Neuromuscular fatigue, even that caused by light submaximal exercise, impairs motor performance and alters motor planning. This impairment is evident in muscle reaction time, force production capacity and joint position sense as well as in more complex tasks such as postural stability. When an individual is fatigued their postural sway increases and they are less able to recover from unexpected postural perturbations. Although a large number of work-related falls are caused by fatigue every year, the mechanisms behind the instability are not well understood. Since postural control does not require a large amount of muscular strength it is unclear whether the post-fatigue changes in posture are due to impairment within the muscle fibers or are a central modification of the motor plan used to execute the movement task. In order to better understand neuromuscular fatigue researchers have labeled fatigue occurring within the muscles ‘peripheral fatigue’ and that occurring within the central nervous system ‘central fatigue’. At the onset of a muscular contraction peripheral and central fatigue develop simultaneously, making it difficult to clearly articulate the role that they each play in the decreased motor performance found post-fatigue. Techniques such as transcranial magnetic and electrical nerve stimulation quantify the contribution of central fatigue to the decreased maximal force production but the impact on motor planning is still not well understood. Therefore, the primary aim of this doctoral dissertation was to isolate central fatigue from peripheral muscle fatigue and to compare the influence that it may have on dynamic postural control to the changes caused by general fatigue of the local postural muscles. This overarching research goal was accomplished through five separate studies. The first study in this dissertation determined that at least seven postural trials needed to be performed to ensure that the participants had fully adapted to the postural task before the fatigue protocol was implemented. Experiment 2 characterized the fatigue produced by bilateral, isometric ankle muscle contractions and examined the recovery of the central and peripheral changes throughout a ten-minute post-fatigue recovery period. The results demonstrated that the alternating maximal ankle plantar and dorsiflexor contractions created central and peripheral fatigue. Central fatigue recovered within the first two minutes post-fatigue while peripheral fatigue lasted throughout the ten-minute post-fatigue period. Experiment 3 analyzed the impact of this ankle muscle fatigue protocol on the postural response to a continual, externally driven, sinusoidal oscillation of the support platform. In this study the fatigued participants were able to stabilize their center of mass displacement using two different anticipatory postural responses to the backwards perturbation whereas all of the participants used the same anticipatory response to the forwards perturbation. All three postural responses became progressively more conservative throughout the ten-minute post-fatigue period, despite the rapid recovery of the ankle force production capacity. The final two studies characterized the fatigue produced during a continuous, isometric forearm contraction and assessed the impact on ankle motor performance (Experiment 4) and on postural control (Experiment 5). Peripheral fatigue created in the forearm muscles during this contraction remained throughout the post-fatigue testing session. Central fatigue and a decreased maximal force production capacity were quantified in both the forearm and ankle plantarflexor muscles immediately after the forearm contraction, indicating that central fatigue created during the forearm exercise crossed over to the distal and unrelated ankle plantarflexor muscles. The influence of the central fatigue created during the forearm contraction affected the anticipatory postural response in a similar way to the fatigue created by the ankle fatigue protocol. The post-fatigue modification of the postural response dissipated as the central fatigue recovered. Taken together, these five studies extend the current understanding of how exercise induced neuromuscular fatigue modifies the central nervous system’s control of complex motor tasks.

No description available.

Diss. (sammanfattning) Linköping : Linköpings universitet, 2007. / Härtill 4 uppsatser.

Thesis (M.S.)--University of Michigan, 2000. / Running title: Hemoglobin and attention. Includes bibliographical references.

Thesis (Ph.D.)--Polymer, Textile and Fiber Engineering, Georgia Institute of Technology, 2009. / Committee Chair: Realff, Mary L.; Committee Member: Graham, Samuel; Committee Member: Jacob, Karl I.; Committee Member: May, Gary; Committee Member: Shofner, Meisha.

Thesis (M.S.)--University of Michigan, 2000. / Running title: Hemoglobin and attention. Includes bibliographical references.

Thesis (M.Psych.Clin.) - University of Queensland, 2004. / Includes bibliographical references.

