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Sökning: WFRF:(Sojka Peter)

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  • Nilsson Sojka, Birgitta, et al. (författare)
  • The blood donation experience : self-reported motives and obstacles for donating blood
  • 2008
  • Ingår i: Vox Sanguinis. - Oxon : Blackwell Publishing. - 0042-9007 .- 1423-0410. ; 94:1, s. 56-63
  • Tidskriftsartikel (refereegranskat)abstract
    • Background and Objectives The aim of the study was to investigate motives for donating blood as well as difficulties and obstacles associated with blood donation as perceived by the donors themselves.Materials and Methods Six hundred consecutive blood donors (i.e. all blood donors with a history of at least one previous whole blood donation attending, during nine working days, the Blood Centre of Umea University Hospital) received a self-administered questionnaire that contained questions aimed at elucidating motives for donating blood (general motives for donating blood, specific motives for the first donation and motives for continuing to be an active blood donor). Questions concerning difficulties and obstacles that had to be overcome in order to continue being a blood donor were also included in the questionnaire.Results Altogether 531 whole blood donors filled in the questionnaire (88.5%; 322 men and 209 women). No statistically significant differences were found between male and female blood donors concerning general reasons and motives related to donating blood. The most frequently reported reasons for giving blood the first time were 'influence from a friend' (47.2% of donors) and 'request via media' (23.5% of donors). Among general reasons/motives with highest ranking of importance, the most commonly reported motive for donating blood were 'general altruism' (40.3%), 'social responsibility/obligation' (19.7%) and 'influence from friends' (17.9%). General altruism' and 'social responsibility/obligation' were also the most frequent reasons for continuing to donate blood (68.4 and 16.0%, respectively). The most commonly reported obstacle to becoming a regular blood donor was 'laziness' (19.1%) followed by 'fear of needles' (10.5%).Conclusions Altruism was the most common general motive for donating blood and also for continuing to be an active blood donor. Yet, for the first blood donation, direct 'influence from friends/relatives', 'media appeal' and other types of recruitment were more commonly reported as reasons or motives for donating blood than altruism. The findings support the notion that different strategies should be used/adopted to get people to donate blood the first time (e.g. recruitment through other blood donors using, for example, the 'bring a friend along' method) and to retain these subjects as active blood donors (e.g. by information and by strengthening their sense of being a blood donor or their self-efficacy etc.).
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  • Nilsson Sojka, Birgitta, 1953-, et al. (författare)
  • The blood-donation experience : perceived physical, psychological and social impact of blood donation on the donor.
  • 2003
  • Ingår i: Vox Sanguinis. - 0042-9007 .- 1423-0410. ; 84:2, s. 120-8
  • Tidskriftsartikel (refereegranskat)abstract
    • BACKGROUND AND OBJECTIVES: This study aimed to investigate the impact and effects of blood donation on blood donors as perceived and reported by donors themselves. MATERIALS AND METHODS: A self-administered questionnaire was distributed to 600 consecutive whole-blood donors (who had a history of at least one previous donation) consisting of an open-ended question asking whether the blood donation had any impact on the donor. The answers to this question were considered as descriptions of effects perceived by the donors to be evoked by whole-blood donation. RESULTS: In all, 528 subjects completed the questionnaire (88%; 319 males and 209 females) and answered the question about the effects of blood donation. Altogether, 54% (287 out of 528) of the blood donors reported one or several effects. Exclusively positive effects were described by 29% (151) of blood donors, while exclusively negative effects and mixed effects (i.e. concomitant positive and negative effects in the same subject) were described by 19% (103) and 6% (33), respectively, while no effect was reported by 46% (241) of the donors. A majority of the effects commenced within 1 h of blood donation. The positive effects lasted significantly longer (often for weeks, P < 0.0001) than negative effects (min/h/days). Among positive effects a feeling of satisfaction, of being more alert, and feeling generally better than before the blood donation predominated for both female and male donors. Among negative effects, vertigo/dizziness was reported more frequently by female donors (P < 0.0001). Logistic regression analysis revealed that the negative effects were less likely to occur with increasing age (P < 0.001) and that they were more likely to occur in female donors (P < 0.001) in comparison to male donors, irrespective of age. CONCLUSIONS: The majority of effects elicited by blood donation on blood donors were positive (i.e. feelings of satisfaction, greater alertness, increased wellbeing, etc.). The positive effects did not differ from the negative regarding time of onset, yet their duration was reported to be significantly longer. There was no association between frequency of occurrence of positive effects and the number of blood donations, indicating that there is no 'addictive' relationship between donors and blood donations. The findings in this study of high frequency of occurrence of positive long-lasting effects elicited in blood donors by blood donation may be of great importance for the recruitment of new blood donors as it may make blood donation less frightening and perhaps even attractive.
