This study was supported by grants to Y.M.S from the National Institutes of Health (CA148828), The University of Michigan Gastrointestinal Peptide Center, and Jeffrey A. Colby Colon Cancer Research and the Tom Liu Memorial Funds of the University of Michigan Comprehensive Cancer Center.

1. Colon Tumor Isolation and Cell Dissociation
<ol>
	<li>Intestinal tumors can be isolated from any sporadic or treatment-induced colon cancer model. The mice should be euthanized with CO2. Colons are then collected, flushed with cold phosphate-buffered saline (PBS) and opened longitudinally. Identify regions containing tumors using a stereomicroscope, dissect out with a pair of scissors, and wash with cold PBS.</li>
	<li>Incubate intestinal fragments containing tumors in EDTA chelation buffer (2 mM EDTA,...

<ol>
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The experimental procedures described in this protocol will allow for isolation and culture of primary murine colon tumors. The protocol is adapted from seminal work done by Dr. Clevers group 1,24,27. We optimized the digestion time and collagenase concentration to get a better yield of tumor organoids. The critical steps include tumor cell digestion into single cells, Matrigel resuspension, and selective culture. For tumor cell digestion, in order to obtain efficient dissociation of colon tumors and maintain ...

The intestinal epithelial cells proliferate and turn over at an extraordinary rate, outpacing all other tissues in the vertebrate body 2,3. The dividing cells including intestinal stem cells (ISC) and transit-amplifying cells differentiate into either secretory (goblet, Paneth and enteroendocrine) cells or enterocytes 3. The ISC is located at the base of the crypt. Paneth cells move down to the bottom of crypts and are long-lived, whereas other lineages migrate upwards to the villi 3,4. Here the cells are exposed to the gut contents including microbiota and are shed from the villus tips through an anoikis-induced apoptotic mechanism. Although the colon lacks villi and Paneth cells, the mechanism for maintaining homeostasis is similar 4.
The Wnt signaling pathway has been implicated in playing a crucial role in intestinal proliferation and ISC maintenance 4. Deletion of the transcription factor TCF4, a downstream effector of Wnt signaling, leads to loss of intestinal stem cells and subsequent breakdown of the tissue 5. Similarly, transgenic expression of the Wnt inhibitor DKK1 reduces the epithelial proliferation and depletes secretory cell lineages 6. Conversely, overexpression of the Wnt agonist R-spondin-1 induces potent and rapid proliferation of intestinal crypt cells 7.
Given the importance of Wnt signaling for intestinal homeostasis, Wnt pathway mutations are frequently observed in colon cancer 8. Colon cancer is the third leading cause of death from cancer in United States 9. Excess dietary intake with red meat and alcohol, reduced physical activity, and inherited and somatic mutations are considered to be risk factors of colon cancer 10,11. The adenomatous polyposis coli (Apc) gene, a key Wnt signaling factor, is mutated in a majority of patients with familial, sporadic, and colitis-associated colon cancer 12,13. Mutations of other factors involved in Wnt signaling pathway including Axin2 and &beta;-catenin are also observed in colon cancer 14,15. However, the precise mechanism and effective therapy for colon cancer are still lacking. To facilitate the investigation of the molecular mechanisms for colon cancer, human colon cancer cell lines representing different stages of cancer progression from a benign to an aggressive cell type have been established 16-18. Mouse colon carcinoma cell lines with different metastatic properties are also available 19,20. Nevertheless, primary cells or organoid cultures are preferred over transformed cell lines because they closely mimic the in vivo state and generate more physiologically relevant data 21. Most colon-cancer derived cell lines grow as monolayer attached to the plate or as cell suspensions, lacking of apical-basolateral orientation and tight junctions between cells. Also, normal and tumor intestinal epithelial cells in vivo undergo a spontaneous form of apoptosis termed anoikis as the differentiated cells reach the villus tips and are shed 22. These features are difficult to recapitulate in cell lines but are important in the developmental process of colon cancer 23. These features are maintained in primary organoids. In addition, the tumor organoid cultures provide an efficient system to assess tumor autonomous functions of genes compared to in vivo studies. Genetic manipulation in vivo of the intestine is a time-consuming process mainly through creating transgenic and/or knockout mice using intestine-specific drivers. However, the tumor organoids are readily amenable to viral mediated genetic manipulations and thus a great tool for assessing precise molecular mechanisms. Primary intestinal tumor organoid cultures have been demonstrated to be a feasible and powerful technique. Primary intestinal cell culture can establish functional intestinal organoids with crypt-villi structure in vitro from a single adult Lgr5+ stem cell 24. These organoids can be transplanted and engrafted into damaged colon tissue for regeneration 25. Further adaption of the culture conditions had made similar epithelial organoids from mouse colon and human small intestine and colon feasible 1. For primary normal colon epithelium culture, basal culture medium as well as growth factors including EGF, Noggin, R-spondin and Wnt3a are essential, whereas basal culture medium and EGF is sufficient for growing primary mouse colon tumor organoids 1. Here we describe a detailed protocol to isolate, culture, and generate colon tumor organoids.

