scholarly journals Early Deconditioning of Human Skeletal Muscles and the Effects of a Thigh Cuff Countermeasure

2021 ◽  
Vol 22 (21) ◽  
pp. 12064
Author(s):  
Théo Fovet ◽  
Corentin Guilhot ◽  
Laurence Stevens ◽  
Valérie Montel ◽  
Pierre Delobel ◽  
...  
Keyword(s):  
Vastus Lateralis ◽  
Oxidative Capacity ◽  
Knee Extension ◽  
Control Group ◽  
Vastus Lateralis Muscle ◽  
Maximal Voluntary Isometric Contraction ◽  
Vascular Effect ◽  
Cross Sectional ◽  
Space Agency ◽  
Wide Range

Muscle deconditioning is a major consequence of a wide range of conditions from spaceflight to a sedentary lifestyle, and occurs as a result of muscle inactivity, leading to a rapid decrease in muscle strength, mass, and oxidative capacity. The early changes that appear in the first days of inactivity must be studied to determine effective methods for the prevention of muscle deconditioning. To evaluate the mechanisms of muscle early changes and the vascular effect of a thigh cuff, a five-day dry immersion (DI) experiment was conducted by the French Space Agency at the MEDES Space Clinic (Rangueil, Toulouse). Eighteen healthy males were recruited and divided into a control group and a thigh cuff group, who wore a thigh cuff at 30 mmHg. All participants underwent five days of DI. Prior to and at the end of the DI, the lower limb maximal strength was measured and muscle biopsies were collected from the vastus lateralis muscle. Five days of DI resulted in muscle deconditioning in both groups. The maximal voluntary isometric contraction of knee extension decreased significantly. The muscle fiber cross-sectional area decreased significantly by 21.8%, and the protein balance seems to be impaired, as shown by the reduced activation of the mTOR pathway. Measurements of skinned muscle fibers supported these results and potential changes in oxidative capacity were highlighted by a decrease in PGC1-α levels. The use of the thigh cuff did not prevent muscle deconditioning or impact muscle function. These results suggest that the major effects of muscle deconditioning occur during the first few days of inactivity, and countermeasures against muscle deconditioning should target this time period. These results are also relevant for the understanding of muscle weakness induced by muscle diseases, aging, and patients in intensive care.

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.

Influences of repetitive muscle contractions with different modes on tendon elasticity in vivo

2001 ◽  
Vol 91 (1) ◽  
pp. 277-282 ◽  
Author(s):  
Keitaro Kubo ◽  
Hiroaki Kanehisa ◽  
Yasuo Kawakami ◽  
Tetsuo Fukunaga
Keyword(s):  
Vastus Lateralis ◽  
Force Production ◽  
Knee Extension ◽  
Muscle Contractions ◽  
Vastus Lateralis Muscle ◽  
Maximal Voluntary Isometric Contraction ◽  
Duration Of Action ◽  
Before And After ◽  
Endurance Tests

The present study aimed to investigate the effects of repetitive muscle contractions on the elasticity of human tendon structures in vivo. Before and after each endurance test, the elongation of the tendon and aponeurosis of vastus lateralis muscle ( L) was directly measured by ultrasonography while the subjects performed ramp isometric knee extension up to maximal voluntary isometric contraction (MVC). Six male subjects performed muscle endurance tests that consisted of knee extension tasks with four different contraction modes: 1) 50 repetitions of maximal voluntary eccentric action for 3 s with 3 s of relaxation (ET1), 2) three sets of 50 repetitions of MVC for 1 s with 3 s of relaxation (ET2), 3) 50 repetitions of MVC for 3 s with 3 s of relaxation (ET3), and 4) 50 repetitions of 50% MVC for 6 s with 6 s of relaxation (ET4). In ET1 and ET2, there were no significant differences in L values at any force production levels between before and after endurance tests. In the cases of ET3 and ET4, however, the extent of elongation after the completion of the tests tended to be greater. The L values above 330 N in ET3 and 440 N in ET4, respectively, were significantly greater after endurance tests than before. These results suggested that the repeated longer duration contractions would make the tendon structures more compliant and that the changes in the elasticity might be not be affected by either muscle action mode or force production level but by the duration of action.

Training can improve muscle strength and endurance in 78- to 84-yr-old men

1992 ◽  
Vol 73 (6) ◽  
pp. 2517-2523 ◽  
Author(s):  
G. Grimby ◽  
A. Aniansson ◽  
M. Hedberg ◽  
G. B. Henning ◽  
U. Grangard ◽  
...  
Keyword(s):  
Muscle Strength ◽  
Citrate Synthase ◽  
Vastus Lateralis ◽  
Knee Extension ◽  
Emg Activity ◽  
Vastus Lateralis Muscle ◽  
Neural Activation ◽  
Cross Sectional ◽  
Before And After ◽  
The Right

