scholarly journals Changes in Muscle Power and Muscle Morphology with Different Volumes of Fast Eccentric Half-Squats

Sports ◽  
2019 ◽  
Vol 7 (7) ◽  
pp. 164 ◽  
Author(s):  
Evangelia Zacharia ◽  
Polyxeni Spiliopoulou ◽  
Spyridon Methenitis ◽  
Angeliki-Nikoletta Stasinaki ◽  
Nikolaos Zaras ◽  
...  
Keyword(s):  
Muscle Power ◽  
Fiber Type ◽  
Vastus Lateralis ◽  
Power Performance ◽  
Fascicle Length ◽  
Cross Sectional ◽  
Muscle Morphology ◽  
Strength Performance ◽  
Type Composition ◽  
Before And After

The aim of the study was to evaluate power performance and muscle morphology adaptations in response to 5 weeks of fast-eccentric squat training (FEST) performed twice per week, with three different training volumes. Twenty-five moderately trained females were assigned into three groups performing eight repetitions of FEST of either four sets (4 × 8 group; N = 9), 6 sets (6 × 8 group; N = 8) or eight sets (8 × 8 group, N = 8). Before and after the intervention, countermovement jumping height (CMJh) and power (CMJp), half squat maximal strength (1-RM), quadriceps cross-sectional area (QCSA) and vastus lateralis (VL) architecture and fiber type composition were evaluated. Significant increases (p < 0.05) were found for all groups, with no differences among them in 1-RM (4 × 8: 14.8 ± 8.2%, 6 × 8: 13.1 ± 9.2% and 8 × 8: 21.6 ± 7.0%), CMJh (4 × 8: 12.5 ± 8.5%, 6 × 8: 11.3 ± 9.3% and 8 × 8: 7.0 ± 6.2%), CMJp (4 × 8: 9.1 ± 6.0%, 6 × 8: 7.1 ± 5.2% and 8 × 8: 5.0 ± 3.9%) and QCSA (4 × 8: 7.7 ± 4.7%, 6 × 8: 9.0 ± 6.8% and 8 × 8: 8.2 ± 6.5%). Muscle fiber type distribution remained unaltered after training in all groups. VL fascicle length increased and fascicle angle decreased only in 6 × 8 and 8 × 8 groups. In conclusion, four sets of eight fast-eccentric squats/week increase lower body power and strength performance and maintain type IIX muscle fibers after 5 weeks, at least in moderately trained females.

Fiber Type Composition of the Vastus Lateralis Muscle of Young Men and Women

2000 ◽  
Vol 48 (5) ◽  
pp. 623-629 ◽  
Author(s):  
Robert S. Staron ◽  
Fredrick C. Hagerman ◽  
Robert S. Hikida ◽  
Thomas F. Murray ◽  
David P. Hostler ◽  
...  
Keyword(s):  
Fiber Type ◽  
Vastus Lateralis ◽  
Young Men ◽  
Vastus Lateralis Muscle ◽  
Fiber Types ◽  
Cross Sectional ◽  
Men And Women ◽  
Type Composition ◽  
Lateralis Muscle ◽  
Fiber Type Distribution

SUMMARY This study presents data collected over the past 10 years on the muscle fiber type composition of the vastus lateralis muscle of young men and women. Biopsies were taken from the vastus lateralis muscle of 55 women (21.2 ± 2.2 yr) and 95 men (21.5 ± 2.4 yr) who had volunteered to participate in various research projects. Six fiber types (I, IC, IIC, IIA, IIAB, and IIB) were classified using mATPase histochemistry, and cross-sectional area was measured for the major fiber types (I, IIA, and IIB). Myosin heavy chain (MHC) content was determined electrophoretically on all of the samples from the men and on 26 samples from the women. With the exception of fiber Type IC, no significant differences were found between men and women for muscle fiber type distribution. The vastus lateralis muscle of both the men and women contained approximately 41% I, 1% IC, 1% IIC, 31% IIA, 6% IIAB, and 20% IIB. However, the cross-sectional area of all three major fiber types was larger for the men compared to the women. In addition, the Type IIA fibers were the largest for the men, whereas the Type I fibers tended to be the largest for the women. Therefore, gender differences were found with regard to the area occupied by each specific fiber type: IIA>I>IIB for the men and I>IIA>IIB for the women. These data establish normative values for the mATPase-based fiber type distribution and sizes in untrained young men and women.

