Name: Determining The Electromyographic Fatigue Threshold Following a Single Visit Exercise Test (Video) | JoVE Journal
Uploaded: 2015-07-27T14:00:00.000+00:00
Duration: 6 min
Description: Learn to determine the electromyographic fatigue threshold using surface EMG during incremental cycle ergometry. This single-visit test distinguishes nonfatiguing from fatiguing workloads for personalized training programs.

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5 minutes

This project was funded by, in part, by start-up funds from Wayne State University to M.H. Malek.

All procedures were approved by the University Institutional Review Board for Human Subjects.
1. Preparation of the Participant&#8217;s Leg
<ol>
	<li>Have the participant neatly roll up their shorts for the desired leg. Then tape the shorts so that the quadriceps femoris muscle group is exposed and draw a line around the area the participant needs to shave.</li>
	<li>IMPORTANT: Have the participant shave their leg before the test rather than the previous day as this ensures that there are no stubbles which may interfere with the EMG signal.</li>
	<li>Once the participant has finished shaving the desired area of the leg, clean the shaved area with rubbing alcohol to ensure there are no remnants of the shaving gel (or cream) which can interfere with the EMG signal.</li>
</ol>
2. Measurement of Leg for Electrode Placement
<ol>
	<li>In order to place the EMG electrode on the vastus lateralis muscle, make the following measurements
	<ol>
		<li>Have the participant stand straight facing the researcher.</li>
		<li>Locate the anterior spina iliaca superior (ASIS) and the lateral side of the patella. The ASIS is the hip bone; palpate it by placing the hand on either side of the abdomen below the umbilicus.</li>
		<li>With a tape measure, measure the distance between the two locations identified above and take 2/3 of that value on the line from the ASIS to the lateral side of the patella. Note: Further information regarding placement of EMG electrodes can be found on the SENIAM (Surface Electromyography for the Non-Invasive Assessment of Muscles) URL: http://www.seniam.org/</li>
	</ol>
	</li>
</ol>
3. Placement of the EMG Electrodes
<ol>
	<li>After the location of the vastus lateralis has been identified, take the EMG electrodes (most researchers use commercially available disposable Ag-Ag Cl electrodes) and place over the vastus lateralis without removing the adhesive shield. Then with a pen mark the area where the gel portion of the electrode makes contact with the muscle. Ensure that the interelectrode distance is 20 mm center-to-center.</li>
	<li>Use a piece of sandpaper (60 coarse) to gently abrade these two areas to remove the superficial layer of the skin. During this time, ask the participant their level of discomfort. Stop abrading when the participant indicates the area is warm.</li>
	<li>Clean the abraded areas with a towel that is dampened with rubbing alcohol or an alcohol swab. Allow the area on the leg to dry before placing the EMG electrodes.</li>
	<li>Place the EMG electrodes on the sites that were abraded (Figure 2). Take care not to place the electrodes on the iliotibial band (IT band). Ask the participant to contract the quadriceps femoris muscles in order to palpate the vastus lateralis. Place the electrodes on the muscle to ensure it is not on the IT band. Note: If the electrodes on the IT band, the EMG signal would be dampened when the participant is asked to maximally contract.</li>
	<li>Place the reference electrode (3rd electrode) on a boney attachment site such as the ASIS thus not interfering with movement of the lower limbs during the exercise bout.</li>
</ol>
4. Checking the EMG Signal
<ol>
	<li>Prior to starting the exercise test, check the interelectrode impedance. 
	Note: This step is critical because if the signal has too much noise then the EMG data collected during the exercise test will be invalid.
	<ol>
		<li>Have the participant sit in a chair and connect the EMG leads to their respective electrodes attached to the participant&#8217;s leg.</li>
		<li>At this point, have the participant relax their leg, having no tension in the muscle. Then after about 30 sec of relaxation, have the participant maximally contract their quadriceps femoris muscles for 5 sec and then go back to being completely relaxed.</li>
		<li>When performing the task above (step 4.1.2), record the participants EMG signal on the computer.</li>
		<li>Ensure that the interelectrode impedance is &#60;2,000 ohms. Moreover, if a voltmeter is available in the laboratory, then check the baseline noise and keep below 5 &#181;V. In addition, set the sampling frequency at 1,000 Hz.</li>
	</ol>
	</li>
</ol>
