10 Fakultät Wirtschafts- und Sozialwissenschaften
Permanent URI for this collectionhttps://elib.uni-stuttgart.de/handle/11682/11
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Item Open Access 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.Item Open Access Das untere Sprunggelenk als biomechanischer Einflussfaktor : Entwicklung und Anwendung eines IMU-Systems zur Beschreibung der Orientierung der Achsen des Sprunggelenks(2020) Schlechtweg, Sascha; Alt, Wilfried (Prof. Dr.)Item Open Access Effects of acute exercise at different intensities on fine motor‐cognitive dual‐task performance while walking : a functional near‐infrared spectroscopy study(2021) Park, Soo‐Yong; Reinl, Maren; Schott, NadjaStudies on the effects of acute exercises on cognitive functions vary greatly and depend on the duration and intensity of exercise and the type of cognitive tasks. This study aimed to investigate the neural correlates that underpin the acute effects of high‐intensity interval (HIIE) versus moderate‐intensity continuous exercise (MCE) on fine motor‐cognitive performance while walking (dual‐task, DT) in healthy young adults. Twenty‐nine healthy right‐handers (mean age: 25.1 years ± 4.04; 7 female) performed the digital trail‐making‐test (dTMT) while walking (5 km/h) before and after acute exercise. During task performance, the hemodynamic activation of the frontopolar area (FPA), dorsolateral prefrontal (DLPFC), and motor cortex (M1) was recorded using functional near‐infrared spectroscopy (fNIRS). Both HIIE and MCE resulted in improved dTMT performance, as reflected by an increase in the number of completed circles and a reduction in the time within and between circuits (reflecting improvements in working memory, inhibition, and decision making). Notably, HIIE evoked higher cortical activity on all brain areas measured in the present study than the MCE group. To our knowledge, these results provide the first empirical evidence using a mobile neuroimaging approach that both HIIE and MCE improve executive function during walking, likely mediated by increased activation of the task‐related area of the prefrontal cortex and the ability to effectively use, among other things, high fitness levels as neural enrichment resources.Item Open Access Cross-bridge mechanics estimated from skeletal muscles’ work-loop responses to impacts in legged locomotion(2021) Christensen, Kasper B.; Günther, Michael; Schmitt, Syn; Siebert, TobiasLegged locomotion has evolved as the most common form of terrestrial locomotion. When the leg makes contact with a solid surface, muscles absorb some of the shock-wave accelerations (impacts) that propagate through the body. We built a custom-made frame to which we fixated a rat (Rattus norvegicus, Wistar) muscle (m. gastrocnemius medialis and lateralis: GAS) for emulating an impact. We found that the fibre material of the muscle dissipates between 3.5 and 23μJ ranging from fresh, fully active to passive muscle material, respectively. Accordingly, the corresponding dissipated energy in a half-sarcomere ranges between 10.4 and 68zJ, respectively. At maximum activity, a single cross-bridge would, thus, dissipate 0.6% of the mechanical work available per ATP split per impact, and up to 16% energy in common, submaximal, activities. We also found the cross-bridge stiffness as low as 2.2pNnm-1, which can be explained by the Coulomb-actuating cross-bridge part dominating the sarcomere stiffness. Results of the study provide a deeper understanding of contractile dynamics during early ground contact in bouncy gait.Item Open Access Vertical jump kinetic parameters on sand and rigid surfaces in young female volleyball players with a combined background in indoor and beach volleyball(2023) Giatsis, George; Panoutsakopoulos, Vassilios; Frese, Christina; Kollias, Iraklis A.Little is known about the differences in vertical jump biomechanics executed on rigid (RJS) and sand (SJS) surfaces in female indoor and beach volleyball players. Eleven young female beach volleyball players with a combined indoor and beach volleyball sport background performed squat jumps, countermovement jumps with and without an arm swing, and drop jumps from 40 cm on a RJS (force plate) and SJS (sand pit attached to the force plate). The results of the 2 (surface) × 4 (vertical jump test) repeated-measure ANOVA revealed a significant (p < 0.05) main effect of the surface and the vertical jump test on the jump height and time to achieve peak vertical body center of mass velocity. A significant (p < 0.05) main effect of the test, but not of the surface (p > 0.05), was observed for the other examined biomechanical parameters. The only significant (p < 0.05) jump height gain difference between RJS