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  • Fernandez-Gonzalo, Rodrigo, et al. (författare)
  • Chronic stroke patients show early and robust improvements in muscle and functional performance in response to eccentric-overload flywheel resistance training : a pilot study
  • 2014
  • Ingår i: Journal of NeuroEngineering and Rehabilitation. - : Springer Science and Business Media LLC. - 1743-0003. ; 11, s. Art. no. 150-
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: Resistance exercise comprising eccentric (ECC) muscle actions enhances muscle strength and function to aid stroke patients in conducting daily tasks. The purpose of this study was to assess the efficacy of a novel ECC-overload flywheel resistance exercise paradigm to induce muscle and functional performance adaptations in chronic stroke patients. Methods: Twelve patients (similar to 8 years after stroke onset) performed 4 sets of 7 coupled concentric (CON) and ECC actions using the affected limb on a flywheel leg press (LP) device twice weekly for 8 weeks. Maximal CON and ECC isokinetic torque at 30, 60 and 90 degrees/s, isometric knee extension and LP force, and CON and ECC peak power in LP were measured before and after training. Balance (Berg Balance Scale, BBS), gait (6-Min Walk test, 6MWT; Timed-Up-and-Go, TUG), functional performance (30-s Chair-Stand Test, 30CST), spasticity (Modified Ashworth Scale) and perceived participation (Stroke Impact Scale, SIS) were also determined. Results: CON and ECC peak power increased in both the trained affected (34 and 44%; P < 0.01), and the untrained, non-affected leg (25 and 34%; P < 0.02). Power gains were greater (P = 0.008) for ECC than CON actions. ECC isokinetic torque at 60 and 90 degrees/s increased in the affected leg (P < 0.04). The increase in isometric LP force for the trained, affected leg across tests ranged 10-20% (P < 0.05). BBS (P = 0.004), TUG (P = 0.018), 30CST (P = 0.024) and SIS (P = 0.058) scores improved after training. 6MWT and spasticity remained unchanged. Conclusions: This novel, short-term ECC-overload flywheel RE training regime emerges as a valid, safe and viable method to improve muscle function, balance, gait and functional performance in men and women suffering from chronic stroke.
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  • Hedlund, Mattias, 1968- (författare)
  • Biomechanical and neural aspects of eccentric and concentric muscle performance in stroke subjects : Implications for resistance training
  • 2012
  • Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • Muscle weakness is one of the major causes of post-stroke disability. Stroke rehabilitation programs now often incorporate the same type of resistance training that is used for healthy subjects; however, the training effects induced from these training strategies are often limited for stroke patients. An important resistance training principle is that an optimal level of stress is exerted on the neuromuscular system, both during concentric (shortening) and eccentric (lengthening) contractions. One potential problem for post-stroke patients might be difficulties achieving sufficient levels of stress on the neuromuscular system. This problem may be associated with altered muscular function after stroke. In healthy subjects, maximum strength during eccentric contractions is higher than during concentric contractions. In individuals with stroke, this difference in strength is often increased. Moreover, it has also been shown that individuals with stroke exhibit alteration with respect to how the strength varies throughout the range of motion. For example, healthy subjects exhibit a joint specific torque-angle relationship that normally is the same irrespective of contraction mode and contraction velocity. In contrast, individuals with stroke exhibit an overall change of the torque-angle relationship. This change, as described in the literature, consists of a more pronounced strength loss at short muscle length. In individuals with stroke, torque-angle relationships are only partially investigated and so far these relationships have not been analysed using testing protocols that include eccentric, isometric, and concentric modes of contraction. This thesis investigates the torque-angle relationship of elbow flexors in subjects with stroke during all three modes of contractions – isometric, concentric, and eccentric ­– and the relative loading throughout the range of movement during a resistance exercise. In addition, this thesis studies possible central nervous system mechanisms involved in the control of muscle activation during eccentric and concentric contractions. The torque-angle relationship during maximum voluntary elbow flexion was examined in stroke subjects (n=11), age-matched healthy subjects (n=11), and young subjects (n=11) during different contraction modes and velocities. In stroke subjects, maximum torque as well as the torque angle relationship was better preserved during eccentric contractions compared to concentric contractions. Furthermore, the relative loading during a resistance exercise at an intensity of 10RM (repetition maximum) was examined. Relative loading throughout the concentric phase of the resistance exercise, expressed as percentage of concentric torque, was found to be similar in all groups. However, relative loading during the eccentric contraction phase, expressed as the percentage of eccentric isokinetic torque, was significantly lower for the stroke group. In addition, when related to isometric maximum voluntary contraction, the loading for the stroke group was significantly lower than for the control groups during both the concentric and eccentric contraction phases.Functional magnetic