The authors have no acknowledgements.

<ol>
	<li>Deyhle, M. R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Skeletal+Muscle+Inflammation+Following+Repeated+Bouts+of+Lengthening+Contractions+in+Humans.">Skeletal Muscle Inflammation Following Repeated Bouts of Lengthening Contractions in Humans.</a> Front. Physiol. 6, 424 (2015).</li><li>Hyldahl, R. D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Extracellular+matrix+remodeling+and+its+contribution+to+protective+adaptation+following+lengthening+contractions+in+human+muscle.">Extracellular matrix remodeling and its contribution to protective adaptation following lengthening contractions in human muscle.</a> FASEB J. 29 (7), 2894-2904 (2015).</li><li>Hyldahl, R. D., Olson, T., Welling, T., Groscost, L., Parcell, A. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Satellite+cell+activity+is+differentially+affected+by+contraction+mode+in+human+muscle+following+a+work-matched+bout+of+exercise.">Satellite cell activity is differentially affected by contraction mode in human muscle following a work-matched bout of exercise.</a> Front. Physiol. 5, 485 (2014).</li><li>Clarkson, P. M., Kearns, A. K., Rouzier, P., Rubin, R., Thompson, P. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Serum+creatine+kinase+levels+and+renal+function+measures+in+exertional+muscle+damage.">Serum creatine kinase levels and renal function measures in exertional muscle damage.</a> Med. Sci. Sports Exerc. 38 (4), 623-627 (2006).</li><li>Clarkson, P. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Exertional+rhabdomyolysis+and+acute+renal+failure+in+marathon+runners.">Exertional rhabdomyolysis and acute renal failure in marathon runners.</a> Sports Med. 37 (4-5), 361-363 (2007).</li><li>Seedat, Y. K., Aboo, N., Naicker, S., Parsoo, I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Acute+renal+failure+in+the+&amp;#34;Comrades+Marathon&amp;#34+runners.">Acute renal failure in the &amp;#34;Comrades Marathon&amp;#34 runners.</a> Ren. Fail. 11 (4), 209-212 (1989).</li><li>Landau, M. E., Kenney, K., Deuster, P., Campbell, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Exertional+rhabdomyolysis:+a+clinical+review+with+a+focus+on+genetic+influences.">Exertional rhabdomyolysis: a clinical review with a focus on genetic influences.</a> J. Clin. Neuromuscul. Dis. 13 (3), 122-136 (2012).</li><li>Warren, G. L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Role+of+CC+chemokines+in+skeletal+muscle+functional+restoration+after+injury.">Role of CC chemokines in skeletal muscle functional restoration after injury.</a> Am. J. Physiol. Cell Physiol. 286 (5), C1031-C1036 (2004).</li><li>Zhang, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=CD8+T+cells+are+involved+in+skeletal+muscle+regeneration+through+facilitating+MCP-1+secretion+and+Gr1(high)+macrophage+infiltration.">CD8 T cells are involved in skeletal muscle regeneration through facilitating MCP-1 secretion and Gr1(high) macrophage infiltration.</a> J. Immunol. 193 (10), 5149-5160 (2014).</li><li>Cermak, N. M., Noseworthy, M. D., Bourgeois, J. M., Tarnopolsky, M. A., Gibala, M. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Diffusion+tensor+MRI+to+assess+skeletal+muscle+disruption+following+eccentric+exercise.">Diffusion tensor MRI to assess skeletal muscle disruption following eccentric exercise.</a> Muscle Nerve. 46 (1), 42-50 (2012).</li><li>Chen, Y. W., Hubal, M. J., Hoffman, E. P., Thompson, P. D., Clarkson, P. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Molecular+responses+of+human+muscle+to+eccentric+exercise.">Molecular responses of human muscle to eccentric exercise.</a> J. Appl. Physiol. 95 (6), 2485-2494 (2003).</li><li>Stasinger, S. K., Di Lorenzo, M. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Phlebotomy Textbook. , 188-203 (2011).</li><li>Hubal, M. J., Chen, T. C., Thompson, P. D., Clarkson, P. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Inflammatory+gene+changes+associated+with+the+repeated-bout+effect.">Inflammatory gene changes associated with the repeated-bout effect.</a> Am. J. Physiol. Regul. Integr. Comp. Physiol. 294 (5), R1628-R1637 (2008).</li><li>Stupka, N., Tarnopolsky, M. A., Yardley, N. J., Phillips, S. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cellular+adaptation+to+repeated+eccentric+exercise-induced+muscle+damage.">Cellular adaptation to repeated eccentric exercise-induced muscle damage.</a> J. Appl. Physiol. 91 (4), 1669-1678 (2001).</li><li>Smith, L. L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Changes+in+serum+cytokines+after+repeated+bouts+of+downhill+running.">Changes in serum cytokines after repeated bouts of downhill running.</a> Appl. Physiol. Nutr. Metab. 32 (2), 233-240 (2007).</li><li>Marqueste, T., Giannesini, B., Fur, Y. L., Cozzone, P. J., Bendahan, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Comparative+MRI+analysis+of+T2+changes+associated+with+single+and+repeated+bouts+of+downhill+running+leading+to+eccentric-induced+muscle+damage.">Comparative MRI analysis of T2 changes associated with single and repeated bouts of downhill running leading to eccentric-induced muscle damage.</a> J. Appl. Physiol. 105 (1), 299-307 (2008).</li><li>Crameri, R. M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Myofibre+damage+in+human+skeletal+muscle:+effects+of+electrical+stimulation+versus+voluntary+contraction.">Myofibre damage in human skeletal muscle: effects of electrical stimulation versus voluntary contraction.</a> J. Physiol. 583 (Pt 1), 365-380 (2007).</li><li>Yu, J. G., Malm, C., Thornell, L. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Eccentric+contractions+leading+to+DOMS+do+not+cause+loss+of+desmin+nor+fibre+necrosis+in+human+muscle.">Eccentric contractions leading to DOMS do not cause loss of desmin nor fibre necrosis in human muscle.</a> Histochem. Cell Biol. 118 (1), 29-34 (2002).</li><li>Jamurtas, A. Z., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Comparison+between+leg+and+arm+eccentric+exercises+of+the+same+relative+intensity+on+indices+of+muscle+damage.">Comparison between leg and arm eccentric exercises of the same relative intensity on indices of muscle damage.</a> Eur. J. Appl. Physiol. 95 (2-3), 179-185 (2005).</li></ol>

