Muscle Physiology

Muscle Physiology
Purpose:

What is the purpose of this exercise?
Are there any safety concerns associated with this exercise? If so, list what they are and what precautions should be taken.

Refer to the appendix of this manual if you need a tutorial on how to make graphs in Microsoft Excel®.
Exercise 1: Muscle Twitch
Data Table 1A: Muscle Twitch of Rectus Data Table 1B: Muscle Twitch of
Lateralis Eye Muscle Quadriceps Femoris
Time (milliseconds) Tension (kilogram-force)
0 0
1 0
2 0
3 10
4 20
5 30
6 40
7 30
8 20
9 10
10 5
11 2
12 0
Time (milliseconds) Tension (kilogram-force)
0 0
3 10
6 20
9 30
12 35
15 40
18 35
21 30
24 25
27 22
30 15
33 12
36 5
39 0

Data Table 1C: Muscle Twitch of Plantaris
Time (milliseconds) Tension (kilogram-force)
0 0
5 5
10 15
15 20
20 25
25 30
30 32
35 36
40 40
45 38
50 35
55 32
60 25
65 22
70 18
75 15
80 12
85 10
90 5
95 3
100 0

Questions

A. What is a muscle twitch?

B. According to the graphs, which muscle has the fastest twitch? Why?

C. What is the latent period and why does it occur?

Exercise 2: Treppe: The Staircase Effect

Data Table 2: Treppe
Time (milliseconds) Tension (kilogram-force)
0 0
3 2
6 0
9 4
12 0
15 8
18 0
21 10
24 0
27 12
30 0
33 15
36 0
39 15
42 0
45 15

Questions:

A. Why is treppe an important phenomenon for athletes to understand?

B. Physiologically, what causes treppe to occur?

Exercise 3: Wave Summation (Temporal Summation)

Data Table 3: Wave Summation
Time (milliseconds) Tension (kilogram-force)
0 0
3 5
5 3
7 8
9 5
11 13
13 9
15 20
17 15
19 25
21 0

Questions:

A. Explain why wave summation occurs. B. Can summation go on infinitely? Why or why not?

Exercise 4: Tetanus

Data Table 4A: Incomplete Tetanus Data Table 4B: Complete Tetanus
Time (milliseconds) Tension (kilogram-force)
0 0
3 5
5 3
7 7
9 5
11 9
13 7
15 11
17 9
19 15
21 13
24 15
27 13
30 15
Time (milliseconds) Tension (kilogram-force)
0 0
3 5
5 7
7 9
9 11
11 13
13 15
15 17
17 20
19 20
21 20
24 20
27 10
30 0

Questions:

A. What is the difference between complete and incomplete tetanus?

B. Will muscle fatigue occur quicker in complete or incomplete tetanus? Explain your reasoning.

Exercise 5: Demonstrating Muscle Fatigue

Data Table 5: Muscle Fatigue
Trial Start Time (seconds) End Time (seconds) Duration (seconds)
1
2
3

Questions:

A. Explain why muscles get fatigued.

B. Which muscle or muscle groups became fatigued with this exercise?

C. What causes the burning sensation in a muscle, and how does that sensation affect muscle contraction?

D. What might have happened in this exercise if more rest was built into the procedure?

Exercise 6: Isometric and Isotonic Contractions

Data Table 6: Isometric and Isotonic Contractions Trial 1 Trial 2 Trial 3
Tension
Length

Type of Contraction

Questions:

A. Which types of muscles do isometric contractions?

B. What happened to the muscle length and tension with each successive trial while doing isotonic contractions? Why do you suppose this occurred?

Conclusions:
Describe how muscles are designed to receive stimuli. How does this design support their ability to contract?