Deviation Of Wrist Research Articles

Frequency and characteristics of the scaphoid cortical ring sign.

The scaphoid cortical ring sign (CRS) has been identified as a radiological indicator of ligamentous injury of the wrist. It has been associated with some pathokinematic states. There exists a range of wrist positions where the CRS may be normally present. The purpose of this study was to define the range of motion when the CRS can normally be observed on a standard posteroanterior radiograph and, in turn, to define the range where the CRS is not expected to be present. One hundred and nine posteroanterior radiographs of normal wrists were evaluated for the presence, partial presence and absence of the scaphoid CRS. The results were correlated with the radio-metacarpal (RM) angle in neutral palmar-dorsiflexion of the wrist. The range of wrist deviation for the wrists studied was -10.0 degrees (radial deviation) to 23.0 degrees (ulnar deviation). We defined the normal (and abnormal) range as being two standard deviations from the mean. The CRS was present in 25% of the radiographs evaluated. Moreover, the CRS was found to be present at 2.7 degrees (+/-7.7 degrees ) of radial deviation with a calculated range of -18.1 degrees to 12.7 degrees. The CRS was absent at 12.4 degrees (+/-11.7 degrees ) of ulnar deviation. It is concluded that the CRS observed at values less than 13 degrees of ulnar deviation may or may not be abnormal. If the CRS is observed at a RM angle of 13 degrees of ulnar deviation or greater, it should be considered pathological. The CRS, however, should be used in conjunction with other clinical findings of carpal instability.

Scaphoid Osteochondroma-A Case Report

Tumors of the scaphoid bone are very rare and their treatment has not been well established. A 9-year-old child presenting with progressive enlargement and deviation of the wrist was found to have osteochondroma of the scaphoid. It was treated by total scaphoidectomy and arthroplasty was accomplished with the tendon of flexor carpi radialis. The tendon strip was coiled along the K-wire across the scaphoid cavity. In the subsequent follow-up of 4.5 years, the result was satisfactory in terms of growth, deformity correction as well as functional recovery although there was the decrease of the carpal height ratio. It is concluded that the modified Anchovy procedure can be applied to this situitation in the children.

Scaphoid kinematic behavior after division of the transverse carpal ligament

Purpose: The effect that carpal tunnel release (CTR) has on scaphoid motion has not been reported. Accordingly the purpose of this study was to determine the flexion/extension behavior of the scaphoid during global wrist radial/ulnar deviation before and after division of the transverse carpal ligament (TCL). Method: In this study we examined the in vitro kinematics of the scaphoid during wrist deviation in 6 cadaver forearms both before and after the division of the TCL using a computerized camera monitoring system. The specimens were evaluated in 13 different positions, from 20° of radial deviation to 40° of ulnar deviation at increments of 5°. Results: The data indicate that the difference in scaphoid position after TCL division is statistically significant when the wrist is in ulnar deviation of 15° or greater. In addition a significant difference in scaphoid extension between pre- and post-TCL division conditions was found at 5° of radial deviation as well as at 5° or more of ulnar deviation and increased with increasing ulnar deviation. Conclusions: Scaphoid kinematics are altered considerably in radial-ulnar deviation after division of the TCL. This alteration may have long-term consequences and contribute to commonly seen post-CTR symptoms. (J Hand Surg 2003;28A:267-271. Copyright © 2003 by the American Society for Surgery of the Hand.)

Fatigue in the forearm resulting from low-level repetitive ulnar deviation.

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 repetitive work. During repetitive work the ratios decreased during the day, indicating the muscles fatigued as the day progressed. The psychophysically determined workloads, although not creating noticeable discomfort to the subjects, were high enough to create low levels of muscle fatigue.

A prospective study of computer users: II. Postural risk factors for musculoskeletal symptoms and disorders.

