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Merryweather AS, Morse JM, Doig AK, Godfrey NW, Gervais P, Bloswick DS. Effects of bed height on the biomechanics of hospital bed entry and egress. Work 2015; 52:707-13. [DOI: 10.3233/wor-152110] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
| | - Janice M. Morse
- College of Nursing, University of Utah, Salt Lake City, UT, USA
| | - Alexa K. Doig
- College of Nursing, University of Utah, Salt Lake City, UT, USA
| | - Nathan W. Godfrey
- Department of Mechanical Engineering, University of Utah, Salt Lake City, UT, USA
| | - Pierre Gervais
- Faculty of Physical Education and Recreation, University of Alberta, Edmonton, Alberta, Canada
| | - Donald S. Bloswick
- Department of Mechanical Engineering, University of Utah, Salt Lake City, UT, USA
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Drinkaus P, Bloswick DS, Sesek R, Mann C, Bernard T. Job Level Risk Assessment Using Task Level Strain Index Scores: A Pilot Study. International Journal of Occupational Safety and Ergonomics 2015; 11:141-52. [PMID: 15938764 DOI: 10.1080/10803548.2005.11076643] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
This paper explores 2 methods of modifying the Strain Index (SI) to assess the ergonomic risk of multi-task jobs. Twenty-eight automotive jobs (15 cases and 13 controls) were studied. The first method is based on the maximum task SI score, and the second method is modeled on the NIOSH Composite Lifting Index (CLI) algorithm, named cumulative assessment of risk to the distal upper extremity (CARD). Significant odds ratios of 11 (CI 1.7-69) and 24 (CI 2.4-240) were obtained using the modified maximum task and CARD, respectively. This indicates that modification of the SI may be useful in determining the risk of distal upper extremity injury associated with a multi-task job.
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Affiliation(s)
- Phillip Drinkaus
- Department of Mechanical Engineering, University of Utah, Salt Lake City, UT, USA.
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Drinkaus P, Sesek R, Bloswick DS, Mann C, Bernard T. Job Level Risk Assessment Using Task Level ACGIH Hand Activity Level TLV Scores: A Pilot Study. International Journal of Occupational Safety and Ergonomics 2015; 11:263-81. [PMID: 16219155 DOI: 10.1080/10803548.2005.11076648] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Existing upper extremity musculoskeletal disorder analytical tools are primarily intended for single or mono-task jobs. However, many jobs contain more than 1 task and some include job rotation. This case/control study investigates methods of modifying an existing tool, the American Conference of Governmental Industrial Hygienists (ACGIH) Hand Activity Level (HAL) Threshold Limit Value (TLV), to assess the upper extremity risk of multi-task jobs. Various methods of combining the task differences and ratios into a job level assessment were explored. Two methods returned significant odds ratios, (p < .05) of 18.0 (95% CI 1.8-172) and 12.0 (95% CI 1.2-120). These results indicate that a modified ACGIH HAL TLV may provide insight into the work-related risk of multi-task jobs. Further research is needed to optimize this process.
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Affiliation(s)
- Phillip Drinkaus
- Department of Mechanical Engineering, Ergonomics and Safety Program, University of Utah, Salt Lake City, UT 84112-9208, USA.