and SJS was observed for the utilization of the stretch-shortening cycle, which was higher in SJS (15.4%) compared to RJS (7.5%). In conclusion, as the testing was conducted during the beach volleyball competitive season, the examined female players showed adaptations relating the effective utilization of the pre-stretch and enhanced stability during the execution of the vertical jump tests on a SJS compared to RJS.Item Open Access Upright posture control in changing gravity conditions(2021) Smirnov, EvgeniiIn order to be able to withstand and to take advantage of external forces and to be able to direct motor actions, living organisms developed ability to sense environmental impacts. For instance, proprioceptors and cutaneous receptors allow vertebrates to take into account, above all, gravitational influences. These receptors participate in planning and correcting posture, locomotion and other movements. In this thesis mechanisms of equilibrium control in changing gravity conditions were studied by means of literature analysis and analysis of data obtained in parabolic flight. This analysis revealed that standing balance in overloading is likely controlled in a manner resembling a single-link inverted pendulum. Such behavior could be beneficial to take advantage of passive body structures and to more actively involve foot receptors in balance regulation in challenging conditions. This adaptation also resembles typical postural responses in balance perturbation tasks. The latter were then studied in more detail. Further literature overview supported the suggestion that plantar foot receptors play an essential role in dynamic stability of upright posture. The obtained conclusions allowed to formulate possible mechanisms of sway and balance control and make suggestions on possible implementation of these mechanisms into the neuromusculoskeletal human model proposed by Walter, Gunther, Haeufle, and Schmitt (2021) in order to make equilibrium control of this model robuster.Item Open Access 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. AlfredoIndividuals 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.Item Open Access Impact of multidirectional transverse calf muscle loading on calf muscle force in young adults(2018) Siebert, Tobias; Eb, Manuel; Ryan, David S.; Wakeling, James M.; Stutzig, NormanIt has been demonstrated that unidirectional transversal muscle loading induced by a plunger influences muscle shape and reduces muscle force. The interaction between muscle and transversal forces may depend on specific neuromuscular properties that change during a lifetime. Compression garments, applying forces from all directions in the transverse plane, are widely used in sports for example to improve performance. Differences in the loading direction (unidirectional vs. multidirectional) may have an impact on force generating capacity of muscle and, thus, on muscle performance. The aim of this study was to examine the effect of multidirectional transversal loads, using a sling looped around the calf, on the isometric force during plantarflexions. Young male adults (25.7 ± 1.5 years, n = 15) were placed in a prone position in a calf press apparatus. The posterior tibial nerve was stimulated to obtain the maximal double-twitch force of the calf muscles with (59.4 N and 108.4 N) and without multidirectional transverse load. Compared to the unloaded condition, the rate of force development was reduced by 5.0±8.1 % (p=0.048) and 6.9±10.7 % (p=0.008) for the 59.4 N and the 108.4 N load, respectively. No significant reduction (3.2±4.8 %, p=0.141) in maximum muscle force (Fm) was found for the lower load (59.4 N), but application of the higher load (108.4 N) resulted in a significant reduction of Fm by 4.8±7.0 % (p=0.008). Mean pressures induced in this study (14.3 mm Hg and 26.3 mm Hg corresponding to the 59.4 N and 108.4 N loads, respectively) are within the pressure range reported for compression garments. Taking the results of the present study into account, a reduction in maximum muscle force would be expected for compression garments with pressures ≥ 26.3 mm Hg. However, it should be noted that the loading condition (sling vs. compression garment) differs and that compression garments may influence other mechanisms contributing to force generation. For example, wearing compression garments may enhance sport performance by enhanced proprioception and reduced muscle oscillation. Thus, superposition of several effects should be considered when analyzing the impact of compression garments on more complex sport performance.Item Open Access Understanding factors that influence physical activity behavior in people with developmental coordination disorder (DCD) : a