This paper describes a muscle physiology laboratory exercise that uses electromyography to emphasize the concepts of force and torque and the role of limb position. Students perform a simple laboratory exercise that enables them to relate the angle of a joint with the concepts of force, torque, and the moment arm. Students observe the combined effects of motor unit recruitment and the variation of action potential frequency on the amount of electrical activity a muscle generates. They note that the amount of force a muscle generates also depends on motor unit recruitment and spike frequency. Here, I provide detailed protocols that students may follow. For the instructor, I provide background information, representative results, an explanation of technical matters, a list of pitfalls students may experience, and settings files for LabChart and LabScribe software. The exercise described here provides an excellent complement to, or serviceable replacement for, other muscle physiology labs while it also illustrates some principles of kinesiology.
"Force, Torque, and the Electromyogram: A Student Laboratory Exercise,"
Georgia Journal of Science, Vol. 75, No. 2, Article 12.
Available at: http://digitalcommons.gaacademy.org/gjs/vol75/iss2/12
Settings for LabChart 7.3.8 with analysis in LabChart.adiset (18 kB)
Settings for LabScribe v.3 with analysis in Excel.iwxset (7 kB)
Settings for LabScribe v.3 with analysis in LabScribe.iwxset (7 kB)
Student handout for LabChart with analysis in Excel.docx (123 kB)
Student handout for LabChart including analysis.docx (122 kB)
Student handout for LabScribe with analysis in Excel.docx (123 kB)
Student handout for LabScribe including analysis.docx (122 kB)
Student turn in.docx (26 kB)