The authors have nothing to disclose.

عدة خطوات حاسمة لحصول على النتائج المرجوة من هذا البروتوكول. أولا، والموضوعات يجب أن اطلع على نحو كاف لبروتوكولات الانكماش، لا سيما القياسات قوة. مما لا شك فيه أن هذا الموضوع يفهم بالضبط ما يتوقع منهم القيام به، ومنحهم فرصة لممارسة الاختبارات قوة قبل جمع البيانات. ال...

The overall goal of this procedure is to induce exertional damage to the quadriceps femoris muscles using voluntary lengthening (eccentric) contractions in human subjects.
Contraction-induced skeletal muscle damage is a common consequence of exercise that is marked by delayed onset muscle soreness1, transient strength loss, and elevated muscle-specific enzymes in the blood2. Exertional muscle damage is most pronounced following exercise to which the subject is unaccustomed, particularly when eccentric contractions are involved3. Exertional muscle damage is typically benign. Soreness subsides, and both serum proteins and strength typically return to pre-damage levels within a few days to weeks after the damaging insult. In extreme cases, exertional muscle damage can lead to a life-threatening syndrome know as rhabdomyolysis. However, exertional muscle damage is usually insufficient to cause clinical rhabdomyolysis in healthy individuals4 in the absence of compounding factors including heat stress, dehydration5, infection6 or rare genetic predispositions7. 
Contraction-induced muscle damage is typically less severe than toxin-induced or freezing-induced injury, methods often used in rodent studies8,9. Yet, contraction-induced injury provides a useful method to study the muscle damage response with notable advantages. First, it is a safe and ethical method for use with human subjects1-3. Thus, interspecies translation of the results is not needed as data can be obtained directly from human subjects. Moreover, translating data obtained from rodent studies is very difficult given that the severity of injury seen in the rodent injury models exceeds the level of damage that would be ethical to induce in human subjects. Second, contraction-induced damage is commonly experienced and a natural process of exercise. Therefore, this mode of damage induction is useful for studying muscle damage in the context of exercise, adaptation to exercise as well as overt muscle injury. Here we describe a safe and reliable method to induce and evaluate skeletal muscle damage using lengthening contractions in humans.

