Research Question
How does the immediate cessation of physical activity affect the strength and body
composition of physically active humans in a time window of 20 days?
1. Personal Engagement
In my family environment, as everyone does sports and is very physically active,
I couldn’t be any different. Since I was 8 years old, I have been completely addicted to
sports, nutrition, and going to the gym. As I have always done sports, I have made many
friends with the same interests and goals as me. Mostly all of them are in good body
shape, eat healthy food, and love sports. As a 16-year-old Brazilian, I consider myself
and my friends kind of different from the rest of the people our age, while they are going
out a lot and consuming alcohol we are taking care of our health. In Brazil, there is a
famous holiday named Carnival, which lasts 10 days. Me, my friends, and my family
decided to go on a trip. We rented a house in the countryside and stayed there for 15 days
chilling and resting. We wouldn't change our lifestyle of eating healthy food and having
a great time of sleep, however, there is no gym or a place to do sports. Therefore, I start
inquiring about what will happen to our bodies if we just stop working out.
2. Background information
WHO defines physical activity as any bodily movement produced by skeletal
muscles that requires energy expenditure, such as taking a walk or playing a football
match. There are several intensities of physical activity, ranging from light to vigorous.
Incorporating different intensities can target different muscle fibers, with endurance
activities primarily engaging slow-twitch fibers and high-intensity activities targeting
fast-twitch fibers. Any intensity up to moderate can improve the health of individuals.
Popular forms of physical activity include working out in the gym (lifting weights),
cycling, running, and participating in sports. Engaging in regular physical activity can
reduce the risk of heart disease, stroke, diabetes, and several cancers. It also aids in
preventing hypertension, maintaining a healthy body weight, and can enhance mental
health, quality of life, and overall well-being.
Exercise triggers numerous positive biological responses in the human body. A key
change is the increase in metabolic rate. Regular physical activity boosts the body's
metabolism, meaning it burns more calories at rest. This elevated metabolic rate can
persist even after the exercise session is over, a phenomenon known as the afterburn effect
or excess post-exercise oxygen consumption (EPOC). Exercise also enhances muscle fat
utilization, strengthens ligaments and tendons, and increases both lactate threshold and
capillary density in muscles. Additionally, VO2 max, a measure that indicates the
maximum oxygen use during intense workouts, also rises. Over time, these adaptations
make the body stronger and more efficient, enhancing athletic performance. The more
consistent an individual is with their exercises, the quicker these benefits manifest,
leading to a faster progression in strength and health.
Working out at a gym exemplifies physical activity that triggers these biological
reactions. This exercise form, particularly resistance training, emphasizes lifting heavier
weights with fewer repetitions, a method known as low-volume, high-intensity training.
This type of training predominantly engages fast-twitch muscle fibers, leading to rapid
gains in strength and muscle size. The primary goal of such training is to enhance physical
strength. Consistent resistance training over time can result in increased muscle mass
(hypertrophy), stronger bones, reduced body fat, and improved mental well-being.
Detraining, as defined by the National Institute of Health, refers to the physiological and
performance declines observed when an individual ceases regular physical activity. While
consistent exercise can lead to gains in strength, muscle mass, and neuromuscular
adaptations, these benefits can wane during periods of inactivity. Additionally, detraining
can lead to a decrease in the metabolic rate, meaning the body will burn fewer calories at
rest. This reduction can contribute to weight gain and a decrease in overall fitness. The
magnitude of these changes is influenced by several factors, including the length of
inactivity, an individual's genetics, diet, sleep quality, and more. The concept of
detraining underscores the "use it or lose it" principle, highlighting the significance of
ongoing physical activity to preserve fitness achievements.
3. Hypothesis
In physically active individuals, the cessation of all forms of physical activity can
lead to a decline in muscle strength due to the muscles not being actively engaged. This
is supported by a study titled "Substituting sedentary time with physical activity in
youngest-old to oldest-old community-dwelling older adults: Associations with body
composition", which found that replacing sedentary behavior with moderate-to-vigorous
physical activity was associated with a decrease in body fat percentage, BMI, and waist
circumference. These changes, characterized by an increase in body fat percentage, can
occur as caloric expenditure decreases while caloric intake may remain constant or even
increase due to sedentary behavior. The research emphasized the strong and independent
relationship between physical activity, sedentary behavior, and body composition.
