1. Neurons and Newtons Michelle Dabkowski ~ Academy of Notre Dame The correlation between electrical signals on an EKG machine and the amount of sarcomeres recruited in the muscle

2. Introduction This is a muscle fiber: a single skeletal muscle cell The muscle fiber is made up of many myofibrils The myofibrils are made up of separate sarcomeres in which contraction occurs The plasma that separates each sarcomeres are called the transverse or t- tubules The entire fiber is surrounded by the sarcolemma in which nerve pulses are transmitted These are connected at triad junctions

3. Introduction Relaxed Sarcomere Contracted Sarcomere When muscle contraction occurs the sarcomeres shorten The thick myosin heads attach to the thin filaments in the sarcomere and pull them closer towards the M-Disk Thin filament Thick filament M-disk

4. Introduction What can be used to collect the energy produced by the muscle? Electrocardiogram (ECG/EKG) machine: Measures electrical outputs created by the heart and muscles Measured by attached electrodes Attached the electrodes to the arm Positive- on top left of forearm Negative- on top right of forearm Neutral- directly under negative electrode Image of graph of EKG machine

5. Problem: Will the amount of force varied by degree affect the electrical signals on an EKG machine that correlates to the amount of sarcomeres recruited? Materials: Computer Weights (2.27kg, 4.45kg) 10 Subjects EKG machine Electrodes (30) Logger Pro® 3.2 (computer program) Hypothesis: If a mass is increased by 2.27kg, 4.54kg than the amount of sarcomeres recruited will correlate to the electrical output

6. Procedure 1.Clear testing area allowing sufficient room for all subjects and prepare the EKG program by connecting the machine to the computer. 2. Tell and read the entire procedure to those who are willing and in a comfortable position to participate. 3. Choose dominant arm and clear arm from clothing or coverings. 4. Place electrodes on the forearm so that the positive will be on the left, the negative will be on the right and the neutral will be directly below the negative. 5. Connect the lead to the indicated electrodes as stated in number 4. 6. Turn on EKG machine program and set the data collection to zero to begin. 7. Begin collecting while the subject lifts their arm with no weight in an upward curving motion bringing the hand closer to the bicep. eewerwr 8. Save collected data and reset the data collection to zero. 9. Repeat steps 7 and 8 using a 2.27kg weight and a 4.45kg weight. 10. Carefully unclip the leads and remove the electrodes from the arm. 11. Repeat steps 3 to 9 with the second through the tenth subject. 12. Disconnect the EKG machine from the computer and save all data. Place EKG away and clear work space.

7. Variables Independent Variable: The amount of weight lifted by the arm Dependent Variable: The amount of electrical signal produced (recorded on the EKG machine) Control: No weight (0 kg) lifted by the arm Constant: All subjects were girls of the same age Amount of increase of weight and weights used EKG machine and computer program Tested in the same area

8. Data Analysis Subjects0 kg2.27 kg4.54 kg % Difference between 0-2.27kg % Difference between 0-4.54 kg #10.6251 N0.6729 N0.7797 N7.646776516%24.73204287% #20.4057 N0.567 N0.596 N39.7584422%46.90658122% #30.2372 N0.3872 N0.3954 N63.23777403%66.69477234% #40.3053 N0.814 N1.732 N166.6229938%467.3108418%outlier #50.4894 N0.5758 N0.8457 N17.65427054%72.80343277% #60.6556 N0.8916 N0.9626 N35.99755949%46.82733374% #70.3604 N0.5859 N0.6777 N62.56936737%88.04106548% #80.8642 N1.674 N2.779 N93.70516084%221.5690812%outlier #90.8357 N0.9105 N1.104 N8.950580352%32.1048223% #100.4406 N0.61 N0.6669 N38.44757149%51.36177939% average0.52192 N0.76889 N1.0539 N53.45904966%111.8351753% stdev0.204789 N0.338828 N0.670802 N45.47983535%129.8362162%

9. Subjects0 kg2.27 kg4.54 kg % Difference between 0-2.27kg % Difference between 0-4.54 kg #10.6251 N0.6729 N0.7797 N7.646776516%24.73204287% #20.4057 N0.567 N0.596 N39.7584422%46.90658122% #30.2372 N0.3872 N0.3954 N63.23777403%66.69477234% #50.4894 N0.5758 N0.8457 N17.65427054%72.80343277% #60.6556 N0.8916 N0.9626 N35.99755949%46.82733374% #70.3604 N0.5859 N0.6777 N62.56936737%88.04106548% #90.8357 N0.9105 N1.104 N8.950580352%32.1048223% #100.4406 N0.61 N0.6669 N38.44757149%51.36177939% average0.506213 N0.650113 N0.7535 N34.28279275%53.68397877% stdev0.177951 N0.163525 N0.206775 N20.36079531%19.74036972% Data Analysis

12. Discussion Linear correlation Mass lifted by the forearm vs. the electrical output indicated by EKG machine The mass of the weight was doubled Requirement of the same amount of increase in sarcomeres Electrical output increased by twice the amount when the 4.54kg weight was lifted as when the 2.27kg was lifted Standard Deviation: (How far the data varies from the average of that data) In newtons, how much does the electrical output from each subject differ from the average of all the subjects Although the variance is small, it shows that none of the values are significant Mr. Cusing.. this is where I need help

13. Limitation/ Continuation Limitations: Due to placement Electrodes often read the heart pulse Although able to be discerned, slowed the process of experimentation Could have still affected data Experimentation produced two outliers If kept in, it would corrupt data Number of experimental subject could have been larger to better support data Continuations: If repeated Subject group would be much larger Electrodes would be placed in an area that would produce better data (i.e. the calf) Different subject with different body types could be tested Do larger muscle would recruit more sarcomeres creating a different correlation between that an the electrical output? Does gender matter? Different weights Is there a maximum in which there are no more sarcomeres to be recruited?

14. Conclusion The purpose was to determine if the amount of force would affect the electrical signal that correlates to the amount of sarcomeres recruited This supports the idea that the more one needs to lift and the more sarcomeres that are recruited, the more electrical output the muscle will send This is the principal behind the electrical output needed to lift everyday things The hypothesis, which was that it would correlate, was supported When the mass was increased, the amount of sarcomeres recruited was increased and this correlated to electrical output as determined on the EKG machine

15. References Carl. “Cartoon of Sarcomere.” Cartoon. Art of MBoC3 1995. 13 Nov. 2010. "Electrocardiogram (ECG or EKG)." Www.heart.org. American Heart Association, 21 June 2010. Web. 13 Nov. 2010.. "Leg Muscle Anatomy." Bodybuilding Supplements. Body Building 4 You, 2008. Web. 13 Nov. 2010.. "Muscle Contractions." Lecture. Higher Learning. Cengage Learning Inc., 2010. Web. 13 Nov. 2010.. "Skeletal Muscle Fiber Sarcomeres (Sarcomere)." GetBodySmart. ConceptCreators Inc., 2008. Web. 13 Nov. 2010.. Tate, Philip, Trent D. Stephens, and Rod R. Seeley. "The Muscular System." Essentials of Anatomy and Physiology. Third ed. Dubuque: McGraw-Hill, 1999. 150-90. Print.