Brook

winess it as well. That was the normal knee jerk, where latency and amplitude was measured. In the second experiment, the hammer did not come in contact with the subject. He just moved his knee whenever he heard the sound of the hammer hitting the surface of the counter. In this part, amplitude was controlled by him, so it was denoted in our data. The third experiment was very much like the first except the subject did not know when the hammer was going to hit him. His face had to be facing a different direction. This method was called the Jendrassik Maneuver.

Results

In this lab, my group and I were able to see the extension and flexion of the muscles in the upper leg, namely the quadriceps and hamstring. If the leg bent is considered zero degrees, as the leg is extended, the angle becomes closer to ninety degrees. After calibrating the Flexicomp program as well as a protractor, the group was able to observe the angle or amplitude of a kick, as well as how long it took to complete the reflex, or its latency. The calibration curve is Graph 1.

Next, we measured the amplitude and latency for 20 normal knee jerks (Table 1).

Table 1- Normal Knee jerks

TRIAL NUMBER LATENCY AMPLITUDE

1 0.13 8.30

2 0.12 10.90

3 0.13 10.50

4 0.13 7.70

5 0.13 9.30

6 0.16 7.30

7 0.12 10.70

8 0.16 6.10

9 0.13 9.00

10 0.13 9.40

11 0.19 5.00

12 0.12 11.50

13 0.09 15.60

14 0.10 14.80

15 0.11 14.50

16 0.14 11.30

17 0.12 12.40

18 0.10 14.40

19 0.13 9.70

20 0.10 15.50

The average latency and amplitude, for the normal, involuntary knee jerks was calculated to be