10 Fakultät Wirtschafts- und Sozialwissenschaften

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    Sensorbasierte Messung und Bedeutung körperlicher Aktivität bei Patienten nach Hüftfraktur in der geriatrischen Rehabilitation
    (2012) Nicolai, Simone Elisabeth; Schlicht, Wolfgang (Prof. Dr. phil. habil.)
    Einleitung Der Umfang der körperlichen Aktivität älterer Bevölkerungsschichten liegt zum Großteil weit unter den allgemeinen Aktivitätsempfehlungen, obwohl diese als Schlüsselfaktor für eine gute Lebensqualität und die Aufrechterhaltung der Selbständigkeit gilt. Im Fokus der Forschung standen bislang neben der breiten Bevölkerungsschicht vor allem ältere noch zuhause lebende Menschen. Der demographische Wandel wird verstärkt dazu führen, dass das Gesundheitssystem und die Pflegekassen durch die zunehmende Anzahl hochaltriger, gebrechlicher Personen finanziell stärker belastet werden. Eine Personengruppe, die besonders gefährdet ist, langfristig immobil zu werden, ist die Gruppe der Patienten nach proximaler Femurfraktur (PFF). Die Fragestellungen der vorliegenden Arbeit sollen daher exemplarisch anhand dieser Personengruppe behandelt werden. Vordringliches Ziel dieser Studie war die objektive Beschreibung und Bewertung der in der geriatrischen Rehabilitation mittels Sensor gemessenen körperlichen Aktivität und deren Verlauf bei Patienten nach PFF. Weitere Ziele waren die Ermittlung der Veränderungssensitivitäten inkl. Boden- und Deckeneffekte der angewandten Messverfahren und die Überprüfung möglicher Zusammenhänge zwischen der körperlichen Aktivität und der körperlichen Leistungsfähigkeit sowie psychosozialen Parameter. Methoden Fünfundsechzig geriatrische Patienten nach PFF (Alter M = 82,54 Jahre ± 7,17 SD) wurden zu Beginn der Rehabilitation (T1) und nach zwei Wochen (T2) untersucht. Neben der körperlichen Aktivität wurden funktionelle, biomechanische und fragebogenbasierte Parameter erhoben. Zusätzlich fand zu einem definierten Nachbeobachtungszeitraum (sechszehn Wochen nach T1; TFU) eine weitere sensorbasierte Messung der körperlichen Aktivität statt. Ergebnisse Die körperliche Aktivität erhöhte sich während und nach der Rehabilitation für die Gesamtgruppe signifikant. Es konnten moderate Zusammenhänge zwischen der körperlichen Aktivität und vor allem funktionellen und fragebogenbasierten Parametern (wie z. B. Alltagsfunktion oder Mobilität) aufgezeigt werden. Die Generierung eines Prädiktionsmodells zur Erklärung der körperlichen Aktivität innerhalb der Rehabilitation war mit 55 % erklärter Varianz nur in Teilen möglich. Eine Prädiktion der körperlichen Aktivität war zum Nachbeobachtungszeitpunkt für die Gesamtgruppe ebenfalls nur teilweise möglich (erklärte Varianz 22 %). Die Messung der körperlichen Aktivität erwies sich als veränderungssensitiv. Es konnten keine Boden- oder Deckeneffekte aufgezeigt werden. Schlussfolgerung Die Messung der körperlichen Aktivität war in dem untersuchten Kollektiv gut durchführbar. Die sensorbasierte Messung der körperlichen Aktivität stellt eine gute Möglichkeit dar, um in Ergänzung zur Funktion und physischen Kapazität einen Teilaspekt des ICF-Bereichs Partizipation quantitativ abzubilden. Die gefundenen Ergebnisse könnten künftig helfen, die Therapieplanung und -evaluation zu optimieren, um dadurch das rehabilitative Outcome im Sinne einer Reduktion des Immobilitätsrisikos und Teilhabeverlustes zu verbessern und damit zu einer Entlastung des Gesundheits- und Versorgungssysteme beizutragen. Weitere Studien sind nötig um die Übertragbarkeit dieser Schlussfolgerungen für andere geriatrische Fallgruppen zu überprüfen.
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    The effect of multidirectional loading on contractions of the M. medial gastrocnemius
    (2021) Ryan, David S.; Stutzig, Norman; Helmer, Andreas; Siebert, Tobias; Wakeling, James M.
