We would like to thank Jakob Binder for his help in subject acquisition and organization of the examinations, Mrs. Hella Thun for designing Figure 1 and 2 and finally Mr. Dipl.-Ing. (FH), M.Sc. M. Saller for his statistical support.

Ethics statement: The study was approval by the local ethics committee of the University of Munich (# 007-14).
Note: An examination couch freely accessible on both sides and the foot end is required for non-weightbearing testing. A line (tape, approximately 2 meters) on the ground perpendicular the wall is needed for weightbearing testing. A standard goniometer with 2&#176; increments and 20 cm length is used. We recommend documenting the results using a standardized fourfold table containing ADF measurement for the knee extended and flexed for each leg separately.
1. Participant Preparation
<ol>
	<li>Have the subject take off their pants and remove their footwear.</li>
	<li>Mark the axis of the fibula by drawing a line connecting the center of the distal fibula 5 cm and 15 cm above the tip of the fibula.</li>
</ol>
2. Non-weightbearing Measurement (Figure 2A)&#160;
<ol>
	<li>Have two investigators perform the measurement, one conducting the test, the other measuring the degree of ankle dorsiflexion.</li>
	<li>Place the subject in supine position on the examination couch. The examination couch must be freely accessible on both sides and the foot end.</li>
	<li>Have the first investigator place one hand at the level of the subtalar joint to ensure a neutral pronation-supination position of the rear foot and place the other hand around the midfoot. Thereby one hand stabilizes the talonavicular joint, while the other hand applies force on the plantar aspect of the forefoot to achieve maximum ankle dorsiflexion.</li>
	<li>Have the first investigator ensure that the knee is fully extended.</li>
	<li>Have the second investigator perform the measurement of the ankle dorsiflexion using a goniometer. Place one arm of the goniometer connecting the start and end point of the previously marked axis of the fibula. Align the other arm with the plantar aspect of the foot.</li>
	<li>Note the result on the documentation sheet.</li>
	<li>Have the first investigator ensure 90&#176; of knee flexion by placing one hand on the distal dorsal aspect of the thigh while the other hand applies force on the plantar aspect of the forefoot to achieve maximum ankle dorsiflexion.</li>
	<li>Have the first investigator place one hand at the level of the subtalar joint to ensure a neutral pronation-supination position of the rear foot and place the other hand around the midfoot. Thereby one hand stabilizes the talonavicular joint and the other hand applies force on the plantar aspect of the forefoot to achieve maximum ankle dorsiflexion.</li>
	<li>Have the second investigator perform the measurement of the ankle dorsiflexion using a goniometer. Place one arm of the goniometer connecting the start and end point of the previously marked axis of the fibula. Align the other arm with the plantar aspect of the foot.</li>
	<li>Note the result on the documentation sheet.</li>
	<li>Repeat steps 2.1 through 2.10 for the contralateral side.</li>
</ol>
3. Weightbearing Measurement (Figure 2B)
<ol>
	<li>Have one investigator perform the test.</li>
	<li>Place the subject standing opposite a wall.</li>
	<li>Have the subject get into the lunge position with the leg to be measured being the rear leg.</li>
	<li>Have the investigator help the subject to place his/her rear foot centered on the previously marked line. Ensure that the heel and the second toe of the rear leg are centered on the line.</li>
	<li>Have the subject hold onto the wall in order to stabilize their stance.</li>
	<li>Have the subject fully extend their rear leg. Have the investigator ensure that the knee is fully extended. Be aware that even slight knee flexion significantly influences ankle dorsiflexion.</li>
	<li>Have the subject move their hip towards the wall until just before heel lift off of the rear leg. The front leg can be flexed as needed / as comfortable.</li>
	<li>Have the investigator place one hand on the dorsal aspect of the subtalar joint to ensure a neutral pronation-supination position of the rear foot.</li>
	<li>Have the investigator perform the measurement of ankle dorsiflexion with the other hand. Align one arm of the goniometer connecting the start and end point of the previously marked axis of the fibula. Place the other arm on the floor.</li>
	<li>Note the result on the documentation sheet.</li>
	<li>Have the subject get into the lunge position with the leg to be measured being the rear leg. Therefore have the patient move towards the wall until a comfortable position has been reached.</li>
	<li>Have the investigator help the subject to place his/her rear foot centered on the previously marked line. Ensure that the heel and the second toe of the rear leg are centered on the line.</li>
	<li>Have the subject hold onto the wall in order to stabilize their stance.</li>
	<li>Have the subject flex the rear leg as comfortable and move their hip towards the wall until just before heel lift off of the rear leg. The front leg can be flexed as needed / as comfortable.</li>
	<li>Have the investigator ensure that the rear knee is flexed at least 20 degrees. In case of doubt use the goniometer to ensure knee flexion greater than 19 degrees.</li>
	<li>Have the investigator place one hand on the dorsal aspect of the subtalar joint to ensure a neutral pronation-supination position of the rear foot.</li>
	<li>Perform the measurement of ankle dorsiflexion with the other hand. Align one arm of the goniometer connecting the start and end point of the previously marked axis of the fibula. Place the other arm on the floor.</li>
	<li>Note the result on the documentation sheet.</li>
	<li>Repeat steps 3.1 through 3.18 for the contralateral side.</li>
</ol>
4. Data Analysis and Interpretation
<ol>
	<li>Ask the subject to identify the symptomatic side.</li>
	<li>Review the ADF data on the documentation sheet.
	<ol>
		<li>First identify whether ADF with the knee extended is less than 10&#176; on the symptomatic side. If so, consider MGT to be a possible cause. Then, compare ADF with the knee extended and flexed. If knee flexion results in a significant increase of ADF, MGT is present.</li>
		<li>In case ADF is greater than 10&#176;, compare ADF with the knee extended between both legs. If ADF is reduced on the symptomatic compared to the non-symptomatic side consider MGT to be a possible cause. If knee flexion on the symptomatic side results in a significant increase of ADF, MGT is present.</li>
	</ol>
	</li>
</ol>