Furthermore, the importance of reducing sedentary time is highlighted by the latest WHO
guidelines, which suggest that even replacing sedentary time with light physical activity
offers health benefits. Such shifts in body composition and muscle strength are expected
to be evident within a 20-day period, especially in older adults.
4. Variables
Dependent Variables: Measures of body composition including Weight, Body fat
percent, Skeletal Muscle Mass, Body Fat Mass, and intracellular water. Plus, a measure
of the strength of individuals
Independent Variable: Immediate cessation of physical activity
Controlled Variables:
n
1
Controlled Variable
Diet/Nutritional Intake
and Hydration Levels
Influence on Research
Method of Control
Ensures that nutrition and
hydration do not skew results.
Standardized meal plans for all
participants, targeting neutral calorie
intake and WHO-recommended water
intake.
2
Sleep Patterns
Medication/Supplement
3
Intake
Sleep can affect physical and
mental performance.
Fixed bedtime for all participants.
Certain
medications/supplements can
influence results.
Documentation of all medications and
supplements at the start. Exclusion of
participants based on certain medications
if necessary.
Physical activity can affect
baseline measurements.
Only physically active people will be
selected for the experiment.
4
Previous Physical
Activity Levels
5
Age
6
Gender
Biological differences between
genders can influence results.
Separate analyses for men and women.
7
Health Conditions
Certain health conditions can
skew results.
Exclusion of participants with health
conditions that will affect the experiment.
8
Alcohol Consumption
Alcohol can affect physical
and mental performance.
Participants will affirm non-consumption
of alcohol 1 weeks before, during, and 1
week after the experiment via a poll.
9
Environmental Factors
External environmental factors
can influence results.
The study will be conducted in a
controlled environment.
10
Measurement
Techniques
Inconsistent measurement
techniques can lead to
inaccurate results.
Use of standardized equipment and
protocols for all measurements.
11
Injury or Illness
Injury or illness can affect a
participant's performance and
skew results.
Exclusion of participants who experience
injury or illness during the study.
12
Cultural Practices
Cultural or religious practices
can influence behavior and
responses during the
experiment.
Documentation of any cultural or
religious practices that might affect the
study.
13
Smoking
Smoking can influence
physical performance and
health metrics.
Exclusion of participants with smoking
habits.
Selection of participants according to
Age can influence physical and
various age ranges. Different analyses for
mental capabilities.
each age range.
14
Caffeine Intake
Caffeine can affect physical
and mental performance.
Standardization of caffeine intake among
participants as zero.
15
Baseline Body
Composition
Different body compositions
can influence physical
performance and health
metrics.
Measurement and documentation of the
baseline body composition for all
participants.
16
Training History
Past training can influence
current physical capabilities.
Documentation of the duration and
intensity of participants' past training.
17
Adherence to the Study
Protocol
Non-adherence can lead to
inconsistent or inaccurate
results.
Regular check-ins with participants and
use of tools like activity trackers to
ensure adherence.
High-intensity activities
outside of the study can
influence results.
Ensuring no activity with an intensity
higher than low occurs during the study
period.
18 Daily Activity Patterns
5. Materials and Apparatus
1. Bioimpedance InBody 270
6. Procedure and Methodology
1. Participant Recruitment:
 Advertise the research study to potential participants, specifying the age
and gender criteria.
2. Participant Selection:
 From the pool of applicants, select at least 6 participants ensuring the
following distribution:
 25% of all participants have between 14-25 years.
 25% of all participants have between 25-35 years.
 25% of all participants have between 35-45 years.
 25% of all participants have between 45-60 years.
 Ensure that out of the selected participants, three (50%) are men and
three (50%) are women.
3. Initial Documentation:
 Conduct an initial interview with each participant to document:
 Medication and supplement intake.
 Cultural and religious practices.
 Training history.
 Baseline body composition.

Provide participants with a poll to confirm non-consumption of alcohol
during the experiment and 1 week before and after.
4. Dietary and Hydration Control:
 Provide participants with standardized meal plans.
