Lab 8
Muscle Physiology
Gilbert R. Pitts, Ph.D., Joseph R. Schiller, Ph.D., and James F.
Thompson, Ph.D.
Lab 8 Activities
1. Biopac Exercise L02-EMG-2:
Skeletal Muscle Physiology
Multiple Motor Unit Recruitment
Biopac Exercises
1.
2.
3.
4.
Set Up
Calibration
Data Recording
Data Analysis
L02 - Electromyography (EMG) II
Default: Record
To Analyze later.
Set Up
1
2
Calibration
With your dominant hand first, clench
as hard as you can for 2 seconds; hit
continue to start recording
Estimate Max Grip Force – note and then hit redo
First record the maximal force for your
dominant hand and note the amount
of force you generated in Kg (y axis)
Hit suspend, and redo to collect the
appropriate data
48 kg (round to a number divisible by 4)
Multiple Motor Unit Recruitment (MMUR)
Now you will clench at 25, 50, 75, and
100% of your maximal force; get a ~2
second plateau for each
not good,
redo
good
good
good
25%
50%
75%
100%
Muscle Fatigue
MMUR
Now, clench as hard as you
can for as long as you can
until you reach 50% of your
maximal force, then let go
Fatigue
48
24
Complete Data Recording
Next, repeat previous steps for your non-dominant arm
Record All Group Members
Hit “stop” and then “done”
Select “record from another subject” to record for the
next group member; repeat until everyone has gone
Data Analysis
First, print your graph:
File> Print> Print Graph > Set Up> select “landscape”
Under Display:
1.
Autoscale Horizontal will “zoom out” to the entire data
screen.
2.
Autoscale Waveform to make the data fit the screen.
Data Analysis Screen
Check that the channels are set correctly
I-beam and zoom tools
Measuring MMUR on 4 Clenches
• Highlight the “plateau” of each clench
on the clench force graph (blue line)
and record clench data into table 1 on
your lab report (page 8-9)
• Only highlight the flat portion for each
clench (do not highlight the steep
portions)
highlight
plateau
Measuring Fatigue on Continuous Clench
• Set
measurement box to channel 41
(Clench Force) and select “value” as
the measurement (your lab manual says
3rd
channel 1 – this is wrong)
• Click on the peak force (don’t highlight
anything!)
– Record the value of the clench force
• Highlight the continuous clench from
the maximum force through 50% of the
maximum and record data into table 2
on your lab report (page 8-9)
highlight
the range of 100% to 50%
of your max clench force
48 kg
24
kg
Lab Report Assignment
Write you instructor’s name as well as the day and time of
your laboratory class on all sheets you turn in.
Attach the graph you printed to the lab report sheet (page
Lab 8-9)
Mark and label on your data plot:
25%max, 50%max, 75%max, 100%max, and Muscle Fatigue
for both the dominant and non-dominant arm
Also label, with brackets, the dominant and non-dominant
arm segments
Graph Labels
The labels go on the clench force graph (in the blue line)
100%max
Muscle Fatigue
100%max
75%max
Muscle Fatigue
75%max
50%max
50%max
25%max
25%max
Dominant Arm
Non-Dominant Arm
End Lab 8 Presentation