5. Setting-up the Cycle Ergometer
<ol>
	<li>After checking the interelectrode impedance, have the participant move from the chair to the cycle ergometer.</li>
	<li>Have the participant stand next to the cycle ergometer and raise their knee until the thigh is parallel with the ground. Then have the participant hold this position and adjust the seat height to match the same height as the participant&#8217;s thigh.</li>
	<li>Thereafter, have the participant sit on the cycle ergometer seat and then pedal a couple times while asking them if they are comfortable with the seat height. If needed, adjust the seat height.</li>
	<li>Ensure that the participant&#8217;s legs are near full extension with a slight bend (~5&#176;) in the knees during each pedal revolution.</li>
	<li>Before starting the test, have the participant wear a polar heart rate monitor so that heart rate can be documented throughout the exercise test.</li>
</ol>
6. Performing the EMG Fatigue Threshold Protocol
<ol>
	<li>Have the participant start cycling and gradually increase their cadence to 70 revolutions/min. Then increase the power output on the cycle ergometer to 50 W.</li>
	<li>Have the participant cycle at this power output for approximately 2-3 min. 
	Note: This is a low intensity exercise and will serve as the warm-up.</li>
	<li>After the warm-up period, increase the power output by 25 W every 2 min until the participant is no longer able to maintain the 70 revolutions/min cadence or requests that the test be stopped. 
	Note: It should be noted that during the exercise test, the EMG signal is recorded for 10 sec epochs during each 2 min stage for sec 10&#8211;20, 30&#8211;40, 50&#8211;60, 70&#8211;80, 90&#8211;100, and 110-12021. Most EMG systems will have an option to set the automatic recording at the desired interval. Thus, for each stage there should be 6 data files.</li>
	<li>Once the incremental test has concluded, have the participant perform a cool down at 50 W. Check that the length of the cool down corresponds with having the participant&#8217;s heart rate return to the value during the warm-up phase. Monitor this by checking the participant&#8217;s heart rate using the polar heart rate monitor.</li>
	<li>Once the cool down is completed, remove the EMG leads and have the participant step off the cycle ergometer and return to the chair. Then carefully remove the EMG electrodes and wipe the areas with a clean towel dampened with rubbing alcohol or an alcohol swab.</li>
</ol>
7. Processing the EMG Signal
<ol>
	<li>After the test is completed, process the raw EMG data files that were collected during the exercise test so that the data can be used to determine the EMG fatigue threshold.
	<ol>
		<li>Perform processing of the EMG signal with either the software used to collect the EMG signal or custom written software using various platforms such as MATLAB or LabVIEW.</li>
		<li>Filter the collected EMG signals using a band-pass filter. Use a setting of 10 to 500 Hz. Note: This alters the frequency of the signal so that low frequency artifacts due to movement of the EMG leads (&#60;10 Hz), and high frequency artifacts from the environment (&#62;500 Hz), are removed. Use a notch filter of 60 Hz if there is any interference from the power supply of the computer or EMG system.</li>
		<li>Once the signal has been filtered, determine the signal amplitude by calculating the root mean square value of the signal: Square each of the data points, sum them, divide by the number of data points, then take the square root of the resulting value. Perform these calculations using the aforementioned software.</li>
	</ol>
	</li>
</ol>
8. Determining the EMG Fatigue Threshold for Each Participant
<ol>
	<li>Perform the following steps for each participant.
	<ol>
		<li>After the EMG signal has been processed; use a statistical program (e.g.: GraphPad Prism) and label the first column &#8220;Time&#8221; and the subsequent columns with the power outputs used for the test.</li>
		<li>For each power output, fill-in the corresponding EMG amplitude value for each 20 sec interval.</li>
		<li>For each power output, analyze the time (x-axis) vs EMG amplitude (y-axis) relationship with linear regression to determine if the slope of the regression line is significantly (p &#60;0.05) different from zero.</li>
		<li>After performing the linear regression analyses for all power outputs, identify the highest power output with a non-significant (p &#62;0.05) slope.</li>
		<li>Then identify the lowest power output with a significant (p &#60;0.05) slope.</li>
		<li>Once these two power outputs have been identified, add them and divide by 2; the resultant power output is the estimated EMG fatigue threshold.</li>
	</ol>
	</li>
</ol>