Evaluation of intramyocellular lipid breakdown during exercise by biochemical assay, NMR spectroscopy, and Oil Red O staining

2007 ◽  
Vol 293 (1) ◽  
pp. E428-E434 ◽  
Author(s):  
K. De Bock ◽  
T. Dresselaers ◽  
B. Kiens ◽  
E. A. Richter ◽  
P. Van Hecke ◽  
...  
Keyword(s):  
Fiber Type ◽  
Vastus Lateralis ◽  
Biochemical Assay ◽  
Vastus Lateralis Muscle ◽  
Intramyocellular Lipids ◽  
Type Composition ◽  
Before And After ◽  
Human Muscles ◽  
Exercise Induced ◽  
Oil Red O

The study compared the net decline of intramyocellular lipids (IMCL) during exercise ( n = 18) measured by biochemical assay (BIO) and Oil Red O (ORO) staining on biopsy samples from vastus lateralis muscle and by1H-MR spectroscopy (MRS) sampled in an 11 × 11 × 18-mm3voxel in the same muscle. IMCL was measured before and after a 2-h cycling bout (∼75% V̇o2 peak). ORO and MRS measurements showed substantial IMCL use during exercise of 31 ± 12 and 47 ± 6% of preexercise IMCL content. In contrast, use of BIO for IMCL determination did not reveal an exercise-induced breakdown of IMCL (2 ± 9%, P = 0.29) in young healthy males. Correlations between different measures of exercise-induced IMCL degradation were low. Coefficients were 0.48 for MRS vs. ORO ( P = 0.07) and were even lower for BIO vs. MRS ( r = 0.38, P = 0.13) or ORO ( r = 0.08, P = 0.78). This study demonstrates that different methods to measure IMCL in human muscles can result in different conclusions with regard to exercise-induced IMCL changes. MRS has the advantage that it is noninvasive, however, not fiber type specific and hampered by an at least 30-min delay in measurements after exercise completion and may overestimate IMCL use. BIO is the only quantitative method but is subject to variation when biopsies have different fiber type composition. However, BIO yields lower IMCL breakdown compared with ORO and MRS. ORO has the major advantage that it is fiber type specific, and it therefore provides information that is not available with the other methods.

scholarly journals Biological Determinants of Track and Field Throwing Performance

2021 ◽  
Vol 6 (2) ◽  
pp. 40
Author(s):  
Nikolaos Zaras ◽  
Angeliki-Nikoletta Stasinaki ◽  
Gerasimos Terzis
Keyword(s):  
Fiber Type ◽  
Small Body ◽  
The Body ◽  
Track And Field ◽  
Neural Activation ◽  
Biological Factors ◽  
Cross Sectional ◽  
Type Composition ◽  
Biological Determinants

Track and field throwing performance is determined by a number of biomechanical and biological factors which are affected by long-term training. Although much of the research has focused on the role of biomechanical factors on track and field throwing performance, only a small body of scientific literature has focused on the connection of biological factors with competitive track and field throwing performance. The aim of this review was to accumulate and present the current literature connecting the performance in track and field throwing events with specific biological factors, including the anthropometric characteristics, the body composition, the neural activation, the fiber type composition and the muscle architecture characteristics. While there is little published information to develop statistical results, the results from the current review suggest that major biological determinants of track and field throwing performance are the size of lean body mass, the neural activation of the protagonist muscles during the throw and the percentage of type II muscle fiber cross-sectional area. Long-term training may enhance these biological factors and possibly lead to a higher track and field throwing performance. Consequently, coaches and athletes should aim at monitoring and enhancing these parameters in order to increase track and field throwing performance.

