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  • fibres
  • To test this hypothesis, we measured sarcomeric function in permeabilised individual muscle fibres of idiopathic PAH patients. (ersjournals.com)
  • In permeabilised muscle fibres, sarcomeric contractility can be studied without the confounding effects of processes upstream in the excitation-contraction coupling cascade. (ersjournals.com)
  • The fibres were isolated from quadriceps muscle (vastus lateralis) biopsies of female PAH patients (N=11) and were compared to those from healthy, age- and sex-matched control subjects (N=8). (ersjournals.com)
  • b) Maximal tension (i.e. maximal force per mm 2 cross sectional area at 20°C and a calcium concentration ([Ca 2+ ]) of 32 µM) is significantly reduced in fast-twitch quadriceps muscle fibres of pulmonary hypertension (PAH) patients compared with age- and sex-matched control subjects (CTRL). (ersjournals.com)
  • The two unite at an acute angle, and spread into an aponeurosis which is prolonged downward on the anterior surface of the muscle, and from this the muscular fibres arise. (wikipedia.org)
  • biopsies
  • Quadriceps needle biopsies, taken bilaterally at the end of the infusion, were analysed for muscle protein leucine enrichment with 13 C. (clinsci.org)
  • During the past decade, we have studied muscle biopsies from the quadriceps muscle of Spinal Cord Injury (SCI) patients suffering with Conus and Cauda Equina syndrome, a condition that fully and irreversibly disconnects skeletal muscle fibers from their damaged innervating motor neurons. (nih.gov)
  • Using immunohistochemistry with both non-stimulated and the h-bFES stimulated human muscle biopsies, we have observed the persistent presence of muscle fibers which are positive to labeling by an antibody which specifically recognizes the embryonic myosin heavy chain (MHCemb). (nih.gov)
  • fibers
  • Despite the ravages of long term denervation there is structural and ultrastructural evidence for survival of muscle fibers in mammals, with some fibers surviving at least ten months in rodents and 3-6 years in humans. (nih.gov)
  • Further, in rodents there is evidence that muscle fibers may regenerate even after repeated damage in the absence of the nerve, and that this potential is maintained for several months after denervation. (nih.gov)
  • Whether in mammals, humans included, this is a result of persistent de novo formation of muscle fibers is an open issue we would like to explore in this review. (nih.gov)
  • Relative to the total number of fibers present, only a small percentage of these MHCemb positive fibers are detected, suggesting that they are regenerating muscle fibers and not pre-existing myofibers re-expressing embryonic isoforms. (nih.gov)
  • Although embryonic isoforms of acetylcholine receptors are known to be re-expressed and to spread from the end-plate to the sarcolemma of muscle fibers in early phases of muscle denervation, we suggest that the MHCemb positive muscle fibers we observe result from the activation, proliferation and fusion of satellite cells, the myogenic precursors present under the basal lamina of the muscle fibers. (nih.gov)
  • Using morphological features and molecular biomarkers, we show that severely atrophic muscle fibers, with a peculiar cluster reorganization of myonuclei, are present in rodent muscle seven-months after neurectomy and in human muscles 30-months after complete Conus-Cauda Equina Syndrome and that these are structurally distinct from early myotubes. (nih.gov)
  • Immunohistochemical staining with anti-MHCslow shows that both the green-labeled slow type muscle fibers (white arrows) and the fast (larger, not stained muscle fibers noted by black arrowheads) present several central nuclei. (nih.gov)
  • This mechanism is due to the length of the fibers compared to the connective structure of the muscle. (statpearls.com)
  • It is known that fatigue can be caused by many different mechanisms, ranging from the accumulation of metabolites within muscle fibers to the generation of an inadequate motor command in the motor cortex. (wikipedia.org)
  • AGR = εx/εf where εx = longitudinal strain (or muscle-shortening velocity) and εf is fiber strain (or fiber-shortening velocity) In fusiform muscle, the fibers are longitudinal, so longitudinal strain is equal to fiber strain, and AGR is always 1. (wikipedia.org)
  • The shortening velocity of the pennate muscle as a whole is greater than that of the individual fibers. (wikipedia.org)
  • A smaller fiber length neutralizes this higher architectural gear ratio if the muscle fibers must be squeezed into the same space. (wikipedia.org)
