nghiên cứu một số chỉ tiêu sinh học và năng lực trí tuệ của học sinh miền núi từ 11 đến 17 tuổi tỉnh vĩnh phúc và phú thọ bản tóm tắt tiếng anh

1
MINISTRY OF EDUCATION AND TRAINING
HANOI NATIONAL UNIVERSITY OF EDUCATION
======================






NGUYEN THI BICH NGOC

RESEARCH ON SOME BIOLOGICAL CRITERIA AND
INTELLECTUAL CAPACITY OF THE 11 - 17 YEAR - OLD
MOUNTAINOUS PUPILS IN VINH PHUC AND PHU THO PROVINCES


Major : Physiology of humans and animals
Code : 62.42.30.01



SUMMARY OF PH.D DISSERTATION



HA NOI, 2013
This study is completed at Faculty of Biology,
Hanoi National University of Education

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Supervisor: Prof., Dr., Ta Thuy Lan
Prof., Dr., Le Dinh Trung


Examiner 1: Prof., Dr., Do Cong Huynh
Vietnam Military Medical University
Examiner 2: Prof., Dr., Nguyen Van Tuong
Hanoi Medical University
Examiner 3: Prof., Dr., Nguyen Huu Nhan
VNU University of Science

The thesis will be defended in front of the National Doctoral
Examination Board at Hanoi National University of Education at….


The thesis is also available at:
1. National Library of Vietnam
2. The library of Hanoi National University of Education





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LIST OF PUBLICATIONS

1. Nguyen Thi Bich Ngoc (2008), Some physical strengths of San Diu
pupils aged from 11 to 17 in Vinh Phuc and Phu Tho provinces, Journal of
Science, Hanoi National University of Education, Vol.53 No 7, p.118-123.

2. Nguyen Thi Bich Ngoc & Ta Thuy Lan (2010), The sensation-motor
flexex time of the Kinh and Sandiu pupils from 11 tob17 years old in Vinh
Phuc province, Journal of Physiology Vietnam, The Physiology Vietnam,
The Vietnam Medical Association, Vol.14 No 4.p.56-60.
3. Ta Thuy Lan & Nguyen Thi Bich Ngoc (2011), The ability of attention and
short-term memory of the Kinh and Sandiu pupils from 11 to15 years old in
Vinh Phuc province, Journal of Physiology Vietnam, The Physiology Vietnam,
The Vietnam Medical Association Vol.15 No 2, p. 30-35.
4. Ta Thuy Lan, Nguyen Thi Bich Ngoc (2012), Research on the feeling
reflective time - movement of Muong ethnic minority pupils aged 11 to 17 in Phu
Tho province, Reports on Research and Teaching in Vietnam Biology, National
Scientific Conference First, Ministry of Education and Training, Hanoi National
University of Education, The Agricultural Publisher, p.191-196.
5. Nguyen Thi Bich Ngoc, Ta Thuy Lan (2012), Research on the
intellectual capacity of Kinh and San Diu pupils from 11 to 17 years old in
Vinh Phuc and Phu Tho provinces, Report on Research and Teaching
Biology in Vietnam, Proceedings of the 1
ST
National Scientific Conference
on Biological Research and Teaching in Vietnam, Ministry of Education
and Training, Hanoi National University of Education, The Agricultural
Publisher, p.134-139.

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INTRODUCTION
1. REASONS FOR CHOOSING TOPICS
Research on human biology is a fundamental and large area, requiring the
participation of many scientists from different fields such as medicine, biology,
cybernetics, chemistry and mathematics. During the innovative process of our
country, many studies on biological indicators and wisdom of Vietnamese

