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vastus lateralis

Zhong-Min Wang, Xiaoyan Leng, María Laura Messi, Seung J Choi, Anthony P Marsh, Barbara Nicklas, Osvaldo Delbono
Background: Previous studies support beneficial effects of both resistance exercise training (RT) and caloric restriction (CR) on skeletal muscle strength and physical performance. The goal of this study was to determine the effects of adding CR to RT on single-muscle fiber contractility responses to RT in older overweight and obese adults. Methods: We analyzed contractile properties in 1,253 single myofiber from muscle biopsies of the vastus lateralis, as well as physical performance and thigh muscle volume, in 31 older (65-80 yrs), overweight or obese (body mass index= 27-35 kg/m2) men (n=19) and women (n=12) who were randomly assigned to a standardized, progressive RT intervention with CR (RT+CR; n=15) or without CR (RT; n=16) for 5 months...
March 13, 2018: Journals of Gerontology. Series A, Biological Sciences and Medical Sciences
Jared M Dickinson, Andrew C D'Lugos, Marcus A Naymik, Ashley L Siniard, Amanda J Wolfe, Donald P Curtis, Matthew J Huentelman, Chad C Carroll
Aerobic (AE) and resistance exercise (RE) elicit unique adaptations in skeletal muscle that have distinct implications for health and performance. The purpose of this study was to identify the unique transcriptome response of skeletal muscle to acute AE and RE. In a counter-balanced, cross-over design, six healthy, recreationally active young men (27{plus minus}3y) completed acute AE (40 min cycling, ~70% maximal HR) and RE (8 sets, 10 reps, ~65% 1RM), separated by ~1wk. Muscle biopsies ( vastus lateralis) were obtained before and at 1 and 4h post exercise...
March 15, 2018: Journal of Applied Physiology
Robert James Shute, Matthew William Heesch, Roksana Barbara Zak, Jodi L Kreiling, Dustin R Slivka
PGC-1α mRNA is increased with both exercise and exposure to cold temperature. However, transcriptional control has yet to be examined during exercise in the cold. Additionally, the need for environmental cold exposure after exercise may not be a practical recovery modality. The purpose of this study was to determine mitochondrial-related gene expression and transcriptional control of PGC-1α following exercise in a cold compared to room temperature environment. Eleven recreationally trained males completed two 1-h cycling bouts in a cold (7 {degree sign}C) or room temperature (20 {degree sign}C) environment followed by 3 h of supine recovery in standard room conditions...
March 14, 2018: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology
Steffi L Colyer, Polly M McGuigan
Textile electromyography (EMG) electrodes embedded in clothing allow muscle excitation to be recorded in previously inaccessible settings; however, their ability to accurately and reliably measure EMG during dynamic tasks remains largely unexplored. To quantify the validity and reliability of textile electrodes, 16 recreationally active males completed two identical testing sessions, within which three functional movements (run, cycle and squat) were performed twice: once wearing EMG shorts (measuring quadriceps, hamstrings and gluteals myoelectric activity) and once with surface EMG electrodes attached to the vastus lateralis, biceps femoris and gluteus maximus...
March 2018: Journal of Sports Science & Medicine
Marco A Minetto, Alberto Botter, Giulia Gamerro, Ilaria Varvello, Giuseppe Massazza, Rosa G Bellomo, Nicola A Maffiuletti, Raoul Saggini
BACKGROUND: The "contralateral effect" phenomenon refers to the strength gain in the opposite, untrained homonymous muscle following unilateral training. Previous studies showed that neuromuscular electrical stimulation (NMES) of the right quadriceps facilitated maximal voluntary strength and efferent neural drive of the left knee extensors, while no previous study investigated the contralateral effect elicited by focal muscle vibration. AIM: To investigate whether quadriceps NMES and focal vibration, when applied unilaterally, have the same potential to enhance the contralateral muscle strength and the associated neural drive...