<table><tbody><tr><td>Biodex Dynomometer</td><td>Biodex Medical Systems</td><td>850-000</td><td>Other models are available and should produce similar results</td></tr><tr><td>Creatine Kinase kit</td><td>Sigma-Aldrich&amp;nbsp;</td><td>MAK116</td><td></td></tr><tr><td>Serum Vacutainers</td><td>BD Bioscience</td><td>367812</td><td></td></tr><tr><td>Winged safety push button blood collection set</td><td>BD Bioscience</td><td>367338</td><td></td></tr><tr><td>Cryogenic vials</td><td>Sigma-Aldrich</td><td>V5007</td><td>We use the 2&amp;nbsp;ml vials to store serum aliquots</td></tr></tbody></table>

induction and assessment of exertional skeletal muscle damage in humans

الناجم عن تقلص العضلات الضرر عن طريق (إطالة) تقلصات الطوعية غريب الأطوار يقدم نموذجا ممتازا لدراسة تكيف العضلات والانتعاش في البشر. هنا نناقش تصميم بروتوكول ممارسة غريب الأطوار للحث على الضرر في العضلات الرباعية الرؤوس، والتي تميزت التغيرات في القوة، ووجع، والبلازما مستويات الكرياتين كيناز. وهذه طريقة بسيطة والأخلاقية، وقابلة للتطبيق على نطاق واسع منذ يتم تنفيذ ذلك في المشاركين البشري ويقضي على الترجمة بين الأنواع من النتائج. الموضوعات أداء 300 انكماش غريب الأطوار القصوى لعضلات الركبة الباسطة بسرعة 120 درجة / ثانية على المقوى isokinetic. مدى الضرر يمكن قياسه باستخدام تدابير isokinetic ومتساوي القياس نسبيا غير الغازية من فقدان القوة، ووجع، ومستويات الكرياتين كيناز البلازما على مدى عدة أيام بعد العملية. لذلك، يمكن أن توجه تطبيقه على فئات معينة من السكان في محاولة لتحديد آليات العضلاتالتكيف والتجدد.

باستخدام الأساليب المقدمة هنا، وجع خط الأساس، المصل النشاط الكرياتين كيناز، وقوة أخذت (متساوي القياس وisokinetic) القياسات في 7 شبان غير مدربين. في اليوم التالي، خضعت الموضوعات عضلة إتلاف بروتوكول انكماش غريب الأطوار المذكورة أعلاه. لتوفير مؤشرات تلف ا?...

Watch this Scientific Journal Video about Induction and Assessment of Exertional Skeletal Muscle Damage in Humans at JoVE.com

Induction and Assessment of Exertional Skeletal Muscle Damage in Humans

This article describes a safe and reliable method to induce and quantify exertional skeletal muscle damage in human subjects.

الاستقراء وتقييم الأضرار الجهدي الهيكل العظمي والعضلات في البشر

Contraction-induced muscle damage via voluntary eccentric (lengthening) contractions offers an excellent model for studying muscle adaptation and recovery ...

induction-assessment-exertional-skeletal-muscle-damage

Research

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Medicine

7.4K Views.  Brigham Young University. This article describes a safe and reliable method to induce and quantify exertional skeletal muscle damage in human subjects.

Video: Induction and Assessment of Exertional Skeletal Muscle Damage in Humans

In Vivo Canine Muscle Function Assay

We describe a minimally-invasive and reproducible method to measure canine pelvic limb muscle strength and muscle response to repeated eccentric 
contractions. The pelvic limb of an anesthetized dog is immobilized in a stereotactic frame to align the tibia at a right angle to the femur. Adhesive wrap affixes the 
paw to a pedal mounted on the shaft of a servomotor to measure torque. Percutaneous nerve stimulation activates pelvic limb muscles of the paw to either push (extend) or 
pull (flex) against the pedal to generate isometric torque. Percutaneous tibial nerve stimulation activates tibiotarsal extensor muscles. Repeated eccentric (lengthening) 
contractions are induced in the tibiotarsal flexor muscles by percutaneous peroneal nerve stimulation. The eccentric protocol consists of an initial isometric contraction 
followed by a forced stretch imposed by the servomotor. The rotation effectively lengthens the muscle while it contracts, e.g., an eccentric contraction. During 
stimulation flexor muscles are subjected to an 800 msec isometric and 200 msec eccentric contraction. This procedure is repeated every 5 sec. To avoid fatigue, 4 min rest 
follows every 10 contractions with a total of 30 contractions performed.

