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.

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Effect of Setup Configurations of Split Computer Keyboards on Wrist Angle

Physical Therapy ◽

10.1093/ptj/81.4.1038 ◽

2001 ◽

Vol 81 (4) ◽

pp. 1038-1048 ◽

Cited By ~ 15

Author(s):

Richard W Marklin ◽

Guy G Simoneau

Keyword(s):

Physical Therapists ◽

Separation Distance ◽

Opening Angle ◽

Upper Limbs ◽

Ulnar Deviation ◽

Tunnel Syndrome ◽

Computer Keyboard ◽

Set Up

Abstract Background and Purpose. 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. Methods. 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. Results. 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. Discussion and Conclusion. 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.

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The Effect of Split and Vertically-Inclined Computer Keyboards on Wrist and Forearm Posture

Proceedings of the Human Factors and Ergonomics Society Annual Meeting ◽

10.1177/1071181397041001141 ◽

1997 ◽

Vol 41 (1) ◽

pp. 642-646 ◽

Cited By ~ 1

Author(s):

Richard W. Marklin ◽

Guy G. Simoneau ◽

John F. Monroe

Keyword(s):

Risk Factor ◽

Neutral Position ◽

Ulnar Deviation ◽

Occupational Risk Factor ◽

Tunnel Syndrome ◽

Computer Keyboard ◽

The Right ◽

Neutral Posture

The significant findings from this study of 90 clerical subjects, whose forearm and wrist posture were measured while they typed on three alternative QWERTY computer keyboard designs, are the following: 1) when setup correctly, commercially-available split QWERTY keyboards reduced mean ulnar deviation of the right and left wrists from approximately 12 deg. to within 5 deg. of a neutral position compared to a conventional QWERTY keyboard. 2) with at least a 30 deg. tilt of the keyboard halves, a commercially-available vertically-inclined QWERTY keyboard reduced mean pronation of the forearm by approximately 20 deg. compared to a conventional QWERTY computer keyboard (60 to 40 deg.) The finding that split keyboards place the wrist closer to a neutral posture in the radial/ulnar plane substantially reduces one occupational risk factor of work-related musculoskeletal disorders (WMSDs), namely ulnar deviation of the wrist. The finding that vertically-inclined keyboards reduce forearm pronation substantially is advantageous, at least theoretically, to the keyboard user. However, since the origins of WMSDs, which include carpal tunnel syndrome (CTS) and tenosynovitis, tend to be multifactorial, the extent to which split keyboards or vertically-inclined keyboards could reduce the frequency or severity of WMSDs is unknown.

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Dynamic CT Scan of the Normal Scapholunate Joint in a Clenched Fist and Radial and Ulnar Deviation

Hand ◽

10.1177/1558944717726372 ◽

2017 ◽

Vol 13 (6) ◽

pp. 666-670 ◽

Cited By ~ 3

Author(s):

Paul M. Kelly ◽

John G. Hopkins ◽

Andrew J. Furey ◽

Daniel S. Squire

Keyword(s):

Ct Scan ◽

Range Of Motion ◽

Ct Imaging ◽

Dynamic Ct ◽

Long Term Effects ◽

Ulnar Deviation ◽

Left Wrist ◽

The Right ◽

User Friendly

Background: Injuries to the scapholunate can have severe long-term effects on the wrist. Early detection of these injuries can help identify pathology. The purpose of this study was to evaluate the motions of the scapholunate joint in normal wrists in a clenched fist and through radial and ulnar deviation using novel dynamic computed tomography (CT) imaging. Methods: Fifteen participants below 40 years of age consented to have their wrist scanned. Eight participants were randomized to have the right wrist scanned and 7 the left wrist. Volunteers were positioned at the back of the gantry with the wrist placed on the table, palmar side down. Participants began with the hand in a relaxed fist position and then proceeded through an established range of motion protocol. Dynamic CT imaging was captured throughout the range of motion. Results: The movement in the healthy scapholunate joint through a clenched fist and radial and ulnar deviation is minimal. The averages were 1.19, 1.01, and 0.95 mm, representing the middle, dorsal, and volar measurements, respectively. Conclusions: This novel dynamic CT scan of the wrist is a user-friendly way of measuring of the scapholunate distance, which is minimal in the normal wrist below 40 years of age.