March 12, 2018: European Journal of Physical and Rehabilitation Medicine
Jamie S McPhee, James Cameron, Thomas Maden-Wilkinson, Mathew Piasecki, Moi Hoon Yap, David A Jones, Hans Degens
The contributions of fibre atrophy, fibre loss, in situ specific force and voluntary activation to weakness in sarcopenia remain unclear. To investigate, forty older (20 women; age 72±4yrs) and 31 younger adults (15 women, age 22±3yrs) completed measurements. The knee extensor maximal voluntary torque (MVC) was measured as well as voluntary activation, patella tendon moment arm length, muscle volume and fascicle architecture to estimate in situ specific force. Fibre cross-sectional area (FCSA), fibre numbers and connective tissue contents were also estimated from vastus lateralis biopsies...
February 26, 2018: Journals of Gerontology. Series A, Biological Sciences and Medical Sciences
Mirco Floreani, Enrico Rejc, Paolo Taboga, Alessandro Ganzini, Rado Pišot, Bostjan Šimunič, Gianni Biolo, Carlo Reggiani, Angelina Passaro, Marco Narici, Joern Rittweger, Pietro Enrico di Prampero, Stefano Lazzer
In this study, we investigated: i) the effects of bed rest and a subsequent physical training program on metabolic cost (Cw), mechanical work and efficiency during walking in older and young men; ii) the mechanisms underlying the higher Cw observed in older than young men.Twenty-three healthy male subjects (N = 16 older adults, age 59.6±3.4 years; N = 7 young, age: 23.1±2.9 years) participated in this study. The subjects underwent 14 days of bed rest followed by two weeks of physical training (6 sessions)...
2018: PloS One
Ryan J Colquhoun, Mitchel A Magrini, Cody T Haun, Tyler W D Muddle, Patrick M Tomko, Micheal J Luera, Cameron S Mackey, Christopher G Vann, Jeffrey S Martin, Kaelin C Young, Jason M DeFreitas, Michael D Roberts, Nathaniel D M Jenkins
Previous investigations have reported a relationship between skeletal muscle phenotype and motor unit (MU) firing parameters during submaximal contractions. The purpose of the current investigation, however, was to examine the relationships between motor unit firing behavior during a maximal voluntary contraction, Myosin Heavy Chain (MHC) isoform content, and various molecular neuromuscular targets of the vastus lateralis (VL) muscle in resistance-trained men. Ten resistance-trained males completed a trapezoidal ramp contraction up to 100% of their maximal voluntary isometric strength (MVIC)...
March 2018: Physiological Reports
Giovanna Camparis Lessi, Rodrigo Scattone Silva, Fábio Viadanna Serrão
OBJECTIVES: Studies comparing the effects of fatigue between men and women after anterior cruciate ligament (ACL) reconstruction are lacking. The purpose of this study was to compare the effects of muscle fatigue on trunk, pelvis and lower limb kinematics and on lower limb muscle activation between male and female athletes who underwent ACL reconstruction. DESIGN: Cross-sectional study. SETTING: Laboratory setting. PARTICIPANTS: Fourteen recreational athletes (7 males and 7 females) with unilateral ACL reconstruction participated of this study...
February 5, 2018: Physical Therapy in Sport
Sang Woo Jun, Suk Joong Yong, Min Jo, Young Ho Kim, Sung Hoon Kim
BACKGROUND: Electromyography and the modified Ashworth scale (MAS) are among the most effective methods for evaluating spasticity; however, these are often inappropriate for clinical use, owing to the complicated procedure and subjective evaluation outcomes. METHODS: A passive stretch reflex test was performed on 10 subjects with brain lesions. Furthermore, mechanomyography and electromyography were conducted on the vastus lateralis muscle (agonist) and semitendinosus muscle (antagonist) of the subjects with brain lesions...