In Vivo Canine Muscle Function Assay

We describe a minimally-invasive and painless method to measure canine hindlimb muscle strength and muscle response to repeated eccentric contractions.

فيفو الناب في العضلات وظيفة الفحص

We describe a minimally-invasive and reproducible method to measure canine pelvic limb muscle strength and muscle response to repeated eccentric 
...

Manual Muscle Testing:  A Method of Measuring Extremity Muscle Strength Applied to Critically Ill Patients

Survivors of acute respiratory distress syndrome (ARDS) and other causes of critical illness often have generalized weakness, reduced exercise tolerance, and persistent nerve and muscle impairments after hospital discharge.1-6 Using an explicit protocol with a structured approach to training and quality assurance of research staff, manual muscle testing (MMT) is a highly reliable method for assessing strength, using a standardized clinical examination, for patients following ARDS, and can be completed with mechanically ventilated patients who can tolerate sitting upright in bed and are able to follow two-step commands. 7, 8 
This video demonstrates a protocol for MMT, which has been taught to &ge;43 research staff who have performed &gt;800 assessments on &gt;280 ARDS survivors. Modifications for the bedridden patient are included. Each muscle is tested with specific techniques for positioning, stabilization, resistance, and palpation for each score of the 6-point ordinal Medical Research Council scale.7,9-11 Three upper and three lower extremity muscles are graded in this protocol: shoulder abduction, elbow flexion, wrist extension, hip flexion, knee extension, and ankle dorsiflexion. These muscles were chosen based on the standard approach for evaluating patients for ICU-acquired weakness used in prior publications. 1,2.

Survivors of acute respiratory distress syndrome (ARDS) and critical illness frequently develop long-lasting muscle weakness. Manual muscle testing (MMT) is a standardized clinical examination commonly used to measure strength of peripheral skeletal muscle groups. This video demonstrates MMT using the 6-point Medical Research Council scale.

التطبيقية وسيلة لقياس قوة العضلات إلى أقصى المرضى ذوي الحالات الحرجة : دليل اختبار العضلات

Survivors of acute respiratory distress syndrome (ARDS) and other causes of critical illness often have generalized weakness, reduced exercise tolerance, ...

An in vivo Rodent Model of Contraction-induced Injury and Non-invasive Monitoring of Recovery

Muscle strains are one of the most common complaints treated by physicians. A muscle injury is typically diagnosed from the patient history and physical exam alone, however the clinical presentation can vary greatly depending on the extent of injury, the patient's pain tolerance, etc. In patients with muscle injury or muscle disease, assessment of muscle damage is typically limited to clinical signs, such as tenderness, strength, range of motion, and more recently, imaging studies. Biological markers, such as serum creatine kinase levels, are typically elevated with muscle injury, but their levels do not always correlate with the loss of force production. This is even true of histological findings from animals, which provide a "direct measure" of damage, but do not account for all the loss of function. Some have argued that the most comprehensive measure of the overall health of the muscle in contractile force. Because muscle injury is a random event that occurs under a variety of biomechanical conditions, it is difficult to study. Here, we describe an in vivo animal model to measure torque and to produce a reliable muscle injury. We also describe our model for measurement of force from an isolated muscle in situ. Furthermore, we describe our small animal MRI procedure.

An in vivo Rodent Model of Contraction-induced Injury and Non-invasive Monitoring of Recovery

An in vivo animal model of injury is described. The method takes advantage of the subcutaneous position of the fibular nerve. Velocity, timing of muscle activation, and arc of motion are all pre-determined and synchronized using commercial software. Post injury changes are monitored in vivo using MR imaging/spectroscopy.

