Reflex Lab

Purpose: 

To see the difference between voluntary and involuntary movements of the body. Why are reflexes faster than voluntary movement?

Materials:

• Computer
• Reflex Hammer
• Accelerometer 
• Logger Pro
• Electrode Tabs

Procedure:

1. In this lab we recorded different people's reflexes. First, two electrode tabs were placed on the subject's legs, across the muscle.
2. The reflex hammer, with the accelerometer strapped to it and plugged into the computer using Logger Pro, was hit against the desk. As soon as the subject heard the hammer being hit, they were to voluntarily kick their leg.
3. The next test was just a simple reflex test. The reflex hammer was used to hit the subject's reflex, and it was recorded on the computer.
4. Next, the subject's reflexes were recorded while resistance was happening in another part of the body. The subject locked their hands together and tried to pull them apart as hard as they could. During this time their reflexes were being tested and recorded.
5. The final test was another simple reflex test. The data was taken right after the resistance test, expect the subject was to relax and not have resistance.

Data/Analysis :

This is a graph of the average time our test subject's reflexes took. In the resistance tests it is shown that with resistance the subject's reflexes were much slower than without resistance. The first bar shows that the voluntary test took much longer than the involuntary test. 

• In the voluntary test the subject kicked their leg an average of .426 seconds after they heard the sound of the hammer hitting. While in the involuntary test, it took an average of .076 seconds for the leg to react after being hit with the reflex hammer. The difference in time is due to the actions in the body. In the voluntary test the brain had to process the hitting of the hammer before the subject could kick their leg. However, in the involuntary test, a circuit from the leg to the spinal cord was used, kicking out the use of the brain completely. This made the action of the involuntary test much faster because it was an automatic response, without the need to travel all the way to the brain and back to the leg.