mixed-methods convergent integrated systematic review(2023) Purcell, Catherine; Schott, Nadja; Rapos, Victoria; Zwicker, Jill G.; Wilmut, KateThis systematic review synthesizes the literature on physical activity amongst people with DCD using the COM-B framework. The review questions were: (1) what is the Capability (C), Opportunity (O) and Motivation (M) for physical activity and (2) what does physical activity behavior (B) look like? A mixed-methods systematic review was conducted by searching eight databases (PubMed, APA PsycINFO, EMBASE, Scopus, Child Development and Adolescent Studies, Cochrane Library, Web of Science, CINAHL) up to July 2023. Data were extracted, thematically analyzed, and mapped to the COM-B model. The quality of studies was assessed with the Joanna Briggs Institute (JBI) critical appraisal tool. The protocol was registered with PROSPERO (CRD42022319127). Forty-three papers, 42 of which related to children, were included. Fifteen aligned with physical activity behavior, nine with physical capability, thirteen with psychological capability, one with social opportunity, one with physical opportunity, one with reflective motivation and three with automatic motivation. Pre-school-aged children with DCD engage in comparable levels of physical activity behavior, but differences emerge from 6 years of age. Characteristics of DCD result in reduced physical capability and less varied participation in physical activity. This impacts psychological capability, whereby lower self-perceptions result in a negative feedback loop and reduce the motivation to participate. Barriers relating to social opportunities may result in poor reflective and automatic motivation, although there is evidence that interventions can enhance enjoyment in the short term.Item Open Access A high-protein, low glycemic index diet suppresses hunger but not weight regain after weight loss : results from a large, 3-years randomized trial (PREVIEW)(2021) Zhu, Ruixin; Fogelholm, Mikael; Larsen, Thomas M.; Poppitt, Sally D.; Silvestre, Marta P.; Vestentoft, Pia S.; Jalo, Elli; Navas-Carretero, Santiago; Huttunen-Lenz, Maija; Taylor, Moira A.; Stratton, Gareth; Swindell, Nils; Kaartinen, Niina E.; Lam, Tony; Handjieva-Darlenska, Teodora; Handjiev, Svetoslav; Schlicht, Wolfgang; Martinez, J. Alfredo; Seimon, Radhika V.; Sainsbury, Amanda; Macdonald, Ian A.; Westerterp-Plantenga, Margriet S.; Brand-Miller, Jennie; Raben, AnnePrevious studies have shown an increase in hunger during weight-loss maintenance (WLM) after diet-induced weight loss. Whether a combination of a higher protein, lower glycemic index (GI) diet and physical activity (PA) can counteract this change remains unclear. To compare the long-term effects of two diets [high protein (HP)-low GI vs. moderate protein (MP)-moderate GI] and two PA programs [high intensity (HI) vs. moderate intensity (MI)] on subjective appetite sensations during WLM after ≥8% weight loss (WL). Data derived from the 3-years PREVIEW randomized intervention study. An 8-weeks WL phase using a low-energy diet was followed by a 148-weeks randomized WLM phase. For the WLM phase, participants were assigned to one of the four groups: HP-MI, HP-HI, MP-MI, and MP-HI. Available data from 2,223 participants with overweight or obesity (68% women; BMI ≥ 25 kg/m2). Appetite sensations including satiety, hunger, desire to eat, and desire to eat something sweet during the two phases (at 0, 8 weeks and 26, 52, 104, and 156 weeks) were assessed based on the recall of feelings during the previous week using visual analogue scales. Differences in changes in appetite sensations from baseline between the groups were determined using linear mixed models with repeated measures. There was no significant diet × PA interaction. From 52 weeks onwards, decreases in hunger were significantly greater in HP-low GI than MP-moderate GI (Ptime × diet = 0.018, Pdietgroup = 0.021). Although there was no difference in weight regain between the diet groups (Ptime × diet = 0.630), hunger and satiety ratings correlated with changes in body weight at most timepoints. There were no significant differences in appetite sensations between the two PA groups. Decreases in hunger ratings were greater at 52 and 104 weeks in HP-HI vs. MP-HI, and greater at 104 and 156 weeks in HP-HI vs. MP-MI. This is the first long-term, large-scale randomized intervention to report that a HP-low GI diet was superior in preventing an increase in hunger, but not weight regain, during 3-years WLM compared with a MP-moderate GI diet. Similarly, HP-HI outperformed MP-HI in suppressing hunger. The role of exercise intensity requires further investigation. Clinical Trial Registration: www.ClinicalTrials.gov, identifier: NCT01777893.