و في الجسم الحي النموذجي القوارض من الإصابات الناجمة عن انكماش ، وغير الغازية ورصد الانتعاش

Muscle strains are one of the most  common complaints treated by physicians. A muscle injury is typically diagnosed from the patient history and  physical ...

The Use of Thermal Infra-Red Imaging to Detect Delayed Onset Muscle Soreness

Delayed onset muscle soreness (DOMS), also known as exercise induced muscle damage (EIMD), is commonly experienced in individuals who have been physically inactive for prolonged periods of time, and begin with an unexpected bout of exercise1-4, but can also occur in athletes who exercise beyond their normal limits of training5. The symptoms associated with this painful phenomenon can range from slight muscle tenderness, to severe debilitating pain1,3,5. The intensity of these symptoms and the related discomfort increases within the first 24 hours following the termination of the exercise, and peaks between 24 to 72 hours post exercise1,3. For this reason, DOMS is one of the most common recurrent forms of sports injury that can affect an individual&#x2019;s performance, and become intimidating for many1,4.
For the last 3 decades, the DOMS phenomenon has gained a considerable amount of interest amongst researchers and specialists in exercise physiology, sports, and rehabilitation fields6. There has been a variety of published studies investigating this painful occurrence in regards to its underlying mechanisms, treatment interventions, and preventive strategies1-5,7-12. However, it is evident from the literature that DOMS is not an easy pathology to quantify, as there is a wide amount of variability between the measurement tools and methods used to quantify this condition6. It is obvious that no agreement has been made on one best evaluation measure for DOMS, which makes it difficult to verify whether a specific intervention really helps in decreasing the symptoms associated with this type of soreness or not. Thus, DOMS can be seen as somewhat ambiguous, because many studies depend on measuring soreness using a visual analog scale (VAS)10,13-15, which is a subjective rather than an objective measure. Even though needle biopsies of the muscle, and blood levels of myofibre proteins might be considered a gold standard to some6, large variations in some of these blood proteins have been documented 6,16, in addition to the high risks sometimes associated with invasive techniques. 
Therefore, in the current investigation, we tested a thermal infra-red (IR) imaging technique of the skin above the exercised muscle to detect the associated muscle soreness. Infra-red thermography has been used, and found to be successful in detecting different types of diseases and infections since the 1950&#x2019;s17. But surprisingly, near to nothing has been done on DOMS and changes in skin temperature. The main purpose of this investigation was to examine changes in DOMS using this safe and non-invasive technique.

The purpose of this investigation was to assess whether using an infra-red thermal camera is a valid tool for detecting and quantifying the muscle soreness after exercising.

استخدام التصوير بالأشعة دون الحمراء الحرارية لكشف تأخر بداية ظهور وجع العضلات

Delayed onset muscle soreness (DOMS), also known as exercise induced muscle damage (EIMD), is commonly experienced in individuals who have been physically ...

Induction of Acute Skeletal Muscle Regeneration by Cardiotoxin Injection

Skeletal muscle regeneration is a physiological process that occurs in adult skeletal muscles in response to injury or disease. Acute injury-induced skeletal muscle regeneration is a widely used, powerful model system to study the events involved in muscle regeneration as well as the mechanisms and different players. Indeed, a detailed knowledge of this process is essential for a better understanding of the pathological conditions that lead to skeletal muscle degeneration, and it aids in identifying new targeted therapeutic strategies. The present work describes a detailed and reproducible protocol to induce acute skeletal muscle regeneration in mice through a single intramuscular injection of cardiotoxin (CTX). CTX belongs to the family of snake venom toxins and causes myolysis of myofibers, which eventually triggers the regeneration events. The dynamics of skeletal muscle regeneration is evaluated by histological analysis of muscle sections. The protocol also illustrates the experimental procedures for dissecting, freezing, and cutting the Tibialis Anterior muscle, as well as the routine Hematoxylin &#38; Eosin staining that is widely used for subsequent morphological and morphometric analysis.

This manuscript describes a detailed protocol to induce acute skeletal muscle regeneration in adult mice and subsequent manipulations of the muscles, such as dissection, freezing, cutting, routine staining, and myofiber cross-sectional area analysis.