<table border="1">
	<tbody>
		<tr>
			<td>Name of Reagent/Material</td>
			<td>Company</td>
			<td>Catalog Number</td>
			<td>Comments</td>
		</tr>
		<tr>
			<td>Matrigel Basement Membrane Matrix</td>
			<td>BD Biosciences</td>
			<td>356234</td>
			<td>5 mg/ml</td>
		</tr>
		<tr>
			<td>Collagenase Type IV</td>
			<td>Worthington</td>
			<td>LS004188</td>
			<td>375 U/mg</td>
		</tr>
		<tr>
			<td>Dispase</td>
			<td>Gibco</td>
			<td>17105-041</td>
			<td>1.8 U/mg</td>
		</tr>
		<tr>
			<td>Advanced DMEM/F12</td>
			<td>Invitrogen</td>
			<td>12634010</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Epidermal Growth Factor (EGF), Murine, Natural</td>
			<td>Invitrogen</td>
			<td>53003-018</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>N2 Supplement</td>
			<td>Invitrogen</td>
			<td>17502-048</td>
			<td>100 x</td>
		</tr>
		<tr>
			<td>B27 Supplement</td>
			<td>Invitrogen</td>
			<td>17504-044</td>
			<td>50 x</td>
		</tr>
		<tr>
			<td>Glutamax-I</td>
			<td>Gibco</td>
			<td>35050-079</td>
			<td>100x</td>
		</tr>
		<tr>
			<td>N-Acetylcysteine</td>
			<td>Sigma</td>
			<td>A9165-5G</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Dulbecco's Modified Eagle Medium</td>
			<td>Invitrogen</td>
			<td>11965-092</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>PicoPureTM RNA Isolation Kit</td>
			<td>Invitrogen</td>
			<td>KIT0204</td>
			<td>&nbsp;</td>
		</tr>
	</tbody>
</table>

in vitro organoid culture of primary mouse colon tumors

Several human and murine colon cancer cell lines have been established, physiologic integrity of colon tumors such as multiple cell layers, basal-apical polarity, ability to differentiate, and anoikis are not maintained in colon cancer derived cell lines. The present study demonstrates a method for culturing primary mouse colon tumor organoids adapted from Sato T et al. 1, which retains important physiologic features of colon tumors. This method consists of mouse colon tumor tissue collection, adjacent normal colon epithelium dissociation, colon tumor cells digestion into single cells, embedding colon tumor cells into matrigel, and selective culture based on the principle that tumor cells maintain growth on limiting nutrient conditions compared to normal epithelial cells.
The primary tumor organoids if isolated from genetically modified mice provide a very useful system to assess tumor autonomous function of specific genes. Moreover, the tumor organoids are amenable to genetic manipulation by virus meditated gene delivery; therefore signaling pathways involved in the colon tumorigenesis could also be extensively investigated by overexpression or knockdown. Primary tumor organoids culture provides a physiologic relevant and feasible means to study the mechanisms and therapeutic modalities for colon tumorigenesis.

The time course of a colon tumor organoid formation from a three-month-old Apcmin/+ mouse is shown in Figure 1. At day 0, single cells could be observed several hours following plating (Figure 1A). At day 1, survived colon tumor epithelial cells with refractory nuclei could be observed. At day 3, the size of cells doubled. At day 6, the size of organoid expanded more than ten-fold and showed signs of apoptosis in the middle. At day 14, the orgnoids would grow into irr...

Watch this Scientific Journal Video about In vitro Organoid Culture of Primary Mouse Colon Tumors at JoVE.com

In vitro Organoid Culture of Primary Mouse Colon Tumors

A simple method to establish primary murine colon tumor organoid is described. This method utilizes the feature that colon tumor cells survive and grow into organoids in media containing limited growth factors, whereas normal colon epithelial do not.

