Does Body Composition Affect the
Aspects of Speed and Agility?
Introduction
Obesity is a condition, which causes many health problems for youth. Data from the
National Children and Youth Fitness Study II (NCYFS) indicated that obesity and superobesity
had increased since the mid 20th century by 54% and 98% in children aged six to eleven years
old (McManama & Schmottlach, 1997). A test is needed to determine if obese children have
trouble with movement and everyday activities, which may cause a dislike to exercise. This lack
of exercise in turn would put the now youth at considerable risk for a host of long-term health
problems.
A group of sixth grade students from Our Lady of Mount Carmel Elementary School
were tested to determine if there is a relationship between body composition and speed/agility.
Their body compositions were measured by using a body mass index (BMI) calculation. Then
the students’ speed/agility was measured by a shuttle-run test. The researcher had expected to
find a high positive correlation between the two tests. Thus, as the child’s weight goes up, it is
expected that their shuttle-run times go up as well.
Review of Literature
This section contains information pertaining to the study being conducted. Therefore, the
aspects of obesity, body composition, speed/agility tests, and relevant studies will be addressed.
Obesity
Obesity is defined as having an excess accumulation of fatty tissue in the body (Barrett,
Jarvis, Kroger & London, 2002). The amount of excess fat that deems one as being obese is
equal to 25% of body weight for males and 30% of body weight for females. Superobesity is
defined as weighing more than 50% above ideal weight (Fishburne & Kirchner, 1998).
The cause of obesity is complex. There is no one variable that can be held solely
responsible. However, there are some causes that are more prevalent than others, which can be
addressed through lifestyle changes. Improper diet is a common cause of obesity. Today, many
children are eating foods that are dense in calories and low in nutrition. Another cause is the
movement towards a sedentary lifestyle. Now, more than ever, children are inactive. An
increase in movie/television watching, video game playing, and Internet use is the reason for
this. To complicate this issue, over recent years there has been a reduction in mandatory
physical education classes. It has been documented that only 36% of youth participate in
physical activity in school on a daily basis (Buckanan, Dahl, Riben & Pizzey). Other possible
causes of obesity include the following: glandular abnormalities (rare), hereditary, improper
eating habits, insufficient physical activity, and psychosocial problems (Barrett, et al, 2002).
Other than the possible inability to perform certain everyday activities with ease, the
effects of obesity on the body are long-term and degenerative. They include such conditions as
coronary heart disease, cancer, hypertension (high blood pressure), hyperlipidemia (high amount
of fat in blood), diabetes, hypercholesterolemia (elevated cholesterol levels), orthopedic
problems (due to excessive weight bearning on legs) and low back pain/injury (McManama &
Schmottlach, 1997). The above conditions thrive on the psychosocial effect that obesity has on
children. Due to their condition, obese children must exert a notably greater effort when
engaged in activity. This produces reduced enjoyment in activity, which in turn leads to a
reduction in effort. Thus, obese children burn fewer calories and remain overweight (Fishburne
& Kirchner, 1998).
Over the past twenty years, the number of children who are overweight has increased by
more than 50% and the number of extremely overweight children has doubled (Virtua Health,
2001). Today obesity affects 1 in 5 children in the United States (Bucham, et al). It is estimated
that the current generation of children will grow into the most obese generation of adults in
United States History (Bucham, et al). That statistic is shocking when one considers that one
third (approximately 58 million) are already overweight or obese.
Aside from genetic factors and rare metabolic incidence of obesity, there is much that can
be done to prevent or reverse this condition. These solutions are simple and include eating a
proper diet and increase in physical activity. A proper diet entails eating nutritionally dense
foods, which are low in fat. The caloric intake should also be taken into account. When trying
to combat obesity, a healthy range of calorie intake should be between 1200 and 1500 calories
per day (Barrett, et al). If a child if more than 40% overweight a physician or dietician run diet
program should be considered (Virtua Health, 2001). The level of physical activity should be
increased slowly until one reaches at least twenty to thirty minutes of vigorous exercise every
day (McManama & Schmottlach, 1997). In addition, it is crucial that one should deal sensitively
with obese children when exercising, to ensure that exercise sessions are positive (AAHPERD,
1999). This will help to make certain that exercise continues.
