报告
课程 2nd Year Physi S1:2024 - 2nd Year Physi S1:2024
课 Skeletal Muscle Practical MEDS2001/PHSI2007 2024
组长 mlia8312@uni.sydney.edu.au
小组活动
Section A: Testing the EMG setup
Experiment A1: EMG and muscle coactivation
MINQI LIANG 重新加入 HONGYAO LIANG 重新加入
课继续 2024年4月10日 下午4:16
HONGYAO LIANG 组长 MINQI LIANG
课已开始 2024年4月10日 下午2:23
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时间
RMS Biceps(mV)
RMS Triceps(mV)
Biceps(mV)
Triceps(mV)
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0.5
0
1
0.5
0
-0.5
5
0
-5
0.4
0.2
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-0.2
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Experiment A1: Analysis of coactivation data
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Table 1. EMG Peaks for Biceps Contraction.
Biceps Triceps
1 0.09729 0.2611
2 0.2189 0.3358
3 0.2394 0.3228
4 0.1576 0.2329
5 0.1095 0.2973
Mean 0.16 0.29
Table 2. EMG Peaks for Triceps Contraction.
Biceps Triceps
1 0.1993 0.3315
2 0.1738 0.2233
3 0.1448 0.215
4 0.1587 0.2515
5 0.2346 0.3216
Mean 0.18 0.27
时间Δ 16.15 s
RMS Biceps0.327 (mV)
RMS Triceps0.188 (mV)
BicepsΔ -0.397 (mV)
Triceps0.173 (mV)
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0.4
0.2
0
-0.2
0.8
0.6
0.4
0.2
0
1.5
1
0.5
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-0.5
-1
-1 5
2
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-2
Experiment A2: Holding increasing loads
1. From your data, describe the electrical activity of the biceps and triceps muscles relative to one another when we
tried to: 
Bend the arm upwards against resistance and made the biceps contract.
Straighten the arm (downwards against resistance) and made the triceps contract.
when attempting to bend to bend the arm upward against resistance and contract the biceps, electrical activity in the
biceps increases signicantly.
Using Excel, plot a bar graph with a scatter overlay of your raw data for this co activation experiment from Table 1 and
Table 2 above, and upload  screen shot of your graph below.
Does the spread of your data (shown partially by the error bars on your columns, and comprehensively by your scatter
overlay) indicate population variability or experimental error?
Experiment A2: Analysis of increasing the load
1分
48 49 50 51 52 53
Weight/Load (how many books?) RMS value for biceps (mV) RMS value for triceps (mV)
1 0.02214 0.07288
2 0.1001 0.08244
3 0.212 0.1017
4 0.4991 0.1473
0 -0.07863 0.06318
时间4.12 s
RMS Biceps(mV)
RMS Triceps(mV)
Biceps(mV)
Triceps(mV)
1.4
1.2
1
0.8
0.6
0.4
0.2
0
0 2
0.25
0.2
0.15
0.1
0.05
4
3
2
1
0
-1
-2
-3
0.4
0.2
0
-0.2
Experiment B: Demonstration, collection and analysis
of data
Add an image of your completed graph
For the graph above, write a gure legend describing the data.
As the chart above shows, as the number of books increases, the RMS value for biceps and triceps both increase.
If electrical activity goes up, what do you think happens to the force generated by the muscle? Why?
If electrical activity increases, the force generated by the muscles increases due to enhanced calcium ion release and
increased bridge formation, resulting in stronger muscle contractions.
Experiment B: Tutorial Items
Muscle length (mm) Passive force (mN) Total force (mN) Active force (mN)
26 4.09 13.53 9.44
28 6.24 30.15 23.91
30 6.84 34.95 28.11
32 6.39 80.84 74.45
34 6.33 120.47 114.14
36 11.77 209.92 198.15
38 14.65 233.54 218.89
40 20.91 316.84 295.93
42 32.28 389.12 356.84
44 55.26 391.32 336.06
46 109.42 291.78 182.36
Write a descriptive gure legend for the graph you have created above.
The gure illustrates the relationship between muscle length and the corresponding applied force, total force, and
main force produced by the muscle. The data points represent measurements taken at dierent muscle lengths (mm)
and the corresponding values of the applied force (mN), total force (mN), and main force (mN).
What is meant by the terms resting length and optimal length of muscle?
The rest length of a muscle is the length of the muscle in a relaxed state without external force, and the optimal length
is the length that can produce the greatest force.
Experiment C: Demonstration, collection and analysis
of data
From your Force - Length graph:
Estimate the resting length of the muscle (the length at which passive force is 5 mN).
Name the major components in muscle that contribute to passive force, and why they contribute.
27mm, produced primarily by structural components such as elastin and connective tissue in muscles, it helps maintain
postural stability and prepares muscles to respond to external stimuli or the demands of exercise.
From your Force - Length graph:
Estimate the optimal length of the muscle.
Name the components in muscle that contribute to active force, and why they contribute.
42mm, The active force has the maximum data at 42mm. The components of muscle that produce primary power
include muscle bers and muscle proteins within muscle cells, which generate force to perform motor functions
through muscle contraction mechanisms.
Is crossbridge cycling occurring during an isometric contraction? Explain your answer.
Yes, the cross bridge cycle can occur during isometric contraction, as it involves the attachment and separation of the
myosin head from the actin lament.
Section D: Hand Grip
Weight (g) Maximum velocity of lift (um/ms)
0 309
5 208
10 184
15 163
20 148
25 121
30 106
35 89
40 73
45 63
50 48
55 37
60 27
65 13
Add a copy of your graph below
In your Load - Velocity graph, what is the independent and dependent variable?
independent variable is weight and dependent variable is maximum velocity of lift.
How did the latent period change as the load was increased? Why?
According to the data provided, the latency period decreases with increasing load. This means that as the weight lifted
increases, the time it takes for the muscles to generate enough force to start moving the load decreases.
Eect of Fatigue on Hand Grip Force
Evaluation
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Was the subject able to maintain an 80% maximal contraction for 2 min? Why or why not?
No. Prolonged muscle contraction may result in limited blood ow and insucient oxygen supply to the muscles, as
well as failure of neuronmuscular conduction, reduced release of calcium ions, and disturbance of excitation-
contraction coupling.
In a few words indicate what you most enjoyed in this Practical:
Muscle contraction experiments are interesting
In a few words indicate what could be improved in this Practical:
Everything's ne
时间Δ 3.21 s
ForceΔ 99.5 (%)
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