 Ensure participants follow the WHO-recommended water intake
(𝑊𝑒𝑖𝑔ℎ𝑡 × 35𝑚𝑙)
 Monitor and document participants' adherence to the meal plans.
5. Sleep Pattern Regulation:
 Instruct participants on the fixed bedtime.
6. Environmental Control:
 Prepare the controlled environment for the study, ensuring consistent
conditions for all participants.
 Monitor environmental factors like temperature, humidity, and lighting.
7. Activity and Exercise Control:
 Instruct participants on the allowed daily activity patterns, ensuring no
moderate to high-intensity activities.
8. Medication and Supplement Regulation:
 Review the documented medications and supplements of participants.
 Group or exclude participants, if necessary, based on their medication
intake.
9. Data Collection:
 Use standardized equipment and protocols to collect data on participants'
performance, health metrics, and other relevant variables.
 Ensure consistent measurement techniques across all participants.
10. Monitoring Adherence:

Conduct regular check-ins with participants to ensure they are following the
study protocol.
11. Handling of Injuries or Illnesses:


Document any injuries or illnesses that occur during the study.
Exclude participants who experience significant injury or illness.
7. Risk Assessments
1. Safety:
 Physical Safety of Participants:
 Potential injuries or adverse reactions due to dietary changes,
sleep pattern regulations, or any other interventions.
 Risk of participants experiencing negative side effects from
stopping medications or supplements.
 Potential harm from wearing sleep or activity trackers
continuously.
 Data Safety:
 Risks associated with the storage and handling of participants'
personal and health data.
 Potential breaches of confidentiality or data leaks.

Equipment Safety:
 Malfunction or misuse of standardized equipment used for
measurements.
 Risks associated with the controlled environment setup, such as
poor ventilation or lighting issues.
2. Ethical Issues:
 Informed Consent:
 Ensuring that all participants are fully informed about the
research's purpose, procedures, potential risks, and benefits.
 Ensuring participants understand their right to withdraw from the
study at any time without penalty.
 Privacy and Confidentiality:
 Ensuring that participants' identities and data are kept
confidential and not disclosed without consent.
 Fair Treatment:
 Ensuring that all participants are treated fairly and without bias,
regardless of age, gender, health status, or any other factor.
 Handling of Personal Beliefs and Practices:
 Respecting and accommodating participants' cultural or religious
practices that might affect the study, ensuring no participant feels
marginalized or disrespected.
3. Environmental Issues:
 Waste Management:
 Proper disposal of any waste generated during the study,
especially if any biological samples are taken.
 Energy Consumption:
 The environmental impact of running a controlled environment
continuously, including energy consumption for lighting,
temperature control, etc.
 Resource Usage:
 The environmental footprint of producing standardized meal