It is imperative that prevention starts at a young age. Excessive calorie intake at a young
age increases the number of fat cells one has. On average, the number of fat cells increases five
fold until age 22 (Family Practice Notebook). A non-obese person has 25-30 billion fat cells,
whereas an obese person has approximately 260 billion (Family Practice Notebook). Once fat
cells develop they cannot be eliminated. Only the amount of fat in the cells can be decreased.
Hence, if a child becomes obese, there is a greater chance that they will remain obese throughout
adulthood.
Body Composition
Body composition is a health related fitness component. It is defined as the being the
proportionate amount of total body mass that is lean (bone, muscle, organs, and tissues) or fat
(adipose tissue) (Fishburne & Kirchner, 1998). There are several tests available to the physical
educator, which can determine the body composition of an individual.
Skinfold Caliper testing is the most accurate way of testing body composition for the
physical education teacher. They also can be quite in expensive ranging from three to twenty
dollars (Hawkins, 1983). The AAHPERD Health-Related Physical Fitness test suggests
targeting the triceps and calf skinfolds. This should be done away from the main activity area of
the class and no other students should be allowed to observe a child being measured (Fishburne
& Kirchner, 1998).
A second test is the Waist-to-Hip Ratio. This measurement came about due to research
indicating that it is better to be pear shape than apple shaped. This is conducted by measuring a
person’s waist at its smallest part and the hip at its largest part. Then the hip measurement is
divided into the waist measurement to produce a ratio. Healthy ratios are deemed as being less
than .86 in women and .95 in men (Fisburne & Kirchner, 1998).
The Body Mass Index test is a ratio between height and weight using a mathematical
formula that correlates with body fat (Fishburne & Kirchner, 1998). This formula is as follows:
weight in kilograms divided by meters squared (Wood, 2001). A healthy range constitutes a
body mass index of 20-25, an overweight range is 25-30, and obese is determined as being
greater than 30 (Wood, 2001). The main advantage of this test is that it provides for a quick and
simple calculation without having to come in close personal contact of students. The
disadvantage of this test is that it can be inaccurate when measuring individuals with a great
amount of muscle mass. However, this should not apply to the testing of youth since the
majority of children do not start resistance training before adolescence (age 14 and over).
Speed/Agility Tests
Tests that measure both speed and agility involve participants moving at maximum with
rapid stopping and/or turning (Wood, 2001). These tests are influenced by balance, coordination, position of center of gravity, and running speed. There are four major tests that
measure both speed and agility. They are the Zig Zag test, Hexagon test, 505 Agility test, and
the Shuttle run test (Wood, 2001). Norms for the 85th percentile of the shuttle run test for eleven
year old youth are as follows: 10.3 seconds for boys and 10.6 seconds for girls (Hastad & Lacy,
1998).
Relevant Studies
A study was conducted on 80 elementary students grades one, two, and three to see if the
factors of age, sex, and body composition were predictors of children’s performance on basic
motor abilities and health related fitness components. In regard to body composition, the results
indicated that individuals with large amounts of fat had a negative relationship with activities in
which the body is projected through the air (Moore, Pissanos & Reeve, 1983). Furthermore, for
any amount of work the obese person had greater energy expenditure, which forced the
circulatory system to work harder (Moore, et al, 1983).
Another study was conducted involving 563 elementary children to determine the
relationship of body fatness and motor performance during pre adolescence. The results of this
study indicated that there was only a marginal relationship with exception to moving one’s total
body weight (East & Hensley, 1982).
