scholarly journals Extraordinary Fast-Twitch Fiber Abundance in Elite Weightlifters

2018 ◽  
Author(s):  
Nathan Serrano ◽  
Lauren M. Colenso-Semple ◽  
Kara K. Lazauskus ◽  
Jeremy W. Siu ◽  
James R. Bagley ◽  
...  
Keyword(s):  
Body Mass ◽  
Vastus Lateralis ◽  
Muscle Performance ◽  
Training Experience ◽  
Mhc I ◽  
Potential Link ◽  
National Training ◽  
Fast Twitch ◽  
Time Frames ◽  
Mhc Iia

ABSTRACTHuman skeletal muscle fibers exist across a continuum of slow → fast-twitch. The amount of each fiber type (FT) influences muscle performance but remains largely unexplored in elite athletes, particularly from strength/power sports. To address this nescience, vastus lateralis (VL) biopsies were performed on World/Olympic (female, n=6, “WCF”) and National-caliber (female, n=9, “NCF”; and male, n=6, “NCM”) American weightlifters. Participant accolades included 3 Olympic Games, 19 World Championships, 25 National records, and >170 National/International medals. Samples were analyzed for myosin heavy chain (MHC) content via SDS-PAGE using two distinct techniques: single fiber (SF) distribution (%) and homogenate (HG) composition. These athletes displayed the highest MHC IIa concentrations ever reported in healthy VL (23±9% I, 5±3% I/IIa, 67±13% IIa, and 6±10% IIa/IIx), with WCF expressing a notable 71±17% (NCF=67±8%, NCM=63±16%). The heavyweights accounted for 91% of the MHC IIa/IIx fibers. When compared to SF, HG overestimated MHC I (23±9 vs. 31±9%) and IIx (0±0 vs. 3±6%) by misclassifying I/IIa fibers as I and IIa/IIx fibers as IIx. These findings suggest athlete caliber (World vs. National), training experience, and body mass determine FT% more than sex and refutes the common pronouncement that women possess more slow and fewer fast-twitch fibers than men. Our results also show the abundance of pure MHC IIa and rarity of IIx in elite strength/power-trained athletes, indicate a potential link between MHC IIa/IIx frequency and body mass, and question the fidelity of HG as a measure of FT% distribution. The extreme fast-twitch abundance partially explains how elite weightlifters generate high forces in rapid time-frames. These data highlight the need for more cellular and molecular muscle research on elite anaerobic athletes.

scholarly journals A new method to study in vivo protein synthesis in slow- and fast-twitch muscle fibers and initial measurements in humans

2010 ◽  
Vol 108 (5) ◽  
pp. 1410-1416 ◽  
Author(s):  
J. M. Dickinson ◽  
J. D. Lee ◽  
B. E. Sullivan ◽  
M. P. Harber ◽  
S. W. Trappe ◽  
...  
Keyword(s):  
Fiber Type ◽  
Vastus Lateralis ◽  
Muscle Fibers ◽  
Human Muscle ◽  
Synthesis Rate ◽  
Mhc I ◽  
Fast Twitch ◽  
Mixed Protein ◽  
Mhc Iia

The aim of this study was to develop an approach to directly assess protein fractional synthesis rate (FSR) in isolated human muscle fibers in a fiber type-specific fashion. Individual muscle fibers were isolated from biopsies of the vastus lateralis (VL) and soleus (SOL) obtained from eight young men during a primed, continuous infusion of [5,5,5-2H3]leucine performed under basal conditions. To determine mixed protein FSR, a portion of each fiber was used to identify fiber type, fibers of the same type were pooled, and the [5,5,5-2H3]leucine enrichment was determined via GC-MS. Processing isolated slow-twitch [myosin heavy chain (MHC) I] and fast-twitch (MHC IIa) fibers for mixed protein bound [5,5,5-2H3]leucine enrichment yielded mass ion chromatographic peaks that were similar in shape, abundance, and measurement reliability as tissue homogenates. In the VL, MHC I fibers exhibited a 33% faster ( P < 0.05) mixed protein FSR compared with MHC IIa fibers (0.068 ± 0.006 vs. 0.051 ± 0.003%/h). MHC I fibers from the SOL (0.060 ± 0.005%/h) and MHC I fibers from the VL displayed similar ( P > 0.05) mixed protein FSR. Feasibility of processing isolated human muscle fibers for analysis of myofibrillar protein [5,5,5-2H3]leucine enrichment was also confirmed in non-fiber-typed pooled fibers from the VL. These methods can be applied to the study of fiber type-specific responses in human skeletal muscle. The need for this level of investigation is underscored by the different contributions of each fiber type to whole muscle function and the numerous distinct adaptive functional and metabolic changes in MHC I and MHC II fibers originating from the same muscle.