<ol>
	<li>Wilder, R. P., Sethi, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Overuse+injuries:+tendinopathies,+stress+fractures,+compartment+syndrome,+and+shin+splints.">Overuse injuries: tendinopathies, stress fractures, compartment syndrome, and shin splints.</a> Clin Sorts Med. 23, 55-81 (2004).</li><li>Irving, D. B., Cook, J. L., Menz, H. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Factors+associated+with+chronic+plantar+heel+pain:+a+systematic+review.">Factors associated with chronic plantar heel pain: a systematic review.</a> J Sci Med Sport. 9, 11-22 (2006).</li><li>Patel, A., DiGiovanni, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Association+between+plantar+fasciitis+and+isolated+contracture+of+the+gastrocnemius.">Association between plantar fasciitis and isolated contracture of the gastrocnemius.</a> Foot Ankle Int. 32, 5-8 (2011).</li><li>DiGiovanni, C. W., 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=Isolated+gastrocnemius+tightness.">Isolated gastrocnemius tightness.</a> JBJS Am. 84-A, 962-970 (2002).</li><li>Bol&#236;var, Y. A., Munuera, P. V., Padillo, J. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Relationship+between+tightness+of+the+posterior+muscles+of+the+lower+limb+and+plantar+fasciitis.">Relationship between tightness of the posterior muscles of the lower limb and plantar fasciitis.</a> Foot Ankle Int. 34, 42-48 (2013).</li><li>Hill, R. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ankle+equinus.+Prevalence+and+linkage+to+common+foot+pathology.">Ankle equinus. Prevalence and linkage to common foot pathology.</a> J Am Podiatr Med Assoc. 85, 295-300 (1995).</li><li>Silfverskiold, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Reduction+of+the+uncrossed+two-joints+muscles+of+the+leg+to+one-joint+muscles+in+spastic+conditions.">Reduction of the uncrossed two-joints muscles of the leg to one-joint muscles in spastic conditions.</a> Acta Chir Scand. 56, 315-330 (1923).</li><li>Krause, D. A., Cloud, B. A., Forster, L. A., Schrank, J. A., Hollman, J. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Measurement+of+ankle+dorsiflexion:+a+comparison+of+active+and+passive+techniques+in+multiple+positions.">Measurement of ankle dorsiflexion: a comparison of active and passive techniques in multiple positions.</a> J Sport Rehabil. 20, 333-344 (2011).</li><li>Bennell, K. 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=Intra-rater+and+inter-rater+reliability+of+a+weight-bearing+lunge+measure+of+ankle+dorsiflexion.">Intra-rater and inter-rater reliability of a weight-bearing lunge measure of ankle dorsiflexion.</a> Aust J Physiother. 44, 175-180 (1998).</li><li>Munteanu, S. E., Strawhorn, A. B., Landorf, K. B., Bird, A. R., Murley, G. 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+weightbearing+technique+for+the+measurement+of+ankle+joint+dorsiflexion+with+the+knee+extended+is+reliable.">A weightbearing technique for the measurement of ankle joint dorsiflexion with the knee extended is reliable.</a> J Sci Med Sport. 12, 54-59 (2009).</li><li>Wilken, J., Rao, S., Estin, M., Saltzman, C. L., Yack, H. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+new+device+for+assessing+ankle+dorsiflexion+motion:+reliability+and+validity.">A new device for assessing ankle dorsiflexion motion: reliability and validity.</a> J Orthop Sports Phys Ther. 41, 274-280 (2011).</li><li>Gatt, A., Chockalingam, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Validity+and+reliability+of+a+new+ankle+dorsiflexion+measurement+device.">Validity and reliability of a new ankle dorsiflexion measurement device.</a> Prosthet Orthot Int. 37, 289-297 (2013).</li><li>Baggett, B. D., Young, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ankle+joint+dorsiflexion.+Establishment+of+a+normal+range.">Ankle joint dorsiflexion. Establishment of a normal range.</a> J Am Podiatr Med Assoc. 83, 251-254 (1993).</li><li>Menz, H. B., 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=Reliability+of+clinical+tests+of+foot+and+ankle+characteristics+in+older+people.">Reliability of clinical tests of foot and ankle characteristics in older people.</a> J Am Podiatr Med Assoc. 93, 380-387 (2003).</li><li>Rabin, A., Kozol, Z. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Weightbearing+and+Nonweightbearing+Ankle+Dorsiflexion+Range+of+Motion:+Are+We+Measuring+the+Same+Thing?.">Weightbearing and Nonweightbearing Ankle Dorsiflexion Range of Motion: Are We Measuring the Same Thing?.</a> J Am Podiatr Med Assoc. 12, 406-411 (2012).</li><li>You, J. Y., 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=Gastrocnemius+tightness+on+joint+angle+and+work+of+lower+extremity+during+gait.">Gastrocnemius tightness on joint angle and work of lower extremity during gait.</a> Clin Biomech (Bristol, Avon). 24, 744-750 (2009).</li><li>Baumbach, S. F., 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=The+influence+of+knee+position+on+ankle+dorsiflexion+-+a+biometric+study.">The influence of knee position on ankle dorsiflexion - a biometric study.</a> BMC Musculoskelet Disord. 15, 246 (2014).</li><li>Martin, R. L., McPoil, T. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Reliability+of+ankle+goniometric+measurements:+a+literature+review.">Reliability of ankle goniometric measurements: a literature review.</a> J Am Podiatr Med Assoc. 95, 564-572 (2005).</li><li>Tiberio, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Evaluation+of+functional+ankle+dorsiflexion+using+subtalar+neutral+position.+A+clinical+report.">Evaluation of functional ankle dorsiflexion using subtalar neutral position. A clinical report.</a> Phys Ther. 67, 955-957 (1987).