    Research has shown that compression of muscle can lead to a change in muscle force. Most studies show compression to lead to a reduction in muscle force, although recent research has shown that increases are also possible. Based on methodological differences in the loading design between studies, it seems that muscle length and the direction of transverse loading influence the effect of muscle compression on force production. Thus, in our current study we implement these two factors to influence the effects of muscle loading. In contrast to long resting length of the medial gastrocnemius (MG) in most studies, we use a shorter MG resting length by having participant seated with their knees at a 90° angle. Where previous studies have used unidirectional loads to compress the MG, in this study we applied a multidirectional load using a sling setup. Multidirectional loading using a sling setup has been shown to cause muscle force reductions in previous research. As a result of our choices in experimental design we observed changes in the effects of muscle loading compared to previous research. In the present study we observed no changes in muscle force due to muscle loading. Muscle thickness and pennation angle showed minor but significant increases during contraction. However, no significant changes occurred between unloaded and loaded trials. Fascicle thickness and length showed different patterns of change compared to previous research. We show that muscle loading does not result in force reduction in all situations and is possibly linked to differences in muscle architecture and muscle length.
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    Influence of layer separation on the determination of stomach smooth muscle properties
    (2021) Borsdorf, Mischa; Böl, Markus; Siebert, Tobias
    Uniaxial tensile experiments are a standard method to determine the contractile properties of smooth muscles. Smooth muscle strips from organs of the urogenital and gastrointestinal tract contain multiple muscle layers with different muscle fiber orientations, which are frequently not separated for the experiments. During strip activation, these muscle fibers contract in deviant orientations from the force-measuring axis, affecting the biomechanical characteristics of the tissue strips. This study aimed to investigate the influence of muscle layer separation on the determination of smooth muscle properties. Smooth muscle strips, consisting of longitudinal and circumferential muscle layers (whole-muscle strips [WMS]), and smooth muscle strips, consisting of only the circumferential muscle layer (separated layer strips [SLS]), have been prepared from the fundus of the porcine stomach. Strips were mounted with muscle fibers of the circumferential layer inline with the force-measuring axis of the uniaxial testing setup. The force–length (FLR) and force–velocity relationships (FVR) were determined through a series of isometric and isotonic contractions, respectively. Muscle layer separation revealed no changes in the FLR. However, the SLS exhibited a higher maximal shortening velocity and a lower curvature factor than WMS. During WMS activation, the transversally oriented muscle fibers of the longitudinal layer shortened, resulting in a narrowing of this layer. Expecting volume constancy of muscle tissue, this narrowing leads to a lengthening of the longitudinal layer, which counteracted the shortening of the circumferential layer during isotonic contractions. Consequently, the shortening velocities of the WMS were decreased significantly. This effect was stronger at high shortening velocities.
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    Editorial - the stretch-shortening cycle of active muscle and muscle-tendon complex : what, why and how it increases muscle performance?
    (2021) Seiberl, Wolfgang; Hahn, Daniel; Power, Geoffrey A.; Fletcher, Jared R.; Siebert, Tobias
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    Considerations on the human Achilles tendon moment arm for in vivo triceps surae muscle-tendon unit force estimates
    (2020) Holzer, Denis; Paternoster, Florian Kurt; Hahn, Daniel; Siebert, Tobias; Seiberl, Wolfgang
    Moment arm-angle functions (MA-a-functions) are commonly used to estimate in vivo muscle forces in humans. However, different MA-a-functions might not only influence the magnitude of the estimated muscle forces but also change the shape of the muscle’s estimated force-angle relationship (F-a-r). Therefore, we investigated the influence of different literature based Achilles tendon MA-a-functions on the triceps surae muscle-tendon unit F-a-r. The individual in vivo triceps torque-angle relationship was determined in 14 participants performing maximum voluntary fixed-end plantarflexion contractions from 18.3° ± 3.2° plantarflexion to 24.2° ± 5.1° dorsiflexion on a dynamometer. The resulting F-a-r were calculated using 15 literature-based in vivo Achilles tendon MA-a-functions. MA-a-functions affected the F-a-r shape and magnitude of estimated peak active triceps muscle-tendon unit force. Depending on the MA-a-function used, the triceps was solely operating on the ascending limb (n = 2), on the ascending limb and plateau region (n = 12), or on the ascending limb, plateau region and descending limb of the F-a-r (n = 1). According to our findings, the estimated triceps muscle–tendon unit forces and the shape of the F-a-r are highly dependent on the MA-a-function used. As these functions are affected by many variables, we recommend using individual Achilles tendon MA-a-functions, ideally accounting for contraction intensity-related changes in moment arm magnitude.
