scholarly journals Contractile properties of motor units and expression of myosin heavy chain isoforms in rat fast-type muscle after volitional weight-lifting training

2016 ◽  
Vol 121 (4) ◽  
pp. 858-869 ◽  
Author(s):  
Dawid Łochyński ◽  
Dominik Kaczmarek ◽  
Włodzimierz Mrówczyński ◽  
Wojciech Warchoł ◽  
Joanna Majerczak ◽  
...  
Keyword(s):  
Resistance Training ◽  
Myosin Heavy Chain ◽  
Heavy Chain ◽  
Motor Units ◽  
Weight Lifting ◽  
Contractile Properties ◽  
Medial Gastrocnemius ◽  
Maximum Force ◽  
Force Frequency ◽  
Contractile Characteristics

Dynamic resistance training increases the force and speed of muscle contraction, but little is known about modifications to the contractile properties of the main physiological types of motor units (MUs) that contribute to these muscle adaptations. Although the contractile profile of MU muscle fibers is tightly coupled to myosin heavy chain (MyHC) protein expression, it is not well understood if MyHC transition is a prerequisite for modifications to the contractile characteristics of MUs. In this study, we examined MU contractile properties, the mRNA expression of MyHC, parvalbumin, and sarcoendoplasmic reticulum Ca2+pump isoforms, as well as the MyHC protein content after 5 wk of volitional progressive weight-lifting training in the medial gastrocnemius muscle in rats. The training had no effect on MyHC profiling or Ca2+-handling protein gene expression. Maximum force increased in slow (by 49%) and fast (by 21%) MUs. Within fast MUs, the maximum force increased in most fatigue-resistant and intermediate but not most fatigable MUs. Twitch contraction time was shortened in slow and fast fatigue-resistant MUs. Twitch half-relaxation was shortened in fast most fatigue-resistant and intermediate MUs. The force-frequency curve shifted rightward in fast fatigue-resistant MUs. Fast fatigable MUs fatigued less within the initial 15 s while fast fatigue-resistant units increased the ability to potentiate the force within the first minute of the standard fatigue test. In conclusion, at the early stage of resistance training, modifications to the contractile characteristics of MUs appear in the absence of MyHC transition and the upregulation of Ca2+-handling genes.

Adaptations in physiological properties of rat motor units following 5 weeks of whole-body vibration

2013 ◽  
Vol 38 (9) ◽  
pp. 913-921 ◽  
Author(s):  
Dawid Łochyński ◽  
Marcin Bączyk ◽  
Dominik Kaczmarek ◽  
Maria Jolanta Rędowicz ◽  
Jan Celichowski ◽  
...  
Keyword(s):  
Myosin Heavy Chain ◽  
Heavy Chain ◽  
Whole Body Vibration ◽  
Motor Units ◽  
Medial Gastrocnemius ◽  
Whole Body ◽  
Force Frequency ◽  
Body Vibration ◽  
Myosin Heavy Chain Isoform ◽  
Twitch Contraction

The purpose of the study was to determine the effects of 5-week whole-body vibration (WBV) on contractile parameters and force–frequency relationship of functionally isolated motor units of the rat medial gastrocnemius muscle: fast fatigable (FF), fast fatigue-resistant (FR), and slow (S). Moreover, myosin heavy chain isoform content was quantified. Following WBV, the maximum tetanic force of FF units was increased by ∼25%. The twitch half-relaxation time in all types of motor units and the twitch contraction time in FR units were shortened. The twitch-to-tetanus force ratio was decreased and the force–frequency curves were shifted rightwards in S and FR units. Myosin heavy chain distribution was not changed. These findings suggest modifications of the excitation–contraction coupling towards shortening of a twitch contraction. The observed increase in force of FF units may contribute to gains in muscle dynamic strength reported following WBV treatment.

Enzymatic plasticity of medial gastrocnemius fibers in the adult chronic spinal cat

1990 ◽  
Vol 259 (3) ◽  
pp. C507-C514 ◽  
Author(s):  
B. Jiang ◽  
R. R. Roy ◽  
V. R. Edgerton
Keyword(s):  
Myosin Heavy Chain ◽  
Heavy Chain ◽  
Fiber Type ◽  
Motor Units ◽  
Glycolytic Enzyme ◽  
Medial Gastrocnemius ◽  
Fiber Types ◽  
Cross Sectional ◽  
Fast Myosin ◽  
Weight Support