Bakgrund: Varje år drabbas 55 000 personer i Sverige av cancer och behandlas oftast med kombinerade behandlingar. Den vanligaste biverkningen och det mest påfrestande symtomet vid cancer är fatigue. Fatigue betyder extrem trötthet/utmattninig och är en subjektiv upplevelse. Fatigue är inte en trötthet som går över efter sömn och vila. Syfte: Syftet med denna litteraturstudie är att beskriva hur det är att leva med fatigue vid cancer och cancerbehandling. Metod: En systematisk litteraturstudie som bygger på 15 vetenskapliga artiklar. Artiklarna är både kvalitativa och kvantitativa och har kvalitetsgranskats utifrån Fribergs kriterier för analys av vetenskapliga studier. Litteraturstudien utgår från det teoretiska begreppet livskvalitet. Resultat: Resultatet utmynnade i tre teman; Aspekter som påverkar graden av fatigue, Fatigues negativa påverkan på livskvalitet samt Sätt att hantera fatigue. I det första temat framkom det att fatigue är föränderligt beroende på vilken cancerdiagnos samt cancerbehandling personer genomgår. Det framkom hur fatigue är ett multidimensionellt begrepp där flera andra symtom är relaterade till fatigue. Andra temat innefattar hur avsaknad av energi och social isolation påverkar personers livskvalitet negativt. Det tredje temat innefattar hur personer hittar individuella strategier för att hantera sin fatigue och att fysisk aktivitet är den strategi som visats sig ha mest positiv inverkan på att minska graden av fatigue. Diskussion: I resultatdiskussionen diskuteras begreppet livskvalitet som är den teoretiska utgångspunkten i examensarbetet. Livskvalitet berör både sjukdomsspecifika aspekter samt biverkningar av behandlingen som bidrar till ohälsa. Detta är tillämpbart eftersom fatigue upplevs som psykiskt, fysisk och socialt påfrestande. Livskvalitet är något föränderligt och förändras då personer får en svår sjukdomsdiagnos. Även sjuksköterskans arbete är viktigt i mötet med personer med fatigue då sjuksköterkan kan komma med förslag på strategier som kan göra fatigue mindre påfrestande. / Background: Each year, 55 000people in Sweden affected by cancer and is usually treated with combined treatments. The most common side effect and the most distressing symptom of cancer is fatigue. Fatigue means extreme tiredness/exhaustion and it’s a subjective experience. Fatigue is not tiredness that goes over after sleep or rest. Aim: The aim of this study is to describe what it's like to live with fatigue in cancer and cancer treatment. Methods: A systematic literature review based on 15 scientific articles. The articles are both qualitative and quantitative and quality reviewed for Friberg's criteria for analyzing scientific studies. The literature review is based on the theoretical concept of quality of life. Results: The analysis resulted in three themes: Aspects that affect the level of fatigue, Fatigues negative impact on quality of life and method for managing fatigue. In the first place it was found that fatigue is constantly changing depending on the diagnosis of cancer and cancer treatment that people receiving. It also reached the conclusion how fatigue is a multidimensional concept where several other symptoms are related to fatigue. The Second theme includes the lack of energy and social isolation affects people's quality of life negatively. The third theme involves how people find individual strategies to deal with their fatigue and physical activity is the strategy that proved to have the most positive impact on reducing the severity of fatigue. Discussions: The results discussed the concept of quality of life, the theoretical concept in the literature review. Quality of life concerns both disease-specific aspects and treatment side effects that contribute to ill health. This is applicable because fatigue is experienced as mental, physical and social discomfort. Quality of life is something changing and change as people get a severe disease diagnosis. Even the nurse's work is important when meeting people with fatigue when nurses can make suggestions on strategies that can make fatigue less strenuous.

