| 1. |
- Gunther, A. C., et al.
(författare)
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Pain rather than induced emotions and ICU sound increases skin conductance variability in healthy volunteers
- 2016
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Ingår i: Acta Anaesthesiologica Scandinavica. - : Wiley-Blackwell Publishing Inc.. - 0001-5172 .- 1399-6576. ; 60:8, s. 1111-1120
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundAssessing pain in critically ill patients is difficult. Skin conductance variability (SCV), induced by the sympathetic response to pain, has been suggested as a method to identify pain in poorly communicating patients. However, SCV, a derivate of conventional skin conductance, could potentially also be sensitive to emotional stress. The purpose of the study was to investigate if pain and emotional stress can be distinguished with SCV. MethodsIn a series of twelve 1-min sessions with SCV recording, 18 healthy volunteers were exposed to standardized electric pain stimulation during blocks of positive, negative, or neutral emotion, induced with pictures from the International Affective PictureSystem (IAPS). Additionally, authentic intensive care unit (ICU) sound was included in half of the sessions. All possible combinations of pain and sound occurred in each block of emotion, and blocks were presented in randomized order. ResultsPain stimulation resulted in increases in the number of skin conductance fluctuations (NSCF) in all but one participant. During pain-free baseline sessions, the median NSCF was 0.068 (interquartile range 0.013-0.089) and during pain stimulation median NSCF increased to 0.225 (interquartile range 0.146-0.3175). Only small increases in NSCF were found during negative emotions. Pain, assessed with the numeric rating scale, during the sessions with pain stimulation was not altered significantly by other ongoing sensory input. ConclusionIn healthy volunteers, NSCF appears to reflect ongoing autonomous reactions mainly to pain and to a lesser extent, reactions to emotion induced with IAPS pictures or ICU sound.
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| 2. |
- Tjulin, Åsa, 1976-, et al.
(författare)
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Managers’ learning process during a health-promoting leadership intervention
- 2019
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Ingår i: Health Education. - : Emerald Group Publishing Limited. - 0965-4283 .- 1758-714X. ; 119:5/6, s. 350-365
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Tidskriftsartikel (refereegranskat)abstract
- AbstractPurposeThe increasingly demanding psychosocial working conditions in Swedish public sector workplaces call for implementation of workplace health promotion (WHP) interventions. There is a need to increase first-line public sector managers’ capacities for health-promoting leadership. The purpose of this paper is to investigate first-line managers’ experiences of participating in an intervention aimed at strengthening health-promoting leadership. More precisely, the aim is to study what obstacles and prerequisites the intervention have for their learning processes to become health-promoting managers.Design/methodology/approachA qualitative study in Northern Sweden at workplaces in the county council and municipalities was conducted. The data were gathered through individual interviews with 18 participating first-line managers. Inductive-content analysis was used to analyse the data.FindingsThe results identify time for reflection and collegial discussions about leadership as prerequisites for learning about health-promoting leadership. Managers experienced the intervention as a confirmation of the leadership behaviours already gained. However, the health-promoting leadership intervention was seen as a contradiction, since organisational prerequisites to implement WHP measures were perceived to be lacking. The managers were not involved in the planning of the intervention and questioned why the organisation did not involve them more when the educational activities were created.Originality/valueWhen the organisation understands how and when its managers learn, what they need and want to learn about WHP, and what they already know, tailored participatory interventions can be facilitated that consider the unique prerequisites for the particular organisation.
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| 3. |
- Carlsson, Lars, et al.