<ol><li>Hendrix, C. R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Comparison+of+critical+force+to+EMG+fatigue+thresholds+during+isometric+leg+extension%5BTitle%5D)+AND+%22Medicine+and+science+in+sports+and+exercise%22%5BJournal%5D)">Comparison of critical force to EMG fatigue thresholds during isometric leg extension.</a> Medicine and science in sports and exercise. 41, 956-964 (2009).</li>
<li>Herda, T. J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Quantifying+the+effects+of+electrode+distance+from+the+innervation+zone+on+the+electromyographic+amplitude+versus+torque+relationships%5BTitle%5D)+AND+%22Physiological+measurement%22%5BJournal%5D)">Quantifying the effects of electrode distance from the innervation zone on the electromyographic amplitude versus torque relationships.</a> Physiological measurement. 34, 315-324 (2013).</li>
<li>Ryan, E. D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Inter-individual+variability+among+the+mechanomyographic+and+electromyographic+amplitude+and+mean+power+frequency+responses+during+isometric+ramp+muscle+actions%5BTitle%5D)+AND+%22Electromyography+and+clinical+neurophysiology%22%5BJournal%5D)">Inter-individual variability among the mechanomyographic and electromyographic amplitude and mean power frequency responses during isometric ramp muscle actions.</a> Electromyography and clinical neurophysiology. 47, 161-173 (2007).</li>
<li>Beck, T. W., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((The+influence+of+electrode+placement+over+the+innervation+zone+on+electromyographic+amplitude+and+mean+power+frequency+versus+isokinetic+torque+relationships%5BTitle%5D)+AND+%22Journal+of+neuroscience%22%5BJournal%5D)">The influence of electrode placement over the innervation zone on electromyographic amplitude and mean power frequency versus isokinetic torque relationships.</a> Journal of neuroscience. 162, 72-83 (2007).</li>
<li>Beck, T. W., Stock, M. S., DeFreitas, J. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Time-frequency+analysis+of+surface+electromyographic+signals+during+fatiguing+isokinetic+muscle+actions%5BTitle%5D)+AND+%22Journal+of+strength+and+conditioning+research+%2F+National+Strength%2C+%26+Conditioning+Association%22%5BJournal%5D)">Time-frequency analysis of surface electromyographic signals during fatiguing isokinetic muscle actions.</a> Journal of strength and conditioning research / National Strength, & Conditioning Association. 26, 1904-1914 (2012).</li>
<li>Evetovich, T. K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Mean+power+frequency+and+amplitude+of+the+mechanomyographic+signal+during+maximal+eccentric+isokinetic+muscle+actions%5BTitle%5D)+AND+%22Electromyography+and+clinical+neurophysiology%22%5BJournal%5D)">Mean power frequency and amplitude of the mechanomyographic signal during maximal eccentric isokinetic muscle actions.</a> Electromyography and clinical neurophysiology. 39, 123-127 (1999).</li>
<li>Blaesser, R. J., Couls, L. M., Lee, C. F., Zuniga, J. M., Malek, M. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Comparing+EMG+amplitude+patterns+of+responses+during+dynamic+exercise%3A+polynomial+versus+log-transformed+regression%5BTitle%5D)+AND+%22Scandinavian+journal+of+medicine%2C+%26+science+in+sports%22%5BJournal%5D)">Comparing EMG amplitude patterns of responses during dynamic exercise: polynomial versus log-transformed regression.</a> Scandinavian journal of medicine, & science in sports. In press, (2015).</li>
<li>Briscoe, M. J., Forgach, M. S., Trifan, E., Malek, M. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Validating+the+EMGFT+from+a+single+incremental+cycling+testing%5BTitle%5D)+AND+%22International+journal+of+sports+medicine%22%5BJournal%5D)">Validating the EMGFT from a single incremental cycling testing.</a> International journal of sports medicine. 35, 566-570 (2014).</li>
<li>Zuniga, J. M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Neuromuscular+and+metabolic+comparisons+between+ramp+and+step+incremental+cycle+ergometer+tests%5BTitle%5D)+AND+%22Muscle%22%5BJournal%5D)">Neuromuscular and metabolic comparisons between ramp and step incremental cycle ergometer tests.</a> Muscle. 47, 555-560 (2013).</li>