resonance imaging was used to examine differences between recruited brain regions during the concentric and the eccentric phase of imagined maximum resistance exercise of the elbow flexors (motor imagery) in young healthy subjects (n=18) and in a selected sample of individuals with stroke (n=4). The motor and premotor cortex was less activated during imagined maximum eccentric contractions compared to imagined maximum concentric contraction of elbow flexors. Moreover, BA44 in the ventrolateral prefrontal cortex, a brain area that has been shown to be involved in inhibitory control of motor activity, was additionally recruited during eccentric compared to concentric conditions. This pattern was evident only on the contralesional (the intact hemisphere) in some of the stroke subjects. On the ipsilesional hemisphere, the recruitment in ventrolateral prefrontal cortex was similar for both modes of contractions.  Compared to healthy subjects, the stroke subjects exhibited altered muscular function comprising a specific reduction of torque producing capacity and deviant torque-angle relationship during concentric contractions. Therefore, the relative training load during the resistance exercise at a training intensity of 10RM was lower for subjects with stroke. Furthermore, neuroimaging data indicates that the ventrolateral prefrontal cortex may be involved in a mechanism that modulates cortical motor drive differently depending on mode of the contractions. This might partly be responsible for why it is impossible to fully activate a muscle during eccentric contractions. Moreover, among individuals with stroke, a disturbance of this system could also lie behind the lack of contraction mode-specific modulation of muscle activation that has been found in this population. The altered neuromuscular function evident after a stroke means that stroke victims may find it difficult to supply a sufficient level of stress during traditional resistance exercises to promote adaptation by the neuromuscular system. This insufficiency may partially explain why the increase in strength, in response to conventional resistance training, often has been found to be low among subjects with stroke.
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8.
  • Hedlund, Mattias, et al. (författare)
  • Insufficient loading in stroke subjects during conventional resistance training
  • 2012
  • Ingår i: Advances in Physiotherapy. - : Informa UK Limited. - 1403-8196 .- 1651-1948. ; 14:1, s. 18-28
  • Tidskriftsartikel (refereegranskat)abstract
    • Our objective was to assess the loading during a resistance-training task at a given training intensity in subjects with stroke and in healthy subjects. Subjects with stroke (n = 11) and two control groups (n = 11 in each) underwent strength measurements and a resistance-training task for elbow flexors. Torque and muscular activity obtained during the resistance-training task was related to values obtained during strength measurements. Even if relative loading throughout the concentric phase of the resistance-training task, expressed as percent of concentric isokinetic torque, was found to be similar among groups, we found indications of insufficient loading for the stroke group. Relative loading during the eccentric contraction phase, expressed as percent of eccentric isokinetic torque, was significantly lower for the stroke group. Also, when related to isometric maximum voluntary contraction, the loading was significantly lower for the stroke group, compared with the control groups, during the concentric and eccentric contraction phases. Furthermore, muscle activation during, as well as muscular fatigue after, the resistance-training task was somewhat lower for the stroke group. Hence, for subjects with stroke, the relative loading during resistance training, performed at a training intensity considered adequate for able-bodied, appears to be too low compared with the healthy controls. © 2012 Informa Healthcare.
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  • Hedlund, Mattias, et al. (författare)
  • Is better preservation of eccentric strength after stroke due to altered prefrontal function?
  • 2016
  • Ingår i: Neurocase. - : Informa UK Limited. - 1355-4794 .- 1465-3656. ; 22:2, s. 229-242
  • Tidskriftsartikel (refereegranskat)abstract
    • Ventrolateral prefrontal cortex (VLPFC) is part of a network that exerts inhibitory control over the motor cortex (MC). Recently, we demonstrated that VLPFC was more activated during imagined maximum eccentric than during imagined concentric contractions in healthy participants. This was accompanied with lower activation levels within motor regions during imagined eccentric contractions. The aim was to test a novel hypothesis of an involvement of VLPFC in contraction mode-specific modulation of force. Functional magnetic resonance imaging was used to examine differences in VLPFC and motor regions during the concentric and the eccentric phases of imagined maximum contractions in a selected sample of subjects with stroke (n = 4). The subjects were included as they exhibited disturbed modulation of force. The previously demonstrated pattern within VLPFC was evident only on the contralesional hemisphere. On the ipsilesional hemisphere, the recruitment in VLPFC was similar for both modes of contractions. The findings support a hypothesis of the involvement of VLPFC in contraction mode-specific modulation of maximum force production. A disturbance of this system might underlie the lack of contraction mode-specific modulation commonly found among stroke subjects, often expressed as an increased ratio between eccentric and concentric strength.
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