Testing Procedures and Methods
Description of Subjects
This study consisted of 29 sixth grade (ages 11-12) subjects form Our Lady of Mount
Carmel Elementary School. The gender breakdown was fifteen males and 14 females. These
subjects appeared to be relatively physically (within normal weight limits) fit with the exception
of a few students.
Tests Used for Study
1) Shuttle Run – Subjects run back and forth between a set distance of 30 feet two times.
Each time they reach the 30 foot marker they will pick up an object and
and return it to the starting line by placing it on the line (no dropping,
throwing, etc.)
Administrative Feasibility – This test is easy to administer. However,
only one student can be tested at one time. This can lead to a great deal
of inactivity time and possible class management problems.
Psychometric qualities – Face Validity is assumed. Relability
Coefficient ranges from .68 to .75
Source – AAHER, 1976
2) Body Mass Index – The subjects height and weight are recorded and converted into
kilograms and meters. Then their weight in kilograms is divided by
their height in meters squared.
Administrative Feasibility – This is an easy way to calculate a general
body composition of subjects. In addition, it eliminates personal
contact with students, which may make both students and instructor
uncomfortable.
Psychometric qualities – Not available through given source.
Source – AAHPERD – Physical Best
Equipment
tape measure (at least 15ft. to measure students and distance for shuttle run)
stop watch
bean bags (4 –8 depending upon number of practice stations)
flat surface (black top preferable)
weight scale
scoring sheet
chalk
Administration of Tests
1) Shuttle Run
Pretest Preparation – Prior to arriving at the test site, ten practice runs were completed by
two subjects (not involved in study), which allowed the researcher to become accurate in timing
the shuttle run.. The scoring sheet was prepared well ahead of time and was formatted to fit on a
single page. This page included designated areas for the following: students name/number
(located down the center), designated height and weight spaces (located to the left of each name),
and a slot for shuttle run times (located to the right of each name). The testing site and two
additional practice sites were then set-up on the black top outside of the school prior to the
beginning of class. This was done by using a tape measure to measure the proper distance (30
feet) and chalk to mark the start line and the turning point. The width of each station was
approximately fifteen feet. Two beanbags were placed at the thirty-foot markers (turning points)
for each of the stations. Additional space was left for a fourth station aimed at occupying
students who were neither practicing or testing. This very large station contained basketballs,
footballs, and hula-hoops. When the students arrived, they were directed through their regular
warm-ups. The students were then given standardized directions on how to complete the shuttle
run, a self-demonstration, and a brief explanation as to why they were completing this activity.
Testing procedure – The students were divided into four groups (approximately seven
students per group) and placed at the four separate stations Everyone practiced running the
shuttle run prior to testing. One person was tested at a time while the other members of the
group formed a line to the side of testing area. In addition, the other members of the group were
encouraged to cheer for the person being tested. The testing subject stood on the start line and
began after the instructor gave the signal. Times were rounded to the nearest tenth. After the run
was completed the shuttle run, he/she returned to the line and waited for the rest of the group to
finish. Time allotment only allowed for one measurable trial. When the entire group had
finished, they proceeded to the activity station. Then the next group rotated over to the testing
area. This process continued until all students were tested.
Posttest procedures – Students were brought together for a cool down period. This
consisted of stretches and a question/answer session. Following the class, all materials were
collected.
2) Body Mass Index
Pretest preparation – Students lined up outside the nurse’s office.
Testing procedures – Each student was weighed and measured privately in the nurse’s
office using a standard scale with a height measure attachment.
Posttest Procedures - When a student was finished being measured he/she returned to the
classroom.
* Note – The body mass index calculation was completed at a later date using the formula
of weight in kilograms divided by height in meters squared. This was provided in an automatic
calculation on line at http://www.stan-co.k12.ca.us/calpe/Sites.html. The results were rounded to
the nearest tenth.
Results
The following chart represents a comparison the average time of shuttle run scores for
subjects with a BMI of more than 25 and those with a BMI of less than 25.