<li>Mastalerz, A., Gwarek, L., Sadowski, J., Szczepanski, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((The+influence+of+the+run+intensity+on+bioelectrical+activity+of+selected+human+leg+muscles%5BTitle%5D)+AND+%22Acta+of+bioengineering+and+biomechanics+%2F+Wroclaw+University+of+Technology%22%5BJournal%5D)">The influence of the run intensity on bioelectrical activity of selected human leg muscles.</a> Acta of bioengineering and biomechanics / Wroclaw University of Technology. 14, 101-107 (2012).</li>
<li>Basmajian, J. V., De Luca, C. J. Muscles alive, their functions revealed by electromyography. , 5th edn, Williams, & Wilkins. (1985).</li>
<li>Vries, H. A., Moritani, T., Nagata, A., Magnussen, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((The+relation+between+critical+power+and+neuromuscular+fatigue+as+estimated+from+electromyographic+data%5BTitle%5D)+AND+%22Ergonomics%22%5BJournal%5D)">The relation between critical power and neuromuscular fatigue as estimated from electromyographic data.</a> Ergonomics. 25, 783-791 (1982).</li>
<li>Vries, H. A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((A+method+for+estimating+physical+working+capacity+at+the+fatigue+threshold+%28PWCFT%29%5BTitle%5D)+AND+%22Ergonomics%22%5BJournal%5D)">A method for estimating physical working capacity at the fatigue threshold (PWCFT).</a> Ergonomics. 30, 1195-1204 (1987).</li>
<li>Vries, H. A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Factors+affecting+the+estimation+of+physical+working+capacity+at+the+fatigue+threshold%5BTitle%5D)+AND+%22Ergonomics%22%5BJournal%5D)">Factors affecting the estimation of physical working capacity at the fatigue threshold.</a> Ergonomics. 33, 25-33 (1990).</li>
<li>Astrand, I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((The+physical+work+capacity+of+workers+50-64+years+old%5BTitle%5D)+AND+%22Acta+physiologica+Scandinavica%22%5BJournal%5D)">The physical work capacity of workers 50-64 years old.</a> Acta physiologica Scandinavica. 42, 73-86 (1958).</li>
<li>Hettinger, T., Birkhead, N. C., Horvath, S. M., Issekutz, B., Rodahl, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Assessment+of+physical+work+capacity%5BTitle%5D)+AND+%22Journal+of+Applied+Physiology%22%5BJournal%5D)">Assessment of physical work capacity.</a> Journal of Applied Physiology. 16, 153-156 (1961).</li>
<li>Smith, J. L. <a target="_blank" href="http://scholar.google.com/scholar?hl=en&safe=off&q=author%3aSmith%2C+JL+%22International+encyclopedia+of+ergonomics+and+human+factors%22">International encyclopedia of ergonomics and human factors</a>. Karwowsk, W. , CRC/Taylor, & Francis. (2006).</li>
<li>Kenny, G. P., Yardley, J. E., Martineau, L., Jay, O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Physical+work+capacity+in+older+adults%3A+implications+for+the+aging+worker%5BTitle%5D)+AND+%22American+journal+of+industrial+medicine%22%5BJournal%5D)">Physical work capacity in older adults: implications for the aging worker.</a> American journal of industrial medicine. 51, 610-625 (2008).</li>
<li>Matsumoto, T., Ito, K., Moritani, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((The+relationship+between+anaerobic+threshold+and+electromyographic+fatigue+threshold+in+college+women%5BTitle%5D)+AND+%22European+journal+of+applied+physiology%22%5BJournal%5D)">The relationship between anaerobic threshold and electromyographic fatigue threshold in college women.</a> European journal of applied physiology. 63, 1-5 (1991).</li>
<li>Guffey, D. R., Gervasi, B. J., Maes, A. A., Malek, M. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Estimating+electromygraphic+and+heart+rate+fatigue+threshold+from+a+single+treadmill+test%5BTitle%5D)+AND+%22Muscle%22%5BJournal%5D)">Estimating electromygraphic and heart rate fatigue threshold from a single treadmill test.</a> Muscle. 46, 577-581 (2012).</li>
<li>Camic, C. L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((The+influence+of+the+muscle+fiber+pennation+angle+and+innervation+zone+on+the+identification+of+neuromuscular+fatigue+during+cycle+ergometry%5BTitle%5D)+AND+%22Journal+of+electromyography+and+kinesiology+%3A+official+journal+of+the+International+Society+of+Electrophysiological+Kinesiology%22%5BJournal%5D)">The influence of the muscle fiber pennation angle and innervation zone on the identification of neuromuscular fatigue during cycle ergometry.</a> Journal of electromyography and kinesiology : official journal of the International Society of Electrophysiological Kinesiology. 21, 33-40 (2011).</li>
</ol>