  • spindle
  • Therefore, the architectural gear ratio of a pennate muscle is higher than the architectural gear ratio of spindle like muscles (e.g. fusiform). (wikipedia.org)
  • Anatomy
  • Recent information on the function and anatomy of this muscle will improve the understanding of the functional coordination between the different vasti and allow implementation of a clinical and rehabilitative approach. (statpearls.com)
  • efferent
  • The stimulated nerve bundle includes motor nerves (efferent nerves-descending nerves from the central nervous system to muscles) and sensory nerves (afferent nerves-ascending nerves from sensory organs to the central nervous system). (wikipedia.org)
  • exercise
  • and an exercise regimen that improves or maintains range of motion of the involved joint, strengthens periarticular muscles, and improves cardiovascular fitness. (annals.org)
  • The isolation movement (i.e. targets solely the quadriceps) is the leg extension exercise. (wikipedia.org)
  • A wall sit is an exercise done to strengthen the quadriceps muscles. (wikipedia.org)
  • Wall sits are used as a primary strengthening exercise in many sports requiring strong quadriceps like fencing, ice hockey, sailing (mostly small boat racing), skiing and track and field. (wikipedia.org)
  • This angle is very crucial because if the thighs are not parallel to the ground, the quadriceps will be bearing less load and the effectiveness of the exercise will be diminished. (wikipedia.org)
  • If performing multiple repetitions of the exercise (three is often a recommended number), the participant should rest for half a minute in between in order to allow their muscles to recuperate. (wikipedia.org)
  • The leg extension is a resistance weight training exercise that targets the quadriceps muscle in the legs. (wikipedia.org)
  • The leg extension is an isolated exercise targeting one specific muscle group, the quadriceps. (wikipedia.org)
  • angle
  • The interaction group*time showed no difference in the cross-sectional thickness of the quadriceps muscle (p = 0.100) or in the vastus lateralis fascicle length (p = 0.712), pennation angle (p = 0.603) and muscle thickness (p = 0.552) as assessed by ultrasound before and after the protocol. (pubmedcentralcanada.ca)
  • The Architectural gear ratio is explained through the segmented muscle model 3 proposed by Emanuel Azizi, where a muscle segment is shown as a single muscle fiber attached to the myosepta of a Siren lacertina an aquatic salamander at a certain acute, pennation angle. (wikipedia.org)
  • For example, the pennation angle determines the architectural gear ratio at which a pennate muscle operates. (wikipedia.org)
  • significantly
  • Particularly, the EMG activity of the quadriceps was significantly higher when participants rose from the low height with their feet askew than when they rose from the knee height with their feet placed together (p =0.004) or askew (p =0.002). (deepdyve.com)
  • muscular
  • The investigators evaluated clinical tolerance, biological tolerance, feasibility and efficacy of daily electrostimulation training of shoulder girdle and quadriceps muscles in 10 patients with facioscapulohumeral muscular dystrophy, the third most common inherited myopathy. (clinicaltrials.gov)
  • indirectly
  • This study will involve use of this device on individuals with patellofemoral pain, a relatively common injury among active people, to see if quadriceps stimulation could mitigate disparities in quadriceps activation timing that may indirectly lead to knee pain. (clinicaltrials.gov)
  • assessment
  • Efficacy of electrostimulation training in FSHD patients will be evaluated comparing manual muscle testing, Barré test, quantitative muscle assessment, fatigue severity scale, 6 minutes walking test before the therapy [ Time Frame: after 3 months of therapy and at the end of the study, after 5 months. (clinicaltrials.gov)
  • the efficacy by manual muscle testing, quantitative muscle assessment, fatigue severity scale. (clinicaltrials.gov)
  • functional
  • These results recommend considering initial feet position and seat height when evaluating the functional activity of the quadriceps in patients with unilateral OA using STS test. (deepdyve.com)
  • shoulder
  • We proposed in the present study to test feasibility, clinical and biological tolerance and efficacy of shoulder muscle training by electrostimulation in a group of FSHD patients. (clinicaltrials.gov)
  • 10 patients displaying classical FSHD phenotype participate to this study consisting in daily session of shoulder girdle and quadriceps muscles electrostimulation of 23 minutes for a period of 5 months. (clinicaltrials.gov)