Despite widespread recommendations regarding posture during computer use, associations between specific postures and musculoskeletal health are not well characterized. Six hundred and thirty-two newly hired computer users were followed prospectively to evaluate associations between posture and neck or shoulder (N/S) and hand or arm (H/A) musculoskeletal symptoms and musculoskeletal disorders. Participants' postures were measured at entry and they reported symptoms on weekly diaries. Participants reporting symptoms were examined for specific disorders. Multivariate Cox regression models were used to estimate associations between postural variables and risk of symptoms and disorders, controlling for confounding variables. Keying with an inner elbow angle > 121 degrees, greater downward head tilt, and presence of armrests on the participants chair were associated with lower risk of N/S symptoms or N/S disorders. Keying with elbow height below the height of the "J" key and the presence of a telephone shoulder rest were associated with a greater risk of N/S symptoms or N/S disorders. Horizontal location of the "J" key > 12 cm from the edge of the desk was associated with a lower risk of H/A symptoms and H/A disorders. Use of a keyboard with the "J" key > 3.5 cm above the table surface, key activation force > 48 g, and radial wrist deviation of > 5 degrees while using a mouse was associated with a greater risk of H/A symptoms or H/A disorders. The number of hours keying/week was associated with H/A symptoms and disorders. The results suggest that the risk of musculoskeletal symptoms and musculoskeletal disorders may be reduced by encouraging specific seated postures.

Ergonomic interventions for the furniture manufacturing industry. Part II—Handtools

The objectives of this intervention research project were to develop and evaluate engineering controls for the reduction of the upper extremity injury risk in workers in the furniture manufacturing industry. The analysis of OSHA Form 200 logs and surveys of furniture workers revealed that upholsterers, workers who use random orbital sanders and workers who use spray guns are at higher levels of risk of illness than the rest of the working population. An on-site ergonomic analysis of these three jobs was performed and the following risk factors were identified for each of these three work groups: upholsterers—repetitive, high-force pinch grips; sanders—long-duration static grip forces; and sprayers—awkward postures (ulnar wrist deviations and wrist flexion). Engineering interventions in the form of new or modified handtools were then evaluated in the laboratory to assess their effectiveness in reducing exposure to these risk factors. For sanding, an interface was created that secured the hand to the sander with the intention of reducing the need for static grip forces during sanding. A new handtool was created for upholsterers that replaced the repetitive pinch grips with a power grip. Finally, a commercially available spray gun with ergonomic features was evaluated. Each of these modified tools/methods was compared with the standard methods typically used in industry. The results show that most of the intended beneficial effects were realized. The random orbital sander interface reduced extensor muscle activities by an average of 30%. The upholstery handtool reduced the intrinsic hand muscle activities by an average of 51%. The effects of the adapted spray gun were most prominent when working on horizontal surfaces and showed an average reduction of 40° of wrist flexion and 14° of ulnar deviation as compared to the standard pistol grip spray gun in this activity. Relevance to industry The ergonomic intervention research described in this report documents a reduction in exposure to risk factors for upper extremity cumulative trauma disorders for three work activities in the furniture manufacturing industry.

Pisiform kinematics in vivo

The purpose of this study was to quantify in vivo pisiform kinematics. Wrists of healthy volunteers were imaged by spiral computed tomography during ulnar-radial deviation (n = 11) and during flexion-extension (n = 5). Relative translations and rotations of the carpal bones were determined by using a 3-dimensional matching technique. The error of this registration procedure was less than 0.5 mm for translation and 0.4 degrees for rotation. With radial wrist deviation the pisiform flexes while the triquetrum extends; with ulnar deviation the triquetrum shows more ulnar deviation and extension. With wrist extension the pisiform translates over the distal part of the triquetrum while being pressed against it. With flexion the pisiform moves away from the triquetrum while translating proximally. These in vivo findings provide a further explanation for certain clinical entities, such as degenerative changes of the pisotriquetral joint, and may be used as a reference for normal kinematics of the pisiform.

