Now showing 1 - 10 of 71
  • Publication
    Metadata only
    Resistance training does not increase myocellular garbage dumps: A pilot study on lipofuscin in skeletal muscle fibers of resistance trained young men
    (2024-01-31)
    Jacko, Daniel 
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    Masur, Lukas 
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    Schaaf, Kirill 
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    Zacher, Jonas 
    ;
    ;
    Marées, Markus de 
    ;
    Bloch, Wilhelm 
    ;
    Lipofuscin (LF) is an intracellular aggregate associated with proteostatic impairments, especially prevalent in nondividing skeletal muscle fibers. Reactive oxygen species (ROS) drive LF-formation. Resistance training (RT) improves muscle performance but also increases ROS production, potentially promoting LF-formation. Thus, we aimed to investigate if RT of a mesocycle duration increases LF-formation in type-I and II muscle fibers and whether RT increases the antioxidant capacity (AOC) in terms of SOD1 and SOD2 content. An intervention group (IG) performed 14 eccentrically accented RT-sessions within 7 weeks. Vastus lateralis muscle biopsies were collected before and after the intervention from IG as well as from a control group (CG) which refrained from RT for the same duration. LF was predominantly found near nuclei, followed by membrane-near and a minor amount in the fiber core, with corresponding spot sizes. Overall, LF-content was higher in type-I than type-II fibers (p < 0.05). There was no increase in LF-content in type-I or IIA fibers, neither for the IG following RT nor for the CG. The same is valid for SOD1/2. We conclude that, in healthy subjects, RT can be safely performed, without adverse effects on increased LF-formation.
      5
  • Publication
    Open Access
    Abschlussarbeiten am Institut für Sportwissenschaften der Universität Hildsheim 2022/2023
    (Universitätsverlag Hildesheim, 2024)
    Kaum eine Wissenschaftsdisziplin vereint so unterschiedliche Sachgebiete wie die Sportwissenschaft. Entsprechend vielgestaltig sind auch ihre „Schreib- und Denkkulturen“, die teils den geistes- / sozialwissenschaftlichen, teils den naturwissenschaftlich / medizinischen Disziplinen entstammen. Die in diesem Band zusammengestellten Abstracts spiegeln diese Vielfalt in Inhalt und Form sehr schön wider. Um diese Vielfalt zu erhalten, wurde die redaktionelle Bearbeitung der Abstracts auf ein Minimum reduziert, der äußeren Form nur weite Rahmen gesteckt. Ebenso wurden inhaltliche, formale und orthographische Aspekte nicht redaktionell überarbeitet. Der Band bildet also weitestgehend die originalen Abstracts in all ihren Stärken und Schwächen und in all ihrer Vielfalt ab.
      22  8
  • Publication
    Metadata only
    Myotube growth is associated with cancer-like metabolic reprogramming and is limited by phosphoglycerate dehydrogenase.
    (2023-10)
    Stadhouders, Lian E. M. 
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    Smith, Jonathan A. B. 
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    Gabriel, Brendan M. 
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    Verbrugge, Sander A. J. 
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    Hammersen, Tim D. 
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    Kolijn, Detmar 
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    Vogel, Ilse S. P. 
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    Mohamed, Abdalla D. 
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    de Wit, Gerard M. J. 
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    Offringa, Carla 
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    Hoogaars, Willem M. H. 
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    Jaspers, Richard T. 
    The Warburg effect links growth and glycolysis in cancer. A key purpose of the Warburg effect is to generate glycolytic intermediates for anabolic reactions, such as nucleotides → RNA/DNA and amino acids → protein synthesis. The aim of this study was to investigate whether a similar ‘glycolysis-for-anabolism’ metabolic reprogramming also occurs in hypertrophying skeletal muscle. To interrogate this, we first induced C2C12 myotube hypertrophy with IGF-1. We then added 14C glucose to the differentiation medium and measured radioactivity in isolated protein and RNA to establish whether 14C had entered anabolism. We found that especially protein became radioactive, suggesting a glucose → glycolytic intermediates → non-essential amino acid(s) → protein series of reactions, the rate of which was increased by IGF-1. Next, to investigate the importance of glycolytic flux and non-essential amino acid synthesis for myotube hypertrophy, we exposed C2C12 and primary mouse myotubes to the glycolysis inhibitor 2-Deoxy-d-glucose (2DG). We found that inhibiting glycolysis lowered C2C12 and primary myotube size. Similarly, siRNA silencing of PHGDH, the key enzyme of the serine biosynthesis pathway, decreased C2C12 and primary myotube size; whereas retroviral PHGDH overexpression increased C2C12 myotube size. Together these results suggest that glycolysis is important for hypertrophying myotubes, which reprogram their metabolism to facilitate anabolism, similar to cancer cells.
