International Journal of

Environmental Research
and Public Health

Article
Comparison of Male Adolescents’ Physical Fitness Using
Physical Activity Promotion System and Circuit
Exercise Program
Byung-Sun Lee 1 , Seon-Yeong Shin 1 and Yeon-Oh Han 2, *

1 Health Physical Activity Institute, Subin Art Inn Building, 25 Eonju-ro 159-gil, Gangnam-gu,
Seoul 06024, Korea; shotace@khu.ac.kr (B.-S.L.); healthlab.shin@gmail.com (S.-Y.S.)
2 WEPEAK, Subin Art Inn Building, 25 Eonju-ro 159-gil, Gangnam-gu, Seoul 06024, Korea
* Correspondence: healthlab.han@gmail.com; Tel.: +82-021-577-1206

Abstract: The purpose of this study is to compare the physical fitness level of adolescents through
a physical fitness assessment and a circuit exercise program. A total of 142 middle school students
participated. Physical education class consists of a physical fitness assessment, namely, physical
activity promotion system (PAPS), and a circuit exercise program. The PAPS measurements include
endurance, flexibility, strength, power, body mass index, and total score. The circuit exercise program
consists of twist spine, hand walking, rolling squat, cross knee up, jumping and squat, and level-
up pacer. First, there were significant differences in PAPS and circuit exercise program according
to grade. Second, there was a significant difference in the results of the circuit exercise program
according to the level of each physical fitness variable of PAPS. Third, significant correlations were





 found in the results of the PAPS and circuit exercise program. The use of a circuit exercise program to
measure fitness for adolescents can offer convenience for school physical education and be of value
Citation: Lee, B.-S.; Shin, S.-Y.; Han,
as a measure of physical fitness for adolescents. In addition, the circulatory exercise programs used
Y.-O. Comparison of Male
Adolescents’ Physical Fitness Using
in this study are thought to be applicable to exercise prescriptions to improve endurance, strength,
Physical Activity Promotion System and BMI.
and Circuit Exercise Program. Int. J.
Environ. Res. Public Health 2021, 18, Keywords: adolescents; physical fitness; circuit exercise program; PAPS; school physical education;
7519. https://doi.org/10.3390/ physical activity
ijerph18147519

Academic Editor: Zisis Kozlakidis

1. Introduction
Received: 4 June 2021
Due to the coronavirus disease (COVID-19) outbreak, social distancing and prohibition
Accepted: 9 July 2021
of assembly are being imposed worldwide. As a result, the Ministry of Education has
Published: 15 July 2021
proposed postponing school opening, closing school, and adjusting the number of school
days as a countermeasure [1]. Accordingly, each school conducted online school opening,
Publisher’s Note: MDPI stays neutral
sequential school attendance, and non-face-to-face classes, leading to restricted students’
with regard to jurisdictional claims in
school life and physical activity (PA).
published maps and institutional affil-
iations.
During the adolescent phase in students, numerous changes and development occur
physically, mentally, and socially, and proper PA positively affects emotional stability,
growth, and development [2]. Hallal et al. (2006) emphasized that adequate PA levels in
adolescence positively impact mental and physical health, and health levels in youth are
an essential factor in determining health levels after adolescence [3]. Lee (2015) reported
Copyright: © 2021 by the authors.
that PA in adolescence is crucial for growth and development. Adolescents who continue
Licensee MDPI, Basel, Switzerland.
to participate in PA are taller and have lower body mass index (BMI) than those who do
This article is an open access article
not participate [4].
distributed under the terms and
conditions of the Creative Commons
In WHO (2020) recommendations for PA for adolescents, it is recommended to perform
Attribution (CC BY) license (https://
moderate-to-vigorous physical activity (MVPA) for at least 60 min each day, considering
creativecommons.org/licenses/by/
the development of adolescents’ physical and mental health and their effects on the whole
4.0/). life [5]. However, Guthold et al. (2020) surveyed the activity of adolescents in major

Int. J. Environ. Res. Public Health 2021, 18, 7519. https://doi.org/10.3390/ijerph18147519 https://www.mdpi.com/journal/ijerph
Int. J. Environ. Res. Public Health 2021, 18, 7519 2 of 12