Comparison of self-report, video observation and direct measurement methods for upper extremity musculoskeletal disorder physical risk factors

The prevention of work-related musculoskeletal disorders has become a national priority in many countries. Increasingly, attempts are made to quantify those exposures that increase risk in order to set exposure limit values. This study used commonly employed field measurement methods and tools in order to perform an inter-method comparison between three primary methods of risk factor exposure assessment: self-report questionnaires, observational video analysis and direct measurement. Extreme posture duration, repetition, hand force (estimated from electromyography) and movement velocity were assessed for 18 subjects while performing each of three jobs processing tree seedlings. Results indicated that self-reports were the least precise assessment method, which consistently overestimated exposures for each of the measured risk factors. However, adjustment of the reports as psychophysical scales may increase agreement on a group level. Wrist flexion/extension duration and repetition were best measured by electrogoniometer. Electrogoniometric measures of wrist deviation duration and frequency were less precise than video analysis. Forearm rotation duration and repetition, grip force and velocity appeared to be best quantified by direct measurement as measured by electrogoniometer and electromyography (EMG) (as root-mean-square amplitude). The results highlight the fact that it is as important to consider and report estimated measurement error in order to reduce potential exposure misclassification in epidemiologic studies.

Comparison of self-report, video observation and direct measurement methods for upper extremity musculoskeletal disorder physical risk factors

The prevention of work-related musculoskeletal disorders has become a national priority in many countries. Increasingly, attempts are made to quantify those exposures that increase risk in order to set exposure limit values. This study used commonly employed field measurement methods and tools in order to perform an inter-method comparison between three primary methods of risk factor exposure assessment: self-report questionnaires, observational video analysis and direct measurement. Extreme posture duration, repetition, hand force (estimated from electromyography) and movement velocity were assessed for 18 subjects while performing each of three jobs processing tree seedlings. Results indicated that self-reports were the least precise assessment method, which consistently overestimated exposures for each of the measured risk factors. However, adjustment of the reports as psychophysical scales may increase agreement on a group level. Wrist flexion/extension duration and repetition were best measured by electrogoniometer. Electrogoniometric measures of wrist deviation duration and frequency were less precise than video analysis. Forearm rotation duration and repetition, grip force and velocity appeared to be best quantified by direct measurement as measured by electrogoniometer and electromyography (EMG) (as root-mean-square amplitude). The results highlight the fact that it is as important to consider and report estimated measurement error in order to reduce potential exposure misclassification in epidemiologic studies.

Effect of Setup Configurations of Split Computer Keyboards on Wrist Angle

Alternative computer keyboards whose halves can be slanted toward each other can reduce a risk factor (ulnar deviation) for work-related musculoskeletal disorders (WMSDs) affecting the upper limbs. Two questions that computer keyboard operators face when using keyboards that can be separated into halves (split keyboards) are: (1) At what angle should the keyboard halves be opened? and (2) At what distance apart should the keyboard halves be placed? The objective of this study was to investigate the effects of the opening angle and separation distance between halves of a split keyboard on wrist ulnar deviation and typing efficiency. Eleven experienced computer keyboard operators participated in this study and used a split keyboard that was set up in a conventional (nonsplit) format and also in 3 alternative configurations: (1) centers of keyboard halves were separated at 20-cm distance, (2) keyboard halves were separated half of the distance of shoulder width, and (3) keyboard halves were separated at shoulder width distance. The 3 alternative configurations resulted in ulnar deviation of both wrists that were less than ulnar deviation from typing on a conventional setup. There were no differences in ulnar deviations among the 3 alternative configurations. The results of this research provide physical therapists and ergonomists with a set of configurations of a split keyboard that they can recommend to their patients or clients. All of the alternative configurations of the split keyboard are beneficial in promoting a neutral wrist position, which theoretically would decrease exposure to WMSDs such as tenosynovitis in the wrist and carpal tunnel syndrome.

Direct Measurement Error Identification and Reporting for Upper Extremity Exposure Assessment

Electrogoniometers currently represent the most feasible way of obtaining direct measurements of wrist and forearm posture and motion in varied work environments. Researchers have shown that a significant amount of error may be present in the recordings from these instruments (Buchholz and Wellman, 1997; Armstrong et al., 1993). This study showed that even with “state of the art” correction methods, wrist flexion/extension and wrist deviation duration measurements may still vary by as much as 100% plus or minus the measured result in the 95% confidence interval. Forearm extreme posture duration intervals were equal to or less than 40% of the calculated values. Wrist flexion/extension and forearm rotation repetition measurements were more accurate, giving confidence intervals plus or minus less than 25% of the resulting values. Wrist deviation repetition confidence intervals were wider, at plus or minus 100% or greater and generally including zero. These results highlight the need to address accuracy when reporting measurements of the upper extremities and to promote further research into the development of accurate measurement methods.

