PASCO ME-6807A Human Arm Model - Manual (Page 9)

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9
Experiment 1: Biceps Force versus Perpendicular Load
Introduction
Hold your arm in front of you with your elbow bent at 90°. Now have your partner
pull your hand to try to straighten your elbow. Resist the load force so that your elbow
remains at 90°.
Predictions
1. Which muscle (the biceps or triceps) did you use to resist this load? How do you
know?
2. Was the muscle force greater than, less than, or equal to the load force applied to
your hand?
3. If you partner pulls your hand with a force of 1 N,
guess how much muscle force is needed to keep your
elbow at 90°.
Set-up
1. Clamp the arm model horizontally as illustrated.
2. Clamp the rod to the base of the model as illustrated. Use
the sensor clamp and stud to attach a force sensor to the
rod.
3. Lock the shoulder at 0°.
4. Attach a cord as illustrated. Adjust the length
of the cord so that the elbow is held at about
90°.
5. Connect two force sensors to your interface.
The second force sensor will be held in your hand and
apply the load force to the model’s hand.
6. Set the sampling rate of both force sensors to 20 Hz.
7. Prepare a graph to plot biceps force versus load force.
Required Parts of Human Arm Model
Arm
Cord (1 piece)
45 cm rod
Sensor-mounting clamp and stud
Other Required Equipment
2 Force Sensors PS-2104 or PS-2189
C-clamp SE-7286 (6-pack)
Force Sensor 1
(Biceps Force)