| 1. |
- Elcadi, Guilherme H., 1966-, et al.
(author)
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Oxygenation and Hemodynamics Do Not Underlie Early Muscle Fatigue for Patients with Work-Related Muscle Pain
- 2014
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In: PLOS ONE. - : PLOS (Public library of science). - 1932-6203. ; 9:4
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Journal article (peer-reviewed)abstract
- Patients suffering from work-related muscle pain (WRMP) fatigue earlier during exercise than healthy controls. Inadequate oxygen consumption and/ or inadequate blood supply can influence the ability of the muscles to withstand fatigue. However, it remains unknown if oxygenation and hemodynamics are associated with early fatigue in muscles of WRMP patients. In the present study we applied near-infrared spectroscopy (NIRS) on the extensor carpi radialis (ECR) and trapezius (TD) muscles of patients with WRMP (n = 18) and healthy controls (n = 17). Our objective was to determine if there were group differences in endurance times for a low-level contraction of 15% maximal voluntary contraction (MVC) -sustained for 12-13 min, and to see if these differences were associated with differences in muscle oxygenation and hemodynamics. At baseline, oxygen saturation (StO(2)%) was similar between groups for the ECR, but StO2% was significantly lower for TD for the WRMP patients (76%) compared to controls (85%) (P < 0.01). Also, baseline ECR blood flow was similar in the two groups. For both muscles there were a larger number of patients, compared to controls, that did not maintain the 15% MVC for the allotted time. Consequently, the endurance times were significantly shorter for the WRMP patients than controls (medians, ECR: 347 s vs. 582 s; TD: 430 s vs. 723 s respectively). Responses in StO(2)% during the contractions were not significantly different between groups for either muscle, i.e. no apparent difference in oxygen consumption. Overall, we interpret our findings to indicate that the early fatigue for our WRMP patients was not associated with muscle oxygenation and hemodynamics.
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| 2. |
- Elcadi, Guilherme H., 1966-, et al.
(author)
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Shoulder and forearm oxygenation and myoelectric activity in patients with work related muscle pain and healthy subjects
- 2013
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In: European Journal of Applied Physiology. - New York : Springer. - 1439-6319 .- 1439-6327. ; 113:5, s. 1103-1115
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Journal article (peer-reviewed)abstract
- We tested hypotheses of (i) reduced oxygen usage, oxygen recovery, blood flow and oxygen consumption; and (ii) increased muscle activity for patients diagnosed with work related muscle pain in comparison to healthy controls. Oxygenation was measured with near infrared spectroscopy (NIRS), and muscle activity with EMG for the extensor carpi radialis (ECR) and trapezius descendens (TD) muscles. Eighteen patients with diffuse neck-shoulder-arm pain and seventeen controls (matched in age and sex) were equipped with NIRS and EMG probes. After determining an individual’s maximum voluntary contraction (MVC) force, short term (20 sec) isometric contractions for the ECR and TD of 10%, 30%, 50% and 70% MVC generated ∆StO2% and StO2% recovery (Rslope) from NIRS, and RMS%max from EMG signals. In addition, upper arm venous (VO) and arterial (AO) occlusions generated slopes of total hemoglobin (HbTslope) and deoxyhemoglobin (HHbslope) for the resting ECR as surrogates of blood flow and oxygen consumption, respectively. Mixed Model analyses, t-tests, and Mann-Whitney test were used to assess differences between groups. There was no significant difference in MVC between groups for either muscle. Also, ∆StO2%, Rslope for either muscle, and ECR-HbTslope were not different between groups, thus our hypotheses of reduced oxygen use, recovery, and blood flow for patients were not confirmed. However, patients had a significantly lower ECR-HHbslope confirming our hypothesis of reduced consumption. Further, there was no difference in RMS%max during contractions meaning that the hypothesis of increased activity for patients was not confirmed. When taking into account the number of NIRS variables studied, differences we found between our patient group and healthy controls (i.e. in forearm oxygen consumption and shoulder oxygen saturation level) may be considered modest. Overall our findings may have been impacted by the fact that our patients and controls were similar in muscle strength, which is in contrast to previous studies.
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| 3. |
- Aasa, Björn, et al.