</li><li>Tiberio, D., Bohannon, R. W., Zito, M. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effect+of+subtalar+joint+position+on+the+measurement+of+maximum+ankle+dorsiflexic.">Effect of subtalar joint position on the measurement of maximum ankle dorsiflexic.</a> Clin Biomech (Bristol, Avon). 4, 189-191 (1989).</li><li>Bohannon, R. W., Tiberio, D., Waters, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Motion+measured+from+forefoot+and+hindfoot+landmarks+during+passive+ankle+dorsiflexion+range+of+motion.">Motion measured from forefoot and hindfoot landmarks during passive ankle dorsiflexion range of motion.</a> J Orthop Sports Phys Ther. 13, 20-22 (1991).</li><li>Johanson, M., Baer, J., Hovermale, H., Phouthavong, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Subtalar+joint+position+during+gastrocnemius+stretching+and+ankle+dorsiflexion+range+of+motion.">Subtalar joint position during gastrocnemius stretching and ankle dorsiflexion range of motion.</a> J Athl Train. 43, 172-178 (2008).</li><li>Kim, P. 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=Interrater+and+intrarater+reliability+in+the+measurement+of+ankle+joint+dorsiflexion+is+independent+of+examiner+experience+and+technique+used.">Interrater and intrarater reliability in the measurement of ankle joint dorsiflexion is independent of examiner experience and technique used.</a> J Am Podiatr Med Assoc. 101, 407-414 (2011).</li><li>Youdas, J. W., Krause, D. A., Egan, K. S., Therneau, T. M., Laskowski, E. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+effect+of+static+stretching+of+the+calf+muscle-tendon+unit+on+active+ankle+dorsiflexion+range+of+motion.">The effect of static stretching of the calf muscle-tendon unit on active ankle dorsiflexion range of motion.</a> J Orthop Sports Phys Ther. 33, 408-417 (2003).</li><li>Worrell, T. W., McCullough, M., Pfeiffer, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effect+of+foot+position+on+gastrocnemius/soleus+stretching+in+subjects+with+normal+flexibility.">Effect of foot position on gastrocnemius/soleus stretching in subjects with normal flexibility.</a> TJ Orthop Sports Phys Ther. 19, 352-356 (1994).</li><li>Norkin, C. C., White, D. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Measurement of Joint Motion: A Guide to Goniometry. , (2003).</li><li>Williams, C. M., Caserta, A. J., Haines, T. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+TiltMeter+app+is+a+novel+and+accurate+measurement+tool+for+the+weight+bearing+lunge+test.">The TiltMeter app is a novel and accurate measurement tool for the weight bearing lunge test.</a> J Sci Med Sport. 16, 392-395 (2013).</li><li>Burns, J., Crosbie, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Weight+bearing+ankle+dorsiflexion+range+of+motion+in+idiopathic+pes+cavus+compared+to+normal+and+pes+planus+feet.">Weight bearing ankle dorsiflexion range of motion in idiopathic pes cavus compared to normal and pes planus feet.</a> Foot (Edinb). 15, 91-94 (2005).</li><li>Konor, M. M., Morton, S., Eckerson, J. M., Grindstaff, T. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Reliability+of+three+measures+of+ankle+dorsiflexion+range+of+motion.">Reliability of three measures of ankle dorsiflexion range of motion.</a> Int J Sports Phys Ther. 7, 279-287 (2012).</li><li>Basnett, C. 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=Ankle+dorsiflexion+range+of+motion+influences+dynamic+balance+in+individuals+with+chronic+ankle+instability.">Ankle dorsiflexion range of motion influences dynamic balance in individuals with chronic ankle instability.</a> Int J Sports Phys Ther. 8, 121-128 (2013).</li><li>Kang, M. H., Lee, D. K., Park, K. H., Oh, J. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Association+of+ankle+kinematics+and+performance+on+the+y-balance+test+with+inclinometer+measurements+on+the+weight-bearing-lunge+test.">Association of ankle kinematics and performance on the y-balance test with inclinometer measurements on the weight-bearing-lunge test.</a> J Sport Rehabil. 24, 62-67 (2015).</li><li>Purcell, S. B., Schuckman, B. E., Docherty, C. L., Schrader, J., Poppy, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Differences+in+ankle+range+of+motion+before+and+after+exercise+in+2+tape+conditions.">Differences in ankle range of motion before and after exercise in 2 tape conditions.</a> Am J Sports Med. 37, 383-389 (2009).</li><li>Simondson, D., Brock, K., Cotton, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Reliability+and+smallest+real+difference+of+the+ankle+lunge+test+post+ankle+fracture.">Reliability and smallest real difference of the ankle lunge test post ankle fracture.</a> Man Ther. 17, 34-38 (2012).</li><li>Hoch, M. C., Staton, G. S., Medina McKeon, J. M., Mattacola, C. G., Mckeon, P. O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dorsiflexion+and+dynamic+postural+control+deficits+are+present+in+those+with+chronic+ankle+instability.">Dorsiflexion and dynamic postural control deficits are present in those with chronic ankle instability.</a> J Sci Med Sport. 15, 574-579 (2012).</li><li>Hoch, M. C., Staton, G. S., Mckeon, P. O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dorsiflexion+range+of+motion+significantly+influences+dynamic+balance.">Dorsiflexion range of motion significantly influences dynamic balance.</a> J Sci Med Sport. 14, 90-92 (2011).</li><li>Charles, J., Scutter, S. D., Buckley, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Static+ankle+joint+equinus:+toward+a+standard+definition+and+diagnosis.">Static ankle joint equinus: toward a standard definition and diagnosis.</a> J Am Podiatr Med Assoc. 100, 195-203 (2010).</li></ol>