children have been carried out, which have contributed a lot to the
identification of biological indicators and wisdom of Vietnamese people as
well as the educational planning and advanced human resources strategies
of the country.
However, the number of research projects on biological indexes and
intellectual capacities of children are not spread over different regions in the
country. Children in mountainous areas are in limited and difficult
conditions to develop physical health and intelligence, especially with
ethinic minority pupils. With the intention to contribute to the development
of biological criteria and intellectual capacity of ethinic minority pupils in
Phu Tho and Vinh Phuc provinces, we propose a topic: “Research on some
biological criteria and intellectual capacity of the 11 - 17 year - old
mountainous pupils in Phu Tho and Vinh Phuc provinces”.
2. RESEARCH PURPOSES
2.1. Determine puperty period and some morphological - physical
characteristics, physiological functions of pupils from the age of 11 to 17 in
Phu Tho and Vinh Phuc provinces.
2.2. Evaluate intellectual capacity of pupils from the age of 11 to 17 in Phu
Tho and Vinh Phuc provinces.
2.3. Determine the relationship among research indicators: between
morphological - physical index with respiration, between IQ and reflective
time of feeling - movement, between IQ and attention and concentration
with short-term memory of pupils from the age of 11 to 17 in Phu Tho and
Vinh Phuc provinces.
3. CONTRIBUTIONS OF THE THESIS
The scientific significance of the thesis is to assess the development of
the morphological - physical index, circulatory functional index, respiration
index, nervous system, puberty and intellectual capacity of Kinh, Muong
and San Diu pupils in Phu Tho and Vinh Phuc provinces. Results from this
thesis can be used as a reference in research and teaching topic about

5
children characteristic development of school age children in order to
improve quality of care, protection and education for these children.
4. STRUCTURE OF THE THESIS
In addition to the introduction, conclusion and recommendations, the
main content of this thesis consists of 4 chapters: Chapter 1: Overview of
the research; Chapter 2: Subjects and Research Methods; Chapter 3:
Findings; Chapter 4: Discussion.
Chapter 1
OVERVIEW OF THE RESEARCH
1.1. OVERVIEW OF CHILDREN'S DEVELOPMENT STAGE
The process of physical growth and development of a child has
uneven periods; there are periods of rapid growth interspersing with slow
growth periods, in which each stage has different morphological anatomy
and physiology characteristics.
1.2. RESEARCH ON BIOLOGICAL INDICATORS AND INTELLECTUAL
CAPACITY IN THE WORLD
The researches such as PhD theses of Christian Friedrich Jampert,
Philibert Guerneau de Montbeilard, D 'Arcy Thomson, Martin R, Cotes J.E.
(1966), Camphell E.J.M (1968), Ivan Sechenov, Pavlov I.P, Terman L,
Wechsler D, Ukhtomski A.A, Vygotski L.X Under the impact of living
conditions and genetic characteristics, the development in terms of a child’
body in terms morphology, function and intelligence completes with ages.
1.3. RESEARCH ON BIOLOGICAL INDICATORS AND
INTELLECTUAL CAPACITY IN VIETNAM
Studies prior to 1975 are collected in "Biological constant of Vietnamese
people”, which summarized adequately in terms of biological indicators of
Vietnamese people. After the unification (1975), many authors have studied this
topic such as Ta Thuy Lan, Tran Thi Loan, Do Cong Huynh, Tham Thi Hoang

Diep, Dao Huy Khue, Doan Yen and colleagues, Mai Van Hung, Tran Trong Thuy,
Do Hong Cuong Especially, there was a project, named "Biological value of
ordinary Vietnamese in the 90s - the twentieth century", by Hanoi Medical
University and Ministry of Health. In general, research on biological indicators and
intellectual capacity of Vietnamese children provides a great variety of directions.
Although research results are somewhat differences but they have determined
changes of biological indicators by age and by gender. Exercising has a positive