(författare)
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Enhanced systolic myocardial function in elite endurance athletes during combined arm-and-leg exercise
- 2011
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Ingår i: European Journal of Applied Physiology. - : Springer Science and Business Media LLC. - 1439-6319 .- 1439-6327. ; 111:6, s. 905-913
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Tidskriftsartikel (refereegranskat)abstract
- The aim here was to employ color tissue velocity imaging (TVI), to test the hypothesis that highly trained endurance athletes exhibit enhanced systolic function of the left ventricular (LV) myocardium both at rest and during combined arm-and-leg exercise in comparison with untrained subjects. For each of the ten elite male (EG) and ten matched control participants (CG), LV dimensions and systolic function were assessed at rest using echocardiography. Subsequently, these subjects exercised continuously on a combined arm-and-leg cycle ergometer for 3 min each at 50, 60, 70, 80, 90 and 100% of VO2max. Oxygen uptake, heart rate, systolic blood pressure (SBP) and peak contraction systolic velocities of the LV myocardium (PSV) were recorded in the end of each level. At rest, the trained and untrained groups differed with respect to LV dimensions, but not systolic function. At 60–100% VO2max, the EG group demonstrated both higher PSV and SBP. The observation that the EG athletes had higher PSV than CG during exercise at 60–100% VO2max, but not at rest or at 50% of VO2max, suggested an enhanced systolic capacity. This improvement is likely to be due to an enhanced inotropic contractility, which only becomes apparent during exercise.
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| 4. |
- Jedenmalm, Anneli, et al.
(författare)
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Validation of a 3D CT method for measurement of linear wear of acetabular cups : A hip simulator study
- 2011
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Ingår i: Acta Orthopaedica. - : Medical Journals Sweden AB. - 1745-3674 .- 1745-3682. ; 82:1, s. 35-41
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Tidskriftsartikel (refereegranskat)abstract
- Material and methods Ultra-high molecular weight polyethylene cups with a titanium mesh molded on the outside were subjected to wear using a hip simulator. Before and after wear, they were (1) imaged with a CT scanner using a phantom model device, (2) measured using a coordinate measurement machine (CMM), and (3) weighed. CMM was used as the reference method for measurement of femoral head penetration into the cup and for comparison with CT, and gravimetric measurements were used as a reference for both CT and CMM. Femoral head penetration and wear vector angle were studied. The head diameters were also measured with both CMM and CT. The repeatability of the method proposed was evaluated with two repeated measurements using different positions of the phantom in the CT scanner. Results The accuracy of the 3D CT method for evaluation of linear wear was 0.51 mm and the repeatability was 0.39 mm. Repeatability for wear vector angle was 17 degrees A degrees. Interpretation This study of metal-meshed hip-simulated acetabular cups shows that CT has the capacity for reliable measurement of linear wear of acetabular cups at a clinically relevant level of accuracy.
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| 5. |
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| 6. |
- Mekjavic, I.B., et al.
(författare)
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Hyperbaric oxygen therapy does not affect recovery from delayed onset muscle soreness
- 2000
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Ingår i: Medicine & Science in Sports & Exercise. - : Ovid Technologies (Wolters Kluwer Health). - 0195-9131 .- 1530-0315. ; 32:3, s. 558-563
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: This study investigated whether hyperbaric oxygen therapy (HBOT) improves recovery after exercise-induced muscle injury. METHODS: Healthy male subjects (N = 24) were randomly assigned to either a placebo group or a HBOT group. Subjects were tested for maximal isometric strength (preexercise) of their right elbow flexors. Each subject then completed a high-force eccentric workout of the elbow flexor muscle group to induce delayed onset muscle soreness (DOMS). On the seven successive days after this workout, the subjects were exposed to a hyperbaric environment of 2.5 ATA for 60 min, inspiring either a normoxic mixture (P(I)O2 = 0.2 ATA; placebo group) or a hyperoxic gas mixture (P(I)O2 = 2.5 ATA; HBOT group). Before the eccentric workout and daily for the next 10 d, measurements were obtained regarding: maximal isometric muscle strength of the elbow flexor muscles, right upper arm circumferences, and rating of the perceived muscle soreness. RESULTS: Isometric strength decreased significantly from preexercise levels of 25.1 +/- 3.8 kp to postexercise levels of 12.0 +/- 4.6 kp, for the HBOT group, and from 24.6 +/- 3.4 kp to 12.5 +/- 3.7 kp, respectively, for the placebo group. Over the 10-d recovery period, there was no difference in the rate of recovery of muscle strength between the two groups. Perceived soreness peaked at about 48 h after exercise with no difference between groups. Also, the exercise-induced increases in arm circumference were similar in the two groups. CONCLUSIONS: These results indicate that HBOT is not an effective therapy for the treatment of DOMS.