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    Preventing functional loss during immobilization after osteoporotic wrist fractures in elderly patients : a randomized clinical trial
    (2014) Schott, Nadja; Korbus, Heide
    Background Distal radius fractures are among the most common fractures and account for approximately one-sixth of all fractures diagnosed. Therapy results after distal radius fracture, especially of elderly patients, are often suboptimal. The inevitable immobilization for several weeks leads to reduction in range of motion, deterioration of muscle strength, malfunction of fine motor skills as well as changes of motor and sensory representations in the brain. Currently, there are no strategies to counteract these immobilization problems. The overall aim of the study is to investigate the therapeutic potential of motor-cognitive approaches (mental practice or mirror therapy) on hand function after wrist fracture. Methods/design This study is a controlled, randomized, longitudinal intervention study with three intervention groups. One experimental group imagines movements of the fractured upper extremity without executing them (mental practice). The second experimental group receives a mirror therapy program consisting of the performance of functional movement synergies using the unaffected forearm, wrist, and hand. The control group completes a relaxation training regime. Additionally, all patients receive usual care by the general practitioner. We include women aged 60 years and older having a distal radius fracture and sufficient cognitive function. All groups are visited at home for therapy sessions 5 times per week for the first 3 weeks and 3 times per week for weeks 4 to 6. Measurements are taken at therapy onset, and after 3, 6 and 12 weeks. The primary outcome measure will assess upper extremity functioning (Patient-Rated Wrist Evaluation [PRWE]), while secondary outcome measures cover subjective wrist function (Disabilities of the Arm and Shoulder; [DASH], objective impairment (range of motion, grip force) and quality of life (EuroQol-5D, [EQ5D]). Discussion Results from this trial will contribute to the evidence on motor-cognitive approaches in the early therapy of distal radius fractures. Trial registration The trial is registered at ClinicalTrials.gov with registration number NCT01394809 and was granted permission by the Medical Ethical Review Committee of the University of Tübingen in June 2011.
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    Profiles of motor-cognitive interference in Parkinson’s disease : the Trail-Walking Test to discriminate between motor phenotypes
    (2022) Klotzbier, Thomas J.; Schott, Nadja; Almeida, Quincy J.
    Background and Aims. Most research on Parkinson’s disease (PD) focuses on describing symptoms and movement characteristics. Studies rarely focus on the early detection of PD and the search for suitable markers of a prodromal stage. Early detection is important, so treatments that may potentially change the course of the disease can be attempted early on. While gait disturbances are less pronounced in the early stages of the disease, the prevalence, and severity increase with disease progression. Therefore, postural instability and gait difficulties could be identified as sensitive biomarkers. The aim was to evaluate the discriminatory power of the Trail-Walking Test (TWT; Schott, 2015) as a potential diagnostic instrument to improve the predictive power of the clinical evaluation concerning the severity of the disease and record the different aspects of walking. Methods. A total of 20 older healthy (M = 72.4 years, SD = 5.53) adults and 43 older adults with PD and the motor phenotypes postural instability/gait difficulty (PIGD; M = 69.7 years, SD = 8.68) and tremor dominant (TD; M = 68.2 years, SD = 8.94) participated in the study. The participants performed a motor-cognitive dual task (DT) of increasing cognitive difficulty in which they had to walk a given path (condition 1), walk to numbers in ascending order (condition 2), and walk to numbers and letters alternately and in ascending order (condition 3). Results. With an increase in the cognitive load, the time to complete the tasks (seconds) became longer in all groups, F(1.23, 73.5) = 121, p < 0.001, ɳ2p = 0.670. PIGD showed the longest times in all conditions of the TWT, F(2, 60) = 8.15, p < 0.001, ɳ2p = 0.214. Mutual interferences in the cognitive and motor domain can be observed. However, clear group-specific patterns cannot be identified. A differentiation between the motor phenotypes of PD is especially feasible with the purely motor condition (TWT-M; AUC = 0.685, p = 0.44). Conclusions. PD patients with PIGD must be identified by valid, well-evaluated clinical tests that allow for a precise assessment of the disease’s individual fall risk, the severity of the disease, and the prognosis of progression. The TWT covers various aspects of mobility, examines the relationship between cognitive functions and walking, and enables differentiation of the motor phenotypes of PD.