The authors have nothing to disclose.

We here present a method for determining neuromuscular fatigue in the quadriceps femoris muscles for dynamic exercise. This method provides a straightforward and non-invasive approach to using surface EMG. Moreover, the versatility of this method is that researchers can adapt it to other modes of exercise such as the treadmill20.
Theoretically, for intensities at or below the EMG fatigue threshold the participant should be able to sustain the exercise workbout indefinitely12,13...

Surface electromyography (EMG) is a noninvasive approach of studying motor unit recruitment during isometric1-3, isokinetic4-6, or continuous7-10 muscle action. The amplitude of the EMG signal represents muscle activation which consists of the number of motor units activated, the firing rate of the motor units, or both11. The concept of the EMG fatigue threshold is used to indicate the highest workload in which an individual can exercise indefinitely without an increase in EMG amplitude8.
It is important to briefly discussion the origin of the EMG fatigue threshold. The original study by deVries et al.12 involved a protocol that consisted of multiple (usually 3 to 4) discontinuous work bouts, where the EMG amplitude was plotted versus time for each work bout. The power output was then plotted versus the slope coefficients from the EMG amplitude versus time relationship, and then extrapolated to zero slope (the y-intercept)12. The authors12 originally termed that protocol the physical working capacity at the fatigue threshold (PWCFT). In a another study, deVries et al.13 used discontinuous work bouts, but used linear regression to find the first power output that resulted in a significant slope for the EMG amplitude versus time relationship. The authors13 also termed that protocol the PWCFT, creating some confusion in the literature. In a subsequent article, deVries et al.14 modified their earlier protocol13 and developed a continuous incremental protocol. The EMG amplitude was plotted against time for each power output and the PWCFT was defined as the average of the highest power output that resulted in no change in EMG amplitude over time and the lowest power output that resulted in an increase in EMG amplitude over time14.
It should be noted that the term PWC was originally introduced in the late 1950s15,16 and is synonymous with a plethora of literature (past, present, and across different countries) examining aerobic capacity at a given workload17. Moreover, the term is used in the ergonomic and industrial literature which focus on day-to-day productivity of workers performing repetitive action during 8 hour work days such as individuals in an assembly plant18.
The term EMG fatigue threshold was initially used by Matsumoto and colleagues19 after they modified the deVries12 protocol where the power output versus slope coefficients of the EMG amplitude versus time relationship are plotted and extrapolated to the point of zero slope. More recently, Guffey et al.20 and Briscoe et al.8 used the method of deVries et al.14 and the terminology of Matsumoto et al.19 to operationally define the EMG fatigue threshold. Moving forward, we recommend that the term EMG fatigue threshold be used. Thus, the EMG amplitude versus time relationship is plotted for each power output and then analyzed using linear regression analyses (Figure 1). To estimate the EMG fatigue threshold, the highest power output with a non-significant (p &#62;0.05) slope and the lowest power output with a significant (p &#60;0.05) slope is identified and then the average is calculated14. This protocol is simple, convenient, and completed within 15-20 min. Moreover, the incremental rate can be modulated based on the individual&#8217;s level of habitual physical activity, and therefore has potential applications in clinical settings.