The authors have nothing to disclose. 
A biometric version of this study has been published 17. The herein presented paper focuses on the actual conduct of the clinical examinations for isolated MGT. The findings of the biometric paper 17 on the influence of the degree of knee flexion are implanted in this paper.

Examinations on 20 healthy individuals revealed, that 20 degrees of knee flexion already eliminates the influence of the M. gastrocnemius on ADF. Further knee flexion resulted in no significant ADF increase. The herein presented video description of a standardized non-weightbearing and weightbearing examination for MGT builds the prerequisite for future studies establishing physiological norm values.
The study has limitations. First, no custom-made measurement device was used to asses...

Limited ankle dorsiflexion (ADF) alters the gait kinematics and is held responsible for common foot pathologies including Achilles tendinopathy, stress fractures, metatarsalgia and plantar heel pain 1-5. The most common cause for limited ADF is isolated Musculus gastrocnemius tightness (MGT) 3,6.
The joint kinematics of the ankle are influenced by knee flexion as the M. gastrocnemius bridges both joints. The muscle is under tension when the knee is fully extended, as the origin of the muscle is then furthest proximal. The M. gastrocnemius then restrains ADF. Knee flexion approximates the muscle&#39;s origin, thereby reducing the tension of the M. gastrocnemius, and consequently increases ADF. Ankle dorsiflexion is then limited by other anatomical structures of the ankle joint. Figure 1 illustrates this principle. In the case of MGT, ADF is limited with the knee fully extended but substantially increases by flexion of the knee 4.
Clinical examination for MGT takes advantage of the above outlined principled and was first published in 1923 by Silfverski&#246;ld, a Swedish orthopedic surgeon 7. Since then, numerous examination techniques have been described, all of which compare the ADF with the knee extended and flexed. Published clinical tests can be categorized into non-weightbearing 5,8, weightbearing 9,10, and instrumented 11,12. Today, non-weightbearing examination is most commonly conducted 13. The patient is placed supine on the examination couch and ADF is assessed with the knee fully extended and typically 90&#176; flexed (Figure 2A). On the contrary, weightbearing ADF measurements are conducted with the subject upright in lunge stance. The rear knee is extended or bent and the subject is asked to lean forward just before heel liftoff (Figure 2B). For both tests MGT is diagnosed, if the ADF with the knee extended is impaired and knee flexion results in a significant increase of ADF.
Although non-weightbearing tests are frequently performed, weightbearing testing has several advantages. First, only one investigator is needed for weightbearing examination, whereas two examiners are required to achieve reliable non-weightbearing measurements. Second, the weightbearing examination more closely reflects the load during gait. Third, the force applied to the ankle is independent of the examiner. Fourth, weightbearing examination features a higher intra- and inter- rater reliability 9,10,13-15.
The major limitation of all tests for MGT is that&#160;the minimal degree of knee flexion needed to eliminate the restraining effect of the M. gastrocnemius on ADF is unknown 8,15. Whereas 90&#176; of knee flexion are typically applied in non-weightbearing testing 5,8,16, this is not feasible for the weightbearing examination. The broad population is unable to perform a Lunge with 90&#176; of knee flexion without lifting the heel off the ground. Consequently, most studies conducting weightbearing examinations did not control for knee flexion 8,15. In order to perform reliable weightbearing examinations it is essential to identify the minimal degree of knee flexion needed to eliminate the restraining effect of the M. gastrocnemius on ADF.
Overall, literature argues for weightbearing testing for the diagnosis of MGT. In order to provide a valid weightbearing examination procedure, the minimal degree of knee flexion required to eliminate the ADF restraining effect of the M. gastrocnemius must be known. The aim of this study was to investigate the influence of knee flexion on ADF in non-weightbearing and weightbearing testing and to provide a step-by-step guide to conduct non-weightbearing and weightbearing examination for MGT.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Examination couch</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Standard goniometer&#160;</td>
			<td colspan="2">MDF Instruments USA, Inc. Malibu, CA, USA</td>
			<td>2&#176; increments</td>
		</tr>
	</tbody>
</table>

