EMG Quiz

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Fill in the answers to the questions below and submit a copy of this form before attending lab.

1. What is an EMG?

2. What is the purpose of the electrodes that are placed on the forearm when recording an EMG?

Use the EMG on below to answer the following questions. 3. Which of the following statements best describes the condition of the muscle at point 1 in the EMG trace.

4. Explain the differences in the EMG trace seen at points 2 and 3.

5. In the image on the left how many fibers are in the smallest motor unit?

6. Why do motor units differ in size?

7. How do skeletal muscles increase the strength of contraction?

8. What causes muscles to fatigue and why does it take some muscles longer to fatigue?

Statistics Questions of the week.

9. You have measured the grip strength of 7th, 8th and 9th grade students and would like to know if the average grip strength of students increases as they age. What statistical test would you use to answer this question and why?

10. You measure the grip strength of 20 7th grade athletes and then have them practice squeezing a small ball ten times, every day for a month. At the end of the month you remeasure their grip strength. What statistical test would you do to determine if they had improved and why?

Before coming to class make sure think about factors that might affect grip strength and muscle fatigue. Then fill in the table in your lab manual.