countries with WHO, and four out of five teenagers worldwide were found to have
insufficient PA. Notably, 94.2% of Korean adolescents showed a lack of PA [6]. Furthermore,
in a study by Jang et al. (2020), MVPA, a recommended exercise intensity for adolescents,
was investigated for middle school students. Middle school students’ total PA and MVPA
duration appeared the most by the day they had physical education (PE) classes during the
semester, followed by days without PE classes during the semester and during vacations.
Thus, PE classes at school played a critical role in the PA time of middle school students [7].
Since 2009, the school has been implementing the physical activity promotion system
(PAPS) as part of school sports to prevent obesity and physical deterioration among Korean
students. The PAPS provides information on physical fitness (PF) and health conditions
through comprehensive fitness assessments and exercise prescriptions based on PF. PAPS
is being implemented to effectively manage students’ PF and establish a system to promote
student sports activities [8]. As a follow-up measure of PAPS, efforts are being made
to improve student health and PF through PE and after-school special sports activities,
especially for students with low PF evaluation. However, there are practical difficulties in
inducing active participation of students and guidance of teachers, and the necessity of
finding new methods is suggested [9].
Various exercise methods such as aerobic exercise, resistance exercise, and circuit
exercise program (CEP) have been used to improve the PF of adolescents. Mainly, CEP can
be used in combination of diverse exercises and are effectively known for their positive
effect on physique and PF. A study by Han et al. (2000) found that both aerobic exercise
and CEP showed similar results in improving body weight and blood lipids, indicating
that they are effective in promoting adolescent health [10]. In addition, the CEP performed
on obese children improved the functional fitness and PF factors of cardiorespiratory
endurance, muscular endurance, power, flexibility, agility, and balance [11]. The results
of these prior studies suggest that aerobic exercises, resistance exercises, and CEP, which
combines aerobic and resistance exercises, are effective in improving PF and weight control
in adolescents. The “Move Challenge” of the Healthy Physical Activity Institute (2020)
organized a CEP based on the values of PA presented in the PE curriculum, such as health,
challenge, and competition. The CEP consists of six fitness movements and contributes to
improving the health and PF of students through PA at varying intensities [12].
As shown above, the PF of adolescents in Korea is very low by worldwide standards,
and PAPS is conducted at school PE class to manage PF and exercise prescription of
adolescents. However, recently, due to COVID-19, it is difficult to participate in both school
PE class and PA to improve the PF of students. Therefore, it is believed that it would be
meaningful to check the status of PF levels for middle school students with a CEP that can
be carried out on its own without restrictions on locations. The purpose of this study is
to confirm the PF level of middle school students with a PF improvement program in the
form of CEP and to provide basic data for CEP development for PF improvement.

2. Materials and Methods

2.1. Subjects
The subjects for this study were 200 selected middle school males aged 14 to 16. A
statistical power test was performed by setting an effect size of 0.3 and a power of 0.8 using
G*power, and the final 200 subjects were selected in consideration of the 30% omission
rate. The records of 142 people (1st grade = 48, 2nd grade = 48, and 3rd grade = 46),
excluding 58 people who had insufficient records, were analyzed. We provided a sufficient
explanation of the purpose and method to PE teachers. They executed PAPS and CEP as PE
classes during the 2020 school year and then supplied measurements except for the students’
personal information such as body weight and height. The physical characteristics of the
subjects are shown in Table 1.
Int. J. Environ. Res. Public Health 2021, 18, 7519 3 of 12

Table 1. Characteristic of participants (Mean ± SD).

Variables 1st Grade (n = 48) 2nd Grade (n = 48) 3rd Grade (n = 46)
Ages (years) 14.00 ± 0.00 15.00 ± 0.00 16.00 ± 0.00
BMI (kg·m−2 ) 19.89 ± 5.22 21.70 ± 4.47 23.88 ± 5.03
BMI: body mass index.

2.2. Measurements
Subjects were measured for the data of both PAPS and CEP in two separate PE classes
during the semester. The two tests had a washout period of one week, and the order of
implementation of PAPS and CEP in each school was randomly selected.
The PAPS consists of five measurements, and each school equally measured and
documented the following measurements. The records of PAPS were classified according
to each grade criteria table provided by the Ministry of Education. The PAPS criteria are
shown in Table 2. The three values were classified as follows (high: Lv 1 and 2, middle: Lv 3,
low: Lv 4 and 5) [8]. For the endurance criterion, the ability to run a regular distance (20 m)
shuttle run was measured. Students run to the signal sound, while the interval gradually
decreased. The number of round trips was measured and recorded as a score. For the
flexibility criterion, the degree of bending of the upper body in a sitting position with both
feet straight was measured in 0.1 cm increments and recorded as a score. For the strength
criterion, the force of gripping the grip meter with four fingers and thumb was measured
in 0.1 kg increments and recorded as a score. For the power (standing long jump) criterion,
the nearest straight distance from the start point to the landing point was measured. It
was measured in 0.1 cm increments and recorded as a score. For body mass index (BMI),
students’ height (cm) and weight (kg) were measured. BMI (kg·m−2 ) was calculated, and
the score was recorded. The total score was the sum of all five measurement item scores
in PAPS.