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impact on a number of morphology - physical and functional index. Social factors
have affected development of the body, especially in puberty period.
Therefore, there are many studies on biological indicators and
intellectual capacity of pupils. However, in the recent time with rapit eco-
sio development and improved material and spiritual level, no research has
been done on pupils living in Phu Tho and Vinh Phuc provinces. This thesis
aims to fill this gap in the literature.
Chapter 2
SUBJECTS AND RESEARCH METHODS
2.1. RESEARCH SUBJECTS
We conducted research on 3691 Kinh, Muong and San Diu pupils
from 11 to 17 years old in Phu Tho and Vinh Phuc provinces.
2.2. RESEARCH METHODS
- Sample research design: the cross - sectional study method is used.
- Morphological - physical indexes are assessed by research method of
anthropometry of Nguyen Quang Quyen.
- Research method of circulatory function index is measurement
methods used in medicine and biology.
- Research method of respiratory index is used the ST95 respiratory
function meter (Spiro meter) of FUKADA firm.
- Research method of reflective time of feeling - movement is used the

methods of Do Cong Huynh and colleges.
- Research method of puberty is used the retrospective interview
methods.
- Research method of wisdom is used the Raven's test method.
- Memory is determined by Nechaiev's method.
- Ability to pay attention is determined by Ochan Bourdon's method.
- The survey data were processed using SPSS 16.0 software and Excel
on computer with statistical methods used in biology.
Chapter 3
FINDINGS
3.1. PUBERTY PERIOD
3.1.1. Puperty of female pupils
3.1.1.1. Percentage of pubertal female pupils
Results show that, at the age of 11 years old, there are some female
pupils being pubertal. Most female pupils in three ethnic groups become

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pubertal at the age of 12 to 14. All female pupils are pubertal at the age of
15. Puberty period of Kinh female pupils is earlier than those of Muong and
San Diu female pupils.
3.1.1.2. Puberty age of female pupils
Results show that, puberty age of Kinh female pupils is 12 years and
10 months ± 1 year and 3 months, these of Muong female pupils is 13 years
2 months ± 1 year 3 months and that of San Diu female pupils in 13 years 4
months ± 1 year 8 months.
The age having the first menstrual flux of Kinh pupils is earlier than that
of Muong and San Diu pupils with p<0.05, while there are no differences in age
having the first menstrual flux among Muong and San Diu pupils.
3.1.2. Puperty of male pupils
3.1.2.1. Percentage of pubertal male pupils

Research results show that in the period from 11 to 12 years old, there is
no sign of puberty of male pupils in the three ethnic groups. Male pupils have
signs of puberty at the age 13 and there are 100% of male pupils have signs of
puberty at the age of 17 years old.
3.1.2.2. Puberty age of male pupils
The age that Muong male pupils have signs of puberty (14 years 2
months ± 1 year 1 month) is sooner than that of Kinh male pupils (14 years
5 months ± 1 year 2 months) and San Diu male pupils (14 years 7 months ±
1 year 4 months) with p <0.05, Kinh male pupils has signs of puberty earlier
than San Diu male pupils do with p<0.05.
3.2. SOME OF MORPHOLOGICAL - PHYSICAL INDEXES OF
PUPILS FROM 11 TO 17 YEARS OLD
3.2.1. Height
Table 3.5 shows the results, for a groud of pupils from the age of 11 to
17, the height of male pupils increases from a range of 133.97-134.85 cm to
a range of 159.33-164.45 cm, an average increase of 4.23 to 4.93 cm/year.
The height of female pupils increased from a range of 135.03-136.68 cm at
11 years old to a range of 154.49-156.25 cm at 17 years old, an average
increase of 3.24 to 3.42 cm/year. The height of male pupils in the three ethnic
groups grows fastest in the period of 13 to15 years old (increasing 3.78 to
8.25 cm/year) and the height of female pupils in the period of 12 to 14 years
old (increasing 4.72 to 7.71cm/year). In the period of 11 to 14 years old, the
height of female pupils larger than male pupils, In the period of 15 to 17
years old, the height of male pupils larger than female pupils (p<0.05).

