EMG Lab Report PDF

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EMG lab report ...

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Name: lisseth Abrego , Macy Gonzales Lab: Electromyography (EMG I) Due date: April, 4 2019 Purpose In this experiment we learn that different intensities of muscle contractions create different intensities of electrical activity and even when the arms were resting, there was a small offset of stimulation. The group hypothesized that the dominant arm clenches would create greater strength thus creating greater electrical activity then the non-dominant arm. Introduction Electromyography is the evaluation of the electrical activity of muscle tissues using electrodes that are attached to the skin.(“Electromyography”, 2018). Skeletal muscle performs mechanical work when the muscle applies an electromotive force, voltage that causes an action potential to produce a muscle contraction required to makes an object move. When the muscles are at rest, there are said to have a muscle tone, a low level contraction of your muscles. Physiologically, skeletal muscle is stimulated to contract when the brain activates motor units of the muscle. Motor units are defined as a motor neuron and all of the long, multi- nucleated muscle cells known as muscle fibers that the motor neuron innervates.(Waehner, 2019). The sequential activation of motor units to perform a designated task is referred as motor unit recruitment .An action potential is part of the process that occurs during the firing of a neuron. During the action potential, part of the neural membrane opens to allow positively charge ions inside the cell and negatively charge ions out. This ultimately carries an electrical impulse down the nerve through a series of neuromuscular junctions (Cherry, 2018). A neuromuscular junction (NMJ) is the area of contact between ends of a larger myelinated nerve fiber and the fiber end of a skeletal muscle(“Euroform Healthcare”, 2018 ).The connection acts as a bridge that transmits the action potential signals. Hand dominance is essentially the preference for utilizing one hand over the other one. The choice of which hand is dominant or not is made by genetics and the brain and not by human choice In the experiment performed we utilized an EMG procedure to monitor electrical activity caused by the contraction of the dominant and non-dominant muscle. We began the experiment by sterilized the volunteer’s dominant and non-dominant arm. After sterilizing, we placed 3 disposable electrodes on the volunteer’s dominant arm. The volunteer squeezed a ball every other two seconds and the group measured the strength of each clench. The results were interpreted on a Dell laptop and the 40 mean was gathered. The group then switched the 3 disposable electrodes to the volunteer’s non-dominant arm .The volunteer then squeezed the ball every other two seconds. The clenches were again measured and interpreted. The independent variable was the change in dominant and non-dominant arms. The dependent variable was the change in the average muscle tone measurements of each arm. The control was the amount of clenches of each arm, in a set amount of seconds. We concluded the control of the experiment to be positive because the results showed that the right (dominant) arm had stronger muscle tone than the left (non-dominant) arm (Morin, 2018).

Materials

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Volunteer (1) BIOPAC Electrode Lead Set (1) BIOPAC Student Lab System (1) BIOPAC Disposable Electrode (3) Dell Computer System (Laptop) (1) Alcohol Prep Pads (2) Stress ball (1)

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Methods Initially we began the experiment by staring the computer provided and setting up the BIOPAC Student Lab System program. We then proceeded to establish the volunteer of the experiment. After choosing our volunteer, another member of the group cleaned the volunteer’s dominant arm using one of the alcohol prep pads and attached all three of the BIOPAC disposable electrodes to their arm accordingly to the sample shown on the computer. After the electrodes were attached, another group member clipped the electrode lead set to the volunteer’s dominant arm, following the color code. We then made sure that our volunteer was seated correctly and had their dominant arm resting on their thigh to ensure that the muscles in the shoulder and arm were relaxed. Next, the group started the BIOPAC Student Lab program on the computer by clicking on the BIOPAC BSL icon and choosing Lesson L01- Electromyography (EMG 1). One of the members then clicked on Record. Two seconds after the recording begins, the volunteer should clench their fist as softly as possible for about two seconds, then release for two more seconds, then clench again with a greater force then before for two seconds, then release for two seconds. The last clench should be done with the volunteer’s maximum strength. The volunteer should do this a total of four times, each time increasing the strength of their clench so that the final clench is at its maximum strength as stated. After the clenches were completed and meet the clench samples provided by the program. A group member then clicked suspend which ended that recording. The group then prepped the volunteer’s non-dominant arm and attached the electrodes on the same spots. The procedure of the series of three Clench-Release-Wait cycles, was then repeated with the non-dominant arm. Once the recording has been completed, the volunteer unclip the Leads from the electrodes, then remove the electrodes.