      2
  • Publication
    Metadata only
    A modified formula using energy system contributions to calculate pure maximal rate of lactate accumulation during a maximal sprint cycling test.
    (2023-04)
    Yang, Woo-Hwi 
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    Park, So-Young 
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    Kim, Taenam 
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    Jeon, Hyung-Jin 
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    Heine, Oliver 
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    Purpose: This study aimed at comparing previous calculating formulas of maximal lactate accumulation rate (νLa.max) and a modified formula of pure νLa.max (PνLa.max) during a 15-s all-out sprint cycling test (ASCT) to analyze their relationships. Methods: Thirty male national-level track cyclists participated in this study (n = 30) and performed a 15-s ASCT. The anaerobic power output (Wpeak and Wmean), oxygen uptake, and blood lactate concentrations (La−) were measured. These parameters were used for different calculations of νLa.max and three energy contributions (phosphagen, WPCr; glycolytic, WGly; and oxidative, WOxi). The PνLa.max calculation considered delta La−, time until Wpeak (tPCr−peak), and the time contributed by the oxidative system (tOxi). Other νLa.max levels without tOxi were calculated using decreasing time by 3.5% from Wpeak (tPCr −3.5%) and tPCr−peak. Results: The absolute and relative WPCr were higher than WGly and WOxi (p < 0.0001, respectively), and the absolute and relative WGly were significantly higher than WOxi (p < 0.0001, respectively); νLa.max (tPCr −3.5%) was significantly higher than PνLa.max and νLa.max (tPCr−peak), while νLa.max (tPCr−peak) was lower than PνLa.max (p < 0.0001, respectively). PνLa.max and νLa.max (tPCr−peak) were highly correlated (r = 0.99; R2 = 0.98). This correlation was higher than the relationship between PνLa.max and νLa.max (tPCr −3.5%) (r = 0.87; R2 = 0.77). νLa.max (tPCr−peak), PνLa.max, and νLa.max (tPCr −3.5%) were found to correlate with absolute Wmean and WGly. Conclusion: PνLa.max as a modified calculation of νLa.max provides more detailed insights into the inter-individual differences in energy and glycolytic metabolism than νLa.max (tPCr−peak) and νLa.max (tPCr −3.5%). Because WOxi and WPCr can differ remarkably between athletes, implementing their values in PνLa.max can establish more optimized individual profiling for elite track cyclists.
      4
  • Publication
    Metadata only
    Diagnostics of VLamax and Glycolytic Energy Contribution Indicate Individual Characteristics of Anaerobic Glycolytic Energy Metabolism Contributing to Rowing Performance
    (2023-02) ;
    Park, Soyoung 
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    Wawer, Corinna 
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    Theis, Christian 
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    Yang, Woo-Hwi 
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    The diagnostic of anaerobic glycolytic metabolism which play a subordinate role in elite rowing and parameters such as maximum lactate accumulation rate (νLa.max) have thus far not been associated with ergometer rowing performance. The aim of the study was to quantify the glycolytic energy metabolism (WGly) during a 2000 m ergometer rowing time trial (RTT) and νLa.max during a 10 s maximum ergometer rowing sprint test (RST) and to unravel associations between those variables and RTT performance. Combined post-exercise lactate measurements and oxygen uptake after RST and RTT were used to determine νLa.max and glycolytic energy contribution (WGly) in seven male and three female German U 23 national rowers (N = 10, 19.8 ± 0.9 years, 183.2 ± 7.0 cm height, 79.9 ± 13.3 kg body mass, 16.4 ± 5.1 % body fat). WGly during RTT ranged from 7 to 15.5% and νLa.max between 0.25 and 0.66 mmol∙L−1∙s−1. νLa.max correlated with WGly (p < 0.05, r = 0.74) and the mechanical power output (W) for the first 300 m (300first) during RTT (p < 0.05, r = 0.67). νLa.max further correlated with ∆300first−last (W) for the first and last 300 m (300last) during RTT (p < 0.01, r = 0.87) and also within the subgroup of male rowers. νLa.max displays a wide spectrum of individual differences in rowers. Due to this and its correlation to specific phases of RTT, it contributes to an individual energetic performance profile in rowing. Future studies must undermine the role of νLa.max for exercise performance and whether it serves as a marker that can be specifically targeted for a training-induced increase or decrease.