Table 2. PAPS criteria.

Lv 5 Lv 4 Lv 3 Lv 2 Lv 1
Variables Value
(Very Low) (Low) (Average) (High) (Very High)
score 0~3 4~7 8~11 12~15 16~20
1st grade 15~19 20~35 36~49 50~63 64~73
Endurance
(repetition) 2nd grade 15~21 22~37 38~51 52~65 66~75
3rd grade 16~23 24~39 40~53 54~67 68~79
1st grade −5.1~−4.1 −4.0~1.9 2.0~5.9 6.0~9.9 10.0~25.0
Flexibility (cm) 2nd grade −5.1~−4.1 −4.0~1.9 2.0~6.9 7.0~9.9 10.0~25.0
3rd grade −5.1~−3.1 −3.0 ~2.5 2.6~6.9 7.0 ~9.9 10.0~25.0
1st grade 14.4~16.4 16.5~22.4 22.5~29.9 30.0~41.9 42.0~46.0
Strength (kg) 2nd grade 19.1~21.9 22.0~28.4 28.5~36.9 37.0~44.4 44.5~47.0
3rd grade 19.1~24.9 25.0~32.9 33.0~40.4 40.5~48.4 48.5~50.0
1st grade 122.9~131 131.1~159 159.1~177 177.1~211 211~219.7
Power (cm) 2nd grade 129.9~136 136.1~169 169.1~187 187.1~218 218.1~229.3
3rd grade 1414~145 145.1~180 180.1~201 201.1~238 238.1~244.0
~13.3 13.4~15.3 15.4~17.3 17.4~18.3
1st grade 18.4~21.3
25~ 23.3~24.9 22.4~23.2 21.4~22.3
~13.3 13.8~15.7 15.8~17.7 17.8~18.7
BMI (kg·m−2 ) 2nd grade 18.8~21.8
25~ 23.9~24.9 22.9~23.8 21.9~22.8
~14.2 14.3~16.2 16.3~18.2 18.3~19.2
3rd grade 19.3~22.3
25~ 24.4~24.9 23.4~24.3 22.4~23.3
Total score 0~19 20~39 40~59 60~79 80~100
 Int. J. Environ. Res. Public Health 2021, 18, 7519 4 of 12

Int. J. Environ. Res. Public Health 2021, 18, x FORThe

PEER REVIEW
CEP in this study utilized youth physical activity promotion programs 4 of 12and
consisted of fitness movements to promote health and fitness elements of endurance,
flexibility, strength, and power [12]. The CEP consists of six movements, as shown in
Figure
then move1.oneAllbean
actions
bagwere
whileperformed
turning the in upper
sequencebody and
to recorded
the other in seconds
side increments
(two sets of three at
the end of all movements. Twist spine (flexibility): put one leg over the
repetitions for each side left and right). Hand walking (strength): in the push-up posture, pelvis, fix it on the
floor,
move oneand then
bean move
bag one bean
by hand bag
to the tipwhile
of theturning the upper
toe in order bodyreturn
and then to the to
other
theside
place(two
(onesets
of three repetitions for each side left and right). Hand walking (strength):
set of two repetitions). Rolling squat (strength): prepare in a squat position, roll back until in the push-up
posture,
toes are overmove
your one beanand
head, bag roll
by hand to thetotip
forward of theposition
squat toe in order
(oneand
set then return
of five to the place
repetitions).
(one set of two repetitions). Rolling squat (strength): prepare in a squat
Cross knee up (endurance): first, cross-jump on the step box (10 repetitions) while holding position, roll back
until toes are over your head, and roll forward to squat position (one set
the ball. Second, bend your knees and cross the ball diagonally (5 repetitions on each side of five repetitions).
Cross knee up (endurance): first, cross-jump on the step box (10 repetitions) while holding
alternately). Third, extend your knees and cross the ball diagonally (5 repetitions on each
the ball. Second, bend your knees and cross the ball diagonally (5 repetitions on each
side alternately). Jumping and squat (power): first, jump on top of the box with both feet
side alternately). Third, extend your knees and cross the ball diagonally (5 repetitions
(five repetitions). Second, step up the box (5 repetitions). Level-up pacer (endurance):
on each side alternately). Jumping and squat (power): first, jump on top of the box
Shuttle run by touching the four cones standing at 1.5 m intervals in sequence.
with both feet (five repetitions). Second, step up the box (5 repetitions). Level-up pacer
(endurance): Shuttle run by touching the four cones standing at 1.5 m intervals in sequence.

Figure 1. Schematic representation of circuit exercise program.