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Tung KD, Shorti RM, Downey EC, Bloswick DS, Merryweather AS. The effect of ergonomic laparoscopic tool handle design on performance and efficiency. Surg Endosc 2014; 29:2500-5. [PMID: 25537377 DOI: 10.1007/s00464-014-4005-9] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2014] [Accepted: 10/25/2014] [Indexed: 11/25/2022]
Abstract
BACKGROUND Many factors can affect a surgeon's performance in the operating room; these may include surgeon comfort, ergonomics of tool handle design, and fatigue. A laparoscopic tool handle designed with ergonomic considerations (pistol grip) was tested against a current market tool with a traditional pinch grip handle. The goal of this study is to quantify the impact ergonomic design considerations which have on surgeon performance. We hypothesized that there will be measurable differences between the efficiency while performing FLS surgical trainer tasks when using both tool handle designs in three categories: time to completion, technical skill, and subjective user ratings. METHODS The pistol grip incorporates an ergonomic interface intended to reduce contact stress points on the hand and fingers, promote a more neutral operating wrist posture, and reduce hand tremor and fatigue. The traditional pinch grip is a laparoscopic tool developed by Stryker Inc. widely used during minimal invasive surgery. Twenty-three (13 M, 10 F) participants with no existing upper extremity musculoskeletal disorders or experience performing laparoscopic procedures were selected to perform in this study. During a training session prior to testing, participants performed practice trials in a SAGES FLS trainer with both tools. During data collection, participants performed three evaluation tasks using both handle designs (order was randomized, and each trial completed three times). The tasks consisted of FLS peg transfer, cutting, and suturing tasks. RESULTS Feedback from test participants indicated that they significantly preferred the ergonomic pistol grip in every category (p < 0.05); most notably, participants experienced greater degrees of discomfort in their hands after using the pinch grip tool. Furthermore, participants completed cutting and peg transfer tasks in a shorter time duration (p < 0.05) with the pistol grip than with the pinch grip design; there was no significant difference between completion times for the suturing task. Finally, there was no significant interaction between tool type and errors made during trials. CONCLUSIONS There was a significant preference for as well as lower pain experienced during use of the pistol grip tool as seen from the survey feedback. Both evaluation tasks (cutting and peg transfer) were also completed significantly faster with the pistol grip tool. Finally, due to the high degree of variability in the error data, it was not possible to draw any meaningful conclusions about the effect of tool design on the number or degree of errors made.
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Affiliation(s)
- Kryztopher D Tung
- Mechanical Engineering Department, University of Utah, Salt Lake City, USA,
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5
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Bloswick DS, Dzugan J. Development of an Ergonomics Training Program for the Commercial Fishing Industry: Charges, Challenges and Changes. J Agromedicine 2014. [DOI: 10.1080/1059924x.2014.889626] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Merryweather AS, Loertscher MC, Bloswick DS. A revised back compressive force estimation model for ergonomic evaluation of lifting tasks. Work 2009; 34:263-72. [PMID: 20037241 DOI: 10.3233/wor-2009-0924] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Sesek R, Drinkaus P, Khalighi M, Tuckett RP, Bloswick DS. Development of a carpal tunnel syndrome screening method using structured interviews and vibrotactile testing. Work 2008; 30:403-411. [PMID: 18725703] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/26/2023] Open
Abstract
Carpal tunnel syndrome (CTS) is a debilitating and expensive health problem. An inexpensive screening method that would differentiate between people who do not have CTS and those that may have CTS would be useful. The screening methodology investigated here had two phases: a structured interview and provocative vibrotactile testing (VT). The control group (n = 36) was composed of asymptomatic college students and faculty, the case group was composed of patients currently visiting an occupational medicine clinic for symptoms consistent with CTS. The case group was subdivided into positive and negative for nerve conduction latency, NCL+ (n = 21) and NCL- (n = 13), respectively. Using a scored, structured interview, 33 of the controls and none of the symptomatic cases were identified as non-CTS. The results from the provocative flexion VT indicated that if the difference between the age corrected baseline and the threshold at 15 minutes is 15 microm or more, the subject was likely to be NCL+ (odds ratio 12.6, 95% CI 3.8 to 41.8). Further research may improve this screening methodology to not only determine whether or not a person has CTS, but also to determine the level of median nerve impingement or damage.
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Affiliation(s)
- Richard Sesek
- University of Utah, Salt Lake City, UT 84112-9208, USA.