L'étendue et l'étiologie de la fatigue neuromusculaire dépendent des caractéristiques de la tâche. Parmi ces caractéristiques, l'effet des facteurs matériels est peu documenté. Le tennis est un modèle intéressant pour étudier cet effet puisque cette activité se déroule sur différentes surfaces, susceptibles d'influencer le développement de la fatigue. Cette hypothèse reste à vérifier. Par ailleurs, l'évolution des matériaux a rendu les raquettes modernes plus légères, plus rigides que les raquettes en bois. Aussi, afin de garder du contrôle dans le jeu, les joueurs ont adopter des cordages plus rigides, susceptibles de favoriser le développement de la fatigue. Les objectifs de ce travail étaient donc (i), d'évaluer les origines et l'étendue de la fatigue neuromusculaire en fonction de la surface de jeu à la suite d'un match de longue durée, et (ii) de tester l'effet du cordage sur le développement de la fatigue des muscles de l'avant-bras durant un match de tennis simulé. Dans notre première étude, aucune différence significative de fatigue neuromusculaire n'était mesurée lors de matchs disputés sur différentes surfaces. Nos résultats démontrent une baisse limitée de la force des fléchisseurs plantaires à la suite des matchs, majoritairement attribuée à des altérations des capacités contractiles des fléchisseurs plantaires. Le rôle des facteurs centraux étaient moins clair. Dans la seconde étude, nous avons démontré que jouer avec un cordage rigide favorisait le développement de la fatigue sur les muscles de l'avant-bras par rapport à des cordages souples. La baisse de vitesse mesurée au cours du match simulé pourrait être partiellement liée à cette fatigue localisée. / The etiology and amplitude of neuromuscular fatigue depend on the task characteristics. Among these characteristics, the effect of material factors on the development of neuromuscular fatigue has been scarcely documented. Tennis is an interesting model to study this effect since it is played on different surfaces. Playing surfaces may therefore differently influence the development of fatigue on the lower-limb muscles. However, this hypothesis remains to be tested. In addition, the use of composite materials and the progress of engineering have allowed racquet engineers to design tennis racquet frames which are stiffer, lighter, and more powerfull than old wooden racquets. To keep controling the ball, players now use stiffer string that can influence the development of fatigue on the upper-limb muscles. The objectives of this thesis were (i) to evaluate the effect of the playing surface properties on the development of neuromuscular fatigue in tennis and (ii) to test the influence of string stiffness on the occurrence of forearm muscle fatigue during a simulated tennis match. In the first study, no significant difference of neuromuscular fatigue was observed between surfaces. We have reported a moderate reduction of the maximal voluntary force, which was mainly associated with an alteration of the contractile properties of the plantar flexor muscles. The implication of central factors in the voluntary force decrement was less clear. In the second experimentation, we have demonstrated that playing tennis with high-stiffness string promotes forearm muscle fatigue development, which could partly contribute to the groundstroke ball speed decrement during the game.

Bakgrund: I sjuksköterskans arbete ingår det att stödja och vårda patienter i olika skeden i livet. Många sjuksköterskor arbetar med patienter och närstående i svåra situationer. Compassion fatigue är något som drabbar sjuksköterskor och innebär att sjuksköterskan tar på sig sina patienters smärta och lidande. Detta resulterar i att sjuksköterskans förmåga att engagera och känna för sina patienter försvinner.   Syfte: Syftet var att beskriva sjuksköterskors upplevelser av Compassion fatigue.  Metod: Litteraturöversikt i enlighet med Friberg, (2017). Fyra kvalitativa artiklar, fem kvantitativa artiklar och en artikel med mixmetod utgivna mellan 2008–2018 inkluderades och analyserades.  Resultat: I resultatet för litteraturöversikten identifierades tre teman, Vårdrelationens roll i upplevelser av Compassion fatigue, Sjuksköterskans arbetsmiljön och Arbetslivserfarenhet och ålder.   Diskussion: Watsons teori om mänsklig omsorg ligger tillgrund för diskussionen. Sjuksköterskans självkännedom och förmåga att ta hand om sig själv spelar en stor roll i vårdandet av andra. / Background: The nurse's work includes supporting and caring for patients in different stages of life. Many nurses work close with patients and relatives in difficult situations. Compassion fatigue is something that affects nurses and means that the nurse takes on her patients' pain and suffering. This results in the nurse's ability to engage and feel for their patients disappear.  Aim: The aim was to describe nurses experiences of Compassion fatigue.  Method: Literature review in accordance with Friberg, (2017). Four qualitative articles, five quantitative articles and an article with mix method published between 2008-2018 were included and analyzed.  Results: In the results of the literature review three themes was identified, Caring relationships roll in the experiace of Compassion fatigue, Nurses working environment and Worklife experience and age.  Discussion: Watson's theory of human caring is the foundations for the discussion. Nurses own self-knowledge and ability to take care of themselves plays a major part in caring for others.