Phenotypic adaptations in human muscle fibers 6 and 24 wk after spinal cord injury

2002 ◽  
Vol 92 (1) ◽  
pp. 147-154 ◽  
Author(s):  
R. J. Talmadge ◽  
M. J. Castro ◽  
D. F. Apple ◽  
G. A. Dudley
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Vastus Lateralis ◽  
Muscle Fibers ◽  
Early Time ◽  
Mhc I ◽  
Time Period ◽  
Plasmic Reticulum ◽  
Cord Injury ◽  
Mhc Iia

10.1152/japplphysiol.000247.2001.—The effects of spinal cord injury (SCI) on the profile of sarco(endo) plasmic reticulum calcium-ATPase (SERCA) and myosin heavy chain (MHC) isoforms in individual vastus lateralis (VL) muscle fibers were determined. Biopsies from the VL were obtained from SCI subjects 6 and 24 wk postinjury ( n = 6). Biopsies from nondisabled (ND) subjects were obtained at two time points 18 wk apart ( n = 4). In ND subjects, the proportions of VL fibers containing MHC I, MHC IIa, and MHC IIx were 46 ± 3, 53 ± 3, and 1 ± 1%, respectively. Most MHC I fibers contained SERCA2. Most MHC IIa fibers contained SERCA1. All MHC IIx fibers contained SERCA1 exclusively. SCI resulted in significant increases in fibers with MHC IIx (14 ± 4% at 6 wk and 16 ± 2% at 24 wk). In addition, SCI resulted in high proportions of MHC I and MHC IIa fibers with both SERCA isoforms (29% at 6 wk and 54% at 24 wk for MHC I fibers and 16% at 6 wk and 38% at 24 wk for MHC IIa fibers). Thus high proportions of VL fibers were mismatched for SERCA and MHC isoforms after SCI (19 ± 3% at 6 wk and 36 ± 9% at 24 wk) compared with only ∼5% in ND subjects. These data suggest that, in the early time period following SCI, fast fiber isoforms of both SERCA and MHC are elevated disproportionately, resulting in fibers that are mismatched for SERCA and MHC isoforms. Thus the adaptations in SERCA and MHC isoforms appear to occur independently.

scholarly journals Human vastus lateralis and soleus muscles display divergent cellular contractile properties

2008 ◽  
Vol 295 (5) ◽  
pp. R1593-R1598 ◽  
Author(s):  
Nicholas Luden ◽  
Kiril Minchev ◽  
Erik Hayes ◽  
Emily Louis ◽  
Todd Trappe ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Contractile Function ◽  
Vastus Lateralis ◽  
Single Fiber ◽  
Muscle Adaptation ◽  
Shortening Velocity ◽  
Mhc I ◽  
Myosin Heavy Chain Isoform ◽  
I 18 ◽  
Mhc Iia

The purpose of this study was to investigate potential differences in single-fiber contractile physiology of fibers with the same myosin heavy chain isoform (MHC I and MHC IIa) originating from different muscles. Vastus lateralis (VL) and soleus biopsies were obtained from 27 recreationally active females (31 ± 1 yr, 59 ± 1 kg). A total of 943 single fibers (MHC I = 562; MHC IIa = 301) were isolated and examined for diameter, peak tension (Po), shortening velocity (Vo), and power. The soleus had larger ( P < 0.05) fibers (MHC I +18%; MHC IIa +19%), higher MHC I Vo (+13%), and higher MHC I Po (+18%) compared with fibers from the VL. In contrast, fibers from the VL had higher ( P < 0.05) specific tension (MHC I +18%; MHC IIa +20%), and MHC I normalized power (+25%) compared with the soleus. There was a trend for MHC IIa soleus fibers to have higher Vo [MHC IIa +13% ( P = 0.058)], whereas VL MHC IIa fibers showed a trend for higher normalized power compared with soleus fibers [MHC IIa +33% ( P = 0.079)]. No differences in absolute power were detected between muscles. These data highlight muscle-specific differences in single-fiber contractile function that should serve as a scientific basis for consideration when extending observations of skeletal muscle tissue from one muscle of interest to other muscles of origin. This is important when examining skeletal muscle adaptation to physical states such as aging, unloading, and training.