<table><tbody><tr><td>839 E Monark cycle ergometer&amp;nbsp;</td><td>Monark Exercise AB</td><td>839 E</td><td></td></tr><tr><td>Heart rate monitor</td><td>Polar</td><td>Polar H1</td><td></td></tr><tr><td>Laptop</td><td>Dell Inspiron</td><td>varies</td><td>any laptop computer with USB slots should work.</td></tr><tr><td>EMG amplifiers</td><td>BioPac Systems, Inc.</td><td>100B</td><td>100C are the latest version</td></tr><tr><td>Disposable EMG electrodes</td><td>BioPac Systems, Inc.</td><td>EL-500</td><td></td></tr><tr><td>Sandpaper</td><td>Home Depot</td><td>9 inch x 11 inch 60 Grit course no-slip grip Advanced Sandpaper (3-Pack)</td><td></td></tr></tbody></table>

determining the electromyographic fatigue threshold following a single visit exercise test

Determining The Electromyographic Fatigue Threshold Following a Single Visit Exercise Test

Theoretically, the electromyographic (EMG) fatigue threshold is the exercise intensity an individual can maintain indefinitely without the need to recruit more motor units which is associated with an increase in the EMG amplitude. Although different protocols have been used to estimate the EMG fatigue threshold they require multiple visits which are impractical for a clinical setting. Here, we present a protocol for estimating the EMG fatigue threshold for cycle ergometry which requires a single visit. This protocol is simple, convenient, and completed within 15-20 min, therefore, has the potential to be translated into a tool that clinicians can use in exercise prescription.

As shown in Figure 1, for a single participant, each power output that is completed has six data points that represent the EMG amplitude for the vastus lateralis muscle. Therefore, in this example, the highest power output with a non-significant (p &gt;0.05) slope is 200 watts, whereas the lowest power output with a significant (p &lt;0.05) slope is 225 W. Therefore, for this participant the EMG fatigue threshold is 213 W. Once the EMG fatigue threshold is determined for each participan...

This protocol describes the electromyographic fatigue threshold which demarcates between nonfatiguing and fatiguing exercise workloads. This information could be used to develop a more individualized training program.

Theoretically, the electromyographic (EMG) fatigue threshold is the exercise intensity an individual can maintain indefinitely without the need to recruit ...

The overall goal of this procedure is to describe the electromyographic fatigue threshold, which demarcates between non fatiguing and fatiguing exercise workloads. This is accomplished by first preparing the participant's leg for the placement of the EMG electrodes. The second step is to place the EMG electrodes on the desired superficial quadriceps femoral muscles.Next, the EMG signal is checked to determine the signal to noise ratio and improve electrode placement if necessary. The final step is to have the participant perform an incremental cycle ergometry test to voluntary exhaustion. Ultimately, the EMG fatigue threshold mathematical model is used to estimate the power output at which theoretically, the participant can cycle indefinitely without an increase in EMG amplitude.The main advantage of this technique over existing methods is that we use surface EMG in a single incremental exercise test. This method can provide insight into identifying the highest exercise intensity that demarcates between non fatiguing and fatiguing exercise. Demonstrating the procedure will be Charlie Anderson and Jacob Blackmore.Second year students in the doctorate in physical therapy program Begin by preparing the participant's leg and accurately locating the vastus laterals muscle as described in the accompanying text protocol. Then place gel coated silver, silver chloride electrodes over the vastus laterals without removing the adhesive shield. Mark the location where the gel portion of the electrode makes contact with the muscle and ensure the inter electrode distance is 20 millimeters from center to center.Next, use a piece of 60 grit sandpaper to gently abraid these two areas, removing the superficial layer of the skin. Be sure to ask the participant their level of discomfort during the abrasion and stop when the participant indicates the area is warm. Clean the abbra areas with an alcohol swab and allow the area to air dry for a few seconds.Then ask the participant to contract the quadriceps femoral muscles so that it is possible to palpate the vastus laterals. Place the EMG electrodes on the abbra sites taking care not to place the electrodes on the ileal tidal band. Place the reference electrode on a bony attachment site such as the asis, so as not to interfere with movement of the lower limbs during exercise, adjust the cycle ergometer specifically for each participant as described in the accompanying text protocol.Then have the participant put on a heart monitor in order to document their heart rate throughout the exercise test. Set up the EMG system to take recordings at ten second intervals every 20 seconds. Also, begin monitoring the heart rate by recording the values on a data collection sheet.During each stage, have the participants start cycling and gradually increase their cadence to 70 revolutions per minute after they reach 70 revolutions per minute, increase the power output on the cycle ergometer to 50 watts. Have the participants cycle at this power output for approximately two to three minutes as a warmup, and begin taking EMG signal recordings after the warmup period. Increase the power output by 25 watts every two minutes until the participant is no longer able to maintain 70 revolutions per minute cadence or requests that the test be stopped.Open the E-M-G-F-T data file using a commercial statistical program. The first column is labeled time, whereas the subsequent columns are labeled for each power output. For each power output, there is the corresponding EMG amplitude for each 22nd interval for each power output, the time versus EMG amplitude is plotted.The x axis is labeled as time, and the Y axis is labeled EMG amplitude. Perform linear regression for the time versus EMG amplitude relationship. For each power output.Identify the highest power output without a statistically significant slope and the lowest power output with a statistically significant slope. The EMG fatigue threshold, therefore is the average of these two power outputs. Shown here is the combined power output for a single participant of the fatigue test.This particular participant made it through 11 two minute test periods where the power was increased by 25 watts every two minutes. The power output at 200 watts is the highest power output with a non-significant slope, whereas the power output at 225 watts is the lowest power output with a significant slope. The average of these two power outputs equals 213 watts, which is the EMG fatigue threshold for this particular participant.Once mastered, this testing procedure can be completed within one hour. After watching this video, you should have a good understanding of how to assess neuromuscular fatigue using a non-invasive method such as surface EMG.

