A tap and drag across the data from 0 s to 10 s b

a. Tap and drag across the data from 0 s to 10 s.
b. Choose Statistics from the Analyze menu.
c. Record the maximum force in Table 2, rounding to the nearest 0.1 N.
d. Choose Statistics from the Analyze menu to turn off statistics.
18. Repeat Step 17 for the remaining 10 second intervals: 20−30 s, 40−50 s, 60−70 s, and
80−90 s.
19. Calculate the difference between each maximum value and the next and record these values
in Table 2.
20. Tap and drag to highlight 0−90 s on the graph. Choose Curve Fit from the Analyze menu.
Select Linear as the Fit Equation and record the slope (round to the nearest 0.01) in Table 3.
Select OK.

17 - 4
Human Physiology with Vernier
LabQuest 17
DATA
Table 1
−
Continuous Grip
Time interval Maximum force (N)
∆
Maximum force (N)
0
–
10 s 172.2
20
–
30 s 139.6
40
–
50 s 134.7
60
–
70 s 126.6
80
–
90 s 120.0
Table 2
−
Repetitive Grip
Time interval Maximum force (N)
∆
Maximum force (N)
0
–
10 s 172.7
20
–
30 s 168.5
40
–
50 s 156.9
60
–
70 s 134.8
80
–
90 s 129.0
Table 3
Slope
Part I
–
Continuous gripping
Part II
–
Repetitive gripping
DATA ANALYSIS
1. Examine your graph and the data in Table 1. What conclusion can you draw about the
number of individual muscle fibers that are firing in the last 10 s compared with the first
10 s?

Human Physiology with Vernier
17 - 5
Grip Strength and Muscle Fatigue
2. Is the change in number of muscle fibers that contract occurring at a constant rate?
3. Use your knowledge of fast, slow, and intermediate skeletal muscle fibers to hypothesize
which fibers are contracting in the first, third, and final 10 s intervals.
4. How might you explain the subject’s response to coaching? This should be evident in the last
10 s of data for Parts I and II of the exercise. Discuss the possible involvement of the central
nervous system, in addition to the muscle fibers.
5. Compare the slopes recorded in Table 3. Give a possible explanation for the difference, if
any, in muscle fatigue rates seen in continuous versus repetitive gripping.