Figure 1. Schematic representation of circuit exercise program.
2.3. Statistics
The results from this study were analyzed using SPSS PC+ for Windows (version 20.0).
2.3. Statistics
The following features were considered: (1) descriptive statistics of all variables are pre-
The results from this study were analyzed using SPSS PC+ for Windows (version
sented as mean (M) and standard deviation (SD); (2) one-way ANOVA was conducted to
20.0). The following features were considered: (1) descriptive statistics of all variables are
analyze the differences in the mean between dependent variables for each grade and PF
presented as mean (M) and standard deviation (SD); (2) one-way ANOVA was conducted
level. If the mean difference in each grade is significant, then a post hoc (Scheffe test) was
to analyze the differences in the mean between dependent variables for each grade and
conducted; (3) Kruskal–Wallis Test was conducted to analyze the difference in CEP records
PF level. If the mean difference in each grade is significant, then a post hoc (Scheffe test)
according to BMI level. If there is a significant difference by BMI level, a Mann–Whitney
was conducted; (3) Kruskal–Wallis Test was conducted to analyze the difference in CEP
post hoc was performed; (4) to correlate the dependent variables between the two tests,
records according to BMI level. If there is a significant difference by BMI level, a Mann–
we performed a Spearman correlation coefficient analysis; (5) the significance level (a) for
Whitney post hoc was performed; (4) to correlate the dependent variables between the two
all statistical analyses except Mann–Whitney was set to 0.05. The significance level (a) for
tests, we performed
Mann–Whitney a Spearman
statistics correlation
analysis was set tocoefficient
0.0167. analysis; (5) the significance level
(a) for all statistical analyses except Mann–Whitney was set to 0.05. The significance level
(a) for Mann–Whitney statistics analysis was set to 0.0167.

3. Results
3.1. Comparison of PF Levels by Grade
Int. J. Environ. Res. Public Health 2021, 18, 7519 5 of 12

3. Results
3.1. Comparison of PF Levels by Grade
Table 3 shows the results of the comparison of PF levels by grade. There were signifi-
cant differences between grades in power (p = 0.000), BMI (p = 0.001), and CEP (p = 0.000).
However, there were no significant differences between grades in endurance, flexibility,
strength, and total score.

Table 3. Comparison of PF levels by grade (Mean ± SD).

Variables 1st Grade (n = 48) 2nd Grade (n = 48) 3rd Grade (n = 46) F(df) p Scheffe
Endurance 13.67 ± 5.62 13.85 ± 4.52 11.78 ± 4.99 2.3869(2) 0.096
Flexibility 13.65 ± 4.42 13.77 ± 5.55 14.65 ± 3.68 0.656(2) 0.521
Strength 11.06 ± 3.56 10.50 ± 5.32 14.91 ± 15.39 2.975(2) 0.054
Power 16.00 ± 4.41 12.31 ± 4.64 10.96 ± 4.50 15.799(2) 0.000 *** a > b,c
BMI (kg·m−2 ) 20.27 ± 4.33 21.70 ± 4.47 23.88 ± 5.03 7.286(2) 0.001 *** a<c
Total Score 64.48 ± 14.94 61.94 ± 16.21 62.30 ± 22.41 0.276(2) 0.759
CEP 123.69 ± 42.13 152.79 ± 33.11 168.72 ± 56.08 12.372(2) 0.000 *** a < b,c
BMI: body mass index, CEP: circuit exercise program, a: 1st grade, b: 2nd grade, c: 3rd grade, ***: p < 0.001.

3.2. Comparison of CEP by PAPS Levels

Table 4 shows the results of analyzing the CEP according to the PF level of the PAPS
category. In terms of endurance (p = 0.000), flexibility (p = 0.001), strength (p = 0.001), power
(p = 0.000), BMI (p = 0.001), and total score (p = 0.000), there were significantly differences
between PAPS levels.

Table 4. Comparison of CEP by PAPS levels (Mean ± SD).

Variables n Value CEP (s) F(df) p Scheffe

82 High 124.89 ± 36.98
Endurance 35 Middle 167.54 ± 36.52 39.161(2) 0.000 *** a<b<c
25 Low 197.08 ± 46.64
100 High 138.37 ± 38.94
Flexibility 26 Middle 172.92 ± 55.16 7.643(2) 0.001 *** a<b
16 Low 168.69 ± 66.94
65 High 132.77 ± 28.72
Strength 52 Middle 166.79 ± 63.76 7.959(2) 0.001 *** a<b
25 Low 149.16 ± 36.58
92 High 130.43 ± 37.25
Power 28 Middle 176.04 ± 45.75 23.769(2) 0.000 *** a < b,c
22 Low 186.50 ± 53.43
59 High 134.12 ± 34.03
BMI 27 Middle 134.67 ± 35.32 10.196(2) 0.000 *** a,b < c
56 Low 169.34 ± 57.90
74 High 120.47 ± 28.62
Total score 52 Middle 168.19 ± 36.11 52.495(2) 0.000 *** a<b<c
16 Low 210.69 ± 62.85
BMI: body mass index, CEP: circuit exercise program, a: high group of PF level. b: middle group of PF level. c: low group of PF level.
***: p < 0.001.
Int. J. Environ. Res. Public Health 2021, 18, 7519 6 of 12