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| 7. |
- Norrbrand, Lena
(författare)
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Acute and early chronic responses to resistance exercise using flywheel or weights
- 2010
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Resistance exercise using weights typically offers constant external load during coupled shortening (concentric) and lengthening (eccentric) muscle actions in sets of consecutive repetitions until failure. However, the constant external load and the inherent capability of skeletal muscle to produce greater force in the eccentric compared with the concentric action, would infer that most actions are executed with incomplete motor unit involvement. In contrast, use of the inertia of flywheels to generate resistance allows for maximal voluntary force to be produced throughout the concentric action, and for brief episodes of greater eccentric than concentric loading, i.e. “eccentric overload”. Thus, it was hypothesized that acute flywheel resistance exercise would induce greater motor unit and muscle use, and subsequent fatigue, compared with traditional weight stack/free weight resistance exercise. Furthermore, it was hypothesized that flywheel training would induce more robust neuromuscular adaptations compared with training using weights. A total of 43 trained and untrained men were investigated in these studies.Knee extensor muscle activation, fatigue response and muscle use were assessed during exercises by recording electromyographic signals and by means of functional magnetic resonance imaging, respectively. Flywheel resistance exercise provoked maximal or near maximal muscle activation from the first repetition, induced robust fatigue, and prompted more substantial motor unit and muscle use than weight stack/free weight resistance exercise in both novice and resistance trained men. Both prior to and following five weeks of unilateral knee extension training, the eccentric muscle activation was greater with flywheel than weight stack training. Furthermore, weight stack training generated greater increases of dynamic strength and neural adaptations, while flywheel training generated more prominent hypertrophy of individual quadriceps muscles and greater improvement of maximal isometric strength. Hence, due to the preferential metabolic cost of the concentric rather than eccentric actions, the maximal activation through the entire range of the concentric action within each repetition of a set during flywheel resistance exercise probably evoked the marked fatigue, and prompted more substantial muscle use than resistance exercise using weights. Furthermore, while any cause‐effect relationship remains to be determined, results of the pesent study suggest that brief episodes of “eccentric overload” amplify muscular adaptations following concentriceccentric resistance training.
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| 8. |
- Norrbrand, Lena, et al.
(författare)
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Flywheel resistance training calls for greater eccentric muscle activation than weight training
- 2010
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Ingår i: European Journal of Applied Physiology. - : Springer Science and Business Media LLC. - 1439-6319 .- 1439-6327. ; 110:5, s. 997-1005
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Tidskriftsartikel (refereegranskat)abstract
- Changes in muscle activation and performance were studied in healthy men in response to 5 weeks of resistance training with or without "eccentric overload". Subjects, assigned to either weight stack (grp WS; n = 8) or iso-inertial "eccentric overload" flywheel (grp FW; n = 9) knee extensor resistance training, completed 12 sessions of four sets of seven concentric-eccentric actions. Pre- and post-measurements comprised maximal voluntary contraction (MVC), rate of force development (RFD) and training mode-specific force. Root mean square electromyographic (EMG(RMS)) activity of mm. vastus lateralis and medialis was assessed during MVC and used to normalize EMG(RMS) for training mode-specific concentric (EMG(CON)) and eccentric (EMG(ECC)) actions at 90°, 120° and 150° knee joint angles. Grp FW showed greater (p < 0.05) overall normalized angle-specific EMG(ECC) of vastii muscles compared with grp WS. Grp FW showed near maximal normalized EMG(CON) both pre- and post-training. EMG(CON) for Grp WS was near maximal only post-training. While RFD was unchanged following training (p > 0.05), MVC and training-specific strength increased (p < 0.05) in both groups. We believe the higher EMG(ECC) activity noted with FW exercise compared to standard weight lifting could be attributed to its unique iso-inertial loading features. Hence, the resulting greater mechanical stress may explain the robust muscle hypertrophy reported earlier in response to flywheel resistance training.