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Correlations between body postures and musculoskeletal pain in guitar players

PLoS ONE ◽

10.1371/journal.pone.0262207 ◽

2022 ◽

Vol 17 (1) ◽

pp. e0262207

Author(s):

Sigal Portnoy ◽

Shlomit Cohen ◽

Navah Z. Ratzon

Keyword(s):

Risk Factors ◽

Musculoskeletal Disorders ◽

Musculoskeletal Pain ◽

Upper Body ◽

Musculoskeletal Symptoms ◽

Left Shoulder ◽

Ulnar Deviation ◽

Left Wrist ◽

Physical Comfort ◽

The Right

Background The guitar-playing community is the largest group at risk of developing playing related musculoskeletal disorders. A thorough investigation of the relationships between the various risk factors and players’ report on musculoskeletal pain using objective and accurate means of assessment has yet to be reported. Purpose (a) to explore the correlations between demographic characteristics, anthropometric measurements, playing habits, and personal habits of guitar player and their complaints of musculoskeletal pain, (b) explore the correlations between the upper body kinematics of guitar players during playing the guitar and their complaints of musculoskeletal pain, and (c) compare the upper body kinematics of guitar players during playing the guitar while sitting versus standing. Methods Twenty-five guitar players (27.5±4.6 years old) filled out questionnaires regarding their guitar-playing habits, and the Standardized Nordic Questionnaires for the analysis of musculoskeletal symptoms. Kinematics of their torso and upper limbs were tracked while they played a tune twice, once while sitting and once while standing. Results We found moderate correlations between the number of painful joints in the last year and factors, such as physical comfort while playing, years of playing, and position during playing. During standing, lower back pain severity correlated with the rotation range of the torso, while during sitting, it moderately correlated with the average radial-ulnar deviation of the right wrist. During sitting, we found higher anterior and right tilt of the torso, combined with greater abduction of the right shoulder, higher flexion in the left shoulder and higher radial deviation in the left wrist. Conclusion Our results point to several risk factors, related both to playing habits but also to playing posture, which should be considered by the guitar players in order to prevent playing-related musculoskeletal disorders.

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Musculoskeletal Disorders Symptoms among Taiwanese Bakery Workers

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph17082960 ◽

2020 ◽

Vol 17 (8) ◽

pp. 2960

Author(s):

Yi-Lang Chen ◽

Yan-Ting Zhong ◽

Bang-Nan Liou ◽

Chih-Chuan Yang

Keyword(s):

Musculoskeletal Disorders ◽

The Body ◽

Self Report ◽

Musculoskeletal Discomfort ◽

Ulnar Deviation ◽

Left Wrist ◽

Shoulder Disorders ◽

The Right

In this study, the Nordic Musculoskeletal Questionnaire (NMQ) was administered to a valid sample of 81 Taiwanese bakery workers to explore their discomfort or symptoms of work-related musculoskeletal disorders and identify the risk factors. Wrist postures were also examined during 3 typical dough operations (kneading, rolling, and rounding) by using an electrogoniometer. The prevalence of musculoskeletal discomfort in any part of the body in the past year among the respondents was 93.0%, with the highest prevalence of 66.3% and 51.8% in the hands/wrists (right and left), followed by the prevalence of 50.6% and 45.8% in the shoulders (right and left) and the lower back (48.2%), respectively. The results also revealed that during the 3 dough processing operations, the workers’ wrist movements in specific operations were close to the recommended limits suggested in previous studies, especially the ulnar deviation and palm flexion of the right wrist during dough kneading and the radial deviation of the left wrist during dough rolling and rounding. The study findings can be used to explain why the bakers self-report a high proportion of wrist and shoulder disorders and can also serve as a reference for task rearrangement and redesign.

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AB0158 COMPARISON OF CLINICAL EXAMINATION AND ULTRASOUND OF HAND AND WRIST JOINTS IN RHEUMATOID ARTHRITIS

Annals of the Rheumatic Diseases ◽

10.1136/annrheumdis-2021-eular.1922 ◽

2021 ◽

Vol 80 (Suppl 1) ◽

pp. 1106.1-1106

Author(s):

S. Bouden ◽

B. D. Siwar ◽

A. Ben Tekaya ◽

O. Saidane ◽

R. Tekaya ◽

...