(author)
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Acuity of goal-directed arm movements and movement control : evaluation of differences between patients with persistent neck/shoulder pain and healthy controls
- 2022
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In: European Journal of Physiotherapy. - : Routledge. - 2167-9169 .- 2167-9177. ; 24:1, s. 47-55
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Journal article (peer-reviewed)abstract
- Background: The main aim was to examine whether patients with persistent upper quadrant pain have higher end-point variability in goal directed pointing movements than pain-free controls when the pointing task is performed in total darkness and under full vision. An additional aim was to study associations between the magnitude of end-point variability and a clinical movement control test battery and self-rated functioning among patients.Methods: Seventeen patients and 17 age- and gender-matched pain-free controls performed a pointing task that evaluated end-point variability of repetitive shoulder movements in horizontal adduction and abduction with full vision, and abduction with no visual information, completed a movement control test battery of neck and shoulder control tests and answered questionnaires.Results: Patients had higher end point variability for horizontal abduction when performed with no visual information. For horizontal adduction the variability was higher, but only when it was controlled for movement time. No significant correlations were found between end-point variability and self-rated functioning, nor between end-point variability and neuromuscular control of the glenohumeral joint.Conclusions: This study provides preliminary evidence that patients with persistent neck/shoulder pain can partly compensate proprioceptive deficits in goal-directed arm movement when visual feedback is present.
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| 4. |
- Aasa, Ulrika, et al.
(author)
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Relationships between work-related factors and disorders in the neck-shoulder and low-back region among female and male ambulance personnel.
- 2005
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In: Journal of Occupational Health. - : Wiley. - 1341-9145 .- 1348-9585. ; 47:6, s. 481-9
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Journal article (peer-reviewed)abstract
- This cross-sectional study on a random sample of 1,500 ambulance personnel investigated the relationships between self-reported work-related physical and psychosocial factors, worry about work conditions, and musculoskeletal disorders among female and male ambulance personnel. Three different outcomes, complaints, activity limitation, and sick leave, for the neck-shoulder and low-back region, respectively, were chosen. Among the female personnel, physical demands was significantly associated with activity limitation in the neck-shoulder (OR 4.13) and low-back region (OR 2.17), and psychological demands with neck-shoulder (OR 2.37) and low-back (OR 2.28) complaints. Among the male personnel, physical demands was significantly associated with low-back complaints (OR 1.41) and activity limitation (OR 1.62). Psychological demands and lack of social support were significantly associated with neck-shoulder complaints (OR 1.86 and OR 1.58, respectively) and activity limitation (OR 3.46 and OR 1.71) as well as activity limitation due to low-back complaints (OR 2.22 and OR 1.63). Worry about work conditions was independently associated with activity limitation due to low-back complaints among the female (OR 5.28), and to both neck-shoulder and low-back complaints (OR 1.79 and OR 2.04, respectively) and activity limitation (OR 2.32 and OR 1.95) among the male personnel. In conclusion, the association patterns between physical and psychological demands and MSDs suggest opportunities for intervention.
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| 5. |
- Aasa, Ulrika, et al.
(author)
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Stress monitoring of ambulance personnel during work and leisure time
- 2006
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In: International Archives of Occupational and Environmental Health. - : Springer Science and Business Media LLC. - 0340-0131 .- 1432-1246. ; 80:1, s. 51-59
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Journal article (peer-reviewed)abstract
- Objectives: The aim of the present study was to assess physiological and subjective stress markers during a 24-h ambulance work shift and during the next two work-free days, and relate these parameters to self-reported health complaints. Methods: Twenty-six ambulance personnel were followed during a 24-h work shift and during the next two work-free days with electrocardiogram, cortisol assessments and diary notes. The ambulance personnel also performed tests of autonomic reactivity before and at the end of the work shift. The subjects were categorized into two groups according to their number of health complaints. Results: In general, stress markers did not show differences between the work shift and leisure time. However, a modest deviation in heart rate variability pattern and higher morning cortisol values during work in comparison with work-free days were observed in personnel with many health complaints. Conclusions: Subjective and physiological characteristics of ambulance personnel did not indicate distinctive stress during the 24-h work shift. Relationships between frequent health complaints and specific work-related factors require further prospective studies.