Nine men, 78–84 yr of age, participated in a dynamometer training program 2–3 times/wk, totaling 25 sessions, using voluntary maximal isometric, concentric, and eccentric right knee–extension actions (30 and 180 degrees/s). Measurements of muscle strength with a Kin-Com dynamometer and simultaneous electromyograms (EMG) were performed of both sides before and after the training period. Muscle biopsies were taken from the right vastus lateralis muscle. The total quadriceps cross-sectional area was measured with computerized tomography. Training led to an increase in maximal torque for concentric (10% at 30 degrees/s) and eccentric (13–19%) actions in the trained leg. The EMG activity increased at maximal eccentric activities. The total cross-sectional quadriceps area of the trained leg increased by 3%, but no changes were recorded in muscle fiber areas in these subjects, who already had large mean fiber areas (5.15 microns 2 x 10(3)). The fatigue index measured from 50 consecutive concentric contractions at 180 degrees/s decreased and the citrate synthase activity increased in all but one subject. The results demonstrate that increased neural activation accompanies an increase in muscle strength at least during eccentric action in already rather active elderly men and that muscle endurance may also be improved with training.

scholarly journals The Vastus Medialis obliquus and The Vastus Lateralis Muscle Atrophy is Existed in Patients with Patellofemoral Pain Syndrome

2020 ◽  
Author(s):  
Conglei Dong ◽  
Ming Li ◽  
Kuo Hao ◽  
Chao Zhao ◽  
Kang Piao ◽  
...  
Keyword(s):  
Vastus Lateralis ◽  
Rehabilitation Program ◽  
Area Ratio ◽  
Control Group ◽  
Vastus Lateralis Muscle ◽  
Study Group ◽  
Vastus Medialis ◽  
Cross Sectional ◽  
Vastus Medialis Obliquus ◽  
Lateralis Muscle

Abstract Background: whether the vastus medialis obliquus (VMO) atrophy exists in patients with PFPS and whether the amount of atrophy differs between the VMO and vastus lateralis muscle (VLM) is still obscure. Materials and methods: From June 2016 to March 2019, 61 patients with PFPS were collected into the study group, and an age, sex, and body mass index (BMI) matched cohort of 61 patients with normal knees were randomly selected into the control group. All enrolled subjects had undergone computed Tomography (CT) scans in the supine position. The cross-sectional area of the VMO and VLM in the sections of 0, 5, 10, 15, 20 mm above the upper pole of the patella were measured, and VMO/VLM area ratio were evaluated as well. Results: In the study group and the control group, the VMO area in the section that 0, 5, 10, 15, 20 mm above the upper pole of the patella were 732.64±306.43 mm2 and 941.66±366.83 mm2 (P<0.001), 876.32±341.47 mm2 and 1119.6±405.01 mm2 (P<0.001), 1039.31±410.21 mm2 and 1302.75±425.14 mm2 (P<0.001), 1178.26±449.10 mm2 and 1496.67±474.70 mm2 (P<0.001), 1289.78±487.78 mm2 and 1643.33±507.08 mm2 (P<0.001); the VLM area in the section that 0, 5, 10, 15, 20 mm above the upper pole of the patella were 127.61±66.74 mm2 and 192.2±152.40 mm2 (P=0.003), 183.47±85.41 mm2 and 262.55±187.98 mm2 (P=0.004), 250.66±133.70 mm2 and 352.35±291.96 mm2 (P=0.015), 326.06±139.94 mm2 and 466.27±343.11 mm2 (P=0.013), 574.19±390.00 mm2 (P=0.005); the VMO/ VLM area ratio in the section that 0, 5, 10, 15, 20 mm above the upper pole of the patella were 0.83±0.11 and 7.44±5.13 (P<0.001), 5.37±2.49 and 6.32±4.69 (P=0.168), 4.64±2.43 and 4.15±1.94 (P=0.554), 3.90±1.55 and 3.96±1.66 (P=0.434), 3.42±1.36 and 3.48±1.62 (P=0.826).Conclusion: In patients with PFPS, the VMO and VLM atrophy was existed in the section of 0-20 mm above the upper pole of the patella in comparison with normal people; and the atrophy of the VMO was more evident than that of the VLM in the section that 0-5 mm above the upper pole of the patella. These findings support the rationale for use of general quadriceps exercise combined with VMO strengthening exercise as part of rehabilitation program for patients with PFPS.

Effects of Strength and Power Training on Neuromuscular Variables in Older Adults

2012 ◽  
Vol 20 (2) ◽  
pp. 171-185 ◽  
Author(s):  
Lilian França Wallerstein ◽  
Valmor Tricoli ◽  
Renato Barroso ◽  
André L.F. Rodacki ◽  
Luciano Russo ◽  
...  
Keyword(s):  
Vastus Lateralis ◽  
Quadriceps Muscle ◽  
Control Group ◽  
Attractive Alternative ◽  
Vastus Lateralis Muscle ◽  
The Novel ◽  
Power Training ◽  
Older Individuals ◽  
Cross Sectional ◽  
Neuromuscular Adaptations