  • These muscles form a cuff around the glenohumeral joint and function to stabilize and manipulate the shoulder. (wikipedia.org)
  • ratio
  • We measure hardness and elastography ratio of quadriceps over subcutaneous fat tissue. (bmj.com)
  • Sonoelastography showed sarcopenia patients had more soft than non-sarcopenia patients, furthermore the elastography ratio of quadriceps over subcutaneous tissue was lower than non-sarcopenia patients. (bmj.com)
  • Using hardness content and elastography ratio of quadriceps over subcutaneous ratio render more information of muscle character. (bmj.com)
  • Architectural gear ratio, also called anatomical gear ratio (AGR) is a feature of pennate muscle defined by the ratio between the longitudinal strain of the muscle and muscle fiber strain. (wikipedia.org)
  • It is sometimes also defined as the ratio between muscle-shortening velocity and fiber-shortening velocity. (wikipedia.org)
  • Fiber rotation decreases a muscle's output force but increases output velocity by allowing the muscle to function at a higher gear ratio (muscle velocity/fiber velocity). (wikipedia.org)
  • Preliminary models results show that with muscle bulging, the Architectural gear ratio will increase. (wikipedia.org)
  • tendons
  • The rotator cuff comprises four pennate muscles, the supraspinatus, infraspinatus, subscapularis and teres minor, and their accompanying tendons. (wikipedia.org)
  • peripheral
  • Whether sarcomere contractility is also affected in peripheral muscles of PAH patients is yet unknown. (ersjournals.com)
  • In some applications, FES can be used to directly stimulate muscles, if their peripheral nerves have been severed or damaged (i.e., denervated muscles). (wikipedia.org)
  • Participants
  • Although there is no difference in time Main text of onset among the four muscles of the quadriceps during Methods closed-chain movements, the VL has the largest amount Eight participants (five males and three females) volun - of EMG activity during that type of movement . (deepdyve.com)
  • patients
  • Physical activity declines in PAH patients and muscle disuse is known to affect sarcomere function [ 10 ]. (ersjournals.com)
  • The aim was to evaluate the electromyographic (EMG) activity of the ipsilateral quadriceps during STS task at different seat heights and feet positions in patients with severe unilateral OA. (deepdyve.com)
  • This is a key muscle to be targeted during the rehabili - tation program of patients with knee OA. (deepdyve.com)
  • Patients in the intensive care unit (ICU) are exposed to prolonged immobility, which leads to loss of muscle mass. (pubmedcentralcanada.ca)
  • To evaluate and compare the effects of early ambulation using a bedside cycle ergometer with conventional physical therapy on the thickness and architecture of the quadriceps muscle in critically ill patients receiving invasive mechanical ventilation (IMV). (pubmedcentralcanada.ca)
  • activate
  • FES devices take advantage of this property to electrically activate nerve cells, which then may go on to activate muscles or other nerves. (wikipedia.org)
  • skeletal muscles
  • There is a growing research database which suggests that skeletal muscles, particularly postural muscles of the lower limb, undergo atrophy and structural and metabolic alterations during space flight. (wikipedia.org)
  • While their cell bodies are found in the central nervous system (CNS), α motor neurons are also considered part of the somatic nervous system-a branch of the peripheral nervous system (PNS)-because their axons extend into the periphery to innervate skeletal muscles. (wikipedia.org)
  • reflexes
  • Frequently, problems associated with nerve compression are characterised by pins & needles, numbness, loss of muscle power, altered skin sensation, and reduced reflexes in the limbs. (back-in-business-physiotherapy.com)
  • Cutaneous reflexes demonstrate variations in the muscles activated and the timing at which they are activated depending on which portion of the gait cycle the stimulation occurs. (wikipedia.org)
  • strain
  • At this rate, you will find that you are able to ride for longer periods of time and are less likely to experience muscle strain and fatigue. (purevolume.com)
  • Running does not guarantee an injury but some of the common running injuries to occur are Plantar Fasciitis, Shin Splints, Runner's Knee, IT Band Syndrome, Achilles Tendinitis, Sprained Ankle, Stress Fracture, Muscle Strain or Pull, and Blisters. (mytopfitness.com)