      4
  • Publication
    Open Access
    Investigation of The Psychological Wellbeing after a One-Week-Skiing Intervention with Childhood Cancer Survivors
    (2023) ;
    Lampe, Viktoria 
    ;
    Zimmermann, Tanja 
    After a child’s cancer diagnosis, the life of the whole family changes immediately. Besides physical exposure due to both the disease and the treatment, psychological stress, anxiety and uncertainties arise for all family members. In a family-oriented winter sport rehabilitation camp in the alps the increased physical fitness should be focused besides the adventure and the psychological wellbeing, thus basically the path back to normality. In order to investigate the latter, the parents of eight patients (10.87 yrs. ± 5.33 yrs.) were surveyed before and after the journey via the Strength and Difficulties Questionnaire (SDQ) consisting of 25 items divided into five subscales (social behavior, hyperactivity, emotional problems, problems with peer groups, behavioral problems). It was pointed out that for the given setting open answer options were more meaningful than closed answers. There was only one significance for the subscale behavioral problems. However, the parents stated distinctly positive effects regarding the social togetherness of the children, the atmosphere within the families, the independence and self- confidence of the children. According to the participants the rehabilitation journey could be recommended not only for the improvement of motor parameters and physical effects, but also on a psychological level and for an increased perceived health-related life quality
      31  38
  • Publication
    Metadata only
    Enhanced capacity for CaMKII signaling mitigates calcium release related contractile fatigue with high intensity exercise
    (2023)
    Flück, Martin 
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    Sanchez, Colline 
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    Jacquemond, Vincent 
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    Berthier, Christine 
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    Giraud, Marie-Noëlle 
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    Jacko, Daniel 
    ;
    ; ;
    Baan, Guus 
    ;
    Jaspers, Richard T. 
      3
  • Publication
    Metadata only
    Resistance exercise: a mighty tool that adapts, destroys, rebuilds and modulates the molecular and structural environment of skeletal muscle
    (2023) ;
    So-Young, Park 
    ;
    Schaaf, Kirill 
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    Yang, Woo-Hwi 
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    Theis, Christian 
    ;
    Jacko, Daniel 
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    Purpose: Skeletal muscle regulates health and performance by maintaining or increasing strength and muscle mass. Although the molecular mechanisms in response to resistance exercise (RE) significantly target the activation of protein synthesis, a plethora of other mechanisms and structures must be involved in orchestrating the communication, repair, and restoration of homeostasis after RE stimulation. In practice, RE can be modulated by variations in intensity, continuity and volume, which affect molecular responses and skeletal muscle adaptation. Knowledge of these aspects is important with respect to planning of training programs and assessing the impact of RE training on skeletal muscle. Methods: In this narrative review, we introduce general aspects of skeletal muscle substructures that adapt in response to RE. We further highlighted the molecular mechanisms that control human skeletal muscle anabolism, degradation, repair and memory in response to acute and repeated RE and linked these aspects to major training variables. Results: Although RE is a key stimulus for the activation of skeletal muscle anabolism, it also induces myofibrillar damage. Nevertheless, to increase muscle mass accompanied by a corresponding adaptation of the essential substructures of the sarcomeric environment, RE must be continuously repeated. This requires the permanent engagement of molecular mechanisms that re-establish skeletal muscle integrity after each RE-induced muscle damage. Conclusion: Various molecular regulators coordinately control the adaptation of skeletal muscle after acute and repeated RE and expand their actions far beyond muscle growth. Variations of key resistance training variables likely affect these mechanisms without affecting muscle growth. Keywords: adaptation; hypertrophy; mTOR signaling; muscle damage; proteostasis; resistance exercise; skeletal muscle.
      3
  • Publication
    Metadata only
    Widerständige Praktiken von Schüler:innen im Sportunterricht
    (2023) ;
    Langer, Wiebke
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    Bähr, Ingrid
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    Gerlach, Erin
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    Krieger, Claus
    ;
    Walter, Melina
      24