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*  Properties of slow- and fast-twitch muscle fibres in a mouse model of amyotrophic lateral sclerosis - DRO
This investigation was undertaken to determine if there are altered histological, pathological and contractile properties in presymptomatic or endstage diseased muscle fibres from representative slow-twitch and fast-twitch muscles of SOD1 G93A mice in comparison to wildtype mice. In presymptomatic SOD1 G93A mice, there was no detectable peripheral dysfunction, providing evidence that muscle pathology is secondary to motor neuronal dysfunction. At disease endstage however, single muscle fibre contractile analysis demonstrated that fast-twitch muscle fibres and neuromuscular junctions are preferentially affected by amyotrophic lateral sclerosis-induced denervation, being unable to produce the same levels of force when activated by calcium as muscle fibres from their age-matched controls. The levels of transgenic SOD1 ...
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Individual fibres were mounted between a force transducer and servomotor, and exposed to activating calcium solutions, as described previously [9]. Maximal tension (i.e. maximal force normalised to muscle fibre cross-sectional area (CSA)) was significantly lower in fast-twitch muscle fibres of PAH patients (Npatients=11, nfibres=112) than in control subjects (Npatients=8, nfibres=62) (mean±sem 192±5 versus 226±8 mN·mm−2, p,0.005; fig. 1b). Based on our permeabilised muscle fibre measurements, we observed no significant difference in fast-twitch muscle fibre CSA between groups (PAH versus control: 3387±280 versus 3307±242 µm2; p=0.84).. In muscle fibres, force is generated by the cyclic interaction between myosin-based cross-bridges and actin. Thus, to determine the underlying cause of the reduction in maximal tension, we studied cross-bridge cycling ...
*  Regulation of ClC-1 and KATP channels in action potential-firing fast-twitch muscle fibers
PubMed Central Canada (PMC Canada) provides free access to a stable and permanent online digital archive of full-text, peer-reviewed health and life sciences research publications. It builds on PubMed Central (PMC), the U.S. National Institutes of Health (NIH) free digital archive of biomedical and life sciences journal literature and is a member of the broader PMC International (PMCI) network of e-repositories.
*  Fgf8 drives myogenic progression of a novel lateral fast muscle fibre population in zebrafish | Development
During zebrafish muscle development, two distinct cell populations give rise to slow and fast muscle fibres (Stickney et al., 2000). The location and origin of these populations has been well characterised (Devoto et al., 1996; Hirsinger et al., 2004). The slow muscle derives from the medially located adaxial cells and depends on Hedgehog (Hh) signals from the midline (Barresi et al., 2000; Blagden et al., 1997; Du et al., 1997; Wolff et al., 2003). Slow fibres fall into two subpopulations: the superficial slow fibres (SSF), which subsequently migrate to the lateral somite surface; and the muscle pioneers (MPs) that remain medial and express engrailed genes (Devoto et al., 1996; Hatta et al., 1991; Ekker et al., 1992). More lateral somite cells do not migrate and later differentiate into fast muscle fibres (Blagden et al., 1997; Devoto et al., 1996; Wolff et al., 2003). A medially located ...
*  The proportion of fast and slow neuromuscular junctions in young and old mice
Human skeletal mass and strength increase from birth until ~35 years of age, thereafter a decline in mass and strength occurs in a process called sarcopenia. Beyond 60 years of age muscular weakness falls to a point where it imposes physical disability and individuals lose the ability to live independently. The loss of muscle mass and strength can be attributed, at least in part, to a fast to slow muscle fibre type transition (increased proportion of slow type muscle fibres. An age associated change in the innervation of skeletal muscle with ageing is a probable underlying cause of this fibre type transition. Muscle fibre types are determined by their innervating axon; fast muscle fibres are innervated by fast axons forming fast neuromuscular junctions (NMJs) and slow muscle fibres are ...
*  I Love United Kingdom: Basketball Techniques ; Basketball Plays - Half Court Offense
Because one uses both leg strength and explosive power, jumping height or specifically, jumping muscles can be developed in the same way as any other muscle can be developed. Within the leg muscles of a vertical jumper are fibers known as fast-twitch and slow-twitch fibers... It is in the distribution of these fibers that ultimately determine the limit of one's vertical jump height. What you're born with is what you get when it comes to these two fibers... They are based on the DNA or genetic makeup of your ancestors. Speed requires rapid muscle contraction and rapid muscle contraction is determined by the quantity of fast-twitch fibers in an athlete or dancer's leg muscles. Unfortunately, those dancers or athletes who possess more ...
*  Human muscle fiber type-specific insulin signaling: Impact of obesity and type 2 diabetes - Danish National Research Database...