In vitro human masseter muscle hypersensitivity: a possible explanation for increase in masseter tone

1996 ◽  
Vol 80 (5) ◽  
pp. 1547-1553 ◽  
Author(s):  
P. J. Adnet ◽  
H. Reyford ◽  
B. M. Tavernier ◽  
T. Etchrivi ◽  
I. Krivosic ◽  
...  
Keyword(s):  
Masseter Muscle ◽  
Fiber Type ◽  
Vastus Lateralis ◽  
Threshold Concentration ◽  
Vastus Lateralis Muscle ◽  
Type I ◽  
Cross Sectional ◽  
Significant Difference ◽  
Maximal Tension

To determine whether a difference in fiber-type caffeine and Ca2+ sensitivities exists between human masseter and vastus lateralis skeletal muscle, we compared the fiber-type caffeine sensitivities in chemically skinned muscle fibers from 13 masseter and 18 vastus lateralis muscles. Caffeine sensitivity was defined as the threshold concentration inducing > 10% of the maximal tension obtained after the fiber was loaded with a 1.6 x 10(-2) mM Ca2+ solution for 30 s. Significant difference in the mean caffeine sensitivity was found between type I masseter fibers [2.57 +/- 1.32 (SD) mM] vs. type I (6.02 +/- 1.74 mM) and type II vastus lateralis fibers (11.25 +/- 3.13 mM). Maximal Ca(2+)-activated force per cross-sectional area was significantly different between masseter and vastus lateralis fibers. However, the Ca2+ concentration corresponding to half-maximal tension (pCa50) was not significantly different between type I masseter (pCa50 5.9 +/- 0.02) and type I vastus lateralis muscle (pCa50 6.01 +/- 0.08). These results suggest that the increase in caffeine sensitivity of masseter muscle reflects the presence of a low reactivity threshold of the sarcoplasmic reticulum.

Regulation of fiber size, oxidative potential, and capillarization in human muscle by resistance exercise

1999 ◽  
Vol 276 (2) ◽  
pp. R591-R596 ◽  
Author(s):  
H. Green ◽  
C. Goreham ◽  
J. Ouyang ◽  
M. Ball-Burnett ◽  
D. Ranney
Keyword(s):  
Fiber Type ◽  
Vastus Lateralis ◽  
Succinic Dehydrogenase ◽  
Quadriceps Muscle ◽  
Cellular Tissue ◽  
Cross Sectional Area ◽  
Fiber Types ◽  
Sectional Area ◽  
Oxidative Potential ◽  
Cross Sectional

To examine the hypothesis that increases in fiber cross-sectional area mediated by high-resistance training (HRT) would result in a decrease in fiber capillarization and oxidative potential, regardless of fiber type, we studied six untrained males (maximum oxygen consumption, 45.6 ± 2.3 ml ⋅ kg−1 ⋅ min−1; mean ± SE) participating in a 12-wk program designed to produce a progressive hypertrophy of the quadriceps muscle. The training sessions, which were conducted 3 times/wk, consisted of three sets of three exercises, each performed for 6–8 repetitions maximum (RM). Measurements of fiber-type distribution obtained from tissue extracted from the vastus lateralis at 0, 4, 7, and 12 wk indicated reductions ( P < 0.05) in type IIB fibers (15.1 ± 2.1% vs. 7.2 ± 1.3%) by 4 wk in the absence of changes in the other fiber types (types I, IIA, and IIAB). Training culminated in a 17% increase ( P < 0.05) in cross-sectional area by 12 wk with initial increases observed at 4 wk. The increase was independent of fiber type-specific changes. The number of capillaries in contact with each fiber type increased by 12 wk, whereas capillary contacts-to-fiber area ratios remained unchanged. In a defined cross-sectional field, HRT also increased the capillaries per fiber at 12 wk. Training failed to alter cellular oxidative potential, as measured by succinic dehydrogenase (SDH) activity, regardless of fiber type and training duration. It is concluded that modest hypertrophy induced by HRT does not compromise cellular tissue capillarization and oxidative potential regardless of fiber type.