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9
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Sesek RF, Khalighi M, Bloswick DS, Anderson M, Tuckett RP. Effects of prolonged wrist flexion on transmission of sensory information in carpal tunnel syndrome. J Pain 2006; 8:137-51. [PMID: 16949877 DOI: 10.1016/j.jpain.2006.06.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2006] [Revised: 06/26/2006] [Accepted: 06/30/2006] [Indexed: 01/18/2023]
Abstract
UNLABELLED Carpal tunnel syndrome presents a constellation of symptoms which include discomfort (eg, pain, paraesthesia) and diminished sense of touch. This exploratory study simultaneously measured changes in tactile threshold and discomfort ratings during prolonged wrist flexion in symptomatic patients from a rehabilitation clinic and from a control population. Prolonged (15 min) wrist flexion significantly increased tactile threshold and discomfort ratings above baseline levels in both symptomatic and control populations. Sixty-two percent of the symptomatic sample was found to have abnormal conduction latency. Tactile threshold in symptomatic subjects with normal conduction latency (n = 13) did not differ significantly from control subjects (n = 36) at baseline but showed significant elevation during wrist flexion. In contrast, subjects with abnormal conduction latency (n = 21) exhibited significant elevation relative to control subjects at baseline and throughout wrist flexion as well as a slower recovery after flexion. Conduction latency correlated with baseline (r = .52, P < .0001) and 15-min (r = .67, P < .0001) tactile threshold for the entire subject population, as well as 15-min threshold (r = .53, P = .013) for the subpopulation with abnormal conduction latency. At 2.5 min after flexion, correlation was significant for whole (r = .64, P < .0001) and abnormal conduction latency (r = .58, P = .0063) samples. Regression slope of tactile threshold versus conduction latency was significantly greater than zero and did not differ significantly from linearity. The study demonstrates that increases in mechanosensory threshold and discomfort ratings during prolonged wrist flexion are more profound (and recovery less rapid) in patients with electrophysiologic evidence of injury. PERSPECTIVE This study demonstrates a provocative procedure that enhances the symptoms of carpal tunnel syndrome. This measure may help clinicians discriminate median nerve compression from other types of peripheral nerve injury and help researchers investigate the impact of mechanical stress, tissue compression, and vascular stasis on compression-related neuropathy.
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Affiliation(s)
- Richard F Sesek
- Department of Mechanical Engineering, University of Utah, Salt Lake City, Utah, USA
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10
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Coakwell MR, Bloswick DS, Moser R. High-risk head and neck movements at high G and interventions to reduce associated neck injury. Aviat Space Environ Med 2004; 75:68-80. [PMID: 14736136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 04/28/2023]
Abstract
BACKGROUND Neck injuries are a significant concern for aviators of high performance aircraft. A recent comprehensive technical report on cervical spinal injury associated with exposure to sustained acceleration, from NATO's Research and Technology Organization, recommended delineating the neck muscles used by aviators in this flying environment and developing improved neck muscle strengthening programs in an attempt to reduce such injuries. METHODS A review of current literature was conducted in the fields of biomechanics, ergonomics, orthopedics, neurology, neurosurgery, rehabilitative medicine, and aerospace medicine. An objective description is provided of the muscles involved in specific head and neck movements, and those movements that are associated with a greater risk of injury during high-G sorties. The intensity and duration of force exposures common to high performance aircraft sorties, the effects of seat-back angle on these exposures, and the types and mechanisms of neck injury reported in this environment are also described. RESULTS Primary, secondary, and tertiary preventive interventions are introduced with the goal of providing unit-level flight surgeons an approach to reducing neck injury and promoting prompt, safe return to flying of aviators with identified neck injury. A central component of these interventions is a "specific" and "intensive" neck muscle training regimen, as described in the medical literature. CONCLUSION Increased axial compressive force and unique biomechanics combine to make neck injury likely in high performance aviators. The application of some proposed intervention strategies may reduce the occurrence of these injuries.
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Affiliation(s)
- Mark R Coakwell
- US Air Force School of Aerospace Medicine, Brooks AFB, TX, USA.
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Abstract
This study investigated the ability of the Revised NIOSH Lifting Equation (RNLE) to measure the risk of low back injury as verified by employee health outcomes. In addition, several basic risk factors and combinations of risk factors presumed related to low back disorders were explored. The RNLE was modified to allow analysis of one-handed and two-handed, asymmetric lifts. Predictive performance was not changed. Simplifying the RNLE by removing several variables did not significantly reduce the RNLE's predictive performance. These modifications to the RNLE show promise for increasing both the usability and utility of the RNLE.