تحريض الحاد الهيكل العظمي تجديد العضلات التي Cardiotoxin حقن

Skeletal muscle regeneration is a physiological process that occurs in adult skeletal muscles in response to injury or disease. Acute injury-induced ...

Developmental Biology

Human Skeletal Muscle Biopsy Procedures Using the Modified Bergstr&#246;m Technique

The percutaneous biopsy technique enables researchers and clinicians to collect skeletal muscle tissue samples. The technique is safe and highly effective. This video describes the percutaneous biopsy technique using a modified Bergstr&#246;m needle to obtain skeletal muscle tissue samples from the vastus lateralis of human subjects. The Bergstr&#246;m needle consists of an outer cannula with a small opening (&#8216;window&#8217;) at the side of the tip and an inner trocar with a cutting blade at the distal end. Under local anesthesia and aseptic conditions, the needle is advanced into the skeletal muscle through an incision in the skin, subcutaneous tissue, and fascia. Next, suction is applied to the inner trocar, the outer trocar is pulled back, skeletal muscle tissue is drawn into the window of the outer cannula by the suction, and the inner trocar is rapidly closed, thus cutting or clipping the skeletal muscle tissue sample. The needle is rotated 90&#176;&#160;and another cut is made. This process may be repeated three more times. This multiple cutting technique typically produces a sample of 100-200 mg or more in healthy subjects and can be done immediately before, during, and after a bout of exercise or other intervention. Following post-biopsy dressing of the incision site, subjects typically resume their activities of daily living right away and can fully participate in vigorous physical activity within 48-72 hr. Subjects should avoid heavy resistance exercise for 48 hr to reduce the risk of herniation of the muscle through the incision in the fascia.

The purpose of this video is to present the modified Bergstr&#246;m skeletal muscle biopsy technique on human subjects.

الهيكل العظمي إجراءات خزعة العضلات البشرية باستخدام تقنية التعديل بيرجستروم

The percutaneous biopsy technique enables researchers and clinicians to collect skeletal muscle tissue samples. The technique is safe and highly ...

Ex Vivo Assessment of Contractility, Fatigability and Alternans in Isolated Skeletal Muscles

Described here is a method to measure contractility of isolated skeletal muscles. Parameters such as muscle force, muscle power, contractile kinetics, fatigability, and recovery after fatigue can be obtained to assess specific aspects of the excitation-contraction coupling (ECC) process such as excitability, contractile machinery and Ca2+ handling ability. This method removes the nerve and blood supply and focuses on the isolated skeletal muscle itself. We routinely use this method to identify genetic components that alter the contractile property of skeletal muscle though modulating Ca2+ signaling pathways. Here, we describe a newly identified skeletal muscle phenotype, i.e., mechanic alternans, as an example of the various and rich information that can be obtained using the in vitro muscle contractility assay. Combination of this assay with single cell assays, genetic approaches and biochemistry assays can provide important insights into the mechanisms of ECC in skeletal muscle.

Ex Vivo Assessment of Contractility, Fatigability and Alternans in Isolated Skeletal Muscles

We describe a method to directly measure muscle force, muscle power, contractile kinetics and fatigability of isolated skeletal muscles in an in vitro system using field stimulation. Valuable information on Ca2+ handling properties and contractile machinery of the muscle can be obtained using different stimulating protocols.

فيفو السابقين تقييم من تعب، وانقباض في عضلات الهيكل العظمي تناوب متفرقة

 
Described here is a method to measure contractility of isolated skeletal muscles. Parameters such as muscle force, muscle power, contractile kinetics, ...

Biology

Isometric and Eccentric Force Generation Assessment of Skeletal Muscles Isolated from Murine Models of Muscular Dystrophies

Critical to the evaluation of potential therapeutics for muscular disease are sensitive and reproducible physiological assessments of muscle function. Because many pre-clinical trials rely on mouse models for these diseases, isolated muscle function has become one of the standards for Go/NoGo decisions in moving drug candidates forward into patients. We will demonstrate the preparation of the extensor digitorum longus (EDL) and diaphragm muscles for functional testing, which are the predominant muscles utilized for these studies. The EDL muscle geometry is ideal for isolated muscle preparations, with two easily accessible tendons, and a small size that can be supported by superfusion in a bath. The diaphragm exhibits profound progressive pathology in dystrophic animals, and can serve as a platform for evaluating many potential therapies countering fibrosis, and promoting myofiber stability. Protocols for routine testing, including isometric and eccentric contractions, will be shown. Isometric force provides assessment of strength, and eccentric contractions help to evaluate sarcolemma stability, which is disrupted in many types of muscular dystrophies. Comparisons of the expected results between muscles from wildtype and dystrophic muscles will also be provided. These measures can complement morphological and biochemical measurements of tissue homeostasis, as well as whole animal assessments of muscle function.