8
Table 3.5. The height of the pupils by age, ethnic group and gender
Ethnic
group
Age

Height (cm)

21
- XX


p(1-2)
Male (1)
Female (2)
n
X
± SD
Increase
n
X
± SD
Increase
Kinh



11
120
134.85  5.09
-
121
136.68 4.41
-
-1.83
<0.05

12
120
136.94 4.34
2.09
121
138.25 3.25
1.57
-1.31
<0.05
13
121
142.28 5.27
5.34
120
145.96 4.34
7.71
-3.68
<0.05
14
122
150.53 4.35
8.25
120
150.93 3.52
4.97
-0.40
>0.05
15
121
156.89 4.08

6.36
119
153.08 4.61
2.15
3.81
<0.05
16
117
161.67 3.29
4.78
120
155.89 4.33
2.81
5.78
<0.05
17
118
164.45 3.98
2.78
120
156.25 3.55
0.36
8.20
<0.05
Average increase/ year
4.93

3.26

Muong

11
84
134.18 4.37
-
81
135.47 3.31
-
-1.29
<0.05
12
83
136.95 3.25
2.77
84
138.23 4.36
2.76
-1.28
<0.05
13
82
141.84 5.31
4.89
86
145.03 5.43
6.80
-3.19
<0.05
14
84

148.56 3.55
6.72
84
149.96 3.52
4.93
-1.40
<0.05
15
81
155.25 4.46
6.69
85
152.25 4.38
2.29
3.00
<0.05
16
83
159.23 4.71
3.98
86
155.19 5.37
2.94
4.04
<0.05
17
85
162.85 5.24
3.62
83

155.96 3.42
0.77
6.89
<0.05
Average increase/ year
4.78

3.42

San Diu

11
60
133.97 4.85
-
61
135.03 4.76
-
-1.06
>0.05
12
62
136.31 5.33
2.34
58
137.95 5.25
2.92
-1.64
<0.05
13

59
141.07 5.62
4.76
60
144.57 5.73
6.62
-3.50
<0.05
14
61
144.85 4.94
3.78
57
149.29 5.54
4.72
-4.44
<0.05
15
62
151.67 4.25
6.82
60
151.86 4.97
2.57
0.19
>0.05
16
60
155.96 4.88
4.29

59
153.85 4.92
1.99
2.11
<0.05
17
60
159.33 4.29
3.37
61
154.49 4.43
0.64
4.84
<0.05
Average increase/ year
4.23

3.24

The height of Kinh pupils is larger than Muong pupils and San Diu pupils. The
height of Muong pupils is large than San Diu pupils in most age groups (p<0.05).
3.2.2. Weight
Results in Table 3.6 show that the weight of male pupils increased from a
range of 29.63-30.17 kg at 11 years old to a range of 46.97-48.86 kg at 17 years
old, the fastest rise time is 14 to 16 years old (increasing 3.76 to 5.21 kg/year), an
average increase of 2.89 to 3.12 kg/year. Similar to the height, the weight of
female pupils increased from a range of 28.85-30.15 kg at 11 years old to a range
of 44.33-46.17 kg at 17 years old, the fastest rise time is 13 to 15 years old
(increasing 2.86 to 5.03 kg/year), an average increase of 2.58 to 2.67 kg/year.
In the same age, height and weight of male and female pupils are not

the same. In the period of 11 to 13 years old, weight of male and female
pupils is similar. Weight of female pupils larger than male pupils at the time
of 14 to 15 years old, weight of male pupils is greater than that of female
pupils in the period of 16 to 17 years old (p<0.05). Particularly, Muong
pupils at the age of 14 to 15, the weight difference between male and female
pupils is negligible. This leads to a cross-section of weight growth in Table

9
3.2 at 15 to 16 years old for pupils in all three ethnic Kinh, Muong and San
Diu. Comparing the weight of pupils in three ethnic groups showed that the
weight of Kinh pupils is larger than Muong and San Diu pupils with p<0.05.
Table 3.6. Weight of the pupils by age, ethnic group and gender
Ethnic
group
Age
Weight (kg)