  • Typically, fan-shaped muscles experience varying degrees of fiber strain. (wikipedia.org)
  • Studies on ratfish have looked at the strain on fan-shaped muscles that have a twisted tendon. (wikipedia.org)
  • It has been found that strain becomes uniform over the face of a fan-shaped muscle with the presence of a twisted tendon. (wikipedia.org)
  • stimulation
  • It has been noted that the muscle activation response to cutaneous receptor stimulation can be modulated by a variety of factors. (wikipedia.org)
  • abdominal
  • Depress and retract your scapulae (pull your shoulders down and back) without arching your low back, "brace" (engage your abdominal/core muscles) to stiffen your spine and keep your pelvis level (and stable). (acefitness.org)
  • results
  • Because of the smaller incisions, patients can also keep the muscles of the quadriceps intact, which results in less pain and discomfort following the procedure itself. (douglasrogermd.com)
  • Unloading of skeletal muscle, both on Earth and during spaceflight, results in remodeling of muscle (atrophic response) as an adaptation to the reduced loads placed upon it. (wikipedia.org)
  • variations
  • Due to limitations in the number of spaceflights and crewmembers in which novel countermeasures can be tested, future development, evaluation and validation of new countermeasures to the effects of skeletal muscle unloading will likely employ variations of these same basic ground-based models. (wikipedia.org)
  • similar
  • This movement is similar to the action of springs, where the muscle is continually shortened and stretched resulting in enhanced effectiveness and force. (wikipedia.org)
  • parallel
  • There are several different muscle architecture types including: parallel, pennate and hydrostats. (wikipedia.org)
  • Parallel and pennate (also known as pinnate) are two main types of muscle architecture. (wikipedia.org)
  • The force produced by a given muscle is proportional to the cross-sectional area, or the number of parallel sarcomeres present. (wikipedia.org)
  • Parallel muscles can be further defined into three main categories: strap, fusiform, or fan-shaped. (wikipedia.org)
  • The force produced by pennate muscles is greater than the force produced by parallel muscles. (wikipedia.org)
  • reflex
  • There are two types: autonomic reflex arc (affecting inner organs) and somatic reflex arc (affecting muscles). (wikipedia.org)
  • different
  • Adding front squats to your routine is a great way to target your quadriceps in a different way than regular squats. (purevolume.com)
  • Considerable bio-mechanical changes occur in the lower back and pelvis as a result of altered weight and force distribution and different muscle utilisation . (physio-pedia.com)
  • Force production and gearing vary depending on the different geometries of the muscle. (wikipedia.org)
  • force
  • When weight exceeds the force developed by the muscle, as in an eccentric muscle action, the exercise is referred to as negative work because the muscle is absorbing energy in this loaded position. (wikipedia.org)
  • When in a concentric exercise, shortening of a muscle occurs as the myosin and actin cross bridges repeatedly attach and detach to draw the actin across the myosin - creating force. (wikipedia.org)
  • control
  • Strap muscles, such as the laryngeal muscles, have been thought to control the fundamental frequency used in speech production, as well as singing. (wikipedia.org)
  • extensive
  • These muscles are often used for fast or extensive movements and can be measured by the anatomical cross-sectional area (CSA). (wikipedia.org)
  • Extensive training gradually his built muscles and success in local competitions, both in ski and foot orienteering. (wikipedia.org)
  • pain
  • A large number of PFPS patients can experience significant improvements in pain, function and Quality of Life, at least in the short term, with quadriceps femoris rehabilitation, with or without emphasis on selective activation of the VMO component. (dougkelsey.com)
  • periods
  • Humans in the microgravity environment of space, within our current space vehicles, are exposed to various mission-specific periods of skeletal muscle unloading (unweighting). (wikipedia.org)
  • fundamental
  • Consequently, a more complete understanding of physiologic models for conduct of both fundamental and applied skeletal muscle research. (wikipedia.org)
  • short
  • Access to human crewmembers during both short- and long-duration mission for the study of skeletal muscle adaptation to microgravity and the efficacy of countermeasures has been, and continues to be, limited. (wikipedia.org)