Date: May, 2002

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Abstract:
Electromyography (EMG) is a technique that measures the relative amount of energy produced by a muscle doing work. This experiment compared the integrated EMG values of two forearm muscles, the extensor digiti minimi and extensor digitorum, resulting from the extension of the respectively corresponding little and middle fingers
The data from this experiment proved with statistical significance (P-value<0.01 at ?=0.05) that integrated EMG increases as applied force increases.  The average integrated EMG per unit force of 6 subjects for the middle and little fingers was found to be 0.0344mV/g ± 0.0023 mV/g with an R2 of 0.9866 and 0.0368mV/g ± 0.0023 with an R2 of 0.09865, respectively.  The extensor digitorum was not found to have greater average integrated EMG’s than the digiti minimi as hypothesized (P-value=0.4753 at ?=0.05).  However, normalizing the EMG values by approximating the muscle volume of the digitorum to be 2.25 times larger than the digiti minimi, the digiti minimi was observed to have statistically greater integrated EMG values than the digitorum (slopedigitorum=0.0007mV/g and interceptdigitorum=0.0806mV, whereas slopedigiti minimi=0.004mV/g and interceptdigiti minimi=0.0472mV; P-value < 0.01 at ?=0.05).  Since the 2.25:1 ratio of middle finger to little finger muscle was selected by inspection of various pictures (Appendix, Fig. A.1), the smallest possible ratio that would still produce statistically significant results was found to be 1.5X (because the intercept and slope for the digiti minimi EMG vs. Force graph are always greater than that of the digitorum; intercept: p-value=0.00183, ?=0.05 and slope: p-value=0.00082, ?=0.05).
In addition, individual physiologies in terms of subjects’ physical activities offered insight on the aberrations from these results.  Further tests on subjects who are involved in physical activities that require more extension in certain fingers are recommended (e.g. right-handed violin and guitar players and left-handed trumpet players).