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Workers within production and assembly lines are often exposed to ergonomically unfavorable tasksand conditions. Reaction forces and reaction torques generated by industrial power tools may causenot only discomfort but also health issues and injury. The forceful tasks in combination with highlyrepetitive hand-arm motions and prolonged tool use paves the way for loss in workforce capacitywhich in turn can lead to great losses in productivity and product quality. An umbrella term for themany injuries and diseases that may arise from the use of such tools is Cumulative Trauma Disorders(CTD).This study aimed to investigate the ergonomic effect of power tool use for various tool and taskrelated conditions. The study required the setup of a test rig with a simulated handle of the tool. Theergonomic impact was assessed by measuring the torques associated with different tighteningstrategies, as well as measuring the angular displacement of the tool handle. By varying the jointstiffness and workplace orientation, the complexity of the task was varied and thus quantified.Measurements of muscle activity during each tightening procedure provided a quantification of thephysiological impact on the operator. By combining the measurements on the operator withsubjective assessment of perceived exertion and discomfort, a more holistic perspective on thetightening procedure was obtained.The results obtained from the study stressed the negative impact on the operator which the QuickStep tightening strategy on medium hard joints implies, regardless of workspace orientation. TheTurbo Tight and Tensor Pulse tightening strategies turned out to generate the lowest reactiontorques and handle deflections, regardless of joint stiffness and workspace orientation. The findingsfrom the muscle activity measurements in combination with the subjective evaluation methodsfurther confirmed the mildness of the Turbo Tight and Tensor Pulse strategies. Moreover, horizontalworkspace resulted in lower tool handle deflection compared to vertical workspace for all tighteningstrategies and joint stiffnesses. / Många antällda på monteringsband exponeras ofta för ergonomiskt ofördelaktiga arbetsuppgifter och arbetsförhållanden. De handhållna monteringsverktyg som används genrerar ofta reaktionskrafter som i många fall kan orsaka en känsla av obehag eller ge upphov till mer bestående hälsobesvär. De kraftfulla och repetetiva arbetsuppgifterna som montering många gånger innebär kan bana väg för förluster i arbetskraftskapacitet, vilket i sin tur kan leda till stora förluster i produktivitet och produktkvalitet. En paraplyterm för de många åkommor och besvär som kan uppstå som ett resultat av användandet av handhållna monteringsverktyg är ’förslitningsskador’ (Cumulative Trauma Disorders på engelska). Målsättningen för denhär studien har varit att undersöka de ergonomiska effekter som användandet av handhållna monteringsverktyg innebär vid olika vektygs- och arbetsuppgiftsrelaterade parametrar. Studien genomfördes med hjälp av en test rig där ett simulerat verktygshandtag utnyttjades. Den ergonomiska effekten på användaren undersöktes genom mätningar av uppnådda reaktions moment och handtags vinklar associerade med olika åtdragningsstrategier, styvhet av förband samt orientering av arbetsyta. Genom att mäta muskelaktiviteten i underarmen hos testpersonerna erhölls en kvantifiering av den fysiologiska effekten på testpersonerna. Mätningarna av vinkel, moment och muskelaktivitet kombinerades med subjektiva skattningsmetoder för att på så sätt kunna erhålla ett mer holistiskt perspektiv på åtdragningarna och deras effekt på människan. Resultaten från studien underströk de negativa effekterna av åtdragning med Quick Step strategin på medium hårda förband, oavsett orientering av arbetsytan. Turbo Tight och Tensor Pulse strategierna genererade de lägsta reaktions momenten och handtags deflektionerna. Resultaten från muskelsaktivitetsmätningarna och de subjektiva skattningsmetoderna bekräftade den relativa mildheten hos Tensor Pulse och Turbo Tight strategierna. Dessutom påvisades att åtdragningar som sker på en horisontell arbetsyta resulterade i lägre handtagsdeflektion jämfört med åtdragningar på en vertikal arbetsyta, oavsett åtdragningsstrategi och styvhet hos förband.

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<p>In contrast to effortful cognitive functions, emotional functioning may remain stable or even be enhanced in older adults. It is unclear how affective functions in aging correspond to subjective experiences and physiological changes. In <b>Study I</b>, ratings of emotional intensity and neural activity to facial expressions using functional magnetic resonance imaging (fMRI) were analyzed in younger and older adults. Negative expressions resulted in increased neural activity in the right amygdala and hippocampus in younger adults, and increased activation in the right insular cortex in older adults. There were no age differences in subjective ratings. In <b>Study II</b>, subjective ratings of, and skin conductance response (SCR) to, neutral and negative pictures were studied. The ratings of negative pictures were higher for older adults compared to younger adults. SCRs increased in both age groups for the negative pictures, but magnitude of SCRs was significantly larger in younger adults. Finally, in <b>Study III</b>, emotional memory after a one-year retention interval was tested. The memory performance of both age groups was higher in response to negative pictures compared to neutral ones, although the performance was generally higher for younger adults. SCR at encoding was the better arousal predictor for memory, but only in younger adults. The results indicate age-related changes in affective processing. Age differences may involve a gradual shift from bottom-up processes, to more top-down processes. The results are discussed in a wider lifespan perspective taking into consideration the accumulated life experience of older adults.</p>

In contrast to effortful cognitive functions, emotional functioning may remain stable or even be enhanced in older adults. It is unclear how affective functions in aging correspond to subjective experiences and physiological changes. In Study I, ratings of emotional intensity and neural activity to facial expressions using functional magnetic resonance imaging (fMRI) were analyzed in younger and older adults. Negative expressions resulted in increased neural activity in the right amygdala and hippocampus in younger adults, and increased activation in the right insular cortex in older adults. There were no age differences in subjective ratings. In Study II, subjective ratings of, and skin conductance response (SCR) to, neutral and negative pictures were studied. The ratings of negative pictures were higher for older adults compared to younger adults. SCRs increased in both age groups for the negative pictures, but magnitude of SCRs was significantly larger in younger adults. Finally, in Study III, emotional memory after a one-year retention interval was tested. The memory performance of both age groups was higher in response to negative pictures compared to neutral ones, although the performance was generally higher for younger adults. SCR at encoding was the better arousal predictor for memory, but only in younger adults. The results indicate age-related changes in affective processing. Age differences may involve a gradual shift from bottom-up processes, to more top-down processes. The results are discussed in a wider lifespan perspective taking into consideration the accumulated life experience of older adults.