The metabolic plasticity of single fibers in adult cat medial gastrocnemius (MG) 6 mo after complete spinal cord transection (Sp) at T12-T13 was studied. Some Sp cats were trained to weight support (Sp-WS) 30 min/day beginning 1 mo posttransection. Cross-sectional area, succinate dehydrogenase (SDH), alpha-glycerophosphate dehydrogenase (GPD), and myofibrillar adenosinetriphosphatase (ATPase) activities were determined in fibers identified in frozen serial sections. Fibers were categorized as light or dark based on myosin ATPase staining, alkaline preincubation. The percentage of dark ATPase fibers was higher in Sp and Sp-WS (approximately 85%) than in control (approximately 60%). All dark ATPase fibers reacted positively to a fast myosin heavy chain monoclonal antibody. In both spinal groups, a higher percentage of dark ATPase fibers reacted to both fast and slow myosin heavy chain antibodies than in controls. Neither Sp nor Sp-WS cats showed fiber atrophy. Compared with control, SDH activity was decreased in both fiber types of Sp cats. Daily weight-support training ameliorated this adaptation. There were no differences among the three groups in mean GPD and ATPase activities for either fiber type. There was a slight tendency, however, for spinal cats to have higher GPD and ATPase activities (independent of type) than control, probably reflecting the larger proportion of dark ATPase fibers in these cats. These observations indicate that 6 mo after spinalization in adult cats, some of the fibers of a fast muscle became "faster" and developed oxidative and glycolytic enzyme profiles that normally are exhibited in fast fatigable motor units.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Motor Unit Force Potentiation and Calcium Handling Protein Concentration in Rat Fast Muscle After Resistance Training

2021 ◽  
Vol 12 ◽  
Author(s):  
Dawid Łochyński ◽  
Dominik Kaczmarek ◽  
Marcin Grześkowiak ◽  
Joanna Majerczak ◽  
Tomasz Podgórski ◽  
...  
Keyword(s):  
Resistance Training ◽  
Light Chain ◽  
Myosin Light Chain Kinase ◽  
Myosin Light Chain ◽  
Motor Units ◽  
Weight Lifting ◽  
Medial Gastrocnemius ◽  
Calcium Handling ◽  
Conditioning Stimulation ◽  
40 Hz

Post-tetanic potentiation (PTP) of force depends on intramuscular Ca2+ levels and sensitivity and may be affected by fatigue. The aim of this study was to determine the ability of isolated fast fatigue-resistant (FR) and fast-fatigable (FF) motor units (MUs) to potentiate force evoked with single and 40-Hz electrical stimulation after 5 weeks of voluntary weight-lifting training. Tetanic contractions evoked by gradually increasing (10–150 Hz) stimulation frequency served as conditioning stimulation. Additionally, the concentration of myosin light chain kinase and proteins engaged in calcium handling was measured in rat fast medial gastrocnemius muscle. After the training, the potentiation of twitch force and peak rate of force development was increased in FF but not FR MUs. Force potentiation of 40-Hz tetanic contractions was increased in both fast MU types. After the training, the twitch duration of FR MUs was decreased, and FF MUs were less prone to high-frequency fatigue during conditioning stimulation. Muscle concentration of triadin was increased, whereas concentrations of ryanodine receptor 1, junctin, FKBP12, sarcoplasmic reticulum calcium ATPase 1, parvalbumin, myosin light chain kinase, and actomyosin adenosine triphosphatase content were not modified. After short-term resistance training, the twitch contraction time and twitch:tetanus force ratio of FR MUs are decreased, and PTP ability is not changed. However, PTP capacity is increased in response to submaximal activation. In FF MUs increase in PTP ability coexists with lesser fatigability. Further work is required to find out if the increase in triadin concentration has any impact on the observed contractile response.

Effects of isometric training on skeletal myosin heavy chain expression

1998 ◽  
Vol 84 (6) ◽  
pp. 2036-2041 ◽  
Author(s):  
Fadia Haddad ◽  
Anqi X. Qin ◽  
Ming Zeng ◽  
Sam A. McCue ◽  
Kenneth M. Baldwin
Keyword(s):  
Skeletal Muscle ◽  
Resistance Training ◽  
Myosin Heavy Chain ◽  
Heavy Chain ◽  
Training Programs ◽  
Training Session ◽  
Medial Gastrocnemius ◽  
Type I ◽  
Resistance Training Program ◽  
Relative Expression