In vitro Organoid Culture of Primary Mouse Colon Tumors

Several  human and murine colon cancer cell lines have been established, physiologic  integrity of colon tumors such as multiple cell layers, basal-apical ...

in-vitro-organoid-culture-of-primary-mouse-colon-tumors

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34.8K ビュー.  University of Michigan. 一次マウス結腸腫瘍オルガノイドを確立するための簡単​​な方法が記載されている。通常のコロンは上皮ないのに対し、この方法では、結腸腫瘍細胞が生き残ると限られた成長因子を含む培地中でオルガノイドに成長するという特徴を利用しています。

ビデオ: In vitro Organoid Culture of Primary Mouse Colon Tumors

Establishment and Propagation of Human Retinoblastoma Tumors in Immune Deficient Mice

Culturing retinoblastoma tumor cells in defined stem cell media gives rise to primary tumorspheres that can be grown and maintained for only a limited time. These cultured tumorspheres may exhibit markedly different cellular phenotypes when compared to the original tumors. Demonstration that cultured cells have the capability of forming new tumors is important to ensure that cultured cells model the biology of the original tumor. 
Here we present a protocol for propagating human retinoblastoma tumors in vivo using Rag2-/- immune deficient mice. Cultured human retinoblastoma tumorspheres of low passage or cells obtained from freshly harvested human retinoblastoma tumors injected directly into the vitreous cavity of murine eyes form tumors within 2-4 weeks. These tumors can be harvested and either further passaged into murine eyes in vivo or grown as tumorspheres in vitro. Propagation has been successfully carried out for at least three passages thus establishing a continuing source of human retinoblastoma tissue for further experimentation. 
Wesley S. Bond and Lalita Wadhwa are co-first authors.

A method is described to propagate human retinoblastoma tumors in mice. Tumor cells are directly injected into the eyes of immune deficient mice. Secondary tumors have been successfully established using both cells directly harvested from human tumors and cultured tumorspheres.

Culturing retinoblastoma tumor cells in defined stem cell media gives rise to primary tumorspheres that can be grown and maintained for only a limited ...

Evaluation of Nanoparticle Uptake in Tumors in Real Time Using Intravital Imaging

Current technologies for tumor imaging, such as ultrasound, MRI, PET and CT, are unable to yield high-resolution images for the assessment of nanoparticle uptake in tumors at the microscopic level1,2,3, highlighting the utility of a suitable xenograft model in which to perform detailed uptake analyses. Here, we use high-resolution intravital imaging to evaluate nanoparticle uptake in human tumor xenografts in a modified, shell-less chicken embryo model. The chicken embryo model is particularly well-suited for these in vivo analyses because it supports the growth of human tumors, is relatively inexpensive and does not require anesthetization or surgery 4,5. Tumor cells form fully vascularized xenografts within 7 days when implanted into the chorioallantoic membrane (CAM) 6. The resulting tumors are visualized by non-invasive real-time, high-resolution imaging that can be maintained for up to 72 hours with little impact on either the host or tumor systems. Nanoparticles with a wide range of sizes and formulations administered distal to the tumor can be visualized and quantified as they flow through the bloodstream, extravasate from leaky tumor vasculature, and accumulate at the tumor site. We describe here the analysis of nanoparticles derived from Cowpea mosaic virus (CPMV) decorated with near-infrared fluorescent dyes and/or polyethylene glycol polymers (PEG) 7, 8, 9,10,11. Upon intravenous administration, these viral nanoparticles are rapidly internalized by endothelial cells, resulting in global labeling of the vasculature both outside and within the tumor7,12. PEGylation of the viral nanoparticles increases their plasma half-life, extends their time in the circulation, and ultimately enhances their accumulation in tumors via the enhanced permeability and retention (EPR) effect 7, 10,11. The rate and extent of accumulation of nanoparticles in a tumor is measured over time using image analysis software. This technique provides a method to both visualize and quantify nanoparticle dynamics in human tumors.

We present a novel approach to quantify nanoparticle localization in the vasculature of human xenografted tumors using dynamic, real-time intravital imaging in an avian embryo model.

Current technologies for tumor imaging, such as ultrasound, MRI, PET and CT, are unable to yield high-resolution images for the assessment of nanoparticle ...