Finger motion, wrist motion and tendon travel as a function of keyboard angles

Objective. This study assessed the impact of keyboard angles (in terms of Pitch, Roll and Yaw) on tendon travel and wrist and finger joint kinematics for the flexor digitorum profundus and flexor digitorum superficialis. Design. A repeated measures, laboratory study was conducted. Independent variables were three Pitch angles, three Roll angles, three Yaw angles, and three keyboard separation distances. Dependent variables were tendon travel, wrist deviation, wrist and finger joint kinematics, and Borg comfort rating. Background. The increased usage of computers and the risk of cumulative trauma disorders have led to the development of alternate keyboards. This study is a biomechanical assessment of several keyboard designs. Methods. Lightweight wrist and finger goniometers were used to measure motion of the wrist in three planes, and for three finger joints. Fifteen experienced typists (eight women, seven men) typed a standard text on 30 keyboard conditions. Regression equations were used to calculate tendon travel from joint positions. Results. Tendon travel is sensitive to changes in Pitch, Roll and Yaw angles with ∼13% difference between the minimal and maximal tendon travel. A flat keyboard produced more tendon travel than keyboards with greater Pitch and Roll angles. Conclusions. There is a trade-off between wrist and finger positions; as the wrist extends more, the finger joints flex more to compensate. Keyboards imposed different trade-offs between the wrist and finger positions , affecting the overall tendon travel. Relevance Alternate keyboard designs can significantly affect tendon travel and may address reduced repetitiveness in typing by reducing the amount of tendon travel.

An assessment of alternate keyboards using finger motion, wrist motion and tendon travel

Objective. To assess the biomechanical impact of commercially available alternate keyboard designs. Design. A repeated measures study was conducted in a laboratory setting, with planned comparisons of Pitch, Roll and Yaw angles of the keyboards. Ten keyboard conditions were tested. Dependent measures included tendon travel, wrist deviations, and wrist and finger kinematics. Background. Various alternate keyboard designs have recently been introduced, which vary Pitch, Roll and Yaw angles, separation distance between keyboard halves, and include other novel features such as cup-shaped depressions for the keys. Yet little objective research has been conducted regarding the biomechanical implications of these various design features. This study attempts to quantify the keyboard designs in terms of several recognized risk factors associated with cumulative trauma disorders that arise with repetitive typing. Methods. Wrist and finger goniometers were used to measure joint motions during a standardized typing task. 15 experienced typists (8 women, 7 men) served as subjects. Regression equations were used to generate estimates of tendon travel. Results. Tendon travel was affected primarily by Pitch but not Roll or Yaw angles while wrist deviations responded to changes in all three angles. Males had significantly greater amount of tendon travel than female subjects; this difference was only partially accounted for by anthropometry. Differences in joint motion may have a greater impact on the amount of tendon travel. Conclusions. Alternate keyboard designs can affect tendon travel by as much as 11%. Relevance As various alternate keyboard designs are marketed, quantifiable biomechanical data such as that provided by this study, will help to assess their impact on the risk factors for cumulative trauma disorders.

Evaluation of bent-handled files

The file is a non-powered hand tool extensively used in the manufacturing industry. However, the conventional flat file with a straight handle frequently causes excessive ulnar deviation of the user's wrist. Therefore, repetitive and long-time use of the file likely inflicts the user with cumulative trauma disorders (CTDs) at the upper extremities, in particular carpal tunnel syndrome (CTS). In this work, we present a novel bent-handled flat file, designed from an ergonomic perspective as an improvement over the conventional file with a straight handle. This novel re-designed product was tested to verify its effectiveness. Five criteria were tested: the subject's working posture (right arm), task efficiency (filings), task precision (flatness), the degree of right-arm fatigue (the decrease of grip force), and the subject's subjective preference ratings. According to our results, the bent-handled flat file is superior to the straight-handled flat file because the former can sustain the operator's forearm and hand in a neutral position, reduce the degree of right-arm fatigue, and adhere to the subject's preferences. The other two criteria, task efficiency and task precision, show no significant difference. The ergonomically friendly files (with the handles bent from 50° to 70°) ensure optimal use. The bent-handled file has the same function in filings and flatness as the straight-handled file. In particular, the 60° file is excellent. The bent-handled flat file not only reduces cumulative trauma, but fulfills the requirements of the operatives. Relevance to industry The flat file (tool) is extensively used in industry. Results in this study demonstrate that the bent-handled file (from 50° to 70°) not only maintains the operator's forearm and hand in a neutral position, but also reduces the extent of right-arm fatigue and satisfies the subject's preferences. It had no significant difference from the straight-handled file in filings and flatness evaluation. Therefore, the bent-handled flat file is safer than and equally efficient when compared with the conventionally used file