diagnosis of musculus gastrocnemius tightness - key factors for the clinical examination

Common foot and ankle pathologies have been linked to isolated Musculus gastrocnemius tightness (MGT). Various examination techniques have been described to assess MGT. Still, a standardized examination procedure is missing. Literature argues for weightbearing examination but the degree of knee flexion needed to eliminate the restraining effect of the M. gastrocnemius on ankle dorsiflexion (ADF) is unknown. This manuscript investigates the effect of knee flexion on ankle dorsiflexion and provides a detailed description of a standardized examination protocol. Examination on 20 healthy individuals revealed, that 20&#176; of knee flexion is sufficient to fully eliminate the influence of the M. gastrocnemius on ADF. This builds the prerequisite for a standardized examination for MGT. Non-weightbearing and weightbearing examination of ADF has to be conducted with the knee fully extended and at least 20&#176; flexed. Two investigators should conduct non-weightbearing testing with the subject in supine position. In order to obtain reliable results, the axis of the fibula should be marked. One examiner can conduct weightbearing examination with the subject in lunge stance. Isolated MGT is present if ADF is impaired with the knee fully extended and knee flexion results in a significant ADF increase. The herein presented standardized examination is the prerequisite for future studies aiming at establishing norm values.

Both ankles of 20 healthy individuals (mean age of 27.1 &#177; 3.9 years), 50% female, were examined. Non-weightbearing and weightbearing tests at six different degrees of knee flexion (full extension, 20&#176;, 30&#176;, 45&#176;, 60&#176;, 75&#176;) and the Lunge Test (uncontrolled knee flexion) were conducted. A functional brace was used to control knee flexion. Measurements were performed by two investigators blinded to each other&#39;s results. Between each individual, the order of t...

Watch this Scientific Journal Video about Diagnosis of Musculus Gastrocnemius Tightness - Key Factors for the Clinical Examination at JoVE.com

Diagnosis of Musculus Gastrocnemius Tightness - Key Factors for the Clinical Examination

Isolated Musculus gastrocnemius tightness is a common cause for foot and ankle pathologies. Currently no standardized examination procedure exists. This manuscript demonstrates that 20 degree of knee flexion eliminates the restraining effect of the M. gastrocnemius on ankle dorsiflexion and presents a video description of a standardized examination protocol.

Diagnosis of Musculus Gastrocnemius Tightness - Key Factors for the Clinical Examination

Common foot and ankle pathologies have been linked to isolated Musculus gastrocnemius tightness (MGT). Various examination techniques have been described ...

diagnosis-musculus-gastrocnemius-tightness-key-factors-for-clinical

Research

JoVE Journal

Medicine

14.1K Views.  Munich University Hospital. Isolated Musculus gastrocnemius tightness is a common cause for foot and ankle pathologies. Currently no standardized examination procedure exists. This manuscript demonstrates that 20 degree of knee flexion eliminates the restraining effect of the M. gastrocnemius on ankle dorsiflexion and presents a video description of a standardized examination protocol.

Video: Diagnosis of Musculus Gastrocnemius Tightness - Key Factors for the Clinical Examination