21
- XX


p(1-2)
Male (1)
Female (2)
n
X
± SD
Increase
n
X

± SD
Increase
Kinh



11
120
30.17  4.83
-
121
30.15  3.63
-
0.02
>0.05
12
120
31.97  4.41
1.80
121
32.47  4.15
2.32
-0.50
>0.05
13
121
34.58  4.53
2.61
120
35.54  4.37

3.07
-0.96
>0.05
14
122
38.81  4.96
4.23
120
40.46  4.95
4.92
-1.65
<0.05
15
121
42.57  4.58
3.76
119
44.49  4.64
4.03
-1.92
<0.05
16
117
46.85  4.37
4.28
120
45.76  4.34
1.27
1.09
>0.05

17
118
48.86  3.65
2.01
120
46.17  3.45
0.41
2.69
<0.05
Average increase/ year
3.12

2.67

Muong


11
84
30.02  4.25
-
81
29.36  4.13
-
0.66
>0.05
12
83
31.95  4.18
1.93

84
31.06  3.86
1.70
0.89
>0.05
13
82
34.45  3.09
2.50
86
33.87  3.35
2.81
0.58
>0.05
14
84
37.96  4.34
3.51
84
37.81  3.07
3.94
0.15
>0.05
15
81
42.15  3.27
4.19
85
42.25  4.53
4.44

-0.10
>0.05
16
83
46.36  4.38
4.21
86
44.01  3.14
1.76
2.35
<0.05
17
85
47.65  4.42
1.29
83
45.16  3.23
1.15
2.49
<0.05
Average increase/ year
2.94

2.63

San Diu

11
60
29.63  3.54

-
61
28.85  4.07
-
0.78
>0.05
12
62
32.01  3.49
2.38
58
31.24  3.58
2.39
0.77
>0.05
13
59
34.66  4.47
2.65
60
34.09  3.29
2.85
0.57
>0.05
14
61
36.95  4.75
2.29
57
39.12  3.96

5.03
-2.17
<0.05
15
62
40.87  4.64
3.92
60
41.98  3.77
2.86
-1.11
>0.05
16
60
46.08  4.55
5.21
59
43.45  3.22
1.47
2.63
<0.05
17
60
46.97  4.63
0.89
61
44.33  3.04
0.88
2.64
<0.05

Average increase/ year
2.89

2.58

3.2.3. Average bust size
Research results in Table 3.7 show that average bust size of male pupils
increased from a range of 62.88-63.96 cm to a range of 77.32-77.48 cm, an
average increase of 2.23 to 2.43cm/year. Similar to the weight development,
average bust size of female pupils increased from a range of 60.02-63.02 cm
at 11 years old to a range of 74.57-74.95 cm at 17 years old, an average
increase of 1.97 to 2.43 cm/year. The speed of increasing average bust size
by age is unequal. The fast period of increasing average bust size of pupils
takes place at the same time with period of increasing weight and later than
period of increasing height. Overall, average bust size of Kinh pupils is larger
than Muong and San Diu pupils in most of the age groups with the significant
level of 5 percent.

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3.2.4. BMI
The data in Table 3.8 show that BMI of male pupils and female pupils
increases with age, increasing by an annual average of about 0.22 to 0.33
kg/m
2
for male and 0.43 to 0.46 kg/m
2
for female.
Results in Table 3.9 show that pupils who have ordinary situation
account for the majority (84.55% male and 84.83% female), the number of
pupils who have malnourished situation account for a relatively high