Results The Electromyography lab consisted of a subject performing the series of clenches that are described in full detail under Methods. In order to collect the correct data from this experiment, using the BIOPAC software the group clicked over to “Review Saved Data” mode. In this mode, the Channel on measurement settings for CH 40 needs to say mean. The voltages were recorded by clicking the beginning of the first plateau on the graph and dragging to the end of that two-second plateau. The measurement needed was the number in the box directly to the right of the CH40 Mean box at the top part of the page. These steps to record voltage were repeated for each of the three plateaus on each separate arm’s EMG graph. Table 1.1 located below, displays the amplitude recorded in millivolts of each two-second clench of the three clenches. The results of the table showed the subject’s arm clenches to be close in amplitude. However the dominant arm’s amplitude still prevailed with a higher voltage. The maximum clench of the subject’s dominant arm show results of a significantly higher amplitude voltage than the non-dominant arm final clench. In addition, factors such as athleticism, fatigue, and injuries contribute to the subject’s right, dominant arm having the greater clench strength. Table 1.2 contains the results of the subject’s muscle tone, relaxed periods. The results of the graph were collected by highlighting the area between clench 1-2, 2-3 and 3-4. The procedure was repeated in the subject’s dominant and non-dominant arm. The number displayed in the CH40 Mean box was the number recorded for each. The subject did have any noticeable physical differences in the muscle tone of either arm, along with not having much of a difference in the actual millivolts of either of their tone measurements.

Subject Profile: Page 3 of 5

Height: ___________ Gender: _________ Age: ________ Weight: ________ Dominant Arm: _______ A Descriptive title of table and table number goes here. DOMINANT ARM NONDOMINANT ARM CLENCH NUMBER 40 mean 40 mean 1 2 3 4 A Descriptive title of table and table number goes here. DOMINANT ARM NONDOMINANT ARM BETWEEN CLENCHES 40 mean 40 mean 1-2 2-3 3-4

Discussion The results from the EMG lab conducted concluded the dominant arm to have the strongest clench. Throughout the four clenches of the dominant arm, the group witnesses the electrical activity increase between each clench interval. Between the first and second clench there was a (INSERT CALCULATION MACY) slight difference. However, by the

In order to obtain the percent increase in the activity .The group had to subtract the fourth and the first clench. The results from the subtraction were then divided by the fourth clench and multiplied by one hundred thus resulting in the percent increase of the arm being calculated.

The percent increase of the right dominant arm was (INSERT MACY) and the percent increase of the left nondominant arm was (INSERT MACY). The percent calculation results show the right arm to have the highest EMG activity. The right arm can be characterized to have the strongest clench quality in this experiment. The subject tested is right arm dominant, the favor the right arm over the left in their daily life. The arm with the weakest clench was the left arm being the non-dominant arm. The non-dominant arm is not used as much as the dominant arm which results a lower increase percent, as the outcome. The mean of the right dominant arm is (INSERT MACY ) mV resulting to be the highest compared to the mean of the non-dominant arm being (INSERT MACY)mV the difference between both is (INSERT HERE) mV. The volunteer of the experiment is a (INSERT HEIGHT) female, that weighs approximately (INSERT) lbs. The volunteer’s physical activity can be categorized as one of an average person. The strength she possess is the outcome of her regular everyday routine. There is noticeable difference muscle tone present between both flexed forearms. The results of the experiment are proof that the right (dominant) arm of the volunteer is in fact more tone than the left(non-dominant) arm. The group expected to see greater electrical activity in the dominant arm graph than that of the non-dominant, in addition to a higher increase percent and stronger clench results.

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The volunteer met the group’s expectations with her results concluding the right dominant arm to hold the arm with the greatest electrical activity, percent increase and stronger clench results. An experiment that could be carried out to test muscle contractions or clenches could be done on an athlete specifically an arm wrestler. An arm wrestler would be testing the muscle clench by attempting to pin his opponent’s, a robot arm to the table. The independent variable of the experiment would be the arm the wrestler uses, depending on the dominant and non-dominant arm will tell how easily the wrestler is able to pin the opponents’ arm to the table. The dependent variable is the strength of the clench, depending whether the contestant is winning gaining advantage over his opponent; or losing thus trying harder to overcome his opponent, will determine how hard the muscles are working. The controlled variable is the robot’s arm because it will be set to have a certain strength which will prevent it from getting or loosing strength. If the arm wrestler wrestles with the dominant arm, then the clench will be stronger making the impact bigger. The way that the experiment would be conducted would be quite like the EMG lab, electrodes would be attached to both forearms in the same location to observe muscle action as different forces are used to pin the opponent to the table. A table would be done and filled out just like Table 1.1 then after everything is filled out the percent increase would be calculated to compare both arms. The EMG lab was conducted in order to test skeletal muscles through an electrical impulse. According to the results from the group, the data from both arms have noticeable differences. The experiment concluded that the dominant arm was undoubtedly the strongest clench. References Cherry, K. (n.d.). What Happens Before, During, and After an Action Potential? Retrieved from https://www.verywellmind.com/what-is-an-action-potential-2794811 Euroform Healthcare. (n.d.). Retrieved from https://www.euroformhealthcare.biz/medical-physiology/excitation-ofskeletal-muscle-neuromuscular-transmission-and-excitationcontraction-coupling.html Electromyography. (n.d.). Retrieved from https://www.sciencedirect.com/topics/engineering/electromyography Morin, A. (2018, November 24). Your Child's Hand Dominance Isn't Something They Choose. Retrieved from https://www.verywellfamily.com/hand-dominance-what-is-a-dominant-hand-620856 Waehner, P. (n.d.). How Motor Units Affect Strength Training. Retrieved from https://www.verywellfit.com/motor-unitpart-of-muscles-1231223

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