Skin Punch Biopsy Explant Culture for Derivation of Primary Human Fibroblasts

Tissues and cell lines derived from an individual with disease are ideal sources to study disease-related cellular phenotypes. Patient-derived fibroblasts in this protocol have been successfully used in the derivation of induced pluripotent stem cells to model disease1. Early passages of these fibroblasts can also be used for cell-based functional assays to study specific disease pathways, mechanisms2 and subsequent drug screening approaches. The advantage of the presented protocol over enzymatic procedures are 1) the reproducibility of the technique from small amounts of tissue derived from older patients, e.g. patients affected with Parkinson's disease, 2) the technically simple approach over more challenging methodologies using enzymatic treatments, and 3) the time consideration: this protocol takes 15-20 min and can be performed immediately after biopsy arrival. Enzymatic treatments can take up to 4 hr and have the problems of overdigestion, reduction of cell viability and subsequent attachment of cells when not handled properly. This protocol describes the dissection and preparation of a 4-mm human skin biopsy for derivation of a fibroblast culture and has a very high success rate which is important when dealing with patient-derived tissue samples. In this culture, keratinocytes migrate out of the biopsy tissue within the first week after preparation. Fibroblasts appear 7-10 days after the first outgrowth of keratinocytes. DMEM high glucose media supplemented with 20% FBS favors the growth of fibroblasts over keratinocytes and fibroblasts will overgrow the keratinocytes. After 2 passages keratinocytes have been diluted out resulting in relatively homogenous fibroblast cultures which expresses the fibroblast marker SERPINH1 (HSP-47). Using this approach, 15-20 million fibroblasts can be derived in 4-8 weeks for cell banking. The skin dissection takes about 15-20 min, cells are then monitored once a day under the microscope, and media is changed every 2-3 days after attachment and outgrowth of cells.

The fibroblast explant culture protocol from human skin punch biopsies is a technically robust and simple way to derive skin cells within 4-8 weeks for banking of about 15-20 million cells at a low passage number.

Tissues and cell lines derived from an individual with disease are ideal sources to study disease-related cellular phenotypes. Patient-derived fibroblasts ...

Primary Culture of Human Vestibular Schwannomas

Vestibular schwannomas (VSs) represent Schwann cell (SC) tumors of the vestibular nerve, compromising 10% of all intracranial neoplasms. VSs occur in either sporadic or familial (neurofibromatosis type 2, NF2) forms, both associated with inactivating defects in the NF2 tumor suppressor gene. Treatment for VSs is generally surgical resection or radiosurgery, however the morbidity of such procedures has driven investigations into less invasive treatments. Historically, lack of access to fresh tissue specimens and the fact that schwannoma cells are not immortalized have significantly hampered the use of primary cultures for investigation of schwannoma tumorigenesis. To overcome the limited supply of primary cultures, the immortalized HEI193 VS cell line was generated by transduction with HPV E6 and E7 oncogenes. This oncogenic transduction introduced significant molecular and phenotypic alterations to the cells, which limit their use as a model for human schwannoma tumors. We therefore illustrate a simplified, reproducible protocol for culture of primary human VS cells. This easily mastered technique allows for molecular and cellular investigations that more accurately recapitulate the complexity of VS disease.

Vestibular Schwannomas (VSs) are non-malignant tumors of Schwann cell (SC) origin, associated with mutations in the NF2 tumor suppressor gene. We report a reproducible, efficient protocol for primary human VS cell culture that allows for molecular and cellular experimental manipulation and analysis and recapitulates the heterogeneous nature of human disease.

Vestibular schwannomas (VSs) represent Schwann cell (SC) tumors of the vestibular nerve, compromising 10% of all intracranial neoplasms. VSs occur in ...

Ex Vivo Treatment Response of Primary Tumors and/or Associated Metastases for Preclinical and Clinical Development of Therapeutics

The molecular analysis of established cancer cell lines has been the mainstay of cancer research for the past several decades. Cell culture provides both direct and rapid analysis of therapeutic sensitivity and resistance. However, recent evidence suggests that therapeutic response is not exclusive to the inherent molecular composition of cancer cells but rather is greatly influenced by the tumor cell microenvironment, a feature that cannot be recapitulated by traditional culturing methods. Even implementation of tumor xenografts, though providing a wealth of information on drug delivery/efficacy, cannot capture the tumor cell/microenvironment crosstalk (i.e., soluble factors) that occurs within human tumors and greatly impacts tumor response. To this extent, we have developed an ex vivo (fresh tissue sectioning) technique which allows for the direct assessment of treatment response for preclinical and clinical therapeutics development. This technique maintains tissue integrity and cellular architecture within the tumor cell/microenvironment context throughout treatment response providing a more precise means to assess drug efficacy.

