance between the 2 opposing bones. The contact areas of the DRUJ were measured and the contact region centers were calculated and analyzed. The values of the malunited side were compared with those of the contralateral uninjured side. Results In the uninjured wrist, the contact areas of the DRUJ increased slightly from wrist flexion to extension and Ulnar Deviation. In the malunited wrist, we found the contact areas of DRUJ to be progressively reduced from 20° flexion to neutral, 40° extension, and 20° extension, to Ulnar Deviation. The centroid of this area on the sigmoid notch moved to distal from flexion to extension. Compared with the contralateral uninjured wrist, the contact area significantly decreased during wrist extension and Ulnar Deviation, and significantly increased during wrist flexion. The centroids of this area on sigmoid notch all moved volarly in all selected wrist positions. Conclusions The contact areas of the DRUJ and the centroid of contact area on sigmoid notch are altered in patients with malunited distal radius fractures. The contact area of the DRUJ increases during wrist flexion and decreases during wrist extension and Ulnar Deviation. The centroids of the contact area on sigmoid notch move volarly during wrist flexion-extension and Ulnar Deviation. Clinical relevance The in vivo findings suggest that alterations in joint mechanics may have an important role in the dysfunction associated with these injuries.
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Scaphoid and lunate movement in different ranges of carpal radioUlnar Deviation.
The Journal of hand surgery, 2010Co-Authors: Jin Bo Tang, Ren Guo XieAbstract:Purpose We aimed to investigate scaphoid and lunate movement in radial Deviation and in slight and moderate Ulnar Deviation ranges in vivo. Methods We obtained computed tomography scans of the right wrists from 20° radial Deviation to 40° Ulnar Deviation in 20° increments in 6 volunteers. The 3-dimensional bony structures of the wrist, including the distal radius and ulna, were reconstructed with customized software. The changes in position of the scaphoid and lunate along flexion–extension motion (FEM), radioUlnar Deviation (RUD), and supination–pronation axes in 3 parts—radial Deviation and slight and moderate Ulnar Deviation—of the carpal RUD were calculated and analyzed. Results During carpal RUD, scaphoid and lunate motion along 3 axes—FEM, RUD, and supination–pronation—were the greatest in the middle third of the measured RUD (from neutral position to 20° Ulnar Deviation) and the smallest in radial Deviation. Scaphoid motion along the FEM, RUD, and supination–pronation axes in the middle third was about half that in the entire motion range. In the middle motion range, lunate movement along the FEM and RUD axes was also the greatest. Conclusions During carpal RUD, the greatest scaphoid and lunate movement occurs in the middle of the arc—slight Ulnar Deviation—which the wrist frequently adopts to accomplish major hand actions. At radial Deviation, scaphoid and lunate motion is the smallest.
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Changes in carpal ligament length in throwing motion of the wrist
Chinese Journal of Orthopaedic Trauma, 2010Co-Authors: Jin Bo TangAbstract:Objective To investigate changes in wrist ligament length when the wrist is in different throwing positions.Methods Six wrists of 6 volunteers were enrolled in the experiment to obtain CT scans at 5 throwing positions of the wrist:20 degrees of radial Deviation with 60 degrees of extension,10 degrees of radial Deviation with 30 degrees of extension,neutral,20 degrees of Ulnar Deviation with 30 degrees of flexion,and 40 degrees of Ulnar Deviation with 60 degree of flexion.The carpal and distal radioUlnar joint structures were reconstructed 3-dimensionally with customized software.Changes in length of the palmar and dorsal wrist ligaments in throwing motion were computed with the software. Results From wrist radial Deviation with extension to Ulnar Deviation with flexion,the lengths of the radioscaphocapitate(RSC)ligament.the long radiolunate ligament(LRL),the ulnoceapitate ligament(UC)and the ulnotriquetral ligament (UT)decreased significantly(P
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In vivo length changes of selected carpal ligaments during wrist radioUlnar Deviation.