Chart 1
Comparison of Average Shuttle Run Scores Between BMI
of Less Than 25 and BMI of More Than 25
16
13.8
12
Seconds
10.6
8
SR scores
4
0
BMI >25
BMI < 25
The following chart represents a comparison between total number of individual scores
of the shuttle run test and the BMI test.
Chart 2
Comparison Between BMI and SR Times
30
BMI
SR Times
20
10
Subject Numbers
29
27
25
23
21
19
17
15
13
11
9
7
5
3
0
1
Value
40
This chart represents a positive correlation of .70 between the BMI of students and their
shuttle run times.
Chart 3
Correlation Chart Between BMI and SR Times
SR Times
30
20
10
0
0
5
10
15
20
25
30
35
BMI
This chart portrays a comparison of average shuttle run times and body mass index
scores for boys vs. girls.
Chart 4
Average Scores for Boys and Girls
Girls
SR Times
BMI
Boys
11.4
10.6
19.8
18.9
Results
The group as a whole had an average body mass composition of 19.33, which was
actually slightly under the healthy range of 20-25. The students mean score for shuttle run time
was 10.95 seconds. This score varied minimally from the 85th percentile norm for sixth grade
students, which was 10.3 seconds for boys and 10.6 seconds for girls. Other central tendency
scores included a mode of 16.9 for BMI, mode of 10.2 for shuttle run, and ranges of 14.9 and 6.5
respectively. The Pearson calculation revealed a significant positive correlation of .70 between
the variables of BMI and shuttle run times. Furthermore, a comparison of the average shuttle run
scores between sub groups deemed as having BMI >25 and BMI <25 showed a 2.4 second
difference. On average, the group with a BMI greater than 25 ran the shuttle run in 13.0 seconds
as compared to 10.6 seconds for subjects with a BMI of less than 25. A comparison of the
averages of boys vs. girls revealed only a minor difference in scores. Girls had both a slightly
higher body mass index (19.8) and shuttle run times (11.4) as compared to the boys (18.9 and
10.6 respectively).
Discussion
As a whole, the subjects studied were of adequate body proportion (average BMI = 19.3)
and motor ability (SR mean = 10.95). However, the statistical analysis does indicate that there is
a significant positive relationship between body composition and speed/agility (chart 3coefficient = .70). Thus, a person’s body composition does affect their ability to run at a fast rate
and maneuver quickly. This is also evidenced by the difference in shuttle run times, as shown by
chart one, for students with >25 BMI and students with <25 BMI. In general, the more body fat
a student had the slower they ran and maneuvered.
This above data, if accurate, presents a concern for the American public and health
educators in particular. These findings were in contradiction to an earlier study cited in this
research, which indicated that body composition was only marginally related to motor activities.
It could have been in fact that the study those researchers conducted did not contain subjects
capable of skewing the results such as this research did (one eleven year old female tipped that
scales at 170lbs). If obese/overweight children have a more difficult time moving, as indicated
by the research, are they more likely to refrain from much needed exercise? If so, this suggests
that (as other research indicates) the problem of overweight and obese children will reach
epidemic proportions.
This in turn will lead to a multitude of problems including poor health,
shorter life expectancy, increased cost of health care, and possible decreased production in the
work force.
In regard to this study, there were many changes to need to be made to consider accuracy
factors. First, a much larger sample is needed so that the results will not be able to be skewed
from a few extreme scores. In addition, this sample should be more randomized. This will
provide for a better overall representation. Next, this study should have been conducted using a
more reliable method of testing body fat. BMI’s are infamous for reporting unreliable results,
especially with muscular students. Finally, this study should have contained more than one
motor performance variable. To truly determine if body composition inhibits overall physical
performance they need to be tested in several different areas (ie. cardiovascular endurance).
Future studies need to be conducted to determine the relationship between obese
individuals and attitudes towards exercise. In addition, a research of exercise programs that are
sensitive towards obese/overweight individuals needs to be completed to see which ones work
and which ones do not.