scholarly journals Effect of Eccentric and Concentric Contraction Mode on Myogenic Regulatory Factors Expression in Human Vastus Lateralis Muscle

2021 ◽  
Author(s):  
Mostafa Sabouri ◽  
Pejman Taghibeikzadehbadr ◽  
Fatemeh Shabkhiz ◽  
Zahra Izanloo ◽  
Farahnaz Amir Shaghaghi
Keyword(s):  
Vastus Lateralis ◽  
Vastus Lateralis Muscle ◽  
Myogenic Regulatory Factors ◽  
Mhc I ◽  
Regulatory Factors ◽  
Isokinetic Contraction ◽  
Concentric Contraction ◽  
Significant Difference ◽  
Lateralis Muscle ◽  
Mhc Iia

Abstract Background: Skeletal muscle contractions are caused to release myokines by muscle fiber. This study investigated the myogenic regulatory factors, as MHC I, IIA, IIX, Myo-D, MRF4, Murf, Atrogin-1, Decorin, Myonection, and IL-15 mRNA expression in the response of eccentric vs. concentric contraction. Methods: Eighteen healthy men were randomly divided into two eccentric and concentric groups, each of 9 persons. Isokinetic contraction protocols included maximal single-leg eccentric or concentric knee extension tasks at 60°/s with the dominant leg. Contractions consisted of a maximum of 12 sets of 10 reps, and the rest time between each set was 30 seconds. The baseline biopsy was performed four weeks before the study, and post-test biopsies were taken immediately after exercise protocols from Vastus Lateralis muscle. The gene expression levels evaluated using Real-Time PCR methods. Results: A significant difference in MyoD, MRF4, Myonection, and Decorin mRNA, were observed following eccentric or concentric contractions (P≤0.05). The MHC I, MHC IIA, IL-15 mRNA has been changed significantly compared to the pre-exercise in the concentric group (P≤0.05). While only MHC IIX and Atrogin-1 mRNA changed significantly in the eccentric group (P≤0.05). Additionally, the results showed a significant difference in MyoD, MRF4, IL-15, and Decorin were observed at the follow-up values between eccentric or concentric groups (P≤0.05). Conclusion: Our findings highlight the growing importance of elucidating the different responses of muscle growth factors associated with a myogenic activity such as MHC IIA, Decorin, IL-15, Myonectin, Decorin, MuRF1, and MHC IIX mRNA in following to various types of exercise.

Effect of resistance training on single muscle fiber contractile function in older men

2000 ◽  
Vol 89 (1) ◽  
pp. 143-152 ◽  
Author(s):  
Scott Trappe ◽  
David Williamson ◽  
Michael Godard ◽  
David Porter ◽  
Greg Rowden ◽  
...  
Keyword(s):  
Resistance Training ◽  
Muscle Fiber ◽  
Contractile Function ◽  
Vastus Lateralis ◽  
Muscle Fibers ◽  
Older Men ◽  
Single Muscle ◽  
Mhc I ◽  
Before And After ◽  
Mhc Iia