Ex Vivo Treatment Response of Primary Tumors and/or Associated Metastases for Preclinical and Clinical Development of Therapeutics

Established cancer cell lines and xenografts have been the mainstay of cancer research for the past several decades. However, recent evidence suggests that therapeutic response is greatly influenced by the tumor cell microenvironment. Therefore, we have developed an ex vivo analysis of primary tumor specimens for drug development purposes.

The molecular analysis of established cancer cell lines has been the mainstay of cancer research for the past several decades. Cell culture provides both ...

In vitro Functional Characterization of Mouse Colorectal Afferent Endings

This video demonstrates in detail an in vitro single-fiber electrophysiological recording protocol using a mouse colorectum-nerve preparation. The approach allows unbiased identification and functional characterization of individual colorectal afferents. Extracellular recordings of propagated action potentials (APs) that originate from one or a few afferent (i.e., single-fiber) receptive fields (RFs) in the colorectum are made from teased nerve fiber fascicles. The colorectum is removed with either the pelvic (PN) or lumbar splanchnic (LSN) nerve attached and opened longitudinally. The tissue is placed in a recording chamber, pinned flat and perfused with oxygenated Krebs solution. Focal electrical stimulation is used to locate the colorectal afferent endings, which are further tested by three distinct mechanical stimuli (blunt probing, mucosal stroking and circumferential stretch) to functionally categorize the afferents into five mechanosensitive classes. Endings responding to none of these mechanical stimuli are categorized as mechanically-insensitive afferents (MIAs). Both mechanosensitive and MIAs can be assessed for sensitization (i.e., enhanced response, reduced threshold, and/or acquisition of mechanosensitivity) by localized exposure of RFs to chemicals (e.g., inflammatory soup (IS), capsaicin, adenosine triphosphate (ATP)). We describe the equipment and colorectum&#8211;nerve recording preparation, harvest of colorectum with attached PN or LSN, identification of RFs in the colorectum, single-fiber recording from nerve fascicles, and localized application of chemicals to the RF. In addition, challenges of the preparation and application of standardized mechanical stimulation are also discussed.

In vitro Functional Characterization of Mouse Colorectal Afferent Endings

This video demonstrates a protocol for conducting single-fiber electrophysiological recordings on an in vitro mouse colorectum-nerve preparation.

This video demonstrates in detail an in vitro single-fiber electrophysiological recording protocol using a mouse colorectum-nerve preparation. The ...

Clinicopathological Analysis of miRNA Expression in Breast Cancer Tissues by Using miRNA In Situ Hybridization

In this article, we describe a detailed protocol for miRNA detection in breast cancer tissue using in situ hybridization with a digoxigenin-labelled LNA (Locked Nucleic Acid) probe. The probe was recognized by anti-DIG alkaline phosphatase antibodies and later developed using alkaline phosphatase substrate producing fluorescence signals. Here we utilized miRNA in situ hybridization (MISH) technique to analyze expression of miR-489 in tissues from breast cancer patients. This technique can detect the localization of miRNA of interest in individual tissue samples. This technique can be used to compare the expression of desired miRNA in tumor tissue with that in adjacent normal tissue and to identify the specific structures responsible for expressing this miRNA. This technique can be very useful in answering certain clinical questions, such as role of specific miRNA in the development of cancer. Our results indicate that mammary epithelial cells express significantly higher levels of miR-489 than adjacent tumor cells.

Clinicopathological Analysis of miRNA Expression in Breast Cancer Tissues by Using miRNA In Situ Hybridization

Here we present a protocol to detect miRNA expression in breast cancer patient samples using miRNA in situ hybridization.

In this article, we describe a detailed protocol for miRNA detection in breast cancer tissue using in situ hybridization with a digoxigenin-labelled LNA ...

Isolation and Culture of Primary Endothelial Cells from Canine Arteries and Veins

Cardiovascular disease is studied in both human and veterinary medicine. Endothelial cells have been used extensively as an in vitro model to study vasculogenesis, (tumor) angiogenesis, and atherosclerosis. The current standard for in vitro research on human endothelial cells (ECs) is the use of Human Umbilical Vein Endothelial Cells (HUVECs) and Human Umbilical Artery Endothelial Cells (HUAECs). For canine endothelial research, only one cell line (CnAOEC) is available, which is derived from canine aortic endothelium. Although currently not completely understood, there is a difference between ECs originating from either arteries or veins. For a more direct approach to in vitro functionality studies on ECs, we describe a new method for isolating Canine Primary Endothelial Cells (CaPECs) from a variety of vessels. This technique reduces the chance of contamination with fast-growing cells such as fibroblasts and smooth muscle cells, a problem that is common in standard isolation methods such as flushing the vessel with enzymatic solutions or mincing the vessel prior to digestion of the tissue containing all cells. The technique we describe was optimized for the canine model, but can easily be utilized in other species such as human.

