| 1. |
- Aasa, Ulrika
(författare)
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Ambulance Work : Relationships between occupational demands, individual characteristics and health-related outcomes
- 2005
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Although musculoskeletal disorders (MSDs) and other health complaints are an occupational problem for ambulance personnel, there is a lack of knowledge regarding work-related factors associated with MSDs and other health complaints. The overall aim of this thesis was to investigate the relationships between occupational demands, individual characteristics and health-related outcomes among ambulance personnel. A random sample of 234 female and 953 male ambulance personnel participated in a national questionnaire survey on work-related factors, and musculoskeletal and other health complaints. Physical demands was associated with activity limitation due to neck-shoulder and low-back complaints among the female personnel. Among the male personnel, physical demands was associated with low-back complaints and activity limitation due to low-back complaints. Psychological demands was significantly associated with neck-shoulder complaints, sleeping problems, headache and stomach symptoms among both female and male ambulance personnel. Worry about work conditions was associated with musculoskeletal disorders and sleeping problems, headache and stomach symptoms. A local sample of 26 ambulance personnel was followed during a 24-hour work shift and for the next two work-free days. Subjective stress- and energy levels, and cortisol levels were measured at regular intervals, and heart rate was registered continuously by electrocardiogram (ECG). Autonomic reactivity to standardized tests before (pre-work) and at the end of the work shift (post-work) was also investigated. For the whole group, baseline values of heart rate were higher pre-work than post-work, but autonomic reactivity did not differ. Increased reactivity to the mental test, modest deviation in heart rate variability (HRV) pattern during the late night hours at work and higher morning cortisol values during work than during leisure time were observed in personnel with many health complaints, but not among their co-workers without or with few complaints. Ambulance personnel with many health complaints also reported higher psychological demands and tended to be more worried about work conditions. Heart rate (HR), lactate level (LL) and perceived exertion (RPE) were investigated in 17 female and 48 male ambulance personnel during a simulated standardized work task “carry a loaded stretcher”. The ambulance personnel had to carry the loaded stretcher (920 N) up and down three flights of stairs twice. The high physiological strain (HR, LL, RPE) for the male, and near or at maximal strain for the female ambulance personnel, implied the importance to identify what kind of physical capacity is most important for ambulance personnel. Therefore, the explained variance of developed fatigue by tests of cardiorespiratory capacity, muscular strength and endurance, and coordination was investigated. The results showed that VO2max and isometric back endurance were important predictors for development of fatigue when carrying a loaded stretcher. The influence of body size on the relationships between maximal strength and functional performance was investigated in a methodological study. The results confirm that the assessment of physical performance could be confounded by the body weight. Therefore, the models for explaining development of fatigue when carrying the loaded stretcher were adjusted for height and weight. Including height in the models significantly increased the explained variance of accumulated lactate among female, but not among male personnel. Lactate levels were higher among short compared to tall female personnel. Weight had no effect on any of the models. In conclusion, the national survey showed that self-reported physical demands was a risk factor of having MSDs, and that self-reported psychological demands and worry about work were important risk factors of having MSDs and other health complaints. Stress monitoring of ambulance personnel during work and leisure time showed that physiological and subjective stress markers did not show any differences between the 24-hour ambulance work shift and leisure time afterwards. However, ambulance personnel with many health complaints had certain physiological changes during the work shift in comparison with the next two work-free days. The physiological and subjective responses during carrying a loaded stretcher, especially among the female ambulance personnel, showed that female and male ambulance personnel could be exposed to internal exposures at different levels when performing the same work task. A better understanding of the relationships between occupational demands and health-related outcomes require further studies on age- and gender matched groups in long-term perspective studies.
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| 2. |
- Berglund, Lars, 1986-
(författare)
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Deadlift training for patients with mechanical low back pain : a comparison of the effects of a high-load lifting exercise and individualized low-load motor control exercises
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Disability due to low back pain is common. While evidence exist that exercise is effective in reducing pain and disability, it is still largely undetermined which kind of exercises that are most effective. The overall aim of this thesis was to evaluate and compare the effects of a high-load lifting exercise and individualized low-load motor control exercises for patients with nociceptive mechanical low back pain. A secondary aim was to evaluate which patients benefit from training with a high-load lifting exercise.All four papers in this thesis were based on a randomized controlled trial including 70 participants with nociceptive mechanical low back pain as their dominating pain pattern. Participants were randomized into training with either a high-load lifting exercise (HLL), the deadlift, (n=35) or individualized low-load motor control exercises (LMC) (n=35). Both interventions included aspects of pain education. All participants were offered twelve sessions during an eight week period. The effects of the interventions were evaluated directly after and twelve months after the end of the intervention period. Outcome measures were pain intensity, activity, disability, physical performance, lumbo-pelvic alignment and lumbar multifidus muscle thickness.There was a significant between-group effect in favour of the LMC intervention regarding improvements in activity, movement control tests and some tests of trunk muscle endurance. For pain intensity there were no significant differences between groups. A majority of participants in both intervention groups showed clinically meaningful improvements from baseline to two and twelve month follow-up regarding pain intensity and activity. There were no significant differences between HLL and LMC regarding the effect on lumbo-pelvic alignment or lumbar multifidus thickness. The participants who benefit the most from the HLL intervention were those with a low pain intensity and high performance in the Biering-Sørensen test at baseline.The results of this thesis showed that the HLL intervention was not more effective than the LMC intervention. The LMC was in fact more effective in improving activity, performance in movement control tests and some tests of trunk muscle endurance, compared to the HLL intervention.The results imply that the deadlift, when combined with education, could be considered as an exercise to produce clinically relevant improvements on pain intensity in patients who prefer a high-load exercise. However, before considering deadlift training, the results suggest that pain intensity and performance in the Biering-Sørensen test should be evaluated.
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