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    Influence of augmented visual feedback on balance control in unilateral transfemoral amputees
    (2021) Fuchs, Katharina; Krauskopf, Thomas; Lauck, Torben B.; Klein, Lukas; Mueller, Marc; Herget, Georg W.; Von Tscharner, Vinzenz; Stutzig, Norman; Stieglitz, Thomas; Pasluosta, Cristian
    Patients with a lower limb amputation rely more on visual feedback to maintain balance than able-bodied individuals. Altering this sensory modality in amputees thus results in a disrupted postural control. However, little is known about how lower limb amputees cope with augmented visual information during balance tasks. In this study, we investigated how unilateral transfemoral amputees incorporate visual feedback of their center of pressure (CoP) position during quiet standing. Ten transfemoral amputees and ten age-matched able-bodied participants were provided with real-time visual feedback of the position of their CoP while standing on a pressure platform. Their task was to keep their CoP within a small circle in the center of a computer screen placed at eye level, which could be achieved by minimizing their postural sway. The visual feedback was then delayed by 250 and 500 ms and was combined with a two- and five-fold amplification of the CoP displacements. Trials with eyes open without augmented visual feedback as well as with eyes closed were further performed. The overall performance was measured by computing the sway area. We further quantified the dynamics of the CoP adjustments using the entropic half-life (EnHL) to study possible physiological mechanisms behind postural control. Amputees showed an increased sway area compared to the control group. The EnHL values of the amputated leg were significantly higher than those of the intact leg and the dominant and non-dominant leg of controls. This indicates lower dynamics in the CoP adjustments of the amputated leg, which was compensated by increasing the dynamics of the CoP adjustments of the intact leg. Receiving real-time visual feedback of the CoP position did not significantly reduce the sway area neither in amputees nor in controls when comparing with the eyes open condition without visual feedback of the CoP position. Further, with increasing delay and amplification, both groups were able to compensate for small visual perturbations, yet their dynamics were significantly lower when additional information was not received in a physiologically relevant time frame. These findings may be used for future design of neurorehabilitation programs to restore sensory feedback in lower limb amputees.
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    Appraisal of triglyceride-related markers as early predictors of metabolic outcomes in the PREVIEW lifestyle intervention : a controlled post-hoc trial
    (2021) Navas-Carretero, Santiago; San-Cristobal, Rodrigo; Siig Vestentoft, Pia; Brand-Miller, Jennie C.; Jalo, Elli; Westerterp-Plantenga, Margriet; Simpson, Elizabeth J.; Handjieva-Darlenska, Teodora; Stratton, Gareth; Huttunen-Lenz, Maija; Lam, Tony; Muirhead, Roslyn; Poppitt, Sally; Pietiläinen, Kirsi H.; Adam, Tanja; Taylor, Moira A.; Handjiev, Svetoslav; McNarry, Melitta A.; Hansen, Sylvia; Brodie, Shannon; Silvestre, Marta P.; Macdonald, Ian A.; Boyadjieva, Nadka; Mackintosh, Kelly A.; Schlicht, Wolfgang; Liu, Amy; Larsen, Thomas M.; Fogelholm, Mikael; Raben, Anne; Martinez, J. Alfredo
    Individuals with pre-diabetes are commonly overweight and benefit from dietary and physical activity strategies aimed at decreasing body weight and hyperglycemia. Early insulin resistance can be estimated via the triglyceride glucose index {TyG = Ln [TG (mg/dl) × fasting plasma glucose (FPG) (mg/dl)/2]} and the hypertriglyceridemic-high waist phenotype (TyG-waist), based on TyG x waist circumference (WC) measurements. Both indices may be useful for implementing personalized metabolic management. In this secondary analysis of a randomized controlled trial (RCT), we aimed to determine whether the differences in baseline TyG values and TyG-waist phenotype predicted individual responses to type-2 diabetes (T2D) prevention programs. The present post-hoc analyses were conducted within the Prevention of Diabetes through Lifestyle intervention and population studies in Europe and around the world (PREVIEW) study completers (n = 899), a multi-center RCT conducted in eight countries (NCT01777893). The study aimed to reduce the incidence of T2D in a population with pre-diabetes during a 3-year randomized intervention with two sequential phases. The first phase was a 2-month weight loss intervention to achieve ≥8% weight loss. The second phase was a 34-month weight loss maintenance intervention with two diets providing different amounts of protein and different glycemic indices, and two physical activity programs with different exercise intensities in a 2 x 2 factorial design. On investigation days, we assessed anthropometrics, glucose/lipid metabolism markers, and diet and exercise questionnaires under standardized procedures. Diabetes-related markers improved during all four lifestyle interventions. Higher baseline TyG index (p < 0.001) was associated with greater reductions in body weight, fasting glucose, and triglyceride (TG), while a high TyG-waist phenotype predicted better TG responses, particularly in those randomized to physical activity (PA) of moderate intensity. Two novel indices of insulin resistance (TyG and TyG-waist) may allow for a more personalized approach to avoiding progression to T2D.