percentage (14.80% male and 14.95% female). Overweight pupils account
for a very low proportion (0.65% male and 0.22% female) and no pupils are
obese. However, the high percentage of malnourished pupils proves that
nutrition of pupils in the study group is low and the diet is not enough to
provide for a balanced development of the body.
Comparing the state of pupils in three ethnic groups showed that
physical health of Kinh pupils is better than Muong and San Diu pupils.
3.2.5. Pignet index
Results in Table 3.10 show that, pignet index of pupil increases from the
age of 11 to 14, then decreases gradually. The rapidly decreased period of
pignet index of male pupils in all three ethnic groups occurs at the age 15 to 16
and that of female pupils is at the age of 14 to 15. In terms of gender, pignet
index of female pupils are generally better than that of male pupils.
3.3. FUNCTIONAL INDEX OF SOME ORGAN SYSTEM OF PUPILS
FROM 11 TO 17 YEARS OLD
3.3.1. Circulatory function index
3.3.1.1. Heart rate
Results in Table 3.11 show that, the heart rate of pupil decreases with
age. At the age of 11, the pupil’s heart rate is quite high with an average
value of 79.72-80.55 beats/minute for male and an average value of 81.25-
81.81 beats/minute for female. At the age of 17, the rate decreases to a
range of 71.15-71.93 beats/minute for male and a range of 73.03-73.23
beats/minute for female. The heart rate of pupil decreases rapidly in the
period from the age of 11 to 15 after that period, the speed slows down. In
general, the heart rate of female pupils is higher than that of male pupils in
the same age (p<0.05).
3.3.1.2. Systolic blood pressure
Results in Table 3.12 show that, from the age of 11 to 17, systolic
blood pressure of male and female pupil increases from a range of 97.83-

11
98.75 mmHg and 99.81-101.01 mmHg to the ranges of 109.14-109.35
mmHg and 111.14-111.74 mmHg, respectively. The period that has fastest
increase systolic blood pressure in all three ethnic groups is from 13 to 14
years old and for female pupils from 12 to 13 years old.
In all three ethnic groups, systolic blood pressure of female pupils has
a higher value than that of male pupils at the same age (p<0.05).
3.3.1.3. Diastolic blood pressure
Diastolic blood pressure increases at the age of 11 from a range of
57.85-58.82 mmHg for male pupils and from a range of 59.83-60.68 mmHg
for female pupils. At the age of 17, the pressure increases from a range of
68.17-69.29 mmHg for male pupils and from a range of 69.44-70.39 mmHg
for female pupils. The period that has the fastest increases diastolic blood
pressure in all three ethnic groups is from 13 to 15 years old for male pupils
and from 12 to14 years old for female pupils.
In the same age, diastolic blood pressure of female pupils has a higher
value than that of male pupils in all three ethnic groups (p<0.05).
When comparing the diastolic blood pressure and systolic blood
pressure of pupils, we found no statistical difference.
3.3.2. Some respiratory function indicators
3.3.2.1. The respiratory parameters
+ Respiratory frequency
The results in Table 3.14 show that the respiratory frequency of Kinh,
Muong and San Diu pupils reduces from the age of 11 to 17, although the
decline between ages is very low (an average of 0.44 to 1.32 beats/minute/year).
Since 17 years old, respiratory frequency of pupils is equivalent to that of adults.
The period that respiratory frequency of female pupils rapidly decrease (12 - 14
years old) is 1 year earlier than of male pupils (from the age of 13 to 15). In
general, there is no difference in respiratory frequency between male and
female pupils in the three ethnic groups.

+ Vital Capacity (VC)
Results in Table 3.15 show that VC of Kinh, Muong and San Diu
pupils increases at the age of 11 from a range of 1.87-2.02 for male pupils
and from a range of 1.57-1.77 for female pupils. Since, 17 years old, it is
from a range of 3.35-3.52 for male pupils and from a range of 3.03-3.19
liters for female pupils. There is an average increase of 0.25 to 0.26
liters/year for male pupils and 0.24 to 0.25 liter/year for female pupils. The
fastest increasing period of VC in all three ethnic groups is at 13 to 15 years