The purpose of this study was to examine single cell contractile mechanics of skeletal muscle before and after 12 wk of progressive resistance training (PRT) in older men ( n = 7; age = 74 ± 2 yr and weight = 75 ± 5 kg). Knee extensor PRT was performed 3 days/wk at 80% of one-repetition maximum. Muscle biopsy samples were obtained from the vastus lateralis before and after PRT (pre- and post-PRT, respectively). For analysis, chemically skinned single muscle fibers were studied at 15°C for peak tension [the maximal isometric force (Po)], unloaded shortening velocity ( V o), and force-velocity parameters. In this study, a total of 199 (89 pre- and 110 post-PRT) myosin heavy chain (MHC) I and 99 (55 pre- and 44 post-PRT) MHC IIa fibers were reported. Because of the minimal number of hybrid fibers identified post-PRT, direct comparisons were limited to MHC I and IIa fibers. Muscle fiber diameter increased 20% (83 ± 1 to 100 ± 1 μm) and 13% (86 ± 1 to 97 ± 2 μm) in MHC I and IIa fibers, respectively ( P < 0.05). Po was higher ( P < 0.05) in MHC I (0.58 ± 0.02 to 0.90 ± 0.02 mN) and IIa (0.68 ± 0.02 to 0.85 ± 0.03 mN) fibers. Muscle fiber V o was elevated 75% (MHC I) and 45% (MHC IIa) after PRT ( P < 0.05). MHC I and IIa fiber power increased ( P < 0.05) from 7.7 ± 0.5 to 17.6 ± 0.9 μN · fiber lengths · s−1 and from 25.5 to 41.1 μN · fiber lengths · s−1, respectively. These data indicate that PRT in elderly men increases muscle cell size, strength, contractile velocity, and power in both slow- and fast-twitch muscle fibers. However, it appears that these changes are more pronounced in the MHC I muscle fibers.

scholarly journals Immediate Effect of Kinesio Taping on Muscle Response in Young Elite Soccer Players

2013 ◽  
Vol 22 (1) ◽  
pp. 53-58 ◽  
Author(s):  
Moisés de Hoyo ◽  
Alejandro Álvarez-Mesa ◽  
Borja Sañudo ◽  
Luis Carrasco ◽  
Sergio Domínguez
Keyword(s):  
Outcome Measures ◽  
Body Mass ◽  
Sports Medicine ◽  
Vastus Lateralis ◽  
Random Order ◽  
Muscle Performance ◽  
Soccer Players ◽  
Kinesio Taping ◽  
University Laboratory ◽  
Taping Technique

Context:Kinesio taping (KT) is a new taping technique increasingly used in sports medicine to improve muscle performance; however, its real effect is not entirely known.Objective:To assess the immediate effects of KT on muscle performance in young healthy elite soccer players.Design:Crossover study.Setting:University laboratory.Participants:Eighteen young elite soccer players voluntarily participated in the study (mean ± SEM: age 18.20 ± 2.45 y, height 1.76 ± 3.56 m, body mass 65.25 ± 3.76 kg, body-mass index 20.12 ± 1.25 kg/m2).Interventions:Each subject completed 2 different protocols, with and without KT. Interventions were performed in a random order, with a washout period between conditions of 1 wk.Main Outcome Measures:Outcome measures included tensiomyographic response in the vastus lateralis and vastus medialis, power output with 30 and 50 kg, countermovement jump, and 10-m sprint.Results:Data showed no significant differences for any of the outcomes analyzed between interventions.Conclusions:KT does not produce a short-term improvement in muscle performance in young elite soccer players.

scholarly journals Reduction in hybrid single muscle fiber proportions with resistance training in humans

2001 ◽  
Vol 91 (5) ◽  
pp. 1955-1961 ◽  
Author(s):  
D. L. Williamson ◽  
P. M. Gallagher ◽  
C. C. Carroll ◽  
U. Raue ◽  
S. W. Trappe
Keyword(s):  
Resistance Training ◽  
Muscle Fiber ◽  
Vastus Lateralis ◽  
Electrophoretic Analysis ◽  
Training Data ◽  
Single Muscle ◽  
Hybrid Fibers ◽  
Mhc I ◽  
Single Muscle Fiber ◽  
Mhc Iia

