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 influence of sex, stroke and distance on the lactate characteristics in high performance swimming(2013) Holfelder, Benjamin; Brown, Niklas; Bubeck, DieterBackground: In order to achieve world-class performances, regular performance diagnostics is required as an essential prerequisite for guiding high performance sport. In high performance swimming, the lactate performance diagnostic is an important instrument in testing the sport specific endurance capacity. Although the role of lactate as a signaling molecule, fuel and a gluconeogenic substrate is accepted, lactate parameters are discussed concerning stability, explanatory power and interpretability. Methods: We calculated the individual anaerobic threshold (IAT) of Bunc using the swimming-specific lactate threshold test by Pansold. Results: The cross-sectional analysis (ANOVA) of n = 398 high performance swimmers showed significant effects for sex, stroke and distance on the IAT, the percentage of personal best time on the IAT (% of PB on IAT) and maximal lactate values (max. bLA). For the freestyle events the IAT decreased, % of PB on IAT and max. bLA increased from 100 to 400 m significantly in men and women. Women showed significantly higher % of PB on IAT with descriptive lower IAT in 7 of 8 analyzed events. Men showed significantly higher max. bLA in 5 of 8 events. In the second step, the analysis of 1902 data sets of these 398 athletes with a multi-level analysis (MLA) showed also significant effects for sex, swimming distance and stroke. For initial status and development over time, the effect sizes for the variables distance and sex were medium to large, whereas for stroke there were no or small effect sizes. Discussion: These significant results suggest that lactate tests in swimming specifically have to consider the lactate affecting factors sex and distance under consideration of the time period between measurements. Anthropometrical factors and the physiology of women are possible explanations for the relative better performance for lower lactate concentrations compared to men.Item Open Access How to investigate within-subject associations between physical activity and momentary affective states in everyday life : a position statement based on a literature overview(2013) Kanning, Martina; Ebner-Priemer, Ulrich W.; Schlicht, WolfgangSeveral meta-analyses have investigated the association between physical activity and affective states and have found evidence suggesting that exercise exerts a positive effect on affective state. However, in this field of research, most studies have conducted between-subject analyses. Nonetheless, there is more and more interest in the within-subject associations between physical activity and momentary affective states in everyday life. This position statement pertains to this up-and-coming field of research and provides methodological recommendations for further studies. The paper is divided into three parts: First, we summarise and evaluate three methodological requirements necessary for the proper evaluation of within-subject associations between physical activity and momentary affective states in everyday life. We propose that the following issues should be considered: a) to address the dynamic nature of such relationships, repeated assessments are necessary; b) as activities performed in everyday life are mostly spontaneous and unconscious, an objective assessment of physical activity is useful; c) given that recall of affective states is often affected by systematic distortions, real-time assessment is preferable. In sum, we suggest the use of ambulatory assessment techniques, and more specifically the combination of acceloremeter-assessment of physical activity with an electronic diary assessment of the momentary affective state and additional context information. Second, we summarise 22 empirical studies published between 1980 and 2012 using ambulatory assessment to investigate within-subject associations between momentary affective states and physical activity in everyday life. Generally, the literature overview detects a positive association, which appears stronger among those studies that were of high methodological quality. Third, we propose the use of ambulatory assessment intervention strategies to change people's behaviour (ambulatory assessment intervention) and to enable people to be active as often as possible during the day (e.g., reducing sitting time, taking more steps per day).Item Open Access Fast and powerful: biomechanics and bite forces of the mandibles in the American cockroach Periplaneta americana(2015) Weihmann, Tom; Reinhardt, Lars; Weißing, Kevin; Siebert, Tobias; Wipfler, BenjaminKnowing the functionality and capabilities of masticatory apparatuses is essential for the ecological classification of jawed organisms. Nevertheless insects, especially with their outstanding high species number providing an overwhelming morphological diversity, are notoriously underexplored with respect to maximum bite forces and their dependency on the mandible opening angles. Aiming for a general understanding of insect biting, we examined the generalist feeding