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Affiliation(s)
- Richard Sesek
- Department of Mechanical Engineering, University of Utah, Salt Lake City, UT 84112-9208, USA.
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Lyon JL, Lillquist DR, Alder S, Stephenson D, Bloswick DS. An analysis of VDT monitor placement and daily hours of use for female bifocal users. Work 2003; 20:77-80. [PMID: 12632005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/01/2023] Open
Abstract
A population of 72 bifocal wearers was studied to determine the relationship between VDT (video display terminal) placement for those who reported musculoskeletal pain and those who did not. The mean hours worked was 50.4 minutes (p=0.003) greater for those who reported head/neck pain versus those who did not and 48.6 minutes (p=0.004) greater for those who reported shoulder/arm pain that those who did not. There was no statistically significant difference between the means of monitor height, distance, or angle for those who reported pain symptoms versus those who did not. This study indicates that, self reported pain symptoms are correlated with hours of VDT work and that there appears to be a threshold at approximately five hours for pain symptoms among bifocal wearers. No such correlation can be made for monitor placement
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Affiliation(s)
- Joseph L Lyon
- Rocky Mountain Center for Occupational and Environmental Health, Department of Family and Preventive Medicine, Salt Lake City, Utah 84112-5120, USA
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Abstract
PURPOSE The purpose of this study was to evaluate the maneuverability and usability of three knee-extension propelled wheelchairs. METHOD The maneuverability of the knee-extension propelled wheelchairs was determined in a controlled test representing five standard wheelchair activities. The usability of the wheelchairs was evaluated in a field test with elderly residents of an extended care facility in Salt Lake City. RESULTS The results indicate that the wheelchair designs using a swinging (four-bar linkage) or sliding belt mechanism are preferred to a sliding plate design. CONCLUSIONS The use of knee-extension propelled wheelchairs is a feasible alternative to hand propelled wheelchairs. Further development and research is needed to address power requirements, maneuverability, and entrance/egress from the chairs.
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Silvia CE, Bloswick DS, Lillquist D, Wallace D, Perkins MS. An ergonomic comparison between mechanical and manual patient transfer techniques. Work 2003; 19:19-34. [PMID: 12454348] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/27/2023] Open
Abstract
Multiple studies have concluded that manual patient transfer and repositioning techniques are a significant cause of low back injuries. The objective of this study was to compare the low back stresses resulting from the use of two different mechanical patient transfer assist devices with the use of traditional manual transfer techniques. The mechanical transfer systems used were the Barton Patient Transfer System and a Sling-Suspension Lift similar to a "Hoyer Lift". The back compressive forces derived using the Michigan 3D Static Strength Model (Version 4.0) and electromyography (EMG) of the muscles of the low back were compared. This study found that the mechanical assist devices placed less stress on the low back and were more desirable to use than the traditional manual techniques. The Barton System was found to be, in general, less hazardous and more preferred than the Sling Suspension Lift.
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Abstract
Although the bag of the home care nurse is functional and historical, there is limited information in the literature about its use and nurses' preferences. This study analyzes how the bag is used, and examines comfort issues and preferences nurses have for this valuable tool. Implications for design and features are gained from this research as well as specific features to seek when choosing this important ergonomic tool.
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Abstract
Previous optimization techniques for the prediction of lifting motion patterns often require a change in either the number of variables or the order of the mathematical functions used to express the angular displacement of selected joints in response to change in variant conditions. The resolution of predicted results can also be seriously constrained by the number of variables used. These restrictions may often limit the applicability of these methodologies. In this paper, we proposed a new methodology for generating the optimum motion patterns for para-sagittal lifting tasks. A detailed description of this methodology is introduced. An example of an analysis using this methodology is presented. The computer program generated lifting motion patterns with a reduction of the overall objective function values. The actual versus predicted lifting motion patterns are compared. Using this method, constraints can be added anywhere within the lifting cycle without the need of rewriting the whole program. These features provide for a more flexible and efficient prediction of the lifting motion.