FISH for Pre-implantation Genetic Diagnosis

Pre-implantation genetic diagnosis (PGD) is an established alternative to pre-natal diagnosis, and involves selecting pre-implantation embryos from a cohort generated by assisted reproduction technology (ART). This selection may be required because of familial monogenic disease (e.g. cystic fibrosis), or because one partner carries a chromosome rearrangement (e.g. a two-way reciprocal translocation). PGD is available for couples who have had previous affected children, and/or in the case of chromosome rearrangements, recurrent miscarriages, or infertility. Oocytes aspirated following ovarian stimulation are fertilized by in vitro immersion in semen (IVF) or by intracytoplasmic injection of an individual spermatozoon (ICSI). Pre-implantation cleavage-stage embryos are biopsied, usually by the removal of a single cell on day 3 post-fertilization, and the biopsied cell is tested to establish the genetic status of the embryo. Fluorescence in situ hybridization (FISH) on the fixed nuclei of biopsied cells with target-specific DNA probes is the technique of choice to detect chromosome imbalance associated with chromosome rearrangements, and to select female embryos in families with X-linked disease for which there is no mutation-specific test. FISH has also been used to screen embryos for spontaneous chromosome aneuploidy (also known as PGS or PGD-AS) in order to try and improve the efficiency of assisted reproduction; however, the predictive value of this test using the spreading and FISH technique described here is likely to be unacceptably low in most people's hands and it is not recommended for routine clinical use. We describe the selection of suitable probes for single-cell FISH, spreading techniques for blastomere nuclei, and in situ hybridization and signal scoring, applied to PGD in a clinical setting.

This article describes the selection of suitable probes for single-cell FISH, spreading techniques for blastomere nuclei, and in situ hybridization and signal scoring, applied to pre-implantation genetic diagnosis (PGD) in a clinical setting.

Pre-implantation genetic diagnosis (PGD) is an established alternative to pre-natal diagnosis, and involves selecting pre-implantation embryos from a ...

Clinical Examination Protocol to Detect Atypical and Classical Scrapie in Sheep

The diagnosis of scrapie, a transmissible spongiform encephalopathy (TSEs) of sheep and goats, is currently based on the detection of disease-associated prion protein by post mortem tests. Unless a random sample of the sheep or goat population is actively monitored for scrapie, identification of scrapie cases relies on the reporting of clinical suspects, which is dependent on the individual&#39;s familiarization with the disease and ability to recognize clinical signs associated with scrapie. Scrapie may not be considered in the differential diagnosis of neurological diseases in small ruminants, particularly in countries with low scrapie prevalence, or not recognized&#160;if it presents as nonpruritic form like atypical scrapie. To aid in the identification of clinical suspects, a short examination protocol is presented to assess the display of specific clinical signs associated with pruritic and nonpruritic forms of TSEs in sheep, which could also be applied to goats. This includes assessment of behavior, vision (by testing of the menace response), pruritus (by testing the response to scratching), and movement (with and without blindfolding). This may lead to a more detailed neurologic examination&#160;of reporting animals as scrapie suspects. It&#160;could also be used in experimental TSE studies of sheep or goats to evaluate disease progression or to identify clinical end-point.

A short clinical examination protocol is presented to aid in the detection of classical and atypical scrapie in sheep and goats.

The diagnosis of scrapie, a transmissible spongiform encephalopathy (TSEs) of sheep and goats, is currently based on the detection of disease-associated ...

Echocardiographic and Histological Examination of Cardiac Morphology in the Mouse

An increasing number of genetically modified mouse models has become available in recent years. Moreover, the number of pharmacological studies performed in mice is high. Phenotypic characterization of these mouse models also requires the examination of cardiac function and morphology. Echocardiography and magnetic resonance imaging (MRI) are commonly used approaches to characterize cardiac function and morphology in mice. Echocardiographic and MRI equipment specialized for use in small rodents is&#160;expensive and requires a dedicated space. This protocol describes cardiac measurements in mice using a clinical echocardiographic system with a 15 MHz human vascular probe. Measurements are performed on anesthetized adult mice. At least three image sequences are recorded and analyzed for each animal in M-mode in the parasternal short-axis view. Afterwards, cardiac histological examination is performed, and cardiomyocyte diameters are determined on hematoxylin-eosin- or wheat germ agglutinin (WGA)-stained paraffin sections. Vessel density is determined morphometrically after Pecam-1 immunostaining. The protocol has been applied successfully to pharmacological studies and different genetic animal models under baseline conditions, as well as after experimental myocardial infarction by the permanent ligation of the left anterior descending coronary artery (LAD). In our experience, echocardiographic investigation is limited to anesthetized animals and is feasible in adult mice weighing at least 25 g.

Echocardiographic examination is frequently used in mice. Expensive high-resolution ultrasound devices have been developed for this purpose. This protocol describes an affordable echocardiographic procedure combined with histological morphometric analyses to determine cardiac morphology.

An increasing number of genetically modified mouse models has become available in recent years. Moreover, the number of pharmacological studies performed ...

Observational Study Protocol for Repeated Clinical Examination and Critical Care Ultrasonography Within the Simple Intensive Care Studies

Longitudinal evaluations of critically ill patients by combinations of clinical examination, biochemical analysis and critical care ultrasonography (CCUS) may detect adverse events of interventions such as fluid overload at an early stage. The Simple Intensive Care Studies (SICS) is a research line that focuses on the prognostic and diagnostic value of combinations of clinical variables.
The SICS-I specifically focused on the use of clinical variables obtained within 24 h of acute admission for prediction of cardiac output (CO) and mortality. Its sequel, SICS-II, focuses on repeated evaluations during ICU admission. The first clinical examination by trained researchers is performed within 3 h after admission consisting of physical examination and educated guessing. The second clinical examination is performed within 24 h after admission and includes physical examination and educated guessing, biochemical analysis and CCUS assessments of heart, lungs, inferior vena cava (IVC) and kidney. This evaluation is repeated at days 3 and 5 after admission. CCUS images are validated by an independent expert, and all data is registered in an online secured database. Follow-up at 90 days includes registration of complications and survival status according to patient&#39;s medical charts and the municipal person registry. The primary focus of SICS-II is the association between venous congestion and organ dysfunction.
The purpose of publishing this protocol is to provide details on the structure and methods of this on-going prospective observational cohort study allowing answering multiple research questions. The design of the data collection of combined clinical examination and CCUS assessments in critically ill patients are explicated. The SICS-II is open for other centers to participate and is open for other research questions that can be answered with our data.