The purpose of this investigation was to examine the effects of 12 wk of progressive resistance training (PRT) on single muscle fiber myosin heavy chain (MHC; I, I/IIa, I/IIa/IIx, IIa, IIa/IIx, IIx) isoform proportions in young individuals. Young, untrained men (YM; n = 6) and women (YW; n = 6) (age = 22 ± 1 and 25 ± 2 yr for YW and YM, respectively) received pre- and post-PRT muscle biopsies from the right vastus lateralis for single muscle fiber MHC distribution by electrophoretic analysis (192 ± 5 pre- and 183 ± 6 post-fibers/subject analyzed; 4,495 fibers total). Data are presented as percentages of the total fibers analyzed per subject. The PRT protocol elicited an increase in the pure MHC IIa (Δ = + 24 and + 27; YW and YM, respectively; P < 0.05) with no change in the pure MHC I distribution. The hybrid MHC distributions decreased I/IIa/IIx (Δ = −2; YM and YW; P < 0.05), IIa/IIx (Δ = −13 and −19 for YM and YW, respectively; P < 0.05), and total hybrid fiber proportion (I/IIa + I/IIa/IIx + IIa/IIx) decreased (Δ = −19 and −30 for YM and YW, respectively; P < 0.05) with the training, as did the MHC IIx distribution (Δ = −2; YW only; P < 0.05). Alterations in the predominance of MHC isoforms within hybrid fibers (decrease in MHC I-dominant I/IIa and nondominant MHC IIa/IIx, increase in MHC IIa-dominant IIa/IIx; P < 0.05) appeared to contribute to the increase in the MHC IIa proportion. Electrophoresis of muscle cross sections revealed an ∼7% increase ( P< 0.05) in MHC IIa proportion in both groups, whereas the MHC IIx decrease by 7.5 and 11.6% post-PRT in YW and YM, respectively. MHC I proportions increase in YM by 4.8% ( P < 0.05) post-PRT. These findings further support previous resistance training data in young adults with respect to the increase in the MHC IIa proportions but demonstrate that a majority of the change can be attributed to the decrease in single-fiber hybrid proportions.

Proteolytic mRNA expression in response to acute resistance exercise in human single skeletal muscle fibers

2006 ◽  
Vol 101 (5) ◽  
pp. 1442-1450 ◽  
Author(s):  
Yifan Yang ◽  
Bozena Jemiolo ◽  
Scott Trappe
Keyword(s):  
Skeletal Muscle ◽  
Mrna Expression ◽  
Caspase 3 ◽  
Muscle Fibers ◽  
Fiber Types ◽  
Mrna Levels ◽  
Mhc I ◽  
Mrna Ratio ◽  
Fast Twitch ◽  
Mhc Iia

The purpose of this study was to characterize changes in mRNA expression of select proteolytic markers in human slow-twitch [myosin heavy chain (MHC) I] and fast-twitch (MHC IIa) single skeletal muscle fibers following a bout of resistance exercise (RE). Muscle biopsies were obtained from the vastus lateralis of eight young healthy sedentary men [23 ± 2 yr (mean ± SD), 93 ± 17 kg, 183 ± 6 cm] before and 4 and 24 h after 3 × 10 repetitions of bilateral knee extensions at 65% of one repetition maximum. The mRNA levels of TNF-α, calpains 1 and 2, muscle RING (really interesting novel gene) finger-1 (MuRF-1), atrogin-1, caspase-3, B-cell leukemia/lymphoma (Bcl)-2, and Bcl-2-associated X protein (Bax) were quantified using real-time RT-PCR. Generally, MHC I fibers had higher (1.6- to 5.0-fold, P < 0.05) mRNA expression pre- and post-RE. One exception was a higher (1.6- to 3.9-fold, P < 0.05) Bax-to-Bcl-2 mRNA ratio in MHC IIa fibers pre- and post-RE. RE increased (1.4- to 4.8-fold, P < 0.05) MuRF-1 and caspase-3 mRNA levels 4–24 h post-RE in both fiber types, whereas Bax-to-Bcl-2 mRNA ratio increased 2.2-fold ( P < 0.05) at 4 h post-RE only in MHC I fibers. These results suggest that MHC I fibers have a greater proteolytic mRNA expression pre- and post-RE compared with MHC IIa fibers. The greatest mRNA induction following RE was in MuRF-1 and caspase-3 in both fiber types. This altered and specific proteolytic mRNA expression among slow- and fast-twitch muscle fibers indicates that the ubiquitin/proteasomal and caspase pathways may play an important role in muscle remodeling with RE.