Skeletal muscle is a heterogeneous tissue composed of different fiber types. Studies suggest that insulin-mediated glucose metabolism is different between muscle fiber types. We hypothesized that differences are due to fiber-type specific expression/regulation of insulin signaling elements and/or metabolic enzymes. Pools of type I and II fibers were prepared from biopsies of the vastus lateralis muscles from lean, obese and type 2 diabetic subjects before and after a hyperinsulinemic-euglycemic clamp. Type I fibers compared to type II fibers have higher protein levels of the insulin receptor, GLUT4, hexokinase II, glycogen synthase (GS), pyruvate dehydrogenase (PDH-E1α) and a lower protein content of Akt2, TBC1D4 and TBC1D1. In type I fibers compared to type II fibers, the phosphorylation-response to insulin was similar (TBC1D4, TBC1D1 and GS) or decreased (Akt and PDH-E1α). ...
*  How do I slim down bulky, muscular thighs? | Go Ask Alice!
Dear Anonymous,. Many women athletes, once they end competitive play, work on reducing the size of their muscles in different parts of their bodies. As both a softball and soccer player, you are most likely performing power movements in order to train your legs. These power movements probably involve lifting very heavy loads for a few repetitions while weight training and performing explosive movements, such as pressing off of your pivot leg when sprinting.. The amount of muscle in your thighs can be reduced, but it may hamper your athletic performance if you are still active in softball and soccer. As a power athlete, you probably have a larger proportion of fast-twitch muscle fibers (Type II) than slow-twitch fibers (Type I), found predominantly in endurance athletes. Most of your muscle type will not change, as the type of muscle ...
*  Exercise in the fasted state facilitates fibre type-specific intramyocellular lipid breakdown and stimulates glycogen...
The effects were compared of exercise in the fasted state and exercise with a high rate of carbohydrate intake on intramyocellular triglyceride (IMTG) and glycogen content of human muscle. Using a randomized crossover study design, nine young healthy volunteers participated in two experimental sessions with an interval of 3 weeks. In each session subjects performed 2 h of constant-load bicycle exercise (∼75% VO2max ), followed by 4 h of controlled recovery. On one occasion they exercised after an overnight fast (F), and on the other (CHO) they received carbohydrates before (∼150 g) and during (1 g (kg bw)−1 h−1) exercise. In both conditions, subjects ingested 5 g carbohydrates per kg body weight during recovery. Fibre type-specific relative IMTG content was determined by Oil red O staining in needle biopsies from m. vastus lateralis before, immediately after and 4 h after exercise. During F but not during CHO, the exercise bout decreased IMTG content in type ...
*  Human Muscles - Children of the Amphioxus
Various exercises require a predominance of certain muscle fiber utilization over another. Aerobic exercise involves long, low levels of exertion in which the muscles are used at well below their maximal contraction strength for long periods of time (the most classic example being the marathon). Aerobic events, which rely primarily on the aerobic (with oxygen) system, use a higher percentage of Type I (or slow-twitch) muscle fibers, consume a mixture of fat, protein and carbohydrates for energy, consume large amounts of oxygen and produce little lactic acid. Anaerobic exercise involves short bursts of higher intensity contractions at a much greater percentage of their maximum contraction strength. Examples of anaerobic exercise include sprinting and weight lifting. The anaerobic energy delivery system uses predominantly Type ...
Fast twitch muscles fibers have less mitochondria and therefore less capacity for oxygen utilization in the production of energy within the muscle. This makes them better suited to anaerobic activities such as weight training, sprinting, jumping and other explosive type activities. FT fibers create energy anaerobically, that is, without oxygen. This system uses glucose as a prime energy source. The byproduct of this anaerobic energy production is heat and lactic acid. Lactic acid accumulation in the muscle causes fatigue and soreness. The anaerobic energy system is a limited system for energy production ...
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The objective of this study was to determine the combined effects of high H+ and Pi on slow and fast fiber function and to provide a better understanding of how these ions alter the cross-bridge cycle. Additionally, to our knowledge, the results provide the first report of ktr in the fast fiber subtypes IIa and IIx at 30°C. Fiber ktr is thought to reflect the sum of the forward and reverse rate constants of the weak to strong binding step (Fig. 1, step 3) (3). Our finding of a 3.7-fold lower ktr (at 15°C) in the type IIa vs. IIx fiber suggests that the weak to strong binding transition is considerably slower in the IIa fiber and in fact closer to the rate observed in the slow type I fiber (Fig. 2). Interestingly, increasing temperature accelerated ktr considerably more in the slow type I and fast type IIa fiber than in fast IIx fibers. Apparently, the forward rate constant of the weak to strong binding state is less ...
*  Where's Walden?
If all goes well, I'll return in September, mentally refreshed, with a peculiarly developed endurance for walking and very few fast-twitch muscle fibers.
*  Where's Walden? » mozilla
If all goes well, I'll return in September, mentally refreshed, with a peculiarly developed endurance for walking and very few fast-twitch muscle fibers.