12
old for male pupils and 12 to 14 years old for female pupils. In general, VC
of male pupils is larger than that of female pupils, VC of Kinh pupils is
usually higher than that of Muong and San Diu pupils (p<0.05).
Table 3.15. Vital capacity of the pupils by age, ethnic group and gender
Ethnic
group
Age
VC (lit)

21
- XX


p(1-2)
Male (1)
Female (2)
n
X
± SD
Increase

n
X
± SD
Increase
Kinh



11
120
2.02  0.17
-
121
1.77  0.15
-
0.25
<0.05
12
120
2.17  0.22
0.15
121
2.04  0.12
0.27
0.13
<0.05
13
121
2.47  0.22
0.30

120
2.48  0.16
0.44
-0.01
>0.05
14
122
2.94  0.17
0.47
120
2.85  0.15
0.37
0.09
<0.05
15
121
3.26  0.24
0.32
119
2.89  0.24
0.04
0.37
<0.05
16
117
3.47  0.30
0.21
120
3.11  0.23
0.22

0.36
<0.05
17
118
3.52  0.16
0.05
120
3.19  0.22
0.08
0.33
<0.05
Muong

11
84
1.91  0.18
-
81
1.63  0.21
-
0.28
<0.05
12
83
2.11  0.12
0.20
84
1.97  0.17
0.34
0.14

<0.05
13
82
2.35  0.15
0.24
86
2.46  0.24
0.49
-0.11
<0.05
14
84
2.77  0.20
0.42
84
2.82  0.24
0.36
-0.05
>0.05
15
81
3.21  0.22
0.44
85
2.97  0.31
0.15
0.24
<0.05
16
83

3.37  0.19
0.16
86
3.07  0.19
0.10
0.30
<0.05
17
85
3.49  0.22
0.12
83
3.11  0.26
0.04
0.38
<0.05
San Diu

11
60
1.87  0.21
-
61
1.57  0.21
-
0.30
<0.05
12
62
1.98  0.24

0.11
58
1.79  0.17
0.22
0.19
<0.05
13
59
2.15  0.27
0.17
60
2.25  0.23
0.46
-0.10
<0.05
14
61
2.56  0.25
0.41
57
2.43  0.17
0.18
0.13
<0.05
15
62
3.01  0.18
0.45
60
2.77  0.26

0.34
0.24
<0.05
16
60
3.23  0.24
0.22
59
2.92  0.18
0.15
0.31
<0.05
17
60
3.35  0.25
0.12
61
3.03  0.14
0.11
0.32
<0.05
+ Forced Vital Capacity (FVC)
Results in Table 3.16 show that, FVC increases at age 11 from 1.77 to
1.92 liters for male pupils and 1.45 to 1.65 liters for female pupils. Since 17
years old, it is from 3.24 to 3.42 liters for male pupils and 2.92 to 3.08 liters
for female pupils. There is an average increase of 0.25 to 0.26 liters/year for
male pupils and 0.24 to 0.25 liters/year for female pupils. The fastest
increasing piriod of FVC in all three ethnic groups is at 13 to 15 years old
for male pupils and 12 to 14 years old for female pupils. In general, the
FVC of male pupils is greater than that of female pupils (p<0.05).

In general, FVC of Kinh pupil is ussually higher than that of Muong
and San Diu pupils.
+ Forced Expiratory Volume in 1 Second (FEV1)
Results in Table 3.17 show that, FEV
1
of pupil increases with age,
with irregular speed. FEV
1
increases at age 11 increase from a range of

13
1.58-1.66 liters for male pupils and from a range of 1.33-1.45 liters for
female pupils. Since 17 years old, it is a range of 2.90-3.02 liters for male
pupils and from a range of 2.63-2.70 liters for female pupils. There is an
average increase of 0.22 to 0.24 liters/year for male pupils and 0.21 to 0.23
liters/year for female pupils. The fastest increasing period of FEV
1
in all
three ethnic groups is at 13 to 15 years old for male pupils and 12 to 14
years old for female pupils (0.31 to 0.73 liters/year for male pupils and 0.27
to 0.47 liters/year for female pupils).
In terms of gender, FEV
1
of male pupils is greater than that of female
pupils in most age groups with p<0.05. In the three ethnic groups, FEV
1
of
Kinh pupils is often higher than those of Muong and San Diu pupils, FEV
1
of Muong pupils is greater than that of San Diu pupils with p<0.05.