plans for participants, especially if non-local or non-seasonal
ingredients are used.
 Electronic Waste:
 Proper disposal or recycling of any electronic devices, such as
sleep or activity trackers, if they are to be discarded post-study.
8. Raw data
BEFORE THE EXPERIMENT
Male
participant
1
2
3
4
5
6
7
8
9
10
11
12
13
14
Female
participant
1
2
3
4
5
6
7
8
9
10
11
12
13
14
Skeletal
Body Fat
Intracellular
Weight Body Fat Muscle
Mass
Water (%)
Mass
(%)
(kg)
(kg)
(kg)
68.5
7.88
57.3
10.5
75.0
65.3
10.5
63.1
12.8
82.0
70.2
11.0
55.2
14.2
77.5
68.8
8.63
59.7
11.9
72.5
11.3
63.8
13.4
84.5
67.0
71.5
5.73
55.5
8.3
69.0
69.0
9.24
60.8
12.0
77.0
66.7
10.8
61.6
13.5
80.0
69.3
9.54
63.0
12.0
79.5
67.8
9.13
59.5
11.7
78.0
68.1
11.0
61.8
13.2
83.5
68.0
11.2
61.2
13.8
81.0
70.8
7.27
56.0
9.5
76.5
70.0
8.14
59.5
11.0
74.0
1RM
Bench
Press
(kg)
91.25
100.0
102.0
86.25
108.75
85.0
93.75
101.25
103.0
101.0
106.25
103.0
98.0
96.25
Skeletal
Body Fat
Intracellular
Weight Body Fat Muscle
Mass
Water (%)
Mass
(%)
(kg)
(kg)
(kg)
71.2
5.81
35.5
10.2
57.0
68.0
6.88
39.0
11.1
62.0
7.62
42.0
12.0
63.5
67.5
70.8
5.93
36.8
10.5
56.5
72.2
5.50
34.8
10.1
54.5
69.2
6.82
38.1
11.0
62.0
5.87
36.8
10.3
57.0
70.7
69.0
6.96
38.8
11.8
59.0
6.57
39.5
10.6
62.0
70.0
5.99
36.8
10.5
57.0
70.8
67.0
7.94
41.3
12.5
63.5
71.5
5.65
37.0
10.0
56.5
67.8
8.00
42.2
12.8
62.5
68.5
7.38
40.2
12.3
60.0
1RM
Bench
Press
(kg)
62.75
68.75
75.00
62.00
51.00
61.00
61.00
66.00
67.00
61.00
75.00
62.00
69.75
67.00
1RM
Squats
(kg)
1RM
Rows
(kg)
121.25
116.25
107.0
100.0
110.0
105.0
127.5
116.25
125.0
110.0
143.75
115.0
116.25
108.75
92.5
100.0
95.0
87.5
105.0
85.0
95.0
97.5
100.0
97.5
105.0
97.5
92.5
95.0
1RM
Squats
(kg)
1RM
Rows
(kg)
91.25
108.75
98.75
73.75
71.25
88.00
87.50
78.75
92.50
91.25
98.75
73.75
98.75
78.75
71.25
72.5
75.0
68.75
63.75
72.50
70.00
71.25
71.25
70.00
75.00
68.00
76.25
73.75
1RM
Biceps
Curls
(kg)
42.0
46.0
47.5
40.0
47.5
40.0
45.0
46.25
46.25
45.75
48.75
46.25
45.0
43.75
1RM 1RM Lat
Pull
Triceps
Extension Down
(kg)
s (kg)
87.25
38.25
95.0
41.25
89.25
43.25
82.75
36.25
98.0
42.75
80.5
38.0
88.75
40.0
92.0
42.25
93.0
42.0
92.25
41.25
98.75
44.25
93.0
42.0
90.75
41.0
90.0
40.0
1RM
Biceps
Curls
(kg)
32.75
33.50
35.0
31.50
29.25
33.25
32.00
33.25
32.75
32.00
35.00
31.25
35.00
33.75
1RM 1RM Lat
Pull
Triceps
Extension Down
(kg)
s (kg)
63.75
29.25
71.25
29.25
72.50
31.00
65.00
28.25
62.50
26.25
71.25
29.25
65.00
28.75
67.50
29.50
71.25
29.75
65.00
28.75
72.50
31.00
65.00
28.25
72.50
31.25
70.00
30.00
1RM 1RM Lat
Triceps
Pull
Extension Down
s (kg)
(kg)
AFTER THE EXPERIMENT
New
New
New
New
Skeletal
New
Male
Body Fat
Weight Body Fat Muscle
Intracellular
participant
Mass
(kg)
(%)
Mass
Water (%)
(kg)
(kg)
75.4
11.3
56.7
8.52
1
68.0
2
82.6
13.2
62.5
10.9
64.5
3
78.0
14.4
54.6
11.2
69.3
4
72.8
12.0
59.1
8.74
68.0
5
84.9
13.7
63.1
11.6
66.2
6
69.3
8.42
54.9
5.84
70.8
7
77.4
12.1
60.2
9.37
68.3
8
80.4
13.8
61.1
11.1
65.9
9
79.8
12.1
62.4
9.66
68.5
10
78.4
11.8
58.9
9.25
67.1
11
83.9
13.3
61.3
11.2
67.5
12
81.3
14.0
60.6
11.4
67.4
13
76.8
9.60
55.4
7.37
70.0
14
74.4
11.1
58.9
8.26
69.3
1RM
Bench
Press
(kg)
1RM
Squats
(kg)
1RM
Rows
(kg)
1RM
Biceps