Keyword(s):

Rheumatoid Arthritis ◽

Disease Activity ◽

Clinical Examination ◽

Disease Activity Score ◽

Power Doppler ◽

Doppler Signal ◽

Left Wrist ◽

The Mean ◽

The Right ◽

Power Doppler Signal

Background:Ultrasound (US) is an accessible and non-invasive tool to assess joint involvement in rheumatoid arthritis (RA). It is used for diagnostic and prognosis purposes and for following of RA patients by evaluating the disease activity and therefore the response to treatment.Objectives:This study investigates agreement between US of hand and wrist findings and the clinical examination and biological inflammatory parameters in RA patients.Methods:We performed a cross sectional study including patients responding to the ACR/EULAR 2010 criteria for RA diagnosis. We collected US findings assessing synovitis and doppler signal in wrist, metacarpophalangeal (MCP) and proximal interphalangeal (PIP) articulations, and concomitant clinical examination assessing synovitis and pain in the same joints along with C reactive protein (CRP) levels and disease activity score (DAS28). The power Doppler US score (PDUS) from 6 simplified synovial sites (wrists, bilateral second and third MCP joints) was calculated [1].Results:Forty-three patients were included with 91.7% of women. The mean age was 62±12.95 years old. The mean age at diagnosis was 52±14.79 years with a mean disease evolution of 8±8.57 years. Rheumatoid factor and anti-citrullinated antibodies were positive in respectively 78% and 83.9% of cases.The mean disease activity (DAS28) was 1,52 with levels ranging from 1.5 to 7.33.Right wrist was the articulation in which US synovitis was most frequently detected (60.5% of patients), followed by the left wrist (53.5%). Power doppler signal was detected as frequently in the right as in the left wrist articulations (41.9%). Subsequently, clinical synovitis was most frequently detected in right and left wrist with 39,5% and 41,5% respectively. These joints were the most frequently painful, in 51.2% and 48.8% at right and left respectively.US synovitis of the first interphalangeal joint was found in only 2.3% and 4.7% in the right and left hand respectively, with positive power doppler signal in 2.3% of the patients in the same articulations.The overall agreement between US and clinical examination in detecting synovitis of wrist, MCP and PIP joints was of 67.3%. It was of 71.4% in wrists, 54.7% in MCP joints and 87% in PIP joints. This suggests the presence of infra-clinical synovitis. All sites combined, US synovitis were correlated to clinical synovitis (p=0.03).A positive correlation was found between PDUS from 6 simplified joint sites and CRP levels (p value of 0.02). No correlation was found with disease activity score (DAS28).Conclusion:US of hands and wrist articulations is more performant than clinical examination in detecting synovitis. The most frequently involved joints with clinical and US synovitis, pain and positive power doppler signal were the wrist joints. CRP level is predictive of the presence of a high simplified power doppler score which is related to clinical activity of the disease as reported by Kawashiri et al. [1].References:[1]Kawashiri S, Kawakami A, Iwamoto N, Fujikawa K, Satoh K, Tamai M, et al. The power Doppler ultrasonography score from 24 synovial sites or 6 simplified synovial sites, including the metacarpophalangeal joints, reflects the clinical disease activity and level of serum biomarkers in patients with rheumatoid arthritis. Rheumatology (Oxford). mai 2011;50(5):962-5.Disclosure of Interests:None declared

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DMSA-scintigraphy in paediatrics: Is the evaluation of the geometric mean necessary for the calculation of the differential renal function?

Nuklearmedizin ◽

10.1055/s-0038-1625921 ◽

2001 ◽

Vol 40 (04) ◽

pp. 107-110 ◽

Cited By ~ 1

Author(s):

B. Roßmüller ◽

S. Alalp ◽

S. Fischer ◽

S. Dresel ◽

K. Hahn ◽

...