3.3. Comparison of CEP by BMI

The results of the CEP were compared by BMI of underweight (1st grade: less than 15.5,
2nd grade: less than 15.9, 3rd grade: less than 16.5), normal weight (1st grade: 15.6~22.9,
2nd grade: 16.0~23.3, 3rd grade: 16.6~23.7), and overweight (1st grade: 23.0 or more, 2nd
grade: 23.4 or more, 3rd grade: 23.8 or more), and the results are shown in Table 5. There
were significant differences in the three groups (p = 0.000).

Table 5. Comparison of CEP by BMI.

Underweight Normal Weight Overweight

Variables F(df) p Mann–Whitney
(n = 8) (n = 88) (n = 46)
CEP 117.13 ± 38.78 132.23 ± 34.26 189.89 ± 52.56 36.421(2) 0.000 *** a,b < c
BMI: body mass index, CEP: circuit exercise program, a: underweight, b: normal weight, c: overweight, ***: p < 0.001.

3.4. Correlation between PAPS and CEP

The results of the correlation between PAPS and CEP are shown in Table 6. Significant
negative correlations were found in endurance (r = −0.809), flexibility (r = −0.280), strength
(r = −0.287), power (r = −0.660), and total score (r = −0.705). There was a significant
positive correlation in BMI (r = 0.469).

Table 6. Correlation between PAPS and CEP.

Circuit Exercise Program

Variables
r p
Endurance −0.809 0.000 ***
Flexibility −0.280 0.001 ***
Strength −0.287 0.001 ***
Power −0.660 0.000 ***
BMI 0.465 0.000 ***
Total score −0.705 0.000 ***
BMI: body mass index, ***: p < 0.001.

4. Discussion
The physique of adolescents continuously develops and grows, while PF decreases.
An increase in physique is due to an improvement in dietary level, while growth in
obesity and decrease in PF such as endurance and power is due to lack of exercise [13].
In previous studies, the PF level of a student is an important cause of cardiorespiratory
and various causes of death rather than weight status [14]. PF level and PA habits during
childhood and adolescence are presented as essential periods for determining PA habits
throughout life [15]. School PE provides an important opportunity for PA in childhood
and adolescence, and active PA is encouraged [16]. In addition, a study by Jamner et al.
(2004) reported that school PE could increase PA in adolescent students and prevent the
decrease in cardiorespiratory fitness [17]. Several educational and health institutions
provide guidelines for improving adolescent fitness. The US Center for Disease Control
and Prevention and the UK Associations for Physical Education recommend 50% MVPA
during physical education classes. Prior research showed that the MVPA activity rate
among middle and high school students was 40.5%, while the MVPA level decreased as
the grade rose to 48.6% for middle school students and 35.9% for high school students.
In addition, it was suggested that research is needed to participate in physical education
classes actively [18]. The WHO guidelines for recommending youth PA recommend MVPA
5 days a week or more with at least 60 min per day. However, the proportion of Korean
adolescents who participated in PA of moderate or higher was at a very low level of 13.9%,
which gradually decreases every year [19].
Int. J. Environ. Res. Public Health 2021, 18, 7519 7 of 12