Curls
(kg)
86.69
95.00
96.90
81.93
103.31
80.75
88.06
96.19
97.85
96.05
101.94
97.85
93.10
91.44
115.19
110.44
101.65
94.00
104.50
99.75
119.13
110.44
118.75
104.50
136.56
109.25
110.44
104.06
87.88
95.00
90.25
82.88
99.75
80.75
89.25
92.63
95.00
92.63
99.75
92.63
87.88
92.63
39.90
43.70
45.13
38.00
45.13
38.00
42.75
43.94
43.94
43.46
46.31
43.94
42.75
42.31
Skeletal
Body Fat
Female
Weight Body Fat Muscle
Intracellular
Mass
participant
(kg)
(%)
Mass
Water (%)
(kg)
(kg)
1
57.3
10.6
35.1
6.07
70.5
2
62.3
11.5
38.6
7.16
67.4
3
63.8
12.4
41.6
7.91
66.9
4
56.8
10.9
36.4
6.19
70.1
5
54.8
10.5
34.5
5.75
71.8
6
62.3
11.4
37.7
7.10
68.5
7
57.3
10.7
36.4
6.13
70.0
8
59.3
12.2
38.4
7.23
68.3
9
62.3
11.0
39.1
6.85
69.3
10
57.3
10.9
36.4
6.25
70.1
11
63.8
12.9
40.9
8.23
66.4
12
56.8
10.4
36.6
5.91
71.0
13
62.8
13.2
41.8
8.29
67.3
14
60.3
12.7
39.8
7.66
68.2
1RM
Bench
Press
(kg)
58.75
64.94
71.25
59.38
48.45
58.75
58.75
63.36
65.31
58.75
71.25
62.00
66.75
65.31
1RM
Squats
(kg)
1RM
Rows
(kg)
85.94
103.31
94.00
70.88
67.69
83.60
83.13
75.00
92.00
88.44
94.00
73.75
94.00
76.88
67.75
68.75
71.25
63.75
60.56
68.75
66.25
68.75
68.75
68.75
71.25
68.00
76.25
73.75
1RM
Biceps
Curls
(kg)
31.0
31.90
33.25
29.25
27.75
31.25
30.50
32.25
31.0
31.0
33.25
31.25
35.00
33.75
36.34
38.54
41.09
34.44
40.61
36.10
38.00
39.40
39.90
39.09
41.99
39.40
38.85
38.00
78.88
90.25
85.54
78.61
92.90
76.48
84.31
86.80
88.35
87.19
93.44
88.35
85.54
85.00
1RM 1RM Lat
Triceps
Pull
Extension Down
s (kg)
(kg)
27.75
60.94
27.75
69.00
29.75
72.50
26.25
62.50
25.00
59.38
27.75
69.00
27.38
62.50
28.50
65.25
28.75
69.00
27.75
63.75
29.75
72.50
28.25
65.00
31.25
72.50
30.00
70.00
9. Analysis
This section includes the comprehensive compilation of all survey results obtained.
Altogether, 31 people participated in the experiment, however, 3 were excluded due to
alcohol consumption and heavy medication usage. Of all the 28 participants, 14 are males
and 14 are females, happily, this balance between genders enables us to analyze possible
differences in the outcome for the different genders. Additionally, an age range was
implicated aiming to have a balanced outcome that is reliable for all ages.
9.1. Analysis of the effect of the experiment on changes in strength
Before and after the cessation of physical activity, participants did strength tests. The
average strength before and after the cessation of physical activity was calculated for each
gender at each exercise. Thus, with this means, Graph 1and 2 were created with R. This
graph aims to illustrate the difference between the strength in the beginning and at the
end of the experiment for both males and females.
Graph 1:
According to Graph 1, both males and females have experienced a significant decrease in
their strength after the immediate cessation of physical activities. While in some exercises
people can lift heavier weights, the pattern of decrease in strength seems to be very similar
for all exercises even those for both genders. This decrease is expected when someone
takes time out from exercise. However, to obtain more precise and reliable outcomes, a
paired t-test was proceed.