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Affiliation(s)
- C C Chang
- Liberty Mutual Research Center for Safety and Health, 71 Frankland Road, Hopkinton, MA 01748, USA.
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Abstract
The design and testing of a modified tricycle (hip extensor tricycle) designed to isolate and exercise the hip extensor muscles in children with cerebral palsy is presented. Initial laboratory tests involved stability evaluation and EMG studies of two normal children. Field evaluation involved five children diagnosed with cerebral palsy who were given hip extensor tricycles for home use during an 8-week test period. The hip extensor strength and gait pattern of the subjects were recorded at 2-week intervals. The clinical tests indicated that the hip extensor tricycle was more stable, and resulted in more hip extensor muscle activity, than the traditional therapeutic/exercise tricycle. A panel of experts judged that the gait patterns of four of the five subjects improved during the course of the study. Parent evaluations indicated that the use of the hip extensor tricycle improved the subjects' physical condition, coordination, sense of accomplishment, and self-esteem.
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Affiliation(s)
- D S Bloswick
- Department of Mechanical Engineering, University of Utah, Salt Lake City 84112, USA
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Perkins MS, Bloswick DS. The Use of Back Belts to Increase Intraabdominal Pressure as a Means of Preventing Low Back Injuries: A Survey of the Literature. Int J Occup Environ Health 1995; 1:326-335. [PMID: 9990171 DOI: 10.1179/oeh.1995.1.4.326] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
Published reports of relevant empirical research do not suggest a consistent relationship between intraabdominal pressure and the activity of the erector spinae muscles or the magnitude of the intradiscal pressure during lifting. Intraabdominal pressure varies in response to load magnitude and lift method, but there is no pattern of activity that would suggest that an increase in intraabdominal pressure decreases intradiscal pressure. Early models of back biomechanics predicted that the increase in intraabdominal pressure relieved the compressive forces on the low back by providing an extensor moment. In the newer models, intraabdominal pressure functions to stabilize the loaded spine. Studies of human subjects fail to consistently show any clear biomechanical advantage from using a back belt. Some studies suggest a slight decrease in back injury incidence when using a back belt; however, there are conflicting results regarding the severity of the injuries involved and the cost-effectiveness of back belts.
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Affiliation(s)
- MS Perkins
- Center for Occupational and Environmental Health, University of California, Irvine, 19722 MacArthur Boulevard, Irvine, CA 92715, USA
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Smutz WP, France EP, Bloswick DS. Measurement of creep strain of flexor tendons during low-force high-frequency activities such as computer keyboard use. Clin Biomech (Bristol, Avon) 1995; 10:67-72. [PMID: 11415533 DOI: 10.1016/0268-0033(95)92041-j] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/08/1993] [Accepted: 05/23/1994] [Indexed: 02/07/2023]
Abstract
The aim of this study was to measure tendon strain during low-force, high-frequency activities such as computer keyboard use. Prior to creep strain testing an estimate of flexor tendon force during keyboard use was made. Tendon force was measured indirectly by comparing electromyographic activity of the flexor and extensor digitorum muscles in five human volunteers for various hand activities. Results of the electromyographic study showed that flexor tendon forces during keyboard use may be as high as 60 N. Sixty eight flexor digitorum tendons from 17 fresh-frozen cadaver hands were used for the creep strain tests. Three loading conditions (static, 1 Hz cyclic, (1/4) Hz cyclic) and four load levels (10, 20, 50, 100 N) were used. Results of the creep study showed that for a flexor tendon force of 60 N the total strain of the tendon would be approximately 1.8%. This does not appear to be enough strain to cause permanent damage to the tendon according to current cumulative strain models. RELEVANCE: Recent studies have shown an increase in hand and wrist tendinitis among computer users. At the present time the aetiology is unknown, but risk factors commonly associated with tendinitis are hand forces, wrist postures, and frequency of finger movements. This research looks at tendon creep due to repeated force as a possible aetiology.