The increase in students’ physiques and the decrease in PF are causing obesity and
becoming an important social problem. Therefore, the need to evaluate the fitness level of
adolescent students is increasing. In a study by Lee and Oh (2012), adolescent students
with high PF showed lower obesity rates than students with low PF. However, obesity rates
have been reported to be limited in presenting physical health standards. Therefore, the
necessity of a follow-up study to select the standard considering the purpose, target, and
social impact of the test was suggested [20]. In this study, PAPS as a method of measuring
adolescents’ PF in school PE in Korea and CEP as a PA method in school PE was conducted,
and the PF levels of each grade were compared. The power (p = 0.000) from PAPS, the
1st grade, was significantly higher than that of the 2nd grade and 3rd grade. In terms of
BMI (p = 0.01), the 1st grade was significantly lower than the 3rd grade. However, there
was no significant difference in endurance, flexibility, strength, and total score. In the CEP
(p = 0.000), the 1st grade was significantly lower than the 2nd and 3rd grades. In this study,
lower grades presented both a high level of power from PAPS and CEP records. The higher
the grade, the lower the score for the BMI. In the results of the CEP, a low record means a
higher fitness level, and the 1st grade showed a higher level of PF than the 2nd and 3rd
grades. These outcomes are interpreted as a result of decreased PF through the physique
increased as the grade advanced.
PF is a comprehensive ability and a basic element of PA. However, despite the em-
phasis on the importance of PF, students have lower PF than their standard physique
development [21]. In the preceding study, the PF of middle school students by grade was
compared using PAPS. There was a significant difference between grades in cardiorespi-
ratory endurance and muscular strength. Therefore, it was suggested that middle school
students need to improve cardiorespiratory endurance as their physique is steadily im-
proving according to grade, while health-related PF is rather decreasing [22]. In the results
of this study, the power from PAPS decreased significantly with the increase of grade,
but there was no significant difference between grades in cardiorespiratory endurance.
However, as the grade increases, the PF record tends to decrease, and the CEP results show
a significant decrease according to the grade increase, supporting previous studies.
Although many preceding studies have suggested the important role of PA in adoles-
cence, social issues such as the epidemic of infectious diseases and environments with the
absence of school sports, opportunities for PA for students are very scarce. In a previous
study by Park et al. (2015), the mobile application was used to provide opportunities for
voluntary PA to students for 10 weeks. The PA using the mobile application improved
the health and PF of the students and induced the students’ voluntary participation in PA.
School PE and existing online learning were based on teacher intervention. Still, previous
studies have suggested various possibilities of increasing the PAs through participation
and implementation of self-directed PA without teacher intervention [23]. In a study by
Han et al. (2000), both aerobic exercise and CEP had positive effects on students’ body
composition and PF. It was reported that CEP was particularly effective in increasing lean
body mass [10]. In comparing PF levels by grade in this study, significant differences
were found according to grade level in PAPS and CEP. PAPS measures five items using
different PF evaluation tools and presents the PF level for each measurement according
to the results. However, there are limitations in presenting and practicing methods of
improving PF by each measurement. The CEP carried out in this study is a combination of
aerobic and resistance exercises, which can be expected to have a positive effect on both
exercises. Providing CEP consisting of fitness movements for students with low PF levels
will provide an opportunity to improve their PF through PA participation. It also can be an
easy and simple tool for physical education teachers to use in physical education classes to
measure and improve PF for adolescents.
Above all, the physique of students is increasing according to the grade level, but the
PF is decreasing. Previous studies point out the problem of the current school education
system that focuses on improving intellectual ability rather than improving students’ PF.
To increase PA for adolescents, direct and indirect interventions by teachers and the school
Int. J. Environ. Res. Public Health 2021, 18, 7519 8 of 12

PE facility were required. In order to compensate for the decrease in PE time, it is necessary
to provide students ways to participate in various opportunities and methods of PA.
PF makes it easy to perform daily activities and enjoy leisure time efficiently and
effectively. PF is divided into health fitness, such as body composition, and functional
fitness that determines sports ability. PF tests using these characteristics are widely used to
evaluate the effects of health, motor development, physical training, and exercise propen-
sity of children and adolescents [24]. PAPS, which is being conducted in Korean school
PE, evaluates students’ health fitness, and functional fitness in five categories: endurance,
flexibility, strength, power, and body composition. In this study, the results of CEP were
compared according to the level of the PAPS. In endurance (p = 0.000), flexibility (p = 0.001),
strength (p = 0.001), power (p = 0.000), BMI (p = 0.001), and total score (p = 0.000), significant
differences were found in the CEP records for each level of PF. The level of each component
in PAPS affected the CEP records, and the higher the level for each component of PAPS
tended to show higher CEP records.
Several studies have reported the positive effects on body composition and PF of
adolescents from different types of PA conducted in school PE. However, the issues of time,
place, and lack of sports equipment are being raised. CEP that combines exercise methods,
such as aerobic exercise, resistance exercise, flexibility exercise, and plyometric, has been
proposed to improve these issues. In a recent study by Yoon and Moon (2018), significant
changes occurred through CEP in body composition such as body weight, body fat, body fat
percentage, BMI, and in basic PF such as cardiorespiratory endurance, muscular strength,
muscular endurance, and flexibility [25]. A previous study by Shekhawat and Chauhan
(2021) reported that adolescents’ participation in the CEP could focus on each muscle in the
arms, legs, and torso. If carried out regularly, it effectively improves speed and agility by
improving muscular strength [26]. In the study of Lee et al. (2009), a CEP using resistance
exercise was shown to be effective in improving body composition, flexibility, muscular
strength, and muscular endurance [27]. In addition, a study by Kumar and Kumar (2005)
reported that a CEP using plyometric is adequate for power improvement by making it
possible to exert maximum muscular strength with a short muscle contraction time [28].
Therefore, CEP applied with aerobic exercise, resistance exercise, and plyometric
exercise will positively impact PF and body composition. CEP plays an important role in
improving diverse fitness items. It is thought to be effective in enhancing the PF of students
through a professional and individualized PA without the limitation of time, place, and
tools at school and home. It is considered that various forms of CEP development and
education are needed to improve PF through voluntary practice by students and solve
social problems such as adolescent obesity and PF reduction.
In general, it is known that as the body weight increases, the PF appears to be at a lower
level. Although obesity cannot be the standard for setting the PF standard, checking the
level of PF based on the obesity level has the meaning of comparing the physique level and
the fitness level of adolescents. In the preceding study, the PF level of adolescents according
to obesity level resulted that the cardiorespiratory endurance factors were similar to that of
obesity. Therefore, it was possible to evaluate cardiorespiratory endurance according to
obesity level, and the PF of obese adolescents was generally low. However, the similarity
between obesity and strength level was insufficient; thus, a comparison of strength level
and obesity level was not appropriate [29]. In this study, to confirm the PF according to the
body composition level of adolescents, the records of the CEP were compared with BMI
level. The results of the CEP records were significantly lower in the underweight group
and the normal weight group than in the overweight group. These results are consistent
with previous studies that an inverse relationship between obesity and cardiopulmonary
endurance exists: the lower the obesity level is, the higher the PF level is.
PAPS is being implemented to measure, evaluate, and manage adolescents’ PF in
Korean school PE. However, there are insufficient methods to improve the PF of students
and lower the obesity level using the results of PAPS. Therefore, the CEP used in this study
was proposed as a method for weight loss and improvement of fitness levels. In the study
Int. J. Environ. Res. Public Health 2021, 18, 7519 9 of 12