The unstable radiocarpal joint in rheumatoid arthritis

The inflammation of the wrist occurs very early in Rheumatoid arthritis. In cases of wrist deviation the biomechanics of the hole hand are affected. Carpal collapse will severely influence the range of motion (ROM) of the fingers. Operative techniques of how to maintain hand function are discussed. There are different procedures available - partial arthrodesis, arthrodesis and arthroplasty.

Effect of handle design for cylinder trolleys

An experiment was carried out to investigate the effects of handle design on the biomechanical stresses imposed in the use of a cylinder trolley. Nine combinations of handle orientations (35°, 50,° 70°) and handle length (1.0, 1.1, 1.2 m) were tested for the initial starting off phase and the steady moving phase. Two weights of cylinder (19 and 37 kg) were used. Measurements were made of wrist angle, elbow flexion, force at the feet and subjective ratings of effort, discomfort and stability as well as the angle at which the trolley was tilted. The biomechanical loads on the spine and joints of the arm were also calculated. High stresses at the elbow and considerable wrist deviations were found to occur during the starting phase. The elbow stresses were significantly affected by the design of the trolley handle, as was the degree to which the trolley was tilted while moving forward with load. For starting, the best configuration proved to be a 35° handle angle and a 1.0 m handle length. The results were, however, less clear in determining the best configuration for pushing the trolley forwards.

Effects of Computer Keyboard Setup Parameters and User's Anthropometric Characteristics on Wrist Deviation and Typing Efficiency

Two questions that computer keyboard operators face when using keyboards that can be separated into halves (split keyboards) are at what angle should the keyboard halves be opened and at what distance should the keyboard halves be placed apart. The objective of this study was to investigate the effects of the opening angle and separation distance between halves of a split keyboard on wrist radial/ulnar deviation and typing efficiency. Eleven experienced typists participated in this study and typed on a split keyboard configured in the following four arrangements. 1. The keyboard halves were setup the same way as a conventional keyboard. 2. The keyboard halves were contiguous but angled, based on the user's anthropometry, to maintain a theoretical neutral posture of the user's wrists in the radial/ulnar plane. 3. The keyboard halves were separated at a fixed distance of 20 cm, and the halves were angled to maintain a theoretical neutral posture of the user's wrists in the radial/ulnar plane. 4. The keyboard halves were separated at a distance equal to the user's shoulder width, and the halves were parallel to each other, resulting in a theoretical neutral posture of the user's wrists in the radial/ulnar plane. The findings from testing these four keyboard configurations are the following: 1. The mean ulnar deviations from the alternative configurations of the split keyboard (configurations 2, 3, and 4 above) ranged from 7.0 to 8.4 for the left wrist and 2.7 to 5 deg. for the right wrist. There were no significant differences in ulnar deviations among the three alternative configurations. 2. The three alternative configurations resulted in ulnar deviation of both wrists that were significantly less than ulnar deviation from typing on the conventional setup (configuration 1 above). The mean ulnar deviations from the conventional setup were 18.9 deg. for the left wrist and 14.2 deg. for the right wrist. 3. There were no significant differences in typing speed and accuracy between the alternative and conventional configurations.