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| 9. |
- Norrbrand, Lena, 1971-, et al.
(författare)
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Quadriceps muscle use in the flywheel and barbell squat
- 2011
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Ingår i: Aviation, Space and Environmental Medicine. - Alexandria, VA : Aerospace Medical Association. - 0095-6562 .- 1943-4448. ; 82:1, s. 13-19
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Tidskriftsartikel (refereegranskat)abstract
- Background: Resistance exercise has been proposed as an aid to counteract quadriceps muscle atrophy in astronauts during extended missions in Orbit. While space authorities have advocated the squat exercise should be prescribed, no exercise system suitable for in-flight use has been validated with regard to quadriceps muscle use. We compared muscle involvement in the terrestrial “gold standard” squat using free weights and a non-gravity dependent flywheel resistance exercise device aimed at use in space. Methods: Ten strength-trained men performed five sets of 10 repetitions using the Barbell Squat (BS; 10 repetition maximum) or Flywheel Squat (FS; each repetition maximal), respectively. Functional magnetic resonance imaging (MRI) and surface electromyography (EMG) techniques assessed quadriceps muscle use. Exercise-induced contrast shift of MR images was measured by means of transverse relaxation time (T2). EMG root mean square (RMS) was measured during concentric (CON) and eccentric (ECC) actions and normalized to EMG RMS determined during maximal voluntary contraction. Results: The quadriceps muscle group showed greater exercise-induced T2 increase following FS compared with BS. Among individual muscles, the rectus femoris displayed greater T2 increase with FS (+24±14%) than BS (+8±4%). Normalized quadriceps EMG showed no difference across exercise modes. Discussion: Collectively, the results of this study suggest that quadriceps muscle use in the squat is comparable, if not greater, with flywheel compared with free weight resistance exercise. Data appears to provide support for use of flywheel squat resistance exercise as a countermeasures adjunct during spaceflight.
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| 10. |
- Norrbrand, Lena, et al.
(författare)
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Resistance training using eccentric overload induces early adaptations in skeletal muscle size
- 2008
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Ingår i: European Journal of Applied Physiology. - : Springer Science and Business Media LLC. - 1439-6319 .- 1439-6327. ; 102:3, s. 271-281
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Tidskriftsartikel (refereegranskat)abstract
- Fifteen healthy men performed a 5-week training program comprising four sets of seven unilateral, coupled concentric-eccentric knee extensions 2-3 times weekly. While eight men were assigned to training using a weight stack (WS) machine, seven men trained using a flywheel (FW) device, which inherently provides variable resistance and allows for eccentric overload. The design of these apparatuses ensured similar knee extensor muscle use and range of motion. Before and after training, maximal isometric force (MVC) was measured in tasks non-specific to the training modes. Volume of all individual quadriceps muscles was determined by magnetic resonance imaging. Performance across the 12 exercise sessions was measured using the inherent features of the devices. Whereas MVC increased (P < 0.05) at all angles measured in FW, such a change was less consistent in WS. There was a marked increase (P < 0.05) in task-specific performance (i.e., load lifted) in WS. Average work showed a non-significant 8.7% increase in FW. Quadriceps muscle volume increased (P < 0.025) in both groups after training. Although the more than twofold greater hypertrophy evident in FW (6.2%) was not statistically greater than that shown in WS (3.0%), all four individual quadriceps muscles of FW showed increased (P < 0.025) volume whereas in WS only m. rectus femoris was increased (P < 0.025). Collectively the results of this study suggest more robust muscular adaptations following flywheel than weight stack resistance exercise supporting the idea that eccentric overload offers a potent stimuli essential to optimize the benefits of resistance exercise.
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