Muscle function measurements contribute to the evaluation of potential therapeutics for muscle pathology, as well as to the determination of mechanisms underlying physiology of this tissue. We will demonstrate the preparation of the extensor digitorum longus and diaphragm muscles for functional testing. Protocols for isometric and eccentric contractions will be shown, as well as differences in results between dystrophic muscles, representing a pathological state, and wildtype muscles.

متساوي القياس وغريب الأطوار التقييم تكوين القوات من عضلات الهيكل العظمي المعزولة من الفئران نماذج من ضمور العضلات

Critical to the evaluation of potential  therapeutics for muscular disease are sensitive and reproducible physiological  assessments of muscle function. ...

Skeletal Muscle Neurovascular Coupling, Oxidative Capacity, and Microvascular Function with 'One Stop Shop' Near-infrared Spectroscopy

Exercise represents a major hemodynamic stress that demands a highly coordinated neurovascular response in order to match oxygen delivery to metabolic demand. Reactive hyperemia (in response to a brief period of tissue ischemia) is an independent predictor of cardiovascular events and provides important insight into vascular health and vasodilatory capacity. Skeletal muscle oxidative capacity is equally important in health and disease, as it determines the energy supply for myocellular processes. Here, we describe a simple, non-invasive approach using near-infrared spectroscopy to assess each of these major clinical endpoints (reactive hyperemia, neurovascular coupling, and muscle oxidative capacity) during a single clinic or laboratory visit. Unlike Doppler ultrasound, magnetic resonance images/spectroscopy, or invasive catheter-based flow measurements or muscle biopsies, our approach is less operator-dependent, low-cost, and completely non-invasive. Representative data from our lab taken together with summary data from previously published literature illustrate the utility of each of these end-points. Once this technique is mastered, application to clinical populations will provide important mechanistic insight into exercise intolerance and cardiovascular dysfunction.

Here, we describe a simple, non-invasive approach using near-infrared spectroscopy to assess reactive hyperemia, neurovascular coupling and skeletal muscle oxidative capacity in a single clinic or laboratory visit.

اقتران نيوروفاسكولار الهيكل العظمى والعضلات والقدرات الأكسدة والدالة ميكروفاسكولار مع 'واحد وقف متجر' القريبة من الأشعة تحت الحمراء الطيفي

Exercise represents a major hemodynamic stress that demands a highly coordinated neurovascular response in order to match oxygen delivery to metabolic ...

Non-invasive Assessment of Dorsiflexor Muscle Function in Mice

Assessment of skeletal muscle contractile function is an important measurement for both clinical and research purposes. Numerous conditions can negatively affect skeletal muscle. This can result in a loss of muscle mass (atrophy) and/or loss of muscle quality (reduced force per unit of muscle mass), both of which are prevalent in chronic disease, muscle-specific disease, immobilization, and aging (sarcopenia). Skeletal muscle function in animals can be evaluated by a range of different tests. All tests have limitations related to the physiological testing environment, and the selection of a specific test often depends on the nature of the experiments. Here, we describe an in vivo, non-invasive technique involving a helpful and easy assessment of force frequency-curve (FFC) in mice that can be performed on the same animal over time. This permits monitoring of disease progression and/or efficacy&#160;of a potential therapeutic treatment.

Measurement of rodent skeletal muscle contractile function is a useful tool that can be used to track disease progression as well as efficacy of therapeutic intervention. We describe here the non-invasive, in vivo assessment of the dorsiflexor muscles that can be repeated over time in the same mouse.

تقييم غير الغازية لوظيفة العضلات دورسيفليكسور في الفئران

Assessment of skeletal muscle contractile function is an important measurement for both clinical and research purposes. Numerous conditions can negatively ...