The paired t-tests for various exercises between males revealed statistically significant
differences between the before and after measurements, indicating a decline in
performance across exercises. For the Bench Press, a t-statistic of 43.188 and a p-value
of 1.992 × 10−15 was observed, with a mean difference of 4.906429. This suggests a
notable decrease in performance. Similarly, the Squats showed a t-statistic of 24.855
and a p-value of 2.41 × 10−12 , with a mean difference of 5.952857, indicating a
decline. The Rows exercise had a t-statistic of 23.069, a p-value of 6.227 × 10−12 , and
a mean difference of 4.720714, pointing to a reduced performance. Biceps Curls
presented a t-statistic of 32.279, a p-value of 8.485 × 10−14, and a mean difference of
2.195714, suggesting a decrease. The Triceps Extensions had a t-statistic of 26.278, a pvalue of 1.184 × 10−12, and a mean difference of 2.196429, indicating a decline.
Lastly, the Lat Pull Down exercise showed a t-statistic of 17.024, a p-value of 2.87 ×
10−10, and a mean difference of 4.972143, pointing to a reduced performance. The tstatistic measures the size of the difference relative to the variation in the data. The
extremely small p-values in all cases indicate strong evidence against the null
hypothesis, suggesting that the observed declines were statistically significant. The
mean difference provides the average change in performance, with positive values in
this context indicating reductions on the weight lifted by males after the experiment.
Similarly, the paired t-tests between females for various exercises also revealed
statistically significant differences between the before and after measurements,
indicating a decline in performance across exercises. For the Bench Press, a t-statistic of
9.0145 and a p-value of 5.913 × 10−7 was observed, with a mean difference of
2.589286. This suggests a notable decrease in performance. Similarly, the Squats
showed a t-statistic of 7.666 and a p-value of 3.555 × 10−6 , with a mean difference of
3.509286, indicating a decline. The Rows exercise had a t-statistic of 5.9217, a p-value
of 5.053 × 10−5, and a mean difference of 2.620714, pointing to a reduced
performance. Biceps Curls presented a t-statistic of 6.2337, a p-value of 3.05 × 10−5 ,
and a mean difference of 1.275, suggesting a decrease. The Triceps Extensions had a tstatistic of 6.2711, a p-value of 2.874 × 10−5, and a mean difference of 1.044286,
indicating a decline. Lastly, the Lat Pulldown exercise showed a t-statistic of 4.5751, a
p-value of 0.0005208, and a mean difference of 1.512857, pointing to a reduced
performance. The t-statistic measures the size of the difference relative to the variation
in the data. The extremely small p-values in all cases indicate strong evidence against
the null hypothesis, suggesting that the observed declines were statistically significant.
The mean difference provides the average change in performance, with positive values
in this context indicating reductions on the weight lifted after the experiment by
females.
According to the studies, healthy individuals are susceptible to experiencing a decline in
muscle strength, cardiorespiratory fitness, and motor performance when they cease
regular physical activity. The consistent pattern of strength decrease across different
exercises and genders highlights the universal importance of maintaining regular physical
activity. For healthy individuals, consistent exercise is crucial not only for muscle
strength but also for overall well-being, cardiovascular health, and metabolic function.
The observed decline in strength after a period of inactivity serves as a reminder of the
body's adaptive response to its environment and the need for consistent stimuli, like
exercise, to maintain optimal physical health.
9.2. Analysis of the effects of the experiment on changes in body composition
Just as strength tests, people also did body composition tests. Using an InBody machine
people were able to get to know their body composition stats. They did 2 tests, one
before and one after the experiment, and then both results were compared, aiming to
state whether the experiment had a significant impact on body composition or not. To
compare the results, a regression analysis was performed. The null hypothesis for the
regression analyzes is that the experiment does not have any impact, while the
alternative hypothesis is that it has. 2 scatter plots were plotted willing to have a better
understanding of the data by visualizing it.
Graph 2: Body Composition Metrics Comparison for Males
Graph 3: Body Composition Metrics Comparison for Females
As the aim of this section is to state if the immediate cessation of physical activity has an
effect on the body composition metrics, the only factor important is the distance between
both lines. Thus, for males' weight, muscle mass, and intracellular water it is possible to
see that the lines of best fit have a significant distance between each other. This distance
indicates that the data has changed since the beginning of the experiment. However, for
the body fat percentual and fat mass, the lines of best fit are distant from each other on a
certain point, but they get closer, this suggests that the cessation of physical activity had
a varied impact on these metrics among males. Some participants might have experienced
a significant change in body fat percentage and fat mass, while others might not have seen
much difference. This variability could be due to individual differences in genetics, or
other factors not related to physical activity.