The Journal of hand surgery, 2009Co-Authors: Jin Bo TangAbstract:Purpose To investigate changes in the lengths of selected carpal ligaments during wrist radioUlnar Deviation in vivo . Methods We studied in vivo changes in the lengths of fibers of 5 palmar and dorsal intracapsular ligaments of the wrist during radioUlnar Deviation in 6 wrists of healthy volunteers using a noninvasive approach. Using serial computed tomography scans and volume registration techniques, the carpal kinematics were examined at 4 positions, from 40° Ulnar Deviation to 20° radial Deviation, in 20° increments. The 3-dimensional structures of the carpal bones, distal radius and ulna, and metacarpal bones were reconstructed using customized software. We modeled the paths of fibers of 5 palmar and dorsal carpal ligaments: radioscaphocapitate (RSC), long radiolunate (LRL), ulnocapitate (UC), dorsal intercarpal (DIC), and dorsal radiocarpal (DRC) ligaments. We analyzed changes in the lengths of these ligaments during wrist radioUlnar Deviation. Results During wrist Ulnar Deviation, the RSC, LRL, and DIC ligaments lengthened significantly. During radial Deviation, the UC and DRC ligaments lengthened significantly. Compared with their lengths at the neutral position of the carpus, the LRL ligament showed the greatest elongation rate at wrist Ulnar Deviation, and the DRC ligament showed the greatest elongation rate at wrist radial Deviation among the 5 ligaments studied. Conclusions Among ligaments measured, the RSC, LRL, and DIC ligaments are tensed during wrist Ulnar Deviation. The UC and DRC ligaments are tensed during wrist radial Deviation. Results of this in vivo study suggest that radial or Ulnar Deviation may predispose some carpal ligaments to excessive tensile load. The finding that the ligaments undergo different elongation rates during wrist motion may also indicate their roles in maintaining normal wrist kinematics.
Vincent M. Ciriello - One of the best experts on this subject based on the ideXlab platform.
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forearm muscle hemodynamic responses in healthy men during a seven hour exposure to repetitive Ulnar Deviation task a psychophysiological study
International Journal of Industrial Ergonomics, 2014Co-Authors: Rammohan V. Maikala, Vincent M. Ciriello, Jacob J. Banks, Niall V Obrien, Amanda RivardAbstract:Abstract The purpose was to evaluate vascular hemodynamics in the forearm of fourteen healthy men over a seven-hour workday of repetitive work at and above their acceptable workload. Participants performed an Ulnar Deviation task at a frequency of 15 repetitions per minute for seven hours: at their psychophysically chosen acceptable torque (day 1), and at 25% above the acceptable torque (day 2). Hemodynamic responses (Tissue oxygenation index [TOI] and Tissue Hemoglobin Index [THI]) from the carpi Ulnaris flexor and extensor muscle regions of the right hand were collected for the last 5 min of every hour of task performance. Participants selected their acceptable torque as 3.97 ± 2.5 N.m. (minimum: 1.0 and maximum: 9.8 N.m.). During task performance from 1 to 7 h, both tissue hemodynamic responses were not influenced by increasing the workload to above their acceptable level ( P > 0.05). Therefore, increasing the acceptable load by 25% will not diminish the adequate supply and delivery of oxygen to the muscle regions recruited. When blood flow to the forearm was occluded (for 1 min) immediately after the final repetition of the seven-hour task, the half-time recovery, a noninvasive indicator of muscle oxidative capacity, was not significantly different between workloads (average TOI: 10.2 s at the acceptable workload versus 10.8 s at 25% above the acceptable workload, P > 0.05; and average THI: 10.1 s at the acceptable workload versus 10.0 s at 25% above the acceptable workload, P > 0.05). This is a remarkable finding as we hypothesized that recovery in each muscle might be longer for a workload that is greater than the acceptable level for an individual. The fact that hemodynamic responses were also similar during recovery from the task performance across both workloads imply the protectiveness of the psychophysical approach in assessing the physical ability of workers without anoxia or tissue hypoxia, thereby posing no injury to the muscles recruited. Relevance to industry Scientific discipline of “Psychophysics” has been instrumental in developing safe levels of workload to workers exposed to variety of occupational activities without risking injury or adverse health effects. The present optical spectroscopy-related study is an excellent example of integrating two scientific disciplines: Psychophysics and Work physiology in examining the influence of a seven-hour repetitive work exposure on muscle hemodynamics of the upper extremity.