of Therefore et al. (2009) [30], CEP is a recommended form of exercise for maximizing the
aerobic and anaerobic ability of the body. It effectively regulates body composition and
has been reported to improve cardiorespiratory endurance, muscular endurance, muscular
strength, flexibility, power, agility, and balance. However, there was no effect on body fat
percentage, blood pressure, or resting heart rate. It was reported that the age group of 20–29
had a lower body fat percentage and a higher level of autonomic nervous system balance,
compared to other age groups, and therefore, there was no significant difference. Another
study conducted a CEP in school PE to enhance students’ physical fitness. The results were
shown to improve muscular strength, cardiorespiratory endurance, lean mass, and body
composition, but there were no changes in blood lipid and C-reactive protein levels [31]. In
the study of Mayorga-Vega et al. (2013), it was possible to improve the strength and PF of
students through a CEP using elastic bands, balls, and body weight at school sports sites
without strength training equipment. In addition, the CEP is recommended as a practical
exercise method in school PE because it is possible to participate in numerous types of
exercise with minimal exercise time [32].
Obesity and physical deterioration of students are emerging as social problems, and
as in this study, results presented that the higher the obesity level is, the lower the PF is.
Several ways to prevent and manage these problems are proposed; previous studies have
reported positive effects of CEP on students’ PF and body composition. The CEP used in
this study was developed to increase the PA for students in various environments. In the
field of school PE and PA, it is considered that participation in CEP can be utilized as a
program for improving and managing students’ PF and physique.
PA has a positive effect on the physical and mental development of adolescents. In the
global adolescent PA survey conducted by the WHO in 2020, Korean adolescents reported
the lowest PA level. Providing varied methods for increasing the amount of adolescent’s
PA and opportunities to participate in PA is drawing attention as a crucial task [6]. The
Ministry of Education (2009) has distributed and operated PAPS, a health and fitness
enhancement program, to improve PA participation opportunities and PF of adolescents,
which are constantly decreasing. PAPS supplemented the problems of past student physical
ability tests. It is used in school PE fields to diagnose students’ health and PF level through
accurate measurement and to provide exercise prescriptions based on the measurement
results [8]. In addition, Ko et al. (2005) reported that adolescents’ PA decreased due to social
changes caused by economic development and that PF and health problems appeared. To
improve the situation of reduced adolescents’ PA and PF, the health promotion program
“Adolescents PF Test” was developed. These various preceding youth PF measurement
and improvement programs include evaluating cardiorespiratory endurance, muscular
strength and muscular endurance, flexibility, agility, and body composition [33]. It is
recommended to evaluate students’ health and PF through measurement and establish and
operate a health and PF class for students who received a low evaluation.
However, many problems have been raised to teachers and students who are directly
operating and using school PE. In the study of Kang et al. (2013), students were not
interested in subjects and activities that were not related to grading and were negative
about PAPS measurement [2]. Field difficulties for PE teachers in measuring and managing
PAPS were excessive work, methods of measuring, evaluating student health and PF, and
the hassle of inputting measurement data into the National Education Information System.
In this study, correlation analysis was conducted between the PF measurement results of
PAPS and the records of the CEP. As a result of correlation analysis, a negative correlation
was high in endurance (r = −0.809) and the total score (r = −0.705). There were significant
correlations in flexibility (r = −0.280), strength (r = −0.287), power (r = −0.660), and BMI
(r = 0.469).
The CEP conducted in this study consisted of six exercises. It provided teachers with
ease of measurement and management, while students with an interest in PF and health
improvement. CEP is known to be an effective program used not only for the general
public but also for elite athletes to increase their PF. Williams and Cash (2001) found that,
Int. J. Environ. Res. Public Health 2021, 18, 7519 10 of 12