cockroach Periplaneta americana, characterized by its primitive chewing mouth parts. We measured active isometric bite forces and passive forces caused by joint resistance over the entire mandibular range with a custom-built 2D force transducer. The opening angle of the mandibles was quantified by using a video system. With respect to the effective mechanical advantage of the mandibles and the cross-section areas, we calculated the forces exerted by the mandible closer muscles and the corresponding muscle stress values. Comparisons with the scarce data available revealed close similarities of the cockroaches’ mandible closer stress values (58 N/cm2) to that of smaller specialist carnivorous ground beetles, but strikingly higher values than in larger stag beetles. In contrast to available datasets our results imply the activity of faster and slower muscle fibres, with the latter becoming active only when the animals chew on tough material which requires repetitive, hard biting. Under such circumstances the coactivity of fast and slow fibres provides a force boost which is not available during short-term activities, since long latencies prevent a specific effective employment of the slow fibres in this case.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 Older people’s perceptions of friendliness and traffic safety : an experiment using computer-simulated walking environments(2015) Kahlert, Daniela; Schlicht, WolfgangItem 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 Associations of motor performance and executive functions: comparing children with Down syndrome to chronological and mental age-matched controls(2022) Klotzbier, Thomas J.; Holfelder, Benjamin; Schott, NadjaBackground. Children with Down syndrome (DS) exhibit lower motor and cognitive performance than typically developing children (TD). Although there is a relationship between these two developmental domains, only a few studies have addressed this association in children with DS compared to groups of the same chronological age (CA) or mental age (MA) within one study. This study aimed to fill this research gap. Method and Procedures. The Movement Assessment Battery for Children-2 and the Trail-Making Test was used to assess motor and cognitive performances in 12 children (M = 10.5 ± 10.08) with DS, 12 CA-matched, and 12 MA-matched controls. Results. There are significant group differences in the motor dimension (total test score; p < 0.001, η2p = 0.734), for processing speed (p < 0.001, η2p = 0.396), and cognitive flexibility (p < 0.001, η2p = 0.498). Between TD-CA and both other groups, the differences in the magnitude of correlations for the motor dimension balance are also significant (compared to DS: z = −2.489; p = 0.006, and to TD-MA: z = −3.12; p < 0.001). Conclusions. Our results suggest that the relationships depend on the studied cognitive and motor skills. It seems crucial to select a wide range of tasks for both domains that are as isolated as possible for future studies, to better understand the relationships between cognitive and motor skills in children with DS.Item Open Access Assessing basic and higher-level psychological needs satisfied through physical activity(2023) Dunton, Genevieve F.; Do, Bridgette; Crosley-Lyons, Rachel; Naya, Christine H.; Hewus, Micaela; Kanning, MartinaItem Open Access The effects of the combination of high-intensity interval training with 3D-multiple object tracking task on perceptual-cognitive performance: a randomized controlled intervention trial(2021) Park, Soo-Yong; Klotzbier, Thomas J.; Schott, NadjaThe ability to process goal-related visual information while ignoring goal-irrelevant information is essential for the human attention system. The study aimed to investigate how perceptual-cognitive performance was affected during high-intensity interval training (HIIT) using a 3D-multiple object tracking (3D-MOT) task called Neurotracker (NT). In an experimental design, 42 healthy adults (age M = 23.3 SD = 2.94, VO2max 52.8 ± 5.66 mL·kg-1·min-1) were randomly assigned to an intervention (HIIT + NT, NT, HIIT) or control group. NT performance (20 trials per session) was measured pre-and post-test (at 5, 15, and 25 min while running on the treadmill). The participants trained twice a week for a 4-week intervention period. There was a significant interaction effect between pre/post-test and groups regarding perceptual-cognitive performance, indicating similar enhancements in the HIIT + NT and the NT group during exercise. HIIT influences physical fitness but did not show any impact on perceptual-cognitive performance. Due to the specific NT task characteristics, improved physical abilities may not directly impact sport-specific perceptual-cognitive performance. Our findings suggest that training resulted in substantial task-specific gains. Therefore, combination training may be proposed as a training program to improve perceptual-cognitive, and physical performance in a time-efficient way.Item Open Access Influence of layer separation on the determination of stomach smooth muscle properties(2021) Borsdorf, Mischa; Böl, Markus; Siebert, TobiasUniaxial 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.