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Forearm muscle hemodynamic responses in healthy men during a seven-hour exposure to repetitive Ulnar Deviation task – A psychophysiological study
International Journal of Industrial Ergonomics, 2014Co-Authors: Rammohan V. Maikala, Vincent M. Ciriello, Niall V. O'brien, Jacob J. Banks, Amanda RivardAbstract:Abstract The purpose was to evaluate vascular hemodynamics in the forearm of fourteen healthy men over a seven-hour workday of repetitive work at and above their acceptable workload. Participants performed an Ulnar Deviation task at a frequency of 15 repetitions per minute for seven hours: at their psychophysically chosen acceptable torque (day 1), and at 25% above the acceptable torque (day 2). Hemodynamic responses (Tissue oxygenation index [TOI] and Tissue Hemoglobin Index [THI]) from the carpi Ulnaris flexor and extensor muscle regions of the right hand were collected for the last 5 min of every hour of task performance. Participants selected their acceptable torque as 3.97 ± 2.5 N.m. (minimum: 1.0 and maximum: 9.8 N.m.). During task performance from 1 to 7 h, both tissue hemodynamic responses were not influenced by increasing the workload to above their acceptable level ( P > 0.05). Therefore, increasing the acceptable load by 25% will not diminish the adequate supply and delivery of oxygen to the muscle regions recruited. When blood flow to the forearm was occluded (for 1 min) immediately after the final repetition of the seven-hour task, the half-time recovery, a noninvasive indicator of muscle oxidative capacity, was not significantly different between workloads (average TOI: 10.2 s at the acceptable workload versus 10.8 s at 25% above the acceptable workload, P > 0.05; and average THI: 10.1 s at the acceptable workload versus 10.0 s at 25% above the acceptable workload, P > 0.05). This is a remarkable finding as we hypothesized that recovery in each muscle might be longer for a workload that is greater than the acceptable level for an individual. The fact that hemodynamic responses were also similar during recovery from the task performance across both workloads imply the protectiveness of the psychophysical approach in assessing the physical ability of workers without anoxia or tissue hypoxia, thereby posing no injury to the muscles recruited. Relevance to industry Scientific discipline of “Psychophysics” has been instrumental in developing safe levels of workload to workers exposed to variety of occupational activities without risking injury or adverse health effects. The present optical spectroscopy-related study is an excellent example of integrating two scientific disciplines: Psychophysics and Work physiology in examining the influence of a seven-hour repetitive work exposure on muscle hemodynamics of the upper extremity.
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using electrical stimulation to measure physiological changes in the human extensor carpi Ulnaris muscle after prolonged low level repetitive Ulnar Deviation
Applied Ergonomics, 2013Co-Authors: Peter Johnson, Vincent M. Ciriello, Kirsty J. Kerin, Jack T. DennerleinAbstract:The objective of this study was to determine whether muscle fatigue would result from repetitive voluntary contractions performed consecutively over four, 8-h workdays. Using a repeated measures design, ten healthy females participated in three conditions: a control and two repetitive work conditions involving 8 h of repeated Ulnar Deviation of the wrist, at self-selected workloads at 20 and 25 repetitions per minute (RPM). The 2, 20 and 50 Hz force response of the Extensor Carpi Ulnaris muscle was measured before, during work, and in three hours of recovery. Twitch contraction times (CT), one-half relaxation times (½ RT) and 20:50 Hz ratios (low frequency fatigue ratios) were also compared. The average workloads for the 20 and 25 RPM conditions were 20.3% (±11.6%) and 16.3% (±10.8%) MVC respectively. In the exposure conditions there was a decrease in the 20:50 Hz ratios indicating low frequency fatigue (LFF), a significant increase in the muscle's force response across all stimulation frequencies (potentiation), and a corresponding decrease (quickening) in the twitch CTs and ½ RTs. During recovery, the 20:50 Hz ratios, muscle forces and twitch CTs and ½ RTs returned to pre-exposure/baseline levels. There were no carryover effects or significant differences between the two consecutive workdays. For the low-level dynamic workloads tested in this study, LFF coexisted with muscle potentiation and the results indicated that both LFF ratios and the individual force responses at each frequency needs to be evaluated in order to understand the underlying state of the muscle.