Novel isolation methods of primary endothelial cells from blood vessels are needed. This protocol describes a new technique that completely inverts blood vessels of interest, exposing only the endothelial side to enzymatic digestion. The resulting pure endothelial cell culture can be used to study cardiovascular diseases, disease modelling, and angiogenesis.

Cardiovascular disease is studied in both human and veterinary medicine. Endothelial cells have been used extensively as an in vitro model to study ...

Forskolin-induced Swelling in Intestinal Organoids: An In Vitro Assay for Assessing Drug Response in Cystic Fibrosis Patients

Recently-developed cystic fibrosis transmembrane conductance regulator (CFTR)-modulating drugs correct surface expression and/or function of the mutant CFTR channel in subjects with cystic fibrosis (CF). Identification of subjects that may benefit from these drugs is challenging because of the extensive heterogeneity of CFTR mutations, as well as other unknown factors that contribute to individual drug efficacy. Here, we describe a simple and relatively rapid assay for measuring individual CFTR function and response to CFTR modulators in vitro. Three dimensional (3D) epithelial organoids are grown from rectal biopsies in standard organoid medium. Once established, the organoids can be bio-banked for future analysis. For the assay, 30-80 organoids are seeded in 96-well plates in basement membrane matrix and are then exposed to drugs. One day later, the organoids are stained with calcein green, and forskolin-induced swelling is monitored by confocal live cell microscopy at 37 &#176;C. Forskolin-induced swelling is fully CFTR-dependent and is sufficiently sensitive and precise to allow for discrimination between the drug responses of individuals with different and even identical CFTR mutations. In vitro swell responses correlate with the clinical response to therapy. This assay provides a cost-effective approach for the identification of drug-responsive individuals, independent of their CFTR mutations. It may also be instrumental in the development of future CFTR modulators.

Forskolin-induced Swelling in Intestinal Organoids: An In Vitro Assay for Assessing Drug Response in Cystic Fibrosis Patients

This protocol describes an assay for measuring CFTR function and CFTR modulator responses in cultured tissue from subjects with cystic fibrosis (CF). Biopsy-derived intestinal organoids swell in a cAMP-driven fashion, a response that is defective (or strongly reduced) in CF organoids and can be restored by exposure to CFTR modulators.

Recently-developed cystic fibrosis transmembrane conductance regulator (CFTR)-modulating drugs correct surface expression and/or function of the mutant ...

Muscle Imbalances: Testing and Training Functional Eccentric Hamstring Strength in Athletic Populations

Many hamstring injuries that occur during physical activity occur while the muscles are lengthening, during eccentric hamstring muscle actions. Opposite of these eccentric hamstring actions are concentric quadriceps actions, where the larger and likely stronger quadriceps straighten the knee. Therefore, to stabilize the lower limbs during movement, the hamstrings must eccentrically combat against the strong knee-straightening torque of the quadriceps. As such, eccentric hamstring strength expressed relative to concentric quadricep strength is commonly referred to as the &#34;functional ratio&#34; as most movements in sports require simultaneous concentric knee extension and eccentric knee flexion. To increase the strength, resiliency, and functional performance of the hamstrings, it is necessary to test and train the hamstrings at different eccentric speeds. The main purpose of this work is to provide instructions for measuring and interpreting eccentric hamstring strength. Techniques for measuring the functional ratio using isokinetic dynamometry are provided and sample data will be compared. Additionally, we briefly describe how to address hamstring strength deficiencies or unilateral strength differences using exercises that specifically focus on increasing eccentric hamstring strength.

The hamstrings are a group of muscles that are sometimes problematic for athletes, resulting in soft tissue injury in the lower limbs. To prevent such injuries, functional training of the hamstrings requires intensive eccentric contractions. Additionally, hamstring function should be tested in relation to quadricep function at different contraction speeds.

Many hamstring injuries that occur during physical activity occur while the muscles are lengthening, during eccentric hamstring muscle actions. Opposite ...