Structured protocols are necessary to provide answers on research questions in critically ill patients. The Simple Intensive Care Studies (SICS) provides an infrastructure for repeated measurements in critically ill patients including clinical examination, biochemical analysis and ultrasonography. SICS projects have specific focus but the structure is flexible to other investigations.

Longitudinal evaluations of critically ill patients by combinations of clinical examination, biochemical analysis and critical care ultrasonography (CCUS) ...

Transthoracic Echocardiographic Examination in the Rabbit Model

Large animal models such as the rabbit are valuable for translational preclinical research. Rabbits have a similar cardiac electrophysiology compared to that of humans and that of other large animal models such as dogs and pigs. However, the rabbit model has the additional advantage of lower maintenance costs compared to other large animal models. The longitudinal evaluation of cardiac function using echocardiography, when appropriately implemented, is a useful methodology for preclinical assessment of novel therapies for heart failure with reduced ejection fraction (e.g. cardiac regeneration). The correct use of this non-invasive tool requires the implementation of a standardized examination protocol following international guidelines. Here we describe, step by step, a detailed protocol supervised by veterinary cardiologists for performing echocardiography in the rabbit model, and demonstrate how to correctly obtain the different echocardiographic views and imaging planes, as well as the different imaging modes available in a clinical echocardiography system routinely used in human and veterinary patients.

Here we describe, step by step, a detailed protocol for performing echocardiography in the rabbit model. We show how to correctly obtain the different echocardiographic views and imaging planes, as well as the different imaging modes available in a clinical echocardiography system routinely used in human and veterinary patients.

Large animal models such as the rabbit are valuable for translational preclinical research. Rabbits have a similar cardiac electrophysiology compared to ...

OP-IVM: Combining In vitro Maturation after Oocyte Retrieval with Gynecological Surgery

The use of in vitro maturation (IVM) before gynecological operation (OP-IVM) is an extension of conventional IVM that combines IVM following oocyte retrieval with routine gynecological surgery. OP-IVM is suitable for patients undergoing benign gynecological surgery who have the need for fertility preservation (FP) or infertility treatments such as in vitro fertilization and embryo transfer (IVF-ET). In the operating room, patients undergoing benign gynecological surgery are first anesthetized and receive ultrasound-guided immature follicle aspiration (IMFA) treatment. As the subsequent gynecological surgery is performed, the cumulus-oocyte complexes (COCs) are examined, and the immature COCs are transferred into the IVM medium and cultured for 28-32 hours in the IVF laboratory. After assessment, mature oocytes in the MII stage will be selected and cryopreserved in liquid nitrogen for FP or fertilized by intracytoplasmic sperm injection (ICSI) for IVF-ET. By combining IVM with gynecological surgery, immature oocytes that would have been discarded can be saved and used for assisted reproductive technology (ART). The procedure, significance and critical aspects of OP-IVM are described in this article.

In vitro maturation (IVM) before gynecological operation (OP-IVM) combines IVM following oocyte retrieval with routine gynecological surgery and serves as an extension of conventional IVM applications for fertility preservation.

The use of in vitro maturation (IVM) before gynecological operation (OP-IVM) is an extension of conventional IVM that combines IVM following oocyte ...

Basophil Activation Test for Allergy Diagnosis

The basophil activation test (BAT) is a complementary in vitro diagnostic test that can be used in addition to clinical history, skin test (ST), and specific IgE (sIgE) determination in the evaluation of IgE-mediated allergic reactions to food, insect venom, drugs, as well as some forms of chronic urticaria. However, the role of this technique in the diagnostic algorithms is highly variable and not well determined.
BAT is based on the determination of basophil response to allergen/drug cross-linking IgE activation through the measurement of activation markers (such as CD63, CD203c) by flow cytometry. This test can be a useful and complementary tool to avoid controlled challenge tests&#160;to confirm allergy diagnosis, especially in subjects experiencing severe life-threatening reactions. In general, the performance of BAT should be considered if i) the allergen/drug produces false positive results in ST; ii) there is no allergen/drug source to use for ST or sIgE determination; iii) there is discordance between patient history and ST or sIgE determination; iv) symptoms suggest that ST may result in systemic response; v) before considering a CCT to confirm the culprit allergen/drug. The main limitations of the test are related to non-optimal sensitivity, especially in drug allergy, the need to perform the test no longer than 24 h after sample extraction, and the lack of standardization between laboratories in terms of procedures, concentrations, and cell markers.