Occupational Upper Extremity Symptoms in Sign Language Interpreters: Prevalence and Correlates of Pain, Function, and Work Disability

The interactive role of work demands, occupational stressors, and ergonomic risk factors in work-related upper extremity (UE) disorders remains unclear. Professional sign language interpreting, which involves exposure of the upper limbs to a combination of potential ergonomic and psychosocial stressors represents a unique occupational group to investigate the multivariate nature of UE disorders. The present study reports data on the prevalence, patterns of symptoms, associated medical problems, and health care related to upper extremity disorders in sign language interpreters. The contribution of work demands, work style, and psychosocial stressors to the occurrence of self-reported function, pain, muscle tension, and work disability was also studied. A group of 1398 sign language interpreters completed an 83-item national survey on occupational musculoskeletal health (response rate of 58%). Interpreters were asked a series of demographic, workstyle, work environment, medical care, and symptom-related questions. Logistic regression, multivariate regression, and discriminant function analyses were used to examine the data. A large percentage of interpreters reported symptoms in the neck region (73.6%) followed by the hand/wrist (69.6%). Using a NIOSH case definition for work-relatedness, prevalence rates varied from 16% to 32% depending upon the anatomic location. Medical care was primarily sought within the first month of symptoms (21.9%) and nonsteroidal antiinflammatory drugs were the most frequently used treatment (70.3%). A multivariate logistic regression indicated that female gender, number of years worked, pressure at work, fear of developing pain, tendency to work in pain to insure work quality, and increased wrist deviations from neutral were associated with case status. Impact on function, pain, and perceived muscle tension at work were all primarily associated with tendency to work in a painful way to insure work quality and fear of developing a pain problem. Time off work was also associated with these variables as well as with the lack of an opportunity to use one's initiative. Results indicate that upper extremity symptoms are prevalent in this work group and that a combination of work demands, workstyle, and psychosocial stressors are associated with case status and the exacerbation of pain, muscular tension, functional limitations, and work disability.

An ergonomic comparison of industrial spray paint guns

Two spray guns were used by 10 subjects in a laboratory. One gun was a `traditional' spray gun. The other was the OMX gun which had `ergonomic' features including reduced gun and hose weight and two triggers (one for horizontal surfaces and one for vertical). The 10 subjects (5 experienced industrial spray painters and 5 inexperienced students) used each gun for 4 h. The criteria used to evaluate the two guns were: (1) Wrist deviation in all three axes, (2) EMG frequency shift of 3 shoulder muscles over the test period, (3) integrated EMG activity of the forearm flexors, and (4) body discomfort ratings. It was found that the OMX gun resulted in significantly less radial/ulnar deviation in the wrist, and moderately increased flexion/extension and pronation/supination deviations from neutral. During the painting period, up to 50% less fatigue in the shoulder muscles was found for the OMX gun. Additionally, the triggering activation levels for sustained grip contractions were found to be acceptable for the OMX gun when using the short trigger. Finally, the amount of discomfort reported by the subjects was statistically lower in the shoulder, upper back, arm, elbow, forearm, wrist, and hand with the OMX gun design. Collectively, these results indicate that the OMX gun would be expected to reduce exposure to occupational risk factors for workers. This study demonstrated how the incorporation of ergonomic design principles can be used to minimize occupationally-related risk. Relevance to industry Cumulative trauma disorders (CTDs) are soft tissue disorders resulting from repeated exertions and excessive movements of the body. Industrial spray painting fits the profile of a highly repetitive task. Improving spray paint gun design could potentially reduce the risk of CTDs in industrial spray painting tasks.

Defending the Wrist Deviation Test for Carpal Tunnel Syndrome Screening: A Comparison of Vibration Thresholds and Distal Motor Latency.

This research used distal motor latency (DML) and vibration thresholds (VT) to evaluate 84 hand activity and wrist deviation combinations to determine the best association with carpal tunnel syndrome (CTS). Female volunteers, 2 healthy and 2 CTS diagnosed, were age matched and operated a keyboard for 4 hrs a day. Room temperature was 28°C(±2). Beginning DML and VT were taken with a relaxed neutral posture hand. The wrist was deviated in a randomly selected combination, and determinations were taken at 5-min intervals. The trial ended at 20 min or when discomfort was felt. The CTS conditions were discriminated by pain four times, DML once, and VT 14 times. Vibrometry was the most consistent CTS discriminator. The best VT results for wrist positions were obtained with wrist extension and extended extension, whereas the unclenched, clenched, and loaded power grip activities proved to be the most consistent hand activities.