Additionally, for the female portion, it is possible to note a great distance and symmetry
between both lines for all body composition metrics. This suggests that the cessation of
physical activity had a consistent and pronounced effect on all body composition metrics
for females. The symmetry between the lines indicates that the changes in body
composition metrics were uniform across the female participants. However, despite a
graph being a great way to understand data, it is still needed to perform calculations to
have a more reliable outcome. Thus, regression analyses were performed and the p-value
and the r-squared were calculated.
After performing the regression analyses for each variable among male subjects, it was
found that the p-values for all five models were remarkably low. For the "Weight" model,
the p-value was < 2.2e-16, indicating an extremely significant relationship between initial
weight and subsequent weight changes. Similarly, the "Body Fat Percentual" model had
a p-value of 1.01e-12, demonstrating strong statistical significance in the connection
between initial body fat percentage and changes in body fat percentage. The "Skeletal
Muscle Mass" model had a p-value of < 2.2e-16, underscoring the highly significant
relationship between initial muscle mass and changes in muscle mass. In the case of the
"Fat Mass" model, the p-value was 3.6e-14, confirming the strong statistical significance
of the relationship between initial fat mass and changes in fat mass. Lastly, the
"Intracellular Water Percentual" model had a p-value of 9.78e-16, signifying a robust
statistical significance in the association between initial water content and subsequent
changes in water content among male participants. Furthermore, the R-squared values for
these models were notably high, ranging from 0.9872 to 0.9997, indicating that the linear
regression models provide a robust and precise fit to the data, explaining a substantial
proportion (ranging from 98.72% to 99.97%) of the variability in the dependent variables
for male subjects. In essence, these findings underscore the strong and statistically
significant connections between the initial measurements and the subsequent changes in
these variables specifically among male participants. Therefore, the null hypothesis is
rejected, and we state that the experiment implicated a significant effect on the body
composition metrics, as the graphs 2 and 3 illustrates.
10. Conclusion
Aim:
The primary objective of this investigation was to determine, "How does the immediate
cessation of physical activity affect the strength and body composition of physically
active humans in a time window of 20 days?"
Main Findings:
The data collected and analyzed from the study revealed distinct patterns in the effects
of halting physical activity on both strength and body composition. Specifically, there
was a noticeable decrease in muscle strength for both males and females. Additionally,
body composition metrics, such as weight, muscle mass, and intracellular water, showed
significant changes, especially among male participants.
Relating to Hypothesis:
The results obtained support the initial hypothesis that the cessation of physical activity
would lead to a decline in muscle strength due to the muscles not being actively
engaged. Furthermore, the changes in body composition metrics among males were
consistent with the hypothesis, indicating a significant effect on these metrics due to the
cessation of physical activity.
Significance and Implications:
The findings of this study underscore the importance of regular physical activity in
maintaining muscle strength and optimal body composition. The observed decline in
strength and changes in body composition highlight the body's adaptive response to its
environment. These results contribute to the broader understanding of the physiological
effects of inactivity and emphasize the need for consistent physical stimuli to maintain
health and fitness.
Limitations:
While the study provided valuable insights, there were potential limitations. Individual
differences in genetics or other external factors not related to physical activity might
have influenced the results. Additionally, the study's duration and the sample size could
be factors affecting the comprehensiveness of the findings.
Extensions:
Future studies could delve deeper into the long-term effects of physical inactivity on
various body metrics. It would also be beneficial to investigate the potential recovery
rate once physical activity is resumed. Exploring the effects of inactivity on different
age groups or individuals with varying fitness levels could provide a more
comprehensive understanding.
Reflect on the Investigation:
Throughout this investigation, the importance of consistent physical activity in
maintaining health and well-being was evident. The study served as a reminder of the
body's adaptability and the consequences of prolonged inactivity. If given another
opportunity, incorporating a more diverse participant pool and extending the study's
duration might yield even more comprehensive results.