This study tested the hypothesis that an isometric resistance-training program induces upregulation of slow myosin heavy chain (MHC) expression in a fast-twitch skeletal muscle. Thus we studied the effects of two resistance-training programs on rodent medial gastrocnemius (MG) muscle that were designed to elicit repetitive isometric contractions (10–12 per set; 4 sets per session) of different duration (8 vs. 5 s) and activation frequency (100 vs. 60 Hz) per contraction during each training session (total of 6 and 12 sessions). Results showed that both training paradigms produced significant increases in muscle weight (∼11–13%) after completion of training ( P < 0.05). Significant transformations in MHC expression occurred and involved specifically a decrease in the relative expression of the fast type IIb MHC and concomitant increased expression of the fast type IIx MHC. These adaptations were observed in both the “white” and “red” regions of the MG, and they occurred at both the mRNA and protein levels. These adaptations were detected after only six training sessions. Neither of the training programs produced any change in the relative expression of either the slow type I MHC or the moderately fast type IIa MHC, which can be upregulated in the red MG by chronic functional overload. These findings show that the isometric protocols used in this investigation were not sufficient to induce the hypothesized changes in the myosin heavy chain isoform expression in rodent skeletal muscle.

High-Intensity Resistance Training with Insufficient Recovery Time Between Bouts Induce Atrophy and Alterations in Myosin Heavy Chain Content in Rat Skeletal Muscle

2011 ◽  
Vol 294 (8) ◽  
pp. 1393-1400 ◽  
Author(s):  
Rodrigo Wagner Alves De Souza ◽  
Andreo Fernando Aguiar ◽  
Fernanda Regina Carani ◽  
Gerson Eduardo Rocha Campos ◽  
Carlos Roberto Padovani ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Resistance Training ◽  
Myosin Heavy Chain ◽  
Heavy Chain ◽  
High Intensity ◽  
Recovery Time ◽  
Rat Skeletal Muscle

scholarly journals Myosin heavy chain isoform profiles remain altered at 7 months if the lacerated medial gastrocnemius is poorly reinnervated: A study in rabbits

2009 ◽  
Vol 28 (6) ◽  
pp. 732-738 ◽  
Author(s):  
Barry P. Pereira ◽  
Hwan Chour Han ◽  
Zou Yu ◽  
Bee-Leng Tan ◽  
Zheng Ling ◽  
...  
Keyword(s):  
Myosin Heavy Chain ◽  
Heavy Chain ◽  
Medial Gastrocnemius ◽  
Myosin Heavy Chain Isoform

Effects of weight lifting training combined with plyometric exercises on physical fitness, body composition, and knee extension velocity during kicking in football

2008 ◽  
Vol 33 (3) ◽  
pp. 501-510 ◽  
Author(s):  
Jorge Perez-Gomez ◽  
Hugo Olmedillas ◽  
Safira Delgado-Guerra ◽  
Ignacio Ara Royo ◽  
German Vicente-Rodriguez ◽  
...  
Keyword(s):  
Body Composition ◽  
Physical Fitness ◽  
Myosin Heavy Chain ◽  
Heavy Chain ◽  
Vertical Jump ◽  
Anaerobic Capacity ◽  
Weight Lifting ◽  
Control Group ◽  
Type I ◽  
Kicking Performance

The effects of a training program consisting of weight lifting combined with plyometric exercises on kicking performance, myosin heavy-chain composition (vastus lateralis), physical fitness, and body composition (using dual-energy X-ray absorptiometry (DXA)) was examined in 37 male physical education students divided randomly into a training group (TG: 16 subjects) and a control group (CG: 21 subjects). The TG followed 6 weeks of combined weight lifting and plyometric exercises. In all subjects, tests were performed to measure their maximal angular speed of the knee during instep kicks on a stationary ball. Additional tests for muscle power (vertical jump), running speed (30 m running test), anaerobic capacity (Wingate and 300 m running tests), and aerobic power (20 m shuttle run tests) were also performed. Training resulted in muscle hypertrophy (+4.3%), increased peak angular velocity of the knee during kicking (+13.6%), increased percentage of myosin heavy-chain (MHC) type IIa (+8.4%), increased 1 repetition maximum (1 RM) of inclined leg press (ILP) (+61.4%), leg extension (LE) (+20.2%), leg curl (+15.9%), and half squat (HQ) (+45.1%), and enhanced performance in vertical jump (all p ≤ 0.05). In contrast, MHC type I was reduced (–5.2%, p ≤ 0.05) after training. In the control group, these variables remained unchanged. In conclusion, 6 weeks of strength training combining weight lifting and plyometric exercises results in significant improvement of kicking performance, as well as other physical capacities related to success in football (soccer).

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