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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.

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

We present a protocol to assess changes in neuromuscular function. Percutaneous electrical nerve stimulation is a non-invasive method that evokes muscular responses. Electrophysiological and mechanical properties of these responses permit the evaluation of neuromuscular function from brain to muscle (supra-spinal, spinal and peripheral levels).

Assessment of Neuromuscular Function Using Percutaneous Electrical Nerve Stimulation

A functional assessment of the neuromuscular junction (NMJ) can provide essential information on the communication between muscle and nerve. Here we describe a protocol to comprehensively evaluate both the NMJ and muscle functionality using two different muscle-nerve preparations, i.e. soleus-sciatic and diaphragm-phrenic.

Measuring Neuromuscular Junction Functionality

To assess the influence of exercise intensity on physiologic and biologic responses, two different exercise testing protocols were utilized. Methods outlining exercise testing on a cycle ergometer as an incremental maximal oxygen consumption test and endurance, steady state submaximal endurance test are described.

Conducting Maximal and Submaximal Endurance Exercise Testing to Measure Physiological and Biological Responses to Acute Exercise in Humans

This protocol is for evaluating corticospinal tract function within 1 week of stroke. It can be used to select and stratify patients in trials of interventions designed to improve upper limb motor recovery and outcomes and in clinical practice for predicting upper limb functional outcomes 3 months after stroke.

Determining the Functional Status of the Corticospinal Tract Within One Week of Stroke

Simple and accessible methods were developed to measure the motor aspect of cancer-related fatigue objectively and quantitatively. We describe, in detail, ways to administer the physical fatigue test using a simple handgrip device as well as methods to calculate fatigue indices.

Measuring the Motor Aspect of Cancer-Related Fatigue using a Handheld Dynamometer

This method allows the recording of the force of twitch and tetanic contractions and action potentials in three types of motor units in the rat medial gastrocnemius muscle. The functional isolation of a single motor unit is induced by electrical stimulation of the axon.

Functional Isolation of Single Motor Units of Rat Medial Gastrocnemius Muscle

Arms contribution in Sit-To-Stand (SitTS) is determined by the legs' muscle condition. Several compensating strategies were discovered in efforts to achieve complete SitTS cycles. These findings triangulate the spinal cord injury (SCI) persons' biomechanical measures with their subjective feeling of load borne by both their limbs throughout the SitTS approaches.

Quantifying Arms and Legs Contributions during Repetitive Electrically-Assisted Sit-To-Stand Exercise in Paraplegics: A Pilot Study

Cycling biomechanics relies on efficient muscle activation and core stabilization. Infrared thermography (IRT) offers non-invasive monitoring of muscle fatigue. This protocol establishes a standardized methodology for integrating IRT into biomechanical analysis, aiming to optimize performance and prevent injury in amateur cyclists through precise physiological monitoring.

Standardized Protocol For Monitoring Muscle Fatigue and Biomechanics In Amateur Cyclists Using Infrared Thermography

Learn to determine the electromyographic fatigue threshold using surface EMG during incremental cycle ergometry. This single-visit test distinguishes nonfatiguing from fatiguing workloads for personalized training programs.

Determining The Electromyographic Fatigue Threshold Following a Single Visit Exercise Test

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