Now showing 1 - 4 of 4
  • Publication
    Metadata only
    Phosphorylation of αB-crystallin and its cytoskeleton association differs in skeletal myofiber types depending on resistance exercise intensity and volume
    (2019)
    Jacko, Daniel 
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    Hebchen, Jonas 
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    Marées, Markus 
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    Bloch, Wilhelm 
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    αB-crystallin (CRYAB) is an important actor in the immediate cell stabilizing response following mechanical stress in skeletal muscle. Yet, only little is known regarding myofiber type-specific stress responses of CRYAB. We investigated whether the phosphorylation of CRYAB at serine 59 (pCRYABSer59) and its cytoskeleton association are influenced by varying load-intensity and -volume in a fiber type-specific manner. Male subjects were assigned to 1, 5, and 10 sets of different acute resistance exercise protocols: hypertrophy (HYP), maximum strength (MAX), strength endurance (SE), low intensity (LI), and three sets of maximum eccentric resistance exercise (ECC). Skeletal muscle biopsies were taken at baseline and 30 min after exercise. Western blot revealed an increase in pCRYABSer59 only following 5 and 10 sets in groups HYP, MAX, SE, and LI as well as following 3 sets in the ECC group. In type I fibers, immunohistochemistry determined increased pCRYABSer59 in all groups. In type II fibers, pCRYABSer59 only increased in MAX and ECC groups, with the increase in type II fibers exceeding that of type I fibers in ECC. Association of CRYAB and pCRYABSer59 with the cytoskeleton reflected the fiber type-specific phosphorylation pattern. Phosphorylation of CRYAB and its association with the cytoskeleton in type I and II myofibers is highly specific in terms of loading intensity and volume. Most likely, this is based on specific recruitment patterns of the different myofiber entities due to the different resistance exercise loadings. We conclude that pCRYABSer59 indicates contraction-induced mechanical stress exposure of single myofibers in consequence of resistance exercise. NEW & NOTEWORTHY We determined that the phosphorylation of αB-crystallin at serine 59 (pCRYABSer59) after resistance exercise differs between myofiber types in a load- and intensity-dependent manner. The determination of pCRYABSer59 could serve as a marker indirectly indicating contractile involvement and applied mechanical stress on individual fibers. By that, it is possible to retrospectively assess the impact of resistance exercise loading on skeletal muscle fiber entities.
      4
  • Publication
    Metadata only
    Resistance exercise-induced muscle fatigue is not accompanied by increased phosphorylation of ryanodine receptor 1 at serine 2843
    (2018)
    Jacko, Daniel 
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    Friederichs, Gerrit 
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    Ritter, Patrick 
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    Nirenberg, Linnea 
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    Eisenbraun, Jan 
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    de Marées, Markus 
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    Bloch, Wilhelm 
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      2
  • Publication
    Metadata only
    Resistance exercise-induced muscle fatigue is not accompanied by increased phosphorylation of ryanodine receptor 1 at serine 2843
    (2018)
    Jacko, Daniel 
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    ;
    Friederichs, Gerrit 
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    Ritter, Patrick 
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    Nirenberg, Linnea 
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    Eisenbraun, Jan 
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    Marées, Markus 
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    Bloch, Wilhelm 
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    Skeletal muscle fatigue has been shown to be associated with hyperphosphorylation of the ryanodine receptor 1 at serine 2843 (pRyR1Ser2843), due to chronic overloading exercise. We investigated whether pRyR1Ser2843, is a mechanism relevant for muscle fatigue also under acute, in contrast to chronic, muscle loading. 24 male subjects (age: 24,8±3,8; height: 182,8±7,2 cm; weight: 82,5±9,9 kg) were evenly (n = 6) assigned to the following four different resistance exercise (RE) groups: hypertrophy- (HYP), strength endurance- (SE), maximum power- (MAX) at the subjects' 10, 25 and 3 repetition maximum, respectively, and low intensity (LI) RE with 70% of the 10 repetition maximum. Each group completed three different RE volumes (1 set, 5, and 10 sets). Muscle biopsies from the vastus lateralis were taken before and after exercise, analyzed for pRyR1Ser2843 and examined for association with RE-induced muscle fatigue which was determined as reduction in maximum isometric force (isoFmax) in the quadriceps femoris muscle also before and after exercise.The degree of RE-induced muscle fatigue was specific in terms of set volume as well as of RE mode. isoFmax was not reduced in any group after one set of RE. Five sets led to a significant reduction of isoFmax in HYP and SE but not in LI and MAX (p<0,05). Ten sets of RE, as compared to five sets, exclusively induced further muscle fatigue in LI. In terms of RE mode differences, isoFmax reduction was generally higher in HYP and SE than in MAX and Li after five and ten sets of RE (p<0,05). However, pRyR1Ser2843 did not show any significant regulation, regardless of exercise condition. We conclude that despite its relevance in reducing muscle contractility in chronic overloading, pRyR1Ser2843 does not reflect the degree of muscle fatigue exerted by acute hypertrophy-, strength endurance-, maximum power and low intensity-oriented exercise.
      2
  • Publication
    Metadata only
    Motor Expertise and Mental Rotation Performance in Gymnastics
    (Nova Science Publisher's Inc, 2016) ;
    Heinen, Thomas 
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    Heinen, Thomas
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    Goebel, Ruben
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    Velentzas, Konstantinos
      5