Single muscle fiber adaptations with marathon training

2006 ◽  
Vol 101 (3) ◽  
pp. 721-727 ◽  
Author(s):  
Scott Trappe ◽  
Matthew Harber ◽  
Andrew Creer ◽  
Philip Gallagher ◽  
Dustin Slivka ◽  
...  
Keyword(s):  
Muscle Fiber ◽  
Fiber Types ◽  
Functional Profile ◽  
Mhc I ◽  
Marathon Training ◽  
Fiber Size ◽  
Fast Twitch Muscle ◽  
Slow Twitch ◽  
Fast Twitch ◽  
Mhc Iia

The purpose of this investigation was to characterize the effects of marathon training on single muscle fiber contractile function in a group of recreational runners. Muscle biopsies were obtained from the gastrocnemius muscle of seven individuals (22 ± 1 yr, 177 ± 3 cm, and 68 ± 2 kg) before, after 13 wk of run training, and after 3 wk of taper. Slow-twitch myosin heavy chain [(MHC) I] and fast-twitch (MHC IIa) muscle fibers were analyzed for size, strength (Po), speed ( Vo), and power. The run training program led to the successful completion of a marathon (range 3 h 56 min to 5 h 35 min). Oxygen uptake during submaximal running and citrate synthase activity were improved ( P < 0.05) with the training program. Muscle fiber size declined ( P < 0.05) by ∼20% in both fiber types after training. Po was maintained in both fiber types with training and increased ( P < 0.05) by 18% in the MHC IIa fibers after taper. This resulted in >60% increase ( P < 0.05) in force per cross-sectional area in both fiber types. Fiber Vo increased ( P < 0.05) by 28% in MHC I fibers with training and was unchanged in MHC IIa fibers. Peak power increased ( P < 0.05) in MHC I and IIa fibers after training with a further increase ( P < 0.05) in MHC IIa fiber power after taper. These data show that marathon training decreased slow-twitch and fast-twitch muscle fiber size but that it maintained or improved the functional profile of these fibers. A taper period before the marathon further improved the functional profile of the muscle, which was targeted to the fast-twitch muscle fibers.

Single muscle fiber contractile properties of young competitive distance runners

2008 ◽  
Vol 105 (2) ◽  
pp. 629-636 ◽  
Author(s):  
Matthew Harber ◽  
Scott Trappe
Keyword(s):  
Fiber Type ◽  
Peak Force ◽  
Contractile Properties ◽  
Fiber Types ◽  
Distance Runners ◽  
Cross Sectional ◽  
Mhc I ◽  
Contraction Velocity ◽  
Fast Twitch ◽  
Mhc Iia

The purpose of this investigation was to characterize the contractile properties of individual slow- and fast-twitch myofibers from highly trained distance runners. Muscle biopsies were obtained from the gastrocnemius of eight competitive runners (Run) and eight recreationally active individuals (Rec). Slow-twitch [myosin heavy chain (MHC) I] and fast-twitch (MHC IIa) myofibers were isolated and analyzed for diameter (μm), peak force (Po; mN), unloaded contraction velocity ( Vo; fiber lengths/s), and power. Maximum oxygen uptake was higher ( P < 0.05) in Run (71 ± 1 vs. 47 ± 2 ml·kg−1·min−1). Diameter of MHC I and MHC IIa fibers from Run subjects was ∼20% greater ( P < 0.05) than Rec. Peak force of the MHC IIa fibers was 31% higher ( P < 0.05) in Run, whereas Po of MHC I fibers was not different between groups. No differences for specific tension (Po/cross-sectional area) were present between groups for either fiber type. Vo was higher ( P < 0.05) in MHC I (+70%) and MHC IIa (+18%) fibers from Run subjects. In vitro peak absolute power (μN·s−1) of both fiber types was greater ( P < 0.05) in Run (131 and 85% for MHC I and MHC IIa, respectively). Additionally, normalized power (W/l) of the MHC I fibers was 64% higher in Run, whereas no differences were noted for normalized power of MHC IIa fibers. These data indicate that highly trained endurance runners have elevated contraction velocity in both slow- and fast-twitch myofibers. These characteristics of the fast-twitch muscle fibers have not been previously reported in competitive endurance athletes and may contribute to the high level of running performance in these athletes.

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