Keyword(s):

Renal Function ◽

Geometric Mean ◽

Region Of Interest ◽

Posterior View ◽

Renal Abnormality ◽

Anterior View ◽

Differential Renal Function ◽

The Mean ◽

The Right ◽

To Receive

SummaryFor assessment of differential renal function (PF) by means of static renal scintigraphy with Tc-99m-dimer-captosuccinic acid (DMSA) the calculation of the geometric mean of counts from the anterior and posterior view is recommended. Aim of this retrospective study was to find out, if the anterior view is necessary to receive an accurate differential renal function by calculating the geometric mean compared to calculating PF using the counts of the posterior view only. Methods: 164 DMSA-scans of 151 children (86 f, 65 m) aged 16 d to 16 a (4.7 ± 3.9 a) were reviewed. The scans were performed using a dual head gamma camera (Picker Prism 2000 XP, low energy ultra high resolution collimator, matrix 256 x 256,300 kcts/view, Zoom: 1.6-2.0). Background corrected values from both kidneys anterior and posterior were obtained. Using region of interest technique PF was calculated using the counts of the dorsal view and compared with the calculated geometric mean [SQR(Ctsdors x Ctsventr]. Results: The differential function of the right kidney was significantly less when compared to the calculation of the geometric mean (p<0.01). The mean difference between the PFgeom and the PFdors was 1.5 ± 1.4%. A difference > 5% (5.0-9.5%) was obtained in only 6/164 scans (3.7%). Three of 6 patients presented with an underestimated PFdors due to dystopic kidneys on the left side in 2 patients and on the right side in one patient. The other 3 patients with a difference >5% did not show any renal abnormality. Conclusion: The calculation of the PF from the posterior view only will give an underestimated value of the right kidney compared to the calculation of the geometric mean. This effect is not relevant for the calculation of the differntial renal function in orthotopic kidneys, so that in these cases the anterior view is not necesssary. However, geometric mean calculation to obtain reliable values for differential renal function should be applied in cases with an obvious anatomical abnormality.

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Therapeutic Effects of Hab Shabyar on Open-Angle Glaucoma: A Double-Blinded, Randomized, Placebo-Controlled Trial

10.31661/gmj.v0i0.1218 ◽

2019 ◽

Vol 8 ◽

pp. 1218

Author(s):

Ebrahim Khalil BaniHabib ◽

Ali Mostafai ◽

Seyyed Mohammad Bagher Fazljou ◽

Ghadir Mohammdi

Keyword(s):

Placebo Group ◽

Intraocular Pressure ◽

Open Angle Glaucoma ◽

Controlled Trial ◽

Intervention Group ◽

Therapeutic Effects ◽

Open Angle ◽

The Mean ◽

The Right ◽

Double Blinded

Background: Open-angle glaucoma (OAG) is one of the leading causes of blindness worldwide. This study evaluates the therapeutic effects of hab shabyar in patients with open-angle glaucoma. Materials and Methods: In this clinical randomized controlled trial, 50 patients with OAG were randomized into two groups. The intervention group was received a drop of timolol plus 500 mg of hab shabyar every 12 hours. The placebo group was received a drop of timolol every 12 hours plus 500 mg of wheat germ as a placebo. The intraocular pressure in patients with OAG was measured in each group and compared at before the intervention (t1), one month (t2), and two months (t3) after the intervention. Results: The mean decrease in intraocular pressure for the right eye at three times in the intervention group was statistically significant, but the mean decrease in the placebo group was not significant. Similar results were obtained for the left eye at t1 when compared to t3. The patients in the intervention group expressed more satisfaction than the patients in the placebo group (P≤0.001). Conclusion: Our study demonstrated that consumption of timolol plus hab shabyar instead of consuming of timolol alone was probably more effective for reducing intraocular pressure in patients with OAG.[GMJ.2019;In press:e1218]

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Flow cytometric identification and isolation of hypertrophic type II pneumocytes after partial pneumonectomy

AJP Cell Physiology ◽

10.1152/ajpcell.1989.257.3.c528 ◽

1989 ◽

Vol 257 (3) ◽

pp. C528-C536 ◽

Cited By ~ 46

Author(s):

B. D. Uhal ◽

S. R. Rannels ◽

D. E. Rannels

Keyword(s):