The purpose of this study was to compare the neuromuscular adaptations produced by strength-training (ST) and power-training (PT) regimens in older individuals. Participants were balanced by quadriceps cross-sectional area (CSA) and leg-press 1-repetition maximum and randomly assigned to an ST group (n= 14; 63.6 ± 4.0 yr, 79.7 ± 17.2 kg, and 163.9 ± 9.8 cm), a PT group (n= 16; 64.9 ± 3.9 yr, 63.9 ± 11.9 kg, and 157.4 ± 7.7 cm), or a control group (n= 13; 63.0 ± 4.0 yr, 67.2 ± 10.8 kg, and 159.8 ± 6.8 cm). ST and PT were equally effective in increasing (a) maximum dynamic and isometric strength (p< .05), (b) increasing quadriceps muscle CSA (p< .05), and (c) decreasing electrical mechanical delay of the vastus lateralis muscle (p< .05). There were no significant changes in neuromuscular activation after training. The novel finding of the current study is that PT seems to be an attractive alternative to regular ST to maintain and improve muscle mass.

scholarly journals Non-Coding RNAs in the Transcriptional Network That Differentiates Skeletal Muscles of Sedentary from Long-Term Endurance- and Resistance-Trained Elderly

2021 ◽  
Vol 22 (4) ◽  
pp. 1539
Author(s):  
Paola De Sanctis ◽  
Giuseppe Filardo ◽  
Provvidenza Maria Abruzzo ◽  
Annalisa Astolfi ◽  
Alessandra Bolotta ◽  
...  
Keyword(s):  
Exercise Training ◽  
High Intensity ◽  
Vastus Lateralis ◽  
Mammalian Target Of Rapamycin ◽  
Differentially Expressed ◽  
Transcriptional Networks ◽  
Vastus Lateralis Muscle ◽  
Age Related ◽  
Wide Range ◽  
Non Coding Rnas

In a previous study, the whole transcriptome of the vastus lateralis muscle from sedentary elderly and from age-matched athletes with an exceptional record of high-intensity, life-long exercise training was compared—the two groups representing the two extremes on a physical activity scale. Exercise training enabled the skeletal muscle to counteract age-related sarcopenia by inducing a wide range of adaptations, sustained by the expression of protein-coding genes involved in energy handling, proteostasis, cytoskeletal organization, inflammation control, and cellular senescence. Building on the previous study, we examined here the network of non-coding RNAs participating in the orchestration of gene expression and identified differentially expressed micro- and long-non-coding RNAs and some of their possible targets and roles. Unsupervised hierarchical clustering analyses of all non-coding RNAs were able to discriminate between sedentary and trained individuals, regardless of the exercise typology. Validated targets of differentially expressed miRNA were grouped by KEGG analysis, which pointed to functional areas involved in cell cycle, cytoskeletal control, longevity, and many signaling pathways, including AMP-activated protein kinase (AMPK) and mammalian target of rapamycin (mTOR), which had been shown to be pivotal in the modulation of the effects of high-intensity, life-long exercise training. The analysis of differentially expressed long-non-coding RNAs identified transcriptional networks, involving lncRNAs, miRNAs and mRNAs, affecting processes in line with the beneficial role of exercise training.

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.

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.

Exercise-induced cellular alterations in the diaphragm

1992 ◽  
Vol 263 (5) ◽  
pp. R1093-R1098 ◽  
Author(s):  
S. K. Powers ◽  
D. Criswell ◽  
F. K. Lieu ◽  
S. Dodd ◽  
H. Silverman
Keyword(s):  
Exercise Training ◽  
Endurance Training ◽  
Fiber Type ◽  
Capillary Density ◽  
Oxidative Capacity ◽  
Control Group ◽  
Type I ◽  
Fiber Types ◽  
Image Analysis System ◽  
Cross Sectional

Limited data exist concerning the effects of exercise training on cellular oxidative capacity in the diaphragm of senescent animals. In this study we examined the changes in cellular oxidative capacity, muscle cell cross-sectional area (CSA), and capillarity within the costal diaphragm of senescent animals after a 10-wk endurance-training program. Twelve 24-mo-old female Fischer 344 rats were divided into either a sedentary control group (n = 6) or exercise training group (n = 6). The trained animals exercised on a motor-driven treadmill (60 min/day, 5 days/wk) at a work rate equal to approximately 55-65% VO2max. Capillaries were identified histologically and fiber types determined using adenosinetriphosphatase (ATPase) histochemistry. Succinate dehydrogenase (SDH) activity and CSA in individual fibers were measured using a computerized image analysis system. Exercise training did not increase (P > 0.05) the capillary-to-fiber ratio for any fiber type. However, training significantly decreased CSA (P < 0.05) and increased capillary density (capillary number/CSA) (P < 0.05) in type I, type IIa, and type IIb fibers. Furthermore, exercise training resulted in small but significant increase in SDH activity (P < 0.05) in type I and IIa fibers, whereas training did not alter SDH activity (P > 0.05) in type IIb fibers. These data demonstrate that endurance training in senescent animals results in small relative improvements in both oxidative capacity and capillary density in costal diaphragmatic type I and IIa muscle fibers. The increase in both capillary density and fiber SDH activity was largely due to a reduction in fiber CSA.

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).

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