Instruct the subject to position hisher elbow at a 90

Dynamometer should be held in the same hand used in Part I of this experiment. Instruct the
subject to position his/her elbow at a 90° angle, with the arm unsupported, and to close
his/her eyes, or avert them from the screen.
15. Instruct the subject to grip the sensor with full strength and start data collection. The subject
should exert near maximum effort throughout the duration of the experiment.
16. At 80 s, instruct the subject to watch the screen, and attempt to match his/her beginning grip
strength (the level achieved in the first few seconds of the experiment) and to maintain this
grip for the duration of the experiment. Data will be collected for 100 s.
17. Use the force vs . time graph to determine the mean force exerted during different time
intervals.
a Tap and drag across the data from 0 s to 20 s.
b Choose Statistics from the Analyze menu.
c Record the mean force in Table 1, rounding to the nearest 0.1 N.
d Choose Statistics from the Analyze menu to turn off statistics.
18. Repeat Step 17 for two other 20 second intervals: 60−80 s and 80−100 s.
19. Repeat Step 18 to record the maximum and minimum mV during three intervals on the EMG
graph: 0–20 s, 60−80 s, and 80−100 s. Rounding to the nearest 0.01 mV.
20. Calculate the difference between each minimum and maximum value and record this value in
the ∆mV column in Table 1.
Part III Repetitive Grip Strength
21. Have the subject sit with his/her back straight and feet flat on the floor. The Grip Strength
Sensor should be held in the same hand used in Parts I and II of this experiment. Instruct the
subject to position his/her elbow at a 90° angle, with the arm unsupported, and to close
his/her eyes, or avert them from the screen.
22. Instruct the subject to rapidly grip and relax his/her grip on the sensor (approximately twice
per second). Start data collection. The subject should exert maximum effort throughout the
duration of data collection.
23. At 80 s, the lab partner(s) should encourage the subject to grip even harder. Data will be
collected for 100 s.
24. Use the force vs . time graph to determine the mean force exerted during different time
intervals.

a Tap and drag across the data from 0 s to 20 s.
b Choose Statistics from the Analyze menu.
c Record the mean force in Table 1, rounding to the nearest 0.1 N.
d Choose Statistics from the Analyze menu to turn off statistics.
25. Repeat Step 24 for two other 20 second intervals: 60−80 s and 80−100 s.
26. Repeat Step 24 to record the maximum and minimum mV during three intervals on the EMG
graph: 0–20 s, 60−80 s, and 80−100 s. Rounding to the nearest 0.01 mV.
27. Calculate the difference between each minimum and maximum value and record this value in
the ∆mV column in Table 1.
R
ESULTS
Table 1–Continuous Grip Strength without Visual Feedback
Time Interval Mean grip strength
(N)
EMG Data
Max (mV) Min (mV) ∆mV
0–20 s 79.2 3.142 -0.953 4.095
60–80 s 49.3 1.062 -0.434 1.496
80–100 s 57.3 0.576 -0.394 .97
Table 2–Continuous Grip Strength with Visual Feedback
Interval Mean grip strength (N)
EMG data
Max (mV) Min (mV)
–20 s 67.9 1.251 -0.869
–80 s 42.0 1.436 -0.655
100 s 48.9 1.369 -0.855
Table 3–Repetitive Grip Strength
interval Mean grip strength (N)
EMG data
Max (mV) Min (mV)