EMG of the Calf Muscle in Bipedal Forward Motion . Jesse Thornburg

1. EMG of the Calf Muscle in Bipedal Forward Motion . Jesse Thornburg 2.671 Instrumentation and Measurement Speed Results Incline Results Abstract 450 400 350 300 250 200 150 100 50 Numerous leg motions, specifically those which involve elevating the heel, require neurological stimulation of the calf muscles. Athletes seek to exercise these muscles by standing exercises, walking, jumping, and running. This study used an electromyographic (EMG) preamplifier to record voltage signals in the calf, specifically looking at the way these signals vary for different states of forward motion. Standing, walking, and running were compared, with the latter two activities being further observed at different inclines. In total, EMG in the calf was recorded over 7 states of bipedal activity. The mean voltage signal was observed to increase with both speed and incline. Increases in speed also caused the signals’ oscillations to become less uniform and less distinct. 600 500 400 300 200 100 0 256 1234 A good font for text Normalized EMG (mV) Normalized EMG (mV) 0 15 30 45 60 75 90 0 10 20 30 40 50 60 70 80 90 Time (sec) Time (sec) Still 1 mph 5.5 mph 8 mph Flat 6% incline 9% incline 1234 256 Methods Normalized EMG (mV) 600 500 400 300 200 100 0 % Increase in EMG • Errors calculated with a 95% confidence interval and propagation of errors2. http://jmm.consultantlive.com/display/article/1145622/1412245?verify=0 • Mammalian muscles flex or extend based on the voltage signals transmitted from the brain by neurons. • Electromyography (EMG) measures these signals, here with a surface electrode on the gastrocnemius muscle of the calf. • The gastrocnemius receives signals from the 1st and 2nd sacral nerves1. Conclusions • Mean EMG signal and error increased as forward speed increased. Increasing speed also made the signal less distinctly sinusoidal, with the frequency of oscillation becoming less pronounced. • The mean EMG also increased with incline. The change in sinusoidal behavior, however, was less pronounced than with increasing velocity. This trend merits further study. • Comparing test subjects’ EMG showed that as they increase velocity, those who run regularly have lower EMG increase than those who do not run. No relation tying EMG increase with a running regimen was apparent with changing incline. This phenomenon merits further study. Modes of Activity Test Subjects 1. Standing, flat 2. Walking, flat (1.0 mph) 3. Jogging, flat (5.5 mph) 4. Running, flat (8.0 mph) 5. Walking, uphill 6 % (1.0 mph) 6. Walking, uphill 9 % (1.0 mph) 7. Jogging, uphill 9 % (5.5 mph) 1. Runs 6 days/week (9.5 mph, 45 min/run) 2. Runs 3 days/week (8.5 mph, 30 min/run) 3. Does not run regularly - All test subjects were healthy male college students, 18-20 years old References Acknowledgements • Gray, Henry. Anatomy of the Human Body. Philadelphia: Lea & Febiger, 1918; Bartleby.com, 2000. [10/28/09]. <www.bartleby.com/107>. • Hunter, I.W. and B.J. Hughey. “Uncertainty Analysis.” 2.671 Measurement and Instrumentation, Class Notes. MIT Mechanical Engineering Department. • < https://wikis.mit.edu/confluence/display/2DOT671/ >. Thanks to Professor Matthew Lang, Dr. Barbara Hughey, Dianna Cowern, Ian Tracy, and Luke Thornburg for their help on the tests. Dec 3, 2009

2. Skin Membrane Chamber Drug Thermoresistor V V V

3. Baum’s “Canonical” Oz Books • The Wonderful Wizard of Oz • The Marvelous Land of Oz • Ozma of Oz • Dorothy & the Wizard of Oz • The Road to Oz • The Emerald City of Oz • The Patchwork Girl of Oz • Tik-Tok of Oz • The Scarecrow of Oz • Rinkitink in Oz • The Lost Princess of Oz • The Tin Woodman of Oz • The Magic of Oz • Glinda of Oz www.librarything.com/grouppics/theozbooks.jpg en.wikipedia.org/wiki/File:L_frank_baum.jpg