3.3.2.2. Some respiratory indicators
+ The Tiffeneau (FEV
1
/VC)
Results in Table 3.18 show that the Tiffeneau of male pupils changes
from 80.80 to 88.89% and that of female pupils changes from 80.32 to
88.20% depending on ethnic groups. In terms of gender, the Tiffeneau of
male and female pupils are equal in the same group of age.
+ The Gaensler (FEV
1
/FVC)
Results on Gaensler are presented in Table 3.19. Gaensler index of
male pupils ranges from 85.57 to 91.46% and that of female ranges from
84.89 to 93.47% depending on ethnic groups. Gaensler index of pupils in
ethnic groups has no statisticcal difference.
+ The Demeny
Results in Table 3.20 show that the Demeny of male pupils ranges
from 63.33-76.52. The Demeny of female pupils ranges from 54.74-75.09
depending on ethnic groups.
3.3.3. Reflection time of feeling - movement
3.3.3.1. Reflection time of visual - movement
Reflection time of visual - movement of pupils decreases from 11 to
14 years old and stabilized at the age of 15 to 17. For male pupils, reflection
time of visual - movement ranges from 357.11 to 369.17 ms at age of 11. At
14 years old, it decreases from 315.12 to 365.57 ms. From 15 to 17 years
old, it ranges from 316.47 to 342.65 ms. For female pupils, reflection time
of visual - movement ranges from 368.49 to 383.25 ms at the age 11. At 14
years old, it decreases from 325.26 to 355.31 ms. From 15 to 17 years old, it

14

ranges from 326.36 to 358.3 ms. Reflection time of visual - movement of
male and female decreases rapidly from 12 to 13 years old.
Reflection time of visual - movement of male pupils is shorter than
that of female pupils with p<0.05. Reflection time of visual - movement of
Kinh pupils is shorter than those of Muong and San Diu pupils with p<0.05.
3.3.3.2. Auditory - movement reflexion time
Auditory - movement reflexion time of pupils decreases from 11 to 14
years old and stabilizes at the age of 15-17. For male pupils, auditory -
movement reflexion time decreases from 366.51 to 381.15 ms at age 11. At
14 years old, it decreases from 336.38 to 345.17 ms. From 15 to 17 years
old, it ranges from 325.09 to 347.98 ms. For female pupils, auditory -
movement reflexion time ranges from 380.02 to 389.34 ms. At 14 years old,
it decreases from 336.38 to 355.70 ms. From 15 to 17 years old, it ranges
from 337.13 to 358.63 ms. Auditory - movement reflexion time of male and
female pupils decreases rapidly from 12 to 14 years old.
In terms of gender, auditory - movement reflexion time of male pupils
is shorter than that of female pupils with p<0.05. Auditory - movement
reflexion time of Kinh pupils is shorter than those of Muong and San Diu
pupils (p<0.05).
Reflection time of visual - movement is shorter than auditory -
movement reflexion time of pupils in all three ethnic Kinh, Muong and San
Diu with p<0.05.
3.4. INTELLECTUAL ABILITY OF PUPILS FROM 11-17 YEARS OLD
3.4.1. Intelligence Quotient (IQ)
3.4.1.1. IQ
IQ of pupils in three ethnic groups Kinh, Muong and San Diu
increases from the age of 11 to 17. IQ of male pupils in three ethnic groups
Kinh, Muong and San Diu increases gradually from age 11, which are 95.23,
91.91 and 90.00 points to 108.69, 104.76 and 103.62 points, respectively,
when they are 17 years old. There are average increases of 2.24, