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https://www.readbyqxmd.com/read/28106620/effects-of-histidine-and-%C3%AE-alanine-supplementation-on-human-muscle-carnosine-storage
#1
Laura Blancquaert, Inge Everaert, Maarten Missinne, Audrey Baguet, Sanne Stegen, Anneke Volkaert, Mirko Petrovic, Chris Vervaet, Eric Achten, Mieke De Maeyer, Stefaan De Henauw, Wim Derave
PURPOSE: Carnosine is a dipeptide composed of β-alanine and L-histidine and is present in skeletal muscle. Chronic oral β-alanine supplementation can induce muscle carnosine loading and is therefore seen as the rate-limiting factor for carnosine synthesis. However, the effect of L-histidine supplementation on carnosine levels in humans is never established. This study aims to investigate whether 1) L-histidine supplementation can induce muscle carnosine loading and 2) combined supplementation of both amino acids is more efficient than β-alanine supplementation alone...
January 19, 2017: Medicine and Science in Sports and Exercise
https://www.readbyqxmd.com/read/28103427/repeated-maximal-intensity-hypoxic-exercise-superimposed-to-hypoxic-residence-boosts-skeletal-muscle-transcriptional-responses-in-elite-team-sport-athletes
#2
Franck Brocherie, Grégoire P Millet, Gommaar D'Hulst, Ruud Van Thienen, Louise Deldicque, Olivier Girard
AIM: To determine whether repeated maximal-intensity hypoxic exercise induces larger beneficial adaptations on the hypoxia inducible factor-1α pathway and its target genes than similar normoxic exercise, when combined with chronic hypoxic exposure. METHODS: Lowland elite male team-sport athletes underwent 14 days of passive normobaric hypoxic exposure (≥14 h.day(-1) at Fi O2 14.5-14.2%) with the addition of six maximal-intensity exercise sessions either in normobaric hypoxia (Fi O2 ~14...
January 19, 2017: Acta Physiologica
https://www.readbyqxmd.com/read/28101144/histopathological-findings-in-systemic-sclerosis-related-myopathy-fibrosis-and-microangiopathy-with-lack-of-cellular-inflammation
#3
Claudio Corallo, Maurizio Cutolo, Nila Volpi, Daniela Franci, Margherita Aglianò, Antonio Montella, Chiara Chirico, Stefano Gonnelli, Ranuccio Nuti, Nicola Giordano
OBJECTIVES: The objective of this study was to identify specific histopathological features of skeletal muscle involvement in systemic sclerosis (SSc) patients. METHODS: A total of 35 out of 112 SSc-patients (32%, including 81% female and 68% diffuse scleroderma) presenting clinical, biological and electromyographic (EMG) features of muscle weakness, were included. Patients underwent vastus lateralis biopsy, assessed for individual pathologic features including fibrosis [type I collagen (Coll-I), transforming growth factor β (TGF-β)], microangiopathy [cluster of differentiation 31 (CD31), pro-angiogenic vascular endothelial growth factor A (VEGF-A), anti-angiogenic VEGF-A165b], immune/ inflammatory response [CD4, CD8, CD20, human leucocyte antigens ABC (HLA-ABC)], and membranolytic attack complex (MAC)...
January 2017: Therapeutic Advances in Musculoskeletal Disease
https://www.readbyqxmd.com/read/28099172/decrease-of-muscle-fiber-conduction-velocity-correlates-with-strength-loss-after-an-endurance-run
#4
Gennaro Boccia, Davide Dardanello, Cantor Tarperi, Valeria Rosso, Luca Festa, Antonio La Torre, Barbara Pellegrini, Federico Schena, Alberto Rainoldi
Monitoring surface electromyographic (EMG) signals can provide useful insights for characterizing muscle fatigue, which is defined as an exercise-induced strength loss. This experiment investigated the muscle fiber conduction velocity (CV) changes induced by an endurance run. The day before and immediately after a half-marathon run (21.097 km) 11 amateur runners performed maximum voluntary contractions (MVCs) of knee extensor muscles. During the MVC, multichannel EMG was recorded from the vastus lateralis and EMG amplitude and CV were calculated...
January 18, 2017: Physiological Measurement
https://www.readbyqxmd.com/read/28078451/slower-but-not-faster-unilateral-fatiguing-knee-extensions-alter-contralateral-limb-performance-without-impairment-of-maximal-torque-output
#5
Olaf Prieske, Saied J Aboodarda, José A Benitez Sierra, David G Behm, Urs Granacher
PURPOSE: The purpose of the present study was to examine the effects of unilateral fatigue of the knee extensors at different movement velocities on neuromuscular performance in the fatigued and non-fatigued leg. METHODS: Unilateral fatigue of the knee extensors was induced in 11 healthy young men (23.7 ± 3.8 years) at slower (60°/s; FAT60) and faster movement velocities (240°/s; FAT240) using an isokinetic dynamometer. A resting control (CON) condition was included...
January 11, 2017: European Journal of Applied Physiology
https://www.readbyqxmd.com/read/28073778/overexpression-of-pgc-1%C3%AE-increases-peroxisomal-and-mitochondrial-fatty-acid-oxidation-in-human-primary-myotubes
#6
Tai-Yu Huang, Donghai Zheng, Joseph A Houmard, Jeffrey J Brault, Robert C Hickner, Ronald N Cortright
Peroxisomes are indispensable organelles for lipid metabolism in humans and their biogenesis has been assumed to be under regulation by peroxisome proliferator-activated receptors (PPARs). However, recent studies in hepatocytes suggest that the mitochondrial proliferator PGC-1α (peroxisome proliferator-activated receptor gamma coactivator-1 alpha) also acts as an upstream transcriptional regulator for enhancing peroxisomal abundance and associated activity. It is unknown whether the regulatory mechanism(s) for enhancing peroxisomal function is through the same node as mitochondrial biogenesis in human skeletal muscle (HSkM) and whether fatty acid oxidation (FAO) is affected...
January 10, 2017: American Journal of Physiology. Endocrinology and Metabolism
https://www.readbyqxmd.com/read/28067972/single-innervated-segmented-vastus-lateralis-for-midfacial-reanimation-during-radical-parotidectomy
#7
Lauren Sh Chong, Timothy J Eviston, Bruce Ashford, Ardalan Ebrahami, Jonathan R Clark
BACKGROUND: Innervated free muscle transfer using the gracilis muscle or temporalis myoplasty has been successfully utilized for facial reanimation in chronic facial palsy. These techniques are less suited to immediate facial reconstruction in the setting of radical parotidectomy, in which the complexity of the defect, patient age, postoperative radiotherapy, and limited life expectancy pose particular challenges. METHODS: We present a novel description of the use of a chimeric anterolateral thigh (ALT) flap and innervated vastus lateralis to achieve midface static suspension and dynamic reanimation in the setting of radical parotidectomy...
January 9, 2017: Head & Neck
https://www.readbyqxmd.com/read/28063610/ultrasound-measurements-of-skeletal-muscle-architecture-are-associated-with-strength-and-functional-capacity-in-older-adults
#8
Isaac Selva Raj, Stephen R Bird, Anthony J Shield
The goal of this study was to determine whether ultrasound measures of muscle architecture can be used to infer strength and functional capacity in older adults. Thirty-six healthy older adults (aged 68.2 ± 5.3 y) undertook isokinetic dynamometry for isometric and isokinetic concentric knee extensor strength, the 6-m fast walk, timed up and go, stair climb and descent and vertical jump tests. Longitudinal brightness-mode ultrasound scans (probe frequency, 10 MHz) of the vastus lateralis, vastus intermedius, rectus femoris and gastrocnemius medialis were obtained, and muscle architecture measures (thickness, fascicle pennation angle and fascicle length) were correlated with the aforementioned strength and functional measures...
January 4, 2017: Ultrasound in Medicine & Biology
https://www.readbyqxmd.com/read/28059464/adults-with-initial-metabolic-syndrome-have-altered-muscle-deoxygenation-during-incremental-exercise
#9
Alessandro da Costa Machado, Thales Coelho Barbosa, Allan Robson Kluser Sales, Marcio Nogueira de Souza, Antonio Claudio Lucas da Nóbrega, Bruno Moreira Silva
OBJECTIVE: Reduced aerobic power is independently associated with metabolic syndrome (MetS) incidence and prevalence in adults. This study investigated whether muscle deoxygenation (proxy of microvascular O2 extraction) during incremental exercise is altered in MetS and associated with reduced oxygen consumption ( V˙O2peak ). METHODS: Twelve men with initial MetS (no overt diseases and medication-naive; mean ± SD, age 38 ± 7 years) and 12 healthy controls (HCs) (34 ± 7 years) completed an incremental cycling test to exhaustion, in which pulmonary ventilation and gas exchange (metabolic analyzer), as well as vastus lateralis deoxygenation (near infrared spectroscopy), were measured...
January 6, 2017: Obesity
https://www.readbyqxmd.com/read/28057577/heterogeneity-of-blood-flow-and-metabolism-during-exercise-in-patients-with-chronic-obstructive-pulmonary-disease
#10
Zafeiris Louvaris, Helmut Habazettl, Andreas Asimakos, Harrieth Wagner, Spyros Zakynthinos, Peter D Wagner, Ioannis Vogiatzis
The study investigated whether the capacity to regulate muscle blood flow (Q) relative to metabolic demand (VO2) is impaired in COPD. Using six NIRS optodes over the upper, middle and lower vastus lateralis in 6 patients, (FEV1:46±12%predicted) we recorded from each: a) Q by indocyanine green dye injection, b) VO2/Q ratios based on fractional tissue O2 saturation and c) VO2 as their product, during constant-load exercise (at 20%, 50% and 80% of peak capacity) in normoxia and hyperoxia (FIO2:1.0). At 50 and 80%, relative dispersion (RD) for Q, but not for VO2, was greater in normoxia (0...
January 3, 2017: Respiratory Physiology & Neurobiology
https://www.readbyqxmd.com/read/28056670/electromyographic-comparison-of-conventional-machine-strength-training-versus-bodyweight-exercises-in-patients-with-chronic-stroke
#11
Jonas Vinstrup, Joaquin Calatayud, Markus D Jakobsen, Emil Sundstrup, Kenneth Jay, Mikkel Brandt, Peter Zeeman, Jørgen R Jørgensen, Lars L Andersen
OBJECTIVE: To investigate whether bodyweight exercises can induce comparable levels of muscle activity as conventional machine exercises in chronic stroke patients. METHODS: Eighteen patients performed three repetitions of bilateral- and unilateral machine leg press and the bodyweight exercises chair rise and hip thrust. Surface electromyography (EMG) was recorded from 10 lower extremity muscles and normalized to maximal EMG (nEMG) of the non-paretic leg. RESULTS: For the paretic leg, the bodyweight exercises showed comparable levels of nEMG in 6 out of 10 muscles compared with the bilateral leg press...
January 6, 2017: Topics in Stroke Rehabilitation
https://www.readbyqxmd.com/read/28049266/does-vitamin-d-affect-muscle-strength-and-architecture-an-isokinetic-and-ultrasonographic-study
#12
Murat Kara, Timur Ekiz, Özgür Kara, Tülay Tiftik, Fevziye Ünsal Malas, Sibel Özbudak Demir, Neşe Özgirgin
BACKGROUND AND OBJECTIVES: The objective of this study was to explore the association between 25- hydroxyvitamin D (25(OH)D) and muscle strength/architecture. METHODS AND STUDY DESIGN: Thirty patients (27 women, 3 men) were allocated into Group I (n=15, mean age; 44.4±9.4 years) and Group II (n=15, mean age; 39.0±9.9 years) according to the median of 25(OH)D (<13.7 ng/mL vs >13.7 ng/mL, respectively). Peak torque/body weight of the knee flexor/extensor muscles at 60°/sec and 180°/sec and those of ankle flexor/ extensor muscles at 30°/sec and 90°/sec were evaluated by using a Biodex System 3 Pro Multijoint System isokinetic dynamometer...
January 2017: Asia Pacific Journal of Clinical Nutrition
https://www.readbyqxmd.com/read/28048810/su-f-i-25-reproducibility-of-phosphorus-mrs-and-work-measurements-for-evaluating-skeletal-muscle-metabolism
#13
F Settles, E Ripley, D Shengwen, G Clarke
PURPOSE: Skeletal muscle energetics were studied by phosphorus-31 MRS ((31) P-MRS) during exercise. The reproducibility of work performed and the MRS parameters were investigated. METHODS: Reproducibility of the (31) P-MRS exercise parameters was validated in five healthy volunteers (2 M/3 F, age 39.2 ± 21.9 yr, BMI 25.1 ± 4.8 kg/m(2) ). Five minute exercise of the vastus lateralis (VL) was performed on two separate occasions during MRS in a 3 Tesla MRI system...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28048761/mo-fg-campus-iep3-05-a-novel-model-for-evaluating-exercise-induced-skeletal-muscle-metabolism-with-phosphorus-mrs
#14
E Ripley, G Clarke, F Settles
PURPOSE: The phosphocreatine (PCr) recovery rate after exercise is used an index of mitochondrial function in muscle 31P-MRS. We tested the hypothesis that the initial rate of PCr recovery after exercise reflects the equilibrium mitochondrial ATP production rate required to balance ATP requirements during exercise. METHODS: Exercise data is often analyzed by fitting the PCr recovery curve to the Levenberg-Marquardt algorithm to determine the rate constant, k. In this study, the initial rates of change for PCr and inorganic phosphate (Pi) were examined at the beginning and after the end of exercise in the vastus lateralis...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28044199/muscle-fascicle-shortening-behaviour-of-vastus-lateralis-during-a-maximal-force-velocity-test
#15
Hugo Hauraix, Sylvain Dorel, Giuseppe Rabita, Gaël Guilhem, Antoine Nordez
PURPOSE: Muscle fascicles-tendon interactions are the main determinant in production of high joint velocity. Currently, no study has investigated the muscle fascicles behaviour of knee extensor muscles until the highest reachable velocity (e.g., unloaded knee extension). We aimed to track the changes in vastus lateralis fascicles length during knee extensions to quantify muscle fascicles and tendinous tissues contributions to muscle-tendon unit shortening and to determine maximal muscle fascicles shortening velocity...
January 3, 2017: European Journal of Applied Physiology
https://www.readbyqxmd.com/read/28039406/the-effect-of-polyphenols-on-cytokine-and-granulocyte-response-to-resistance-exercise
#16
Adam R Jajtner, Jay R Hoffman, Jeremy R Townsend, Kyle S Beyer, Alyssa N Varanoske, David D Church, Leonardo P Oliveira, Kelli A Herrlinger, Shlomit Radom-Aizik, David H Fukuda, Jeffrey R Stout
This study examined the effect of resistance exercise on the production, recruitment, percentage, and adhesion characteristics of granulocytes with and without polyphenol (PPB) supplementation. Thirty-eight untrained men were randomized into three groups: PPB (n = 13, 21.8 ± 2.5 years, 171.2 ± 5.5 cm, 71.2 ± 8.2 kg), placebo (PL; n = 15, 21.6 ± 2.5 years, 176.5 ± 4.9 cm, 84.0 ± 15.7 kg), or control (CON; n = 10, 23.3 ± 4.3 years, 173.7 ± 12.6 cm, 77.3 ± 16.3 kg). Blood samples were obtained pre (PRE), immediately (IP), 1 h (1H), 5 h (5H), 24 h (24H), 48 h (48H), and 96 h (96H) postresistance exercise (PPB/PL) or rest (CON)...
December 2016: Physiological Reports
https://www.readbyqxmd.com/read/28032343/tracking-motor-units-longitudinally-across-experimental-sessions-with-high-density-surface-electromyography
#17
E Martinez-Valdes, F Negro, C M Laine, D Falla, F Mayer, D Farina
A new method is proposed for tracking individual motor units (MUs) across multiple experimental sessions on different days. The technique is based on a novel decomposition approach for high-density surface electromyography and was tested with two experimental studies for reliability and sensitivity. Experiment I (reliability): ten participants performed isometric knee extensions at 10, 30, 50 and 70% of their maximum voluntary contraction (MVC) force in three sessions, each separated by 1 week. Experiment II (sensitivity): seven participants performed 2 weeks of endurance training (cycling) and were tested pre-post intervention during isometric knee extensions at 10 and 30% MVC...
December 28, 2016: Journal of Physiology
https://www.readbyqxmd.com/read/28029696/vastus-medialis-and-lateralis-activity-during-voluntary-and-stimulated-contractions
#18
Rosa M S Visscher, Diego Rossi, Bernd Friesenbichler, Markus Dohm-Acker, Thomas Rosenheck, Nicola A Maffiuletti
INTRODUCTION: The purpose of this study was to investigate the relative activation of vastus medialis (VM) and vastus lateralis (VL) muscles during voluntary and stimulated isometric contractions at different joint angles. METHODS: Sixteen healthy men (mean age: 26 years) completed maximal voluntary and stimulated contractions of the knee extensor muscles at 30°, 65°, and 100° of knee flexion. VM/VL ratios were calculated from voluntary EMG and evoked torque recordings...
December 28, 2016: Muscle & Nerve
https://www.readbyqxmd.com/read/28028870/neuromuscular-performance-of-maximal-voluntary-explosive-concentric-contractions-is-influenced-by-angular-acceleration
#19
D Hahn, P Bakenecker, F Zinke
Torque production during maximal voluntary explosive contractions is considered to be a functionally more relevant neuromuscular measure than steady-state torque, but little is known about accelerated concentric contractions. This study investigated torque, muscle activity, and fascicle behavior during isometric and fast concentric contractions of quadriceps femoris. Ten participants performed maximal voluntary explosive isometric, isovelocity, and additional concentric knee extensions at angular accelerations ranging from 700 to 4000° s(-2) that resulted in an angular velocity of 300° s(-1) at 40° knee flexion...
December 28, 2016: Scandinavian Journal of Medicine & Science in Sports
https://www.readbyqxmd.com/read/28027463/quantifying-knee-mechanics-during-balance-training-exercises
#20
Lauren C Benson, Thomas G Almonroeder, Kristian M O'Connor
Patellofemoral pain (PFP) is common among runners and those recovering from anterior cruciate ligament reconstruction. Training programs designed to prevent or treat injuries often include balance training, although balance interventions have been reported to coincide with more knee injuries. Knowledge of the effect of balance exercises on knee mechanics may be useful when designing training programs. High knee abduction moment has been implicated in the development of PFP, and imbalance between vastus lateralis (VL) and vastus medialis oblique (VMO) may contribute to patellofemoral stress...
December 24, 2016: Human Movement Science
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