Myosin heavy chain IIX overshoot in human skeletal muscle

Andersen, Jesper L.; Aagaard, Per

doi:10.1002/1097-4598(200007)23:7<1095::aid-mus13>3.0.co;2-o

Cited by 287 publications

(252 citation statements)

References 45 publications

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“…A vast majority of exercises used in strength training involve resistance against concentric as well as eccentric loads. Combined concentric/eccentric leg extension exercise has been shown to eVectively increase the cross-sectional area (CSA) of the quadriceps femoris muscle (Narici et al 1996;Ahtiainen et al 2003), as well as Wbre CSAs, especially of type II (fast) Wbres (Hortobágyi et al 1996;McCall et al 1996;Andersen and Aagaard 2000;Hortobágyi et al 2000;Aagaard et al 2001;Campos et al 2002;Kosek et al 2006).…”

Section: Introductionmentioning

confidence: 99%

Effects of strength training with eccentric overload on muscle adaptation in male athletes

et al. 2009

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In classic concentric/eccentric exercise, the same absolute load is applied in concentric and eccentric actions, which infers a smaller relative eccentric load. We compared the effects of 6 weeks of classic concentric/eccentric quadriceps strength training (CON/ECC, 11 subjects) to eccentric overload training (CON/ECC+, 14 subjects) in athletes accustomed to regular strength training. The parameters determined included functional tests, quadriceps and fibre cross-sectional area (CSA), fibre type distribution by ATPase staining, localisation of myosin heavy chain (MHC) isoform mRNAs by situ hybridization and the steady-state levels of 48 marker mRNAs (RT-PCR) in vastus lateralis biopsies taken before and after training. Both training forms had anabolic effects with significant increases in quadriceps CSA, maximal strength, ribosomal RNA content and the levels of mRNAs involved in growth and regeneration. Only the CON/ECC+ training led to significantly increased height in a squat jump test. This was accompanied by significant increases in IIX fibre CSA, in the percentage of type IIA fibres expressing MHC IIx mRNA, in the level of mRNAs preferentially expressed in fast, glycolytic fibres, and in post-exercise capillary lactate. The enhanced eccentric load apparently led to a subtly faster gene expression pattern and induced a shift towards a faster muscle phenotype plus associated adaptations that make a muscle better suited for fast, explosive movements.

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Section: Introductionmentioning

confidence: 99%

Effects of strength training with eccentric overload on muscle adaptation in male athletes

et al. 2009

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“…In addition, the influences on some muscle characteristics exerted by a decrease in the amount of physical activity following a period of physical training have been examined in detraining studies (Andersen and Aagaard 2000;Francaux and Poortmans 1999;Komulainen and Vihko 1995;Serrano and Rivero 2000;Shima et al 2002;Wibom et al 1992). Some of these studies focused on the influence of detraining on the functional and structural characteristics of mammalian skeletal muscles.…”

Section: Introductionmentioning

confidence: 99%

“…Some of these studies focused on the influence of detraining on the functional and structural characteristics of mammalian skeletal muscles. The results of these studies indicated a relative increase in the fast MHC isoform and a decrease in some muscle oxidative enzyme activities in humans (Andersen and Aagaard 2000;Wibom et al 1992), and a decrease in the CSA of slow muscle fibers in the horse (Serrano and Rivero 2000) after a given detraining period following either resistance training (Andersen and Aagaard 2000) or endurance training (Serrano and Rivero 2000;Wibom et al 1992). On that basis, it seems clear that a complete cessation of physical training leads to the disappearance of at least some training effects on the functional and structural characteristics of mammalian skeletal muscles.…”

Section: Introductionmentioning

confidence: 99%

Effects of prolonged voluntary wheel-running on muscle structure and function in rat skeletal muscle