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| 6. |
- Aasa, Ulrika, et al.
(author)
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The effects of a 1-year physical exercise programme on development of fatigue during a simulated ambulance work task.
- 2008
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In: Ergonomics. - : Informa UK Limited. - 0014-0139 .- 1366-5847. ; 51:8, s. 1179-94
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Journal article (peer-reviewed)abstract
- The aim of the study was to evaluate the effects of individually prescribed physical exercise programmes on development of fatigue during the carrying of a loaded stretcher up and down the stairs. Nineteen ambulance personnel performed the training for 1 year. Testing occurred before and after 1 year of the training. Both the training group (n = 19) and the control group (n = 15) were assessed for physical capacity and lactate concentration in blood and ratings of perceived exertion during carrying a stretcher on the stairs. When comparisons were made between those who had been training three times/week for 1 year and the control group, lactate concentration was significantly decreased. In conclusion, markers of fatigue during stretcher carrying can be reduced by the use of individually prescribed physical exercise programmes.
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| 7. |
- Aasa, Ulrika, et al.
(author)
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The impact of object size and precision demands on fatigue during computer mouse use
- 2011
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In: Advances in Physiotherapy. - : Informa UK Limited. - 1403-8196 .- 1651-1948. ; 13:3, s. 118-127
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Journal article (peer-reviewed)abstract
- Prolonged computer use, especially if fatigue ensues, is associated with visual and musculoskeletal symptoms. The aim was to determine the time-course of perceived fatigue in the wrist, forearm, shoulder and eyes during a 60-min mouse task (painting rectangles), and whether object size and/or mouse use demands were of infl uence. Also, we investigated performance (number of rectangles painted), and whether perceived fatigue was paralleled by local muscle fatigue or tissue oxygenation.Ten women performed the task for three conditions (crossover design). At condition 1, rectangles were 45 25 mm, square paint cursor size 1.3 1.3 mm, and mouse – pointer movement ratio 1:26. At condition 2, the same cursor size and mouse – pointer movement ratio was used, but rectangles were smaller. At condition 3, the smaller rectangles were used, but the cursor size was also smaller and mouse – pointer movement ratio was 1:8. The results showed increased self-reported fatigue over time, with the observed increase greater for the eyes, but no change in physiological responses. Condition 2 resulted in higher performance and increased eye fatigue. Perceived fatigue in the muscles or physiological responses did not differ between conditions. In conclusion, computer work tasks imposing high visual and motor demands, and with high performance, seemed to have an infl uence on eye fatigue.
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| 8. |
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| 9. |
- Barnekow-Bergkvist, Margareta, et al.
(author)
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Prediction of development of fatigue during a simulated ambulance work task from physical performance tests.
- 2004
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In: Ergonomics. - : Informa UK Limited. - 0014-0139 .- 1366-5847. ; 47:11, s. 1238-1250
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Journal article (peer-reviewed)abstract
- The aims of this study were (1) to identify which physical performance tests could best explain the development of fatigue during a simulated ambulance work task, (2) to investigate the effect of height and weight and (3) to investigate in what respects these findings differ between female and male ambulance personnel. Forty-eight male and 17 female ambulance personnel completed a test battery assessing cardio-respiratory capacity, muscular strength and endurance, and co-ordination. The subjects also completed a simulated ambulance work task -- carrying a loaded stretcher. The work task was evaluated by development of fatigue. Univariate and multiple regression analyses were used to investigate to what extent the tests in the test battery were able to explain the variance of developed fatigue. The explained variance was higher for female than for male ambulance personnel (time > 70% of HRpeak: R2 = 0.75 vs 0.10, accumulated lactate: R2 = 0.62 vs 0.42, perceived exertion: R2 = 0.75 vs 0.10). Significant predictors in the models were VO2max, isometric back endurance, one-leg rising, isokinetic knee flexion and shoulder extension strength. Height, but not weight, could further explain the variance. The high physical strain during carrying the loaded stretcher implies the importance of investigating whether improved performance, matching the occupational demands, could decrease the development of fatigue during strenuous tasks.
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