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Affiliation(s)
- W P Smutz
- Orthopedic Biomechanics Institute, Salt Lake City, Utah, USA
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Abstract
The need for an alternative mailbag to the conventional U.S. postal mailbag, which hangs at the side over one shoulder, was investigated. Based on the results of a pilot study, two types of alternative mailbags, both including waist support and one that splits the load into two parts, are recommended. The metabolic energy requirement and lateral trunk muscle fatigue resulting from the use of the alternative mailbags were compared with those resulting from the conventional U.S. postal mailbag. The alternative mailbags resulted in no significant change in metabolic load. Both alternative mailbags resulted in significantly less lateral trunk muscle fatigue. It is proposed that this reduction in fatigue would result in reduced musculoskeletal stress and reduced potential for back injury.
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Affiliation(s)
- D S Bloswick
- Department of Mechanical Engineering, University of Utah, Salt Lake City 84112
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Johns RE, Bloswick DS, Elegante JM, Colledge AL. Chronic, recurrent low back pain. A methodology for analyzing fitness for duty and managing risk under the Americans with Disabilities Act. J Occup Med 1994; 36:537-47. [PMID: 8027879] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Chronic, recurrent low back pain, although one of the most commonly encountered medical conditions in the workplace, is one of the most difficult to manage. With the passage of the Americans with Disabilities Act, the proper management of the worker with recurrent low back pain poses an even greater challenge. We propose an interdisciplinary methodology to evaluate the worker at high medical risk of recurrent low back pain and determine the potential ergonomic risks of essential function tasks in material-handling work. The proposal considers the ethical and legal liabilities of risk assessment and fitness for duty evaluation that physicians, ergonomists, attorneys, and ultimately business managers and supervisors experience in balancing the societal interests represented by the Americans with Disabilities Act.
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Affiliation(s)
- R E Johns
- Hercules Aerospace Company, Bacchus Works, Magna, Utah 84404-0098
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Smutz WP, Miller SC, Eaton CJ, Bloswick DS, France EP. Investigation of low-force high-frequency activities on the development of carpal-tunnel syndrome. Clin Biomech (Bristol, Avon) 1994; 9:15-20. [PMID: 23916073 DOI: 10.1016/0268-0033(94)90053-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/27/1992] [Accepted: 11/26/1992] [Indexed: 02/07/2023]
Abstract
The objective of this study was to determine the effects of repetitive motion on the flexor tendons and synovium in the carpal tunnel. One possible mechanism of tendon damage is fraying of the tendons as they slide past each other in the carpal tunnel. Increases in tendon friction were measured in human cadaver arms. The flexor tendons were loaded using pneumatic cylinders while load cells were used to measure tendon force both distal and proximal to the carpal tunnel. Results showed that tendon force distal to the carpal tunnel decreased by over 10% after 6 h, while tendon force proximal to the carpal tunnel remained constant. Two rhesus monkeys were used to further study the effects of repetitive motion. One arm of each animal was subjected to 729000 repetitive cycles over a 3-week period. Results of the animal study showed that highly repetitive motions encountered over a relatively short period of time had little effect on the tissue in and around the carpal tunnel.
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Affiliation(s)
- W P Smutz
- Orthopedic Biomechanics Institute, Salt Lake City, USA
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Bloswick DS, King EM, Brown D, Gooch JR, Peters M. Evaluation of a device to exercise hip extensor muscles in children with cerebral palsy: a clinical and field study. Assist Technol 1993; 6:147-51. [PMID: 10150742 DOI: 10.1080/10400435.1994.10132239] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
Abstract
This research includes the effectiveness of a tricycle (hip extensor tricycle) designed to isolate and exercise the hip extensor muscles in children with cerebral palsy. Five children diagnosed with cerebral palsy were given hip extensor tricycles for home use during an 8-week test period. The hip extensor strength and gait pattern of the subjects were recorded at 2-week intervals. Additional recorded information included the time and duration of subject use and a parent evaluation that noted subjective physical and psychological improvements. A panel of experts judged that the gait patterns of four subjects improved during the course of the study. There was an assignable cause for the lack of improvement in the fifth subject. The results of the strength testing were found to be inconclusive. The subjects used the device on a regular basis and enjoyed doing so. Parent evaluations indicated that the use of the hip extensor tricycle improved the subjects' physical condition, coordination, sense of accomplishment, and self esteem. It is recommended that future research implement a longer test period along with improved hip extensor strength measurement methods and focus on improvements in evaluation of gait and physical condition.