Kariya

Yamauchi

Kobayashi

et al. 2004

European Journal of Applied Physiology

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We examined the effects of prolonged voluntary wheel-running on skeletal muscle functional and/or structural characteristics in rats. Male Sprague-Dawley rats (5 weeks old) were divided into five groups: (1) 15W-SC, sedentary controls housed in normal plastic cages until age 15 weeks; (2) 15W-VE, housed in a voluntary-exercise (running-wheel) device equipped with housing space until age 15 weeks; (3) 35W-SC, housed in normal plastic cages until age 35 weeks; (4) 35W-VE, housed in the voluntary-exercise device until age 35 weeks, and (5) 35W-MVE, housed in normal plastic cages until age 15 weeks, then in the voluntary-exercise device from age 16 weeks to 35 weeks ("middle age"). At the end of each rat's experimental period, the plantaris muscle was dissected from each hindlimb for analysis of the muscle's functional and/or structural characteristics. Total running distance was similar in 15W-VE and 35W-VE, both being significantly greater than in 35-MVE. The percentage of type IIb myosin heavy chain isoform was significantly lower in each VE group than in the corresponding SC group. This shift from type IIb was significantly greater for 35W-VE than for the other VE groups, which were similar to each other. The cross-sectional area of type IIx fibers was significantly greater in 35W-VE than in 35W-SC, but this was not true for 15W-VE versus 15W-SC or for 35W-MVE versus 35W-SC. No significant difference in citrate synthase activity was detected between any VE group and the corresponding SC group. These results suggest that a prolongation of voluntary wheel-running leads to some advantageous enhancements of functional and/or structural characteristics in rat plantaris.

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“…Descriptive statistical analysis was done using the software and this allowed for the determination of the relative proportion of the various fibre types and CSAs. In order to obtain a reasonable number of fibres as foundation for the analysis of the fibre CSA for each fibre type we decided to reduce this analysis to the three main fibre types (for details of reduction see Andersen and Aagaard 2000) Gel electrophoresis MHC analysis was performed on the muscle biopsies using sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). Twenty to forty serial cross-sections (20 lm) were cut from each biopsy.…”

Section: Histomorphometric Analysismentioning

confidence: 99%

“…changes in firing rate) and muscle fibres. The muscle fibres are highly sensitive to changes in muscle activity; training can result in changed fibre areas and changed composition of MHC (Andersen et al 1994;Andersen and Aagaard 2000). Earlier (Basmajian and DeLuca 1985) and more recent (Blok et al 1999) models of the EMG signal in the frequency domain do not use fibre types.…”

Section: Relationships Between Mhc Isoforms and Emgmentioning

confidence: 99%

Myosin heavy chain isoforms influence surface EMG parameters: a study of the trapezius muscle in cleaners with and without myalgia and in healthy teachers

Larsson

Andersen

Kadi

et al. 2002

European Journal of Applied Physiology

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The present study had two aims: (1) to investigate potential differences in proportion of myosin heavy chain isoforms in the trapezius muscle between female cleaners with and without trapezius myalgia and healthy teachers, and (2) to elucidate if myosin heavy chain composition and surface electromyogram (EMG) during an isokinetic endurance test of shoulder flexors are significantly related. The subjects were divided into three groups: (1) 25 female cleaners with diagnosed work-related trapezius myalgia; (2) 25 female cleaners without work-related trapezius myalgia; (3) a control group of 21 healthy female teachers who were not exposed to repetitive or static muscle work. All subjects performed a test involving150 forward flexions using an isokinetic dynamometer. During the test surface EMG was recorded from the trapezius muscle. Muscle samples were obtained from the descending part of the trapezius muscle. The fibre type area percentage based on ATPase staining and the proportions of different MHC isoforms as determined by gel electrophoresis. The trapezius was dominated by MHC I (71%), followed by MHC IIA (22-24%), and MHC IIX (5-7%); no significant differences between the three groups of subjects were found. The proportion of MHC I correlated negatively with MHC IIA ( r=-0.78; P<0.001) and MHC IIX ( r=-0.53; P<0.001). Significant correlations existed between the proportion of the MHC isoforms and the corresponding proportion of the fibre type area; 27-45% of the variance was explained. The multivariate analysis of the three groups of subjects revealed that MHC variables showed intercorrelations with EMG (both amplitude and frequency variables). However, the directions of the relationships differed among the three groups; the cleaners with myalgia and the teachers showed the greatest similarities in patterns. Intrinsic muscle properties appear to influence the frequency content of the EMG, which is in contrast to some of the theoretical models of the EMG. Our data could suggest that monotonous work such as professional cleaning can change the relationships between muscle structure and the frequency content of the EMG.

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Myosin heavy chain IIX overshoot in human skeletal muscle

Cited by 287 publications

References 45 publications

Effects of strength training with eccentric overload on muscle adaptation in male athletes

Effects of strength training with eccentric overload on muscle adaptation in male athletes

Effects of prolonged voluntary wheel-running on muscle structure and function in rat skeletal muscle

Myosin heavy chain isoforms influence surface EMG parameters: a study of the trapezius muscle in cleaners with and without myalgia and in healthy teachers

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