March 6, 2018: Clinical Biomechanics
Ross D Pollock, Katie A O'Brien, Lorna J Daniels, Kathrine B Nielsen, Anthea Rowlerson, Niharika A Duggal, Norman R Lazarus, Janet M Lord, Andrew Philp, Stephen D R Harridge
In this study, results are reported from the analyses of vastus lateralis muscle biopsy samples obtained from a subset (n = 90) of 125 previously phenotyped, highly active male and female cyclists aged 55-79 years in regard to age. We then subsequently attempted to uncover associations between the findings in muscle and in vivo physiological functions. Muscle fibre type and composition (ATPase histochemistry), size (morphometry), capillary density (immunohistochemistry) and mitochondrial protein content (Western blot) in relation to age were determined in the biopsy specimens...
March 8, 2018: Aging Cell
William B Stoughton, Jianrong Li, Cindy Balog-Alvarez, Joe N Kornegay
Introduction Duchenne muscular dystrophy (DMD) and golden retriever muscular dystrophy (GRMD) are X-linked disorders caused by mutations in the DMD gene. Autophagy was recently identified as a secondary therapeutic target for DMD. We hypothesized that autophagy would be reduced in GRMD. Methods Autophagic gene and protein expression was assessed in normal and GRMD skeletal muscles and correlated with phenotypic biomarkers. Results Muscles were differentially affected. Autophagy gene levels were lower than normal in the GRMD cranial sartorius (CS) but similar in the vastus lateralis (VL)...
March 7, 2018: Muscle & Nerve
Heikki Peltonen, Simon Walker, Anthony C Hackney, Janne Avela, Keijo Häkkinen
Maximum strength training induces various improvements in the rate of force development (RFD) on a group level, but no study has investigated inter-individual adaptations in RFD. Fourteen men (28 ± 6 years old) performed the same 10-week maximum strength and then a 10-week power training program. Maximal force and RFD were recorded during maximal isometric leg extension voluntary contractions repeatedly before every 7th training session (2 sessions/week). After the intervention, subjects were retrospectively divided into three groups based on their RFD improvements: (1) improved only during the maximum strength period (MS-responders, + 100 ± 35%), (2) improved only during the power period (P-responders, + 53 ± 27%) or (3) no improvement at all (non-responders, + 3 ± 9%)...
March 6, 2018: European Journal of Applied Physiology
Erika M Ripley, Geoffrey D Clarke, Vala Hamidi, Robert A Martinez, Floyd D Settles, Carolina Solis, Shengwen Deng, Muhammad Abdul-Ghani, Devjit Tripathy, Ralph A DeFronzo
Mitochondrial dysfunction has been described in insulin resistant (IR) states including type 2 diabetes mellitus (T2DM). Previous studies using31 P-MRS in T2DM reported results as relative concentrations of metabolite ratios, which could obscure changes in phosphocreatine [PCr] and [ATP] and attenuate differences between T2DM and NGT individuals. We used a novel image-guided31 P-MRS method to quantitate phosphorus metabolites in vastus lateralis (VL) muscle in 11 T2DM and 14 NGT subjects. Subjects received OGTT, euglycemic insulin clamp,31 P-MRS study to measure absolute concentrations (mM) of [PCr], inorganic phosphate [Pi], and [ATP], and VL muscle biopsy to evaluate mitochondrial density...
March 6, 2018: American Journal of Physiology. Endocrinology and Metabolism
Sarah Morar Schneider, Vidya Sridhar, Amanda K Bettis, Heather Heath-Barnett, Cynthia J Balog-Alvarez, Lee-Jae Guo, Rachel Johnson, Scott Jaques, Stanislav Vitha, Alan C Glowcwski, Joe N Kornegay, Peter P Nghiem
PURPOSE: Metabolic dysfunction in Duchenne muscular dystrophy (DMD) is characterized by reduced glycolytic and oxidative enzymes, decreased and abnormal mitochondria, decreased ATP, and increased oxidative stress. We analyzed glucose metabolism as a potential disease biomarker in the genetically homologous golden retriever muscular dystrophy (GRMD) dog with molecular, biochemical, and in vivo imaging. PROCEDURES: Pelvic limb skeletal muscle and left ventricle tissue from the heart were analyzed by mRNA profiling, qPCR, western blotting, and immunofluorescence microscopy for the primary glucose transporter (GLUT4)...