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Affiliation(s)
- D S Bloswick
- Department of Mechanical Engineering, Rocky Mountain Center for Occupational and Environmental Health, University of Utah, Salt Lake City, USA
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Abstract
Weakness of the hip extensor muscles contributes to the walking impairment of children with cerebral palsy, but it is difficult to strengthen these muscles. This study demonstrates greater activation of the hip extensor muscles when using a tricycle developed for this purpose than when using a traditional tricycle. The hip-extensor tricycle was also found to be more stable than a traditional tricycle. A 10-week field trial of the hip-extensor tricycle showed that visually analysed gait improved, but hip extensor strength did not. However, children used and enjoyed the tricycle, and parental reports were positive. This tricycle could be used to supplement other means of improving gait in children with CP.
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Affiliation(s)
- E M King
- Department of Physical Medicine and Rehabilitation, University Medical Center, Salt Lake City, Utah 84132
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Abstract
Children with cerebral palsy (CP) often have weak hip extensor muscles and gait-related difficulties. Current therapeutic techniques do not provide sufficient exercise for this muscle group. In addition to calisthenics, therapists use a traditional tricycle to strengthen leg muscles, yet the mechanics of traditional tricycles are not effective in exercising hip extensor muscles. A new therapeutic tricycle was designed specifically to exercise the hip extensor muscles, and tests compared the traditional tricycle to the new hip extensor tricycle in effectiveness of promoting hip extensor activity in two subjects without CP. The tests demonstrated that the hip extensor tricycle was more effective in promoting hip extensor activity. Tests are underway to investigate the effect of the hip extensor tricycle in improving hip extensor strength and gait in patients with cerebral palsy. This paper describes the design of the hip extensor tricycle and a preliminary investigation of its effectiveness.
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Affiliation(s)
- G H Howell
- Department of Mechanical Engineering, University of Utah
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Moser R, Meservy D, Lee JS, Johns RE, Bloswick DS. Education in management aspects of occupational and environmental health and safety programs. J Occup Med 1989; 31:251-6. [PMID: 2918409 DOI: 10.1097/00043764-198903000-00011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
- R Moser
- Rocky Mountain Center for Occupational and Environmental Health, University of Utah, Salt Lake City 84112
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Chaffin DB, Andersson GB, Page GB, Bloswick DS. Low-back muscle models—A sensitivity analysis. J Biomech 1986. [DOI: 10.1016/0021-9290(86)90041-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Abstract
This study explores the feasibility of using the static strength and endurance relationships suggested by Rohmert in 1960 to predict pursuit tracking performance, Ten male subjects are tested on a pursuit rotor before and after being subjected to specific levels of loading on a grip holding device. The loading corresponded to specific levels of each subject's maximum endurance as determined from Rohmert's strength and endurance equation. The hypotheses are: (a) predetermined schedules of strength expenditure cause a systematic decrement in tracking efficiency; and (b) the process of recovering efficiency is dependent upon the expenditure schedules. Resulting data support these hypotheses, suggesting that tracking efficiency can be reliably predicted using some of the strength and endurance relationships postulated by Rohmert.
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Affiliation(s)
- D S Bloswick
- a Picatinny Arsenal , Dover , Now Jersey , U.S.A
| | - N C Ellis
- b Department of Industrial Engineering , Texas A and M University , Bryan , Texas , 77843 , U.S.A
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