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Name:
Date:
Hour:
Muscle Fatigue Lab
Muscle fatigue is the decline in muscle tension as a result of previous contractile activity. A fatigued
muscle is slower to contract and takes longer to relax. The onset of fatigue depends on the type of
skeletal muscle, the duration of the activity, and the fitness of the individual. If a fatigued muscle is
allowed to rest, it will recover. The rate of recovery depends on duration and intensity of previous
exercise. Athletic training is designed to delay the onset of muscle fatigue and increase the speed with
which muscles recover.
Materials
Tennis Ball, stopwatch/timers on phone, lab write-up sheets, string and a ruler
Identify the Problem (in the form of a question):
___________________________________________________________________________________
Hypothesis
Write a hypothesis (in “If…then” statement format and not using the word “I”) as to what type of
physical arm/forearm description a person would need in order to squeeze the ball more times than
other members in the group in 60 seconds.
________________________________________________________________________
________________________________________________________________________
Procedure Part A
1. With your non-writing hand, clinch that hand into a fist so that the forearm muscle is flexed and
not relaxed, using the string/ribbon you will measure the circumference around the forearm in
centimeter (cm) (5-6 cm from their elbow) of each group member (your group may want to
measure a different part of the body instead related to fatigue of squeezing a tennis ball).
Everyone in your group will be measuring the same part of the body related to fatigue of
squeezing a tennis ball. Take the string/ribbon and use the ruler to determine how long the
circumference is around their forearm (or other portion of the body). Be sure to have the data
for each member of the group and include proper units.
2. Record this data in the chart below/next page.
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Name:
Date:
Hour:
DATA:
Name of Members
Qualitative Description
(words)
Quantitative Description
(measurement in
centimeters) include units
Procedure Part B
3.
One person should obtain a tennis ball. Your job is to squeeze the ball with your non-writing
hand as many times as possible in one minute. A legal squeeze places a dent in the ball with the
heel of your hand. Don’t stop squeezing. Don’t give up. 2. Your partner should count how many
squeezes you get every 10 seconds over a one-minute time period. The third person in your
group should record these numbers in the chart below. 3. Once the first person is done, switch
roles and record data for each group member below. 4. For your data, be sure each group
members first and last names are in the data tables and graph.
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Name:
Date:
Hour:
4.
Number of Squeezes for each 10 seconds (start count over each
10 seconds)
Time in
seconds (s)
Person 1
Name:
Person 2
Name:
Person 3
Name:
Person 4
Name:
10 s
20 s
30 s
40 s
50 s
60 s
Procedure C:
5. Graph the data of procedure B. Make a key to the right of the graph and use multiple color
lines to represent each member of the group. Label each axis (including units) and give the
graph a correct title.
Title: __________________________
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Name:
Date:
Hour:
6. Questions and Analysis:
a. What is the independent variable? ___________________
b. What is the dependent variable? ___________________
c. What is the relationship between the independent and dependent variable? (If you were not sure how
to answer question #3 then answer #4 and #5 first.)
d. Consider both parts A and B, what happens to the speed at which a person can flex the muscles in
their hand over time?
e. Consider both parts A and B, what happens to the force with which a person can flex the muscles of
their hand over time?
f. Which of your partners showed the most significant fatigue in part A? _________________________
g. What do you think would have happened if each test had continued for another minute?
h. Write a conclusion for the experiment. First, consider each person in your group and their number of
squeezes versus their forearm size (or other portion that was measured).
Now, determine whether the data supports or refutes your hypothesis (be sure to completely restate
your hypothesis in your conclusion). Be sure to include data from the lab with proper units to support
your conclusion.
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