March 5, 2018: Molecular Imaging and Biology: MIB: the Official Publication of the Academy of Molecular Imaging
Jane L Tarry-Adkins, Catherine E Aiken, Thomas J Ashmore, Susan E Ozanne
Developmental programming phenotypes can be recapitulated in subsequent generations not directly exposed to the initial suboptimal intrauterine environment. A maternal low-protein diet during pregnancy and postnatal catch-up growth ('recuperated') alters insulin signaling and inflammation in rat offspring (F1-generation). We aimed to establish if this phenotype is also present in F2-generation females. Insulin-receptor-substrate-1 protein expression was decreased in para-ovarian adipose tissue at 3 months in offspring exposed to a grand-maternal low-protein diet (F2-recuperated), vs...
March 5, 2018: Scientific Reports
Kwang Ho Cho, Zhe Wu Jin, Hiroshi Abe, Jőrg Wilting, Gen Murakami, José Francisco Rodríguez-Vázquez
The human fasciae latae muscle (TFL) is inserted into the iliotibial tract and plays a critical role in lateral stabilization of the hip joint. We previously described a candidate of the initial iliotibial tract that originated from the gluteus maximus muscle and extended distally. This study extended our observations by examining 30 human embryos and fetuses of gestational age (GA) 7-14 (crown-to-rump length [CR:] 24-108 mm). At GA 7 weeks, the TFL appeared as a small muscle mass floating in the subcutaneous tissue near the origins of the gluteus medius and rectus femoris muscles...
March 3, 2018: Folia Morphologica (Warsz)
Ceren Yarar-Fisher, Keith Fl Polston, Mualla Eraslan, Kathryn Y Henley, Gizem I Kinikli, C Scott Bickel, Samuel T Windham, Amie B McLain, Robert A Oster, Marcas M Bamman
This study compares the effects of an 8-week iso-caloric high protein (HP) diet versus a combination exercise (Comb-Ex) regimen on paralytic vastus lateralis (VL) and non-paralytic deltoid muscle in individuals with long-standing spinal cord injury (SCI). Fiber type distribution, cross-sectional area (CSA), levels of translation initiation signaling proteins (Erk-1/2, Akt, p70S6K1, 4EBP1, RPS6, and FAK), and lean thigh mass were analyzed at baseline and after the 8-week interventions. A total of 11 participants (C5-T12 levels, 21...
March 1, 2018: Journal of Applied Physiology
Kyle J Burghardt, Berhane Seyoum, Sabrina Dass, Elani Sanders, Abdullah Mallisho, Zhengping Yi
STUDY OBJECTIVE: Atypical antipsychotics cause insulin resistance that leads to an increased risk of diabetes mellitus and cardiovascular disease. Skeletal muscle is the primary tissue for uptake of glucose, and its dysfunction is considered one of the primary defects in the development of insulin resistance. Protein kinase B (AKT) plays an important role in overall skeletal muscle health and glucose uptake into the muscle. The objective of this study was to measure AKT isoform-specific gene methylation differences in the skeletal muscle of patients with bipolar disorder treated with atypical antipsychotic or mood stabilizer maintenance therapy...
February 27, 2018: Pharmacotherapy
Sanmy Rocha Nóbrega, Renato Barroso, Carlos Ugrinowitsch, Jean Lucas Fernandes da Costa, Ieda Fernanda Alvarez, Cintia Barcelos, Cleiton Augusto Libardi
The aim of the present study was to compare the effects of self-selected and fixed repetition duration (RD) on resistance exercise (RE) volume, muscle activation, time under tension (TUT) per repetition and per session. Twelve resistance-trained men participated in the study. A randomized cross-over design was utilized and each participant performed two high-intensity RE protocols in a balanced order: 1) three sets of RE with self-selected RD (SELF); 2) three sets of RE with fixed RD (2 sec concentric, 2 sec eccentric [FIX])...
February 22, 2018: Journal of Strength and Conditioning Research
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