Gradient Centrifugation ◽

Type Ii Cells ◽

Type Ii ◽

Acridine Orange Staining ◽

Flow Cytometric ◽

Percoll Density Gradient Centrifugation ◽

Type Ii Pneumocytes ◽

The Mean ◽

Cellular Dna ◽

The Right

Type II pneumocytes were isolated by either Percoll density gradient centrifugation or by immunoglobulin G (IgG) panning from the lungs of normal rats and the right lung of rats subjected to left pneumonectomy. Cells were studied at 7- (pnx-7) and 15- (pnx-15) days postoperative, times during and after, respectively, rapid compensatory growth of the right lung. Acridine orange staining permitted resolution of type II cells from contaminants on the basis of high red fluorescence (greater than 590 nm). Simultaneous measurement of forward-angle light scatter (FALS) suggested a shift of pnx-7 cells toward greater size, which was reversed in pnx-15 cells. By Percoll gradient isolation, approximately 15% of pnx-7 cells analyzed were above the mean FALS of control cells. In contrast, approximately 30% of the pnx-7 cells isolated by IgG panning were above the mean FALS of corresponding control cells. Biochemical analyses of pnx-7 cells separated by cell sorting into "high FALS" and "low FALS" subgroups revealed that high FALS type II cells contained 50% more protein (P less than 0.05) and 140% more RNA (P less than 0.01) than low FALS cells, with no significant change in cellular DNA content. These data are consistent with previous studies of type II cells isolated from the lungs of pneumonectomized animals and confirm the presence of hypertrophic cells in these preparations. They provide a foundation from which to design further flow cytometric studies of the role of hypertrophic type II pneumocytes in compensatory lung growth.

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Digit Variability in Carotenoid Scores Obtained with the Veggie Meter: A Pilot Study (P02-001-19)

Current Developments in Nutrition ◽

10.1093/cdn/nzz029.p02-001-19 ◽

2019 ◽

Vol 3 (Supplement_1) ◽

Author(s):

Velarie Ansu ◽

Stephanie Dickinson ◽

Alyce Fly

Keyword(s):

Indiana University ◽

Left Hand ◽

Funding Sources ◽

Right Hand ◽

Period Data ◽

The Mean ◽

The Right ◽

Post Hoc ◽

Main Effects ◽

Mean Square Errors

Abstract Objectives To determine which digit and hand have the highest and lowest skin carotenoid scores, to compare inter-and-intra-hand variability of digits, and to determine if results are consistent with another subject. Methods Two subjects’ first(F1), second(F2), third(F3) and fifth(F5) digits on both hands were measured for skin carotenoids with a Veggie Meter, for 3 times on each of 18 days over a 37-day period. Data were subjected to ANOVA in a factorial treatment design to determine main effects for hand (2 levels), digits (4), and days (18) along with interactions. Differences between digits were determined by Tukey's post hoc test. Results There were significant hand x digit, hand x day, digit x day, and hand x digit x day interactions and significant simple main effects for hand, digit, and day (all P < 0.001). Mean square errors were 143.67 and 195.62 for subject A and B, respectively, which were smaller than mean squares for all main effects and interactions. The mean scores ± SD for F1, F2, F3, and F5 digits for the right vs left hands for subject A were F1:357.13 ± 45.97 vs 363.74 ± 46.94, F2:403.17 ± 44.77 vs. 353.20 ± 44.13, F3:406.76 ± 43.10 vs. 357.11 ± 45.13, and F5:374.95 ± 53.00 vs. 377.90 ± 47.38. For subject B, the mean scores ± SD for digits for the right vs left hands were F1:294.72 ± 61.63 vs 280.71 ± 52.48, F2:285.85 ± 66.92 vs 252.67 ± 67.56, F3:268.56 ± 57.03 vs 283.22 ± 45.87, and F5:288.18 ± 34.46 vs 307.54 ± 40.04. The digits on the right hand of both subjects had higher carotenoid scores than those on the left hands, even though subjects had different dominant hands. Subject A had higher skin carotenoid scores on the F3 and F2 digits for the right hand and F5 on the left hand. Subject B had higher skin carotenoid scores on F5 (right) and F1 (left) digits. Conclusions The variability due to hand, digit, and day were all greater than that of the 3 replicates within the digit-day for both volunteers. This indicates that data were not completely random across the readings when remeasuring the same finger. Different fingers displayed higher carotenoid scores for each volunteer. There is a need to conduct a larger study with more subjects and a range of skin tones to determine whether the reliability of measurements among digits of both hands is similar across the population. Funding Sources Indiana University.

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