in contrast to aerobic exercise, CEP consisting of resistance exercise increased the subjects’
upper and lower body strengths. In addition, the results of an assessment of appearance
showed increased physical satisfaction, improved physical self-efficacy, and reduced social
physique anxiety. Therefore, it was reported that the positive effects of physical and mental
factors through CEP were shown as improving strength, cardiorespiratory endurance, and
emotional stability [34]. Traditional resistance training methods are effective in improving
muscular strength and endurance in a PE environment. However, Henry et al. (2006)
suggested CEP because resistance exercise was difficult to adapt individually and evaluate
achievement. The CEP is easier for . students to check the effect of the resistance exercise.
The CEP resulted in increased VO2max and muscular strength and decreased body fat
percentage, effectively improving PF and body composition. The CEP was recommended
as a form of exercise suitable for a PE class environment because it provided a high exercise
effect. The exercise time was shorter than that of general aerobic exercise [35].
In this study, a statistically significant correlation was found in endurance, power, and
total score measurements as a result of the correlation analysis between the PF measure-
ments of PAPS and the CEP records in students. Therefore, improvements in endurance and
power can be expected through continuous CEP implementation. Thus, the implemented
CEP will provide PE teachers with convenience in measuring and managing students’ PF.
Additionally, it will provide motivation and interest in students’ participation in PA. In
school PE, the exercise effect for a short period of time is high, which is thought to improve
students’ physique, PF, and emotionality. In the future, the development and dissemination
of various forms of CEP are expected to improve the fitness of adolescents.

5. Conclusions
The purpose of this study was to compare the PF level of middle school students
using PAPS and CEP. First, there were significant differences in the level of PF for each
grade in power, body composition, and CEP records. Second, as a result of comparing the
results of the CEP according to the PAPS fitness level, significant differences were found
in endurance, flexibility, strength, power, body composition, and total score. Third, there
was a significant difference in comparing the results of the CEP according to the BMI level.
Fourth, in the correlation analysis between the PF measurement results of PAPS and the
results of the CEP, significant correlations were found in endurance, flexibility, strength,
power, body composition, and total score.
In conclusion, the amount of PA for adolescent students is low, and the PF level
decreases as the grade advances. In school PE, methods for measuring and managing
the PF of students need to be improved, and diverse opportunities and strategies for PAs
of students are required. The CEP will provide the convenience of teachers in school
PE and contribute to the development of endurance and power through the voluntary
participation of students in PA. In this study, the improvement of youth PF through CEP
was not confirmed, and there was a limit on the use of secondary data and recruitment
of sample groups. In the future, research is needed to confirm the effectiveness of the
development and training of various combinations of CEP for adolescents.
Additionally, the “Move Challenge” CEP contains the value of PA of health, challenge,
and competition in the PE process. Numerous PAs of CEP are organized to improve health
and PF. Through the CEP, we expect the development of the physique and PF through the
convenience of PE teachers and the voluntary participation of students in PA.

Author Contributions: Conceptualization, S.-Y.S. and Y.-O.H.; formal analysis, B.-S.L.; investigation,
S.-Y.S.; methodology, S.-Y.S.; supervision, Y.-O.H.; validation, B.-S.L. and Y.-O.H.; writing—original
draft, B.-S.L.; writing—review and editing, Y.-O.H. All authors have read and agreed to the published
version of the manuscript.
Funding: This research received no external funding.
Int. J. Environ. Res. Public Health 2021, 18, 7519 11 of 12

Institutional Review Board Statement: The study was conducted according to the guidelines of the
Declaration of Helsinki and approved by the Institutional Review Board of Kyung Hee University
(Reg No. KHGIRB-21-212).
Informed Consent Statement: Not applicable (Study using secondary data).
Data Availability Statement: The data presented in this study are available on request from the
corresponding author.
Conflicts of Interest: The authors declare no conflict of interest.

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