scholarly journals Regional and muscle-specific adaptations in knee extensor hypertrophy using flywheel versus conventional weight-stack resistance exercise

2019 ◽  
Vol 44 (8) ◽  
pp. 827-833 ◽  
Author(s):  
Tommy R. Lundberg ◽  
Maria T. García-Gutiérrez ◽  
Mirko Mandić ◽  
Mats Lilja ◽  
Rodrigo Fernandez-Gonzalo
Keyword(s):  
Resistance Exercise ◽  
Muscle Hypertrophy ◽  
Vastus Lateralis ◽  
Knee Extensor ◽  
Rectus Femoris ◽  
Knee Extension ◽  
Knee Extensors ◽  
Cross Sectional ◽  
Proximal Site ◽  
Before And After

This study compared the effects of the most frequently employed protocols of flywheel (FW) versus weight-stack (WS) resistance exercise (RE) on regional and muscle-specific adaptations of the knee extensors. Sixteen men (n = 8) and women (n = 8) performed 8 weeks (2–3 days/week) of knee extension RE employing FW technology on 1 leg (4 × 7 repetitions), while the contralateral leg performed regular WS training (4 × 8–12 repetitions). Maximal strength (1-repetition maximum (1RM) in WS) and peak FW power were determined before and after training for both legs. Partial muscle volume of vastus lateralis (VL), vastus medialis (VM), vastus intermedius (VI), and rectus femoris (RF) were measured using magnetic resonance imaging. Additionally, quadriceps cross-sectional area was assessed at a proximal and a distal site. There were no differences (P > 0.05) between FW versus WS in muscle hypertrophy of the quadriceps femoris (8% vs. 9%), VL (10% vs. 11%), VM (6% vs. 8%), VI (5% vs. 5%), or RF (17% vs. 17%). Muscle hypertrophy tended (P = 0.09) to be greater at the distal compared with the proximal site, but there was no interaction with exercise method. Increases in 1RM and FW peak power were similar across legs, yet the increase in 1RM was greater in men (31%) than in women (20%). These findings suggest that FW and WS training induces comparable muscle-specific hypertrophy of the knee extensors. Given that these robust muscular adaptations were brought about with markedly fewer repetitions in the FW compared with WS, it seems FW training can be recommended as a particularly time-efficient exercise paradigm.

scholarly journals Nature of the coupling between neural drive and force-generating capacity in the human quadriceps muscle

2015 ◽  
Vol 282 (1819) ◽  
pp. 20151908 ◽  
Author(s):  
François Hug ◽  
Clément Goupille ◽  
Daniel Baum ◽  
Brent J. Raiteri ◽  
Paul W. Hodges ◽  
...  
Keyword(s):  
Muscle Force ◽  
Vastus Lateralis ◽  
Quadriceps Muscle ◽  
Myoelectric Activity ◽  
Neural Drive ◽  
Fascicle Length ◽  
Cross Sectional ◽  
Muscle Fascicle ◽  
Generating Capacity ◽  
The Relationship

The force produced by a muscle depends on both the neural drive it receives and several biomechanical factors. When multiple muscles act on a single joint, the nature of the relationship between the neural drive and force-generating capacity of the synergistic muscles is largely unknown. This study aimed to determine the relationship between the ratio of neural drive and the ratio of muscle force-generating capacity between two synergist muscles (vastus lateralis (VL) and vastus medialis (VM)) in humans. Twenty-one participants performed isometric knee extensions at 20 and 50% of maximal voluntary contractions (MVC). Myoelectric activity (surface electromyography (EMG)) provided an index of neural drive. Physiological cross-sectional area (PCSA) was estimated from measurements of muscle volume (magnetic resonance imaging) and muscle fascicle length (three-dimensional ultrasound imaging) to represent the muscles' force-generating capacities. Neither PCSA nor neural drive was balanced between VL and VM. There was a large ( r = 0.68) and moderate ( r = 0.43) correlation between the ratio of VL/VM EMG amplitude and the ratio of VL/VM PCSA at 20 and 50% of MVC, respectively. This study provides evidence that neural drive is biased by muscle force-generating capacity, the greater the force-generating capacity of VL compared with VM, the stronger bias of drive to the VL.