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Maximal Acceptable Torques of Highly Repetitive Screw Driving, Wrist Flexion and Extension with a Pinch grip, Ulnar Deviation, and Handgrip Tasks for Seven Hour Workdays for Male Industrial Workers
Proceedings of the Human Factors and Ergonomics Society Annual Meeting, 2011Co-Authors: Vincent M. Ciriello, Rammohan V. Maikala, Niall V. O'brienAbstract:The purpose of the study was to quantify maximum acceptable torques of six tasks performed on separate days but within the context of the same experiment. The six tasks were screw driving clockwise with a 40 mm handle and a 39 mm yoke handle; flexion and extension with a pinch grip; Ulnar Deviation with a power grip (similar to knife cutting), and a handgrip task (similar to a pliers task). A psychophysical methodology was used in which the subject adjusted the resistance of the task, and the experimenter controlled all other variables. Sixteen male industrial workers performed the six tasks at repetition rates of 15 and 25 motions per minute. Subjects performed the tasks for 7 hours per day, 5 days per week, for 12 days. The subjects were instructed to work as if they were on an incentive basis, getting paid for the amount of work they performed. Symptoms were recorded by the subjects during the last 5 minutes of each hour. The results revealed that mean maximum acceptable torques ranged from 1.15 Nm to ...
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Fatigue in the Forearm Resulting From Low-Level Repetitive Ulnar Deviation
AIHA journal : a journal for the science of occupational and environmental health and safety, 2003Co-Authors: Jack T. Dennerlein, Vincent M. Ciriello, Kirsty J. Kerin, Peter JohnsonAbstract:This study measured low-frequency fatigue (LFF) in the extensor carpi Ulnaris (ECU) muscle while workers completed a repetitive Ulnar Deviation task. Using a repeated measures design, 10 healthy women participated in three conditions, each lasting 2 consecutive days: a control condition in which subjects remained inactive, and two repetitive work conditions involving repeated Ulnar Deviation of the wrist at 20 and 25 repetitions per minute at individual workloads deemed acceptable for 8 hours through a psychophysical protocol. LFF of the ECU muscle and self-reported levels of fatigue were recorded eight times throughout the control and workdays before (time 0), during (2, 4.25, 6.75, 8 hours), and after (9, 10, and 11 hours) exposure. The ratio of the isometric force produced by electrical stimulus at 20 pulses per second (pps) to the isometric force produced by 50 pps provided the measure of LFF. The ratios were lower on workdays compared with the control days, indicating the presence of LFF during repet...
Steven F. Viegas - One of the best experts on this subject based on the ideXlab platform.
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Motion analysis in two dimensions of radial-Ulnar Deviation of type I versus type II lunates.
The Journal of hand surgery, 2000Co-Authors: Koji Nakamura, Moroe Beppu, Rita M. Patterson, Curtis A. Hanson, Paul J. Hume, Steven F. ViegasAbstract:The motions of 2 different types of lunate (type I, no medial hamate facet; type II, medial hamate facet) were evaluated and compared during radial-Ulnar Deviation of the wrist using radiography and magnetic resonance imaging. Ten right wrists (5 type I and 5 type II lunates) were studied using posteroanterior and lateral x-rays. Six of the 10 normal volunteers (3 type 1 and 3 type II lunates) were studied using magnetic resonance imaging in 6 positions of radial-Ulnar Deviation. In the radiographic study the Ulnar shift ratio of the lunate (USR), the shortest distance between the proximal Ulnar tip of the lunate and the distal Ulnar edge of the sigmoid notch of the radius (R-L), the closest distance between the distal Ulnar tip of the lunate and the proximal pole of the hamate (L-H), the radius of curvature of the proximal head of the capitate (Cr) on posteroanterior view, and the radiolunate angle on lateral view were measured in each wrist in each of the 6 positions. There were statistically significant differences between type I and II lunates with regard to average maximum Ulnar Deviation of USR and R-L, total change of USR, R-L distance and L-H distance, average L-H distance and Cr distance in all positions, and average radiolunate angle in neutral and 15° Ulnar Deviation. In the magnetic resonance imaging study the wrists with a type I lunate did not have contact between the lunate and hamate in any position; the wrists with a type II lunate did have contact between the hamate and the lunate, but only in Ulnar Deviation. The results of this study demonstrate that the kinematics of a type I lunate are different from those of a type II lunate during radial-Ulnar Deviation of the wrist.