The basophil activation test is a complementary in vitro diagnostic test for the evaluation of IgE-mediated allergic reactions based on the detection of basophil activation in the presence of a specific stimulus through the measure of activation markers by flow cytometry.

The basophil activation test (BAT) is a complementary in vitro diagnostic test that can be used in addition to clinical history, skin test (ST), and ...

The Miniature Pig: A Large Animal Model for Cochlear Implant Research

Cochlear implants (CI) are the most effective method to treat people with severe-to-profound sensorineural hearing loss. Although CIs are used worldwide, no standard model exists for investigating the electrophysiology and histopathology in patients or animal models with a CI or for evaluating new models of electrode arrays. A large animal model with cochlea characteristics similar to those of humans may provide a research and evaluation platform for advanced and modified arrays before their use in humans. 
To this end, we established standard CI methods with Bama mini-pigs, whose inner ear anatomy is highly similar to that of humans. Arrays designed for human use were implanted into the mini pig cochlea through a round window membrane, and a surgical approach followed that was similar to that used for human CI recipients. Array insertion was followed by evoked compound action potential (ECAP) measurements to evaluate the function of the auditory nerve. This study describes the preparation of the animal, surgical steps, array insertion, and intraoperative electrophysiological measurements. 
The results indicated that the same CI used for humans could be easily implanted in mini-pigs via a standardized surgical approach and yielded similar electrophysiological outcomes as measured in human CI recipients. Mini-pigs could be a valuable animal model to provide initial evidence of the safety and potential performance of novel electrode arrays and surgical approaches before applying them to human beings.

Miniature pigs (mini-pigs) are an ideal large animal model for research into cochlear implants. Cochlear implantation surgery in mini-pigs can be utilized to provide initial evidence of the safety and potential performance of novel electrode arrays and surgical approaches in a living system similar to human beings.

Cochlear implants (CI) are the most effective method to treat people with severe-to-profound sensorineural hearing loss. Although CIs are used worldwide, ...

Development of an Effective Mice Model for Studying Oronasal Fistulas

Establishment of an Oronasal Fistula Mice Model

This study presents a method utilizing heated ophthalmologic cautery to develop a viable model for investigating oronasal fistulas. C57BL/6 mice were used to establish the oronasal fistula (ONF) model. To create the ONF, the mice were anesthetized, immobilized, and their hard palates were exposed. During the surgical procedure, a 2.0 x 1.5 mm full-thickness mucosal injury was induced in the midline of the hard palate using ophthalmologic cautery. It was crucial to control the size of the ONF and minimize bleeding in order to ensure the success of the experiment. Verification of the ONF model's effectiveness was conducted on the 7th-day post-operation, encompassing both anatomical and functional assessments. The presence of the nasal septum within the oral cavity and the outflow of sterile water from the nostrils upon injection into the oral cavity confirmed the successful establishment of the ONF model. The model demonstrated a practical and successful oronasal fistula, characterized by a low mortality rate, significant weight changes, and minimal variation in ONF size. Future studies may consider adopting this methodology to elucidate the mechanisms of palate wound healing and explore novel treatments for oronasal fistulas.

Author Spotlight: Investigating Wound Healing in Mice Models of Oronasal Fistulas 

This article outlines a step-by-step procedure for establishing a mice model with an oronasal fistula. The oronasal fistula was created by employing heated ophthalmologic cautery to damage the midline portion of the hard palate, resulting in the formation of an opening between the oral and nasal cavities.

This study presents a method utilizing heated ophthalmologic cautery to develop a viable model for investigating oronasal fistulas. C57BL/6 mice were used ...

A Murine Maxillary Orthodontic Model Guide to Bone Remodeling Analysis

The Establishment of a Murine Maxillary Orthodontic Model

Due to the lack of reproducible protocols for establishing a murine maxillary orthodontic model, we present a reliable and reproducible protocol to provide researchers with a feasible tool to analyze mechanical loading-associated bone remodeling. This study presents a detailed flowchart in addition to different types of schematic diagrams, operation photos, and videos. We performed this protocol on 11 adult wide-type C57/B6J mice and harvested samples on postoperative days 3, 8, and 14. The micro-CT and histopathological data have proven the success of tooth movements coupled with bone remodeling using this protocol. Furthermore, according to the micro-CT results on days 3, 8, and 14, we have divided bone modeling into three stages: preparation stage, bone resorption stage, and bone formation stage. These stages are expected to help researchers concerned with different stages to set sample collection time reasonably. This protocol can equip researchers with a tool to carry out regenerative analysis of bone remodeling.

Author Spotlight: Insights into an Efficient Murine Maxillary Orthodontic Model Protocol

Here we demonstrate step-by-step a manageable, orthodontic tooth movement protocol operated on a murine maxillary model. With the explicit explanation of each step and visual demonstration, researchers can master this model and apply it to their experimental needs with a few modifications.

Due to the lack of reproducible protocols for establishing a murine maxillary orthodontic model, we present a reliable and reproducible protocol to ...