Effects of sprint cycle training on human skeletal muscle

1994 ◽  
Vol 77 (5) ◽  
pp. 2385-2390 ◽  
Author(s):  
C. A. Allemeier ◽  
A. C. Fry ◽  
P. Johnson ◽  
R. S. Hikida ◽  
F. C. Hagerman ◽  
...  
Keyword(s):  
Fiber Type ◽  
Vastus Lateralis ◽  
Cross Sectional Area ◽  
Aerobic Performance ◽  
Vastus Lateralis Muscle ◽  
Sectional Area ◽  
Cross Sectional ◽  
Fast Fiber ◽  
Cycle Training ◽  
Exercise Induced

Eleven men sprint trained two to three times per week for 6 wk to investigate possible exercise-induced slow-to-fast fiber type conversions. Six individuals served as controls. Both groups were tested at the beginning and end of the study to determine anaerobic performance and maximal oxygen consumption. In addition, pre- and postbiopsies were extracted from the vastus lateralis muscle and were analyzed for fiber type composition, cross-sectional area, and myosin heavy chain (MHC) content. No significant changes were found in anaerobic or aerobic performance variables for either group. Although a trend was found for a decrease in the percentage of type IIb fibers, high-intensity sprint cycle training caused no significant changes in the fiber type distribution or cross-sectional area. However, the training protocol did result in a significant decrease in MHC IIb with a concomitant increase in MHC IIa for the training men. These data appear to support previous investigations that have suggested exercise-induced adaptations within the fast fiber population (IIb-->IIa) after various types of training (endurance and strength).

The Effect of ACL Reconstruction on Involved and Contralateral Limb Vastus Lateralis Morphology and Histology: A Pilot Study

2019 ◽  
Author(s):  
Eric C. Leszczynski ◽  
Christopher Kuenze ◽  
Brett Brazier ◽  
Joseph Visker ◽  
David P. Ferguson
Keyword(s):  
Fiber Type ◽  
Vastus Lateralis ◽  
Knee Extension ◽  
Cross Sectional Area ◽  
Vastus Lateralis Muscle ◽  
Myosin Isoforms ◽  
Sectional Area ◽  
Cross Sectional ◽  
Contralateral Limb ◽  
Significant Difference

AbstractQuadriceps muscle weakness is a commonly reported issue post anterior cruciate ligament reconstruction (ACLR), with minimal information related to skeletal muscle morphology following surgery. The purpose is to examine the morphological and functional differences in the vastus lateralis muscle from patient's ACLR and contralateral leg. Three physically active ACLR participants were recruited and secured to a dynamometer to perform maximal voluntary isometric knee extension contractions (MVIC) of the ACLR and contralateral limb. Muscle biopsies of the ACLR and contralateral vastus lateralis were performed, then sectioned, and stained for myosin isoforms to determine fiber type. Confocal images were acquired, and ImageJ software was used to determine the fiber type and cross-sectional area (CSA). There was a significant reduction in CSA of the type IIa and type IIx muscle fiber cells between healthy (IIa: 7,718 ± 1,295 µm2; IIx; 5,800 ± 601 µm2) and ACLR legs (IIa: 4,139 ± 709 µm2; IIx: 3,708 ± 618 µm2) (p < 0.05), while there was no significant difference in knee extension MVIC torque between legs (healthy limb: 2.42 ± 0.52 Nm/kg; ACLR limb: 2.05 ± 0.24 Nm/kg, p = 0.11). The reduction in the cross-sectional area of the ACLR type II fibers could impair function and increase secondary injury risk.

Sign in / Sign up

Export Citation Format

Share Document