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One major finding of the present study was that slow-twitch fibers are much more susceptible to ONOO− than fast-twitch fibers. At both pH 7.1 and pH 8.5, exposure to ONOO− reduced maximum force in slow-twitch Sol fibers in a concentration-dependent manner, but an identical treatment had much less effect in fast-twitch EDL fibers (Figs. 1 and 2). At physiological pH (i.e., 7.1) ONOO− predominantly reduced maximum Ca2+-activated force, with the Ca2+ sensitivity of the contractile apparatus being far less affected (Fig. 1). Similar to ONOO− treatment, exposure to Sin-1 (an ONOO− donor) also caused much greater reduction in maximum force in slow-twitch Sol fibers than in fast-twitch EDL fibers (Fig. 4C). These differences between EDL and Sol ...
*  Extensor Digitorum Longus Muscle
The extensor digitorum longus muscle is situated along the outside of the lower leg, just behind the tibialis anterior. It comes from close to the midline of the tibia and the shaft of the fibula. Its tendon divides into four parts as it passes over the front of the ankle. These parts continue over the surface of the foot and...
*  Pearl White Fiber Jamu Jelita | Amira Beauty
PEARL WHITE FIBER JAMU JELITA Pearl White Fiber merupakan formulasi pelangsingan badan yang kaya dengan nutrien dari sumber semulajadi seperti teh hijau, oat,
*  Ion-specific and general ionic effects on contraction of skinned fast-twitch skeletal muscle from the rabbit. | JGP
We used single fibers from rabbit psoas muscle, chemically skinned with Triton X-100 nonionic detergent, to determine the salts best suited for adjusting ionic strength of bathing solutions for skinned fibers. As criteria we measured maximal calcium-activated force (Fmax), fiber swelling estimated optically, and protein extraction from single fibers determined by polyacrylamide gel electrophoresis with ultrasensitive silver staining. All things considered, the best uni-univalent salt was potassium methanesulfonate, while a number of uni-divalent potassium salts of phosphocreatine, hexamethylenediamine N,N,N',N'-tetraacetic acid, sulfate, and succinate were equally acceptable. Using these salts, we determined that changes in Fmax correlated best with variations of ionic strength (1/2 sigma ci z2i, where ci is the concentration of ion i, and zi is its valence) rather than ionic equivalents (1/2 sigma ci magnitude of zi). Our data indicate that ...
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Studies from several groups have provided evidence that AMPK plays a role in mediating the increase in glucose transport induced by muscle contractions (3, 8, 16, 18, 20). However, earlier studies on frog sartorius muscle had led to the hypothesis that increases in cytosolic Ca2+ mediate the contraction-induced increase in glucose transport (12, 13), and this hypothesis was supported by studies on rat epitrochlearis muscle showing that raising cytosolic Ca2+ concentration, under conditions that do not result in a decrease in ∼P, results in stimulation of muscle glucose transport (25). More recently, we (24) have obtained evidence that activation of CAMKII by Ca2+ and activation of AMPK each mediates part of the increase in glucose transport induced by contractions in the rat epitrochlearis, a fast-twitch muscle.. In contrast ...
*  CytoSport Fast Twitch Reviews (5/5) - IllPumpYouUp.com
CytoSport Fast Twitch is the first formula specifically designed to fuel explosive Fast Twitch (type 2) muscle fibers. Fast Twitch uniquely helps increase and extend explosive muscular performance. Drinking new Fast Twitch Power Workout Drink before and during workouts helps put you in the intensity zone for mind-blowing workouts.
*  Muscle Tissue Histology MCQ Ques. And Ans. | Physiology Plus
Which fiber type is make up fast-twitch muscle? a. Red fibers b. White fibers c. Intermediate fibers d. All of the above e. None of the above
*  Lecturer 1 | Physiology Plus - Part 2
1. Which fiber type is make up fast-twitch muscle? a. Red fibers b. White fibers c. Intermediate fibers d. All of the above e. None of the above Answer: b 2. What is a receptor in muscle? a. Motor unit b. Motor neuron c. Motor end plate d. Neuromuscular spindle e. Neurotransmitter Answer: d 3. […]. ...
*  histology mcqs | Physiology Plus
1. Which fiber type is make up fast-twitch muscle? a. Red fibers b. White fibers c. Intermediate fibers d. All of the above e. None of the above Answer: b 2. What is a receptor in muscle? a. Motor unit b. Motor neuron c. Motor end plate d. Neuromuscular spindle e. Neurotransmitter Answer: d 3. […]. ...
*  KettlebellRob: September 2011
1) Sprinting will reduce body fat and strengthen you far more than long, slow cardio because sprinting requires maximal recruitment of muscle. After about 8 seconds, sprinting sends acid signals to the muscles, which activates the fast twitch fibers. Fast-twitch fibers are thicker than slow twitch fibers, and it is fast twitch fibers that grow in size when activated by the right training ...
*  Nutrition for Fast Twitch Muscles | Healthy Eating | SF Gate
Healthy skeletal muscles play a huge role in your day-to-day functioning -- they support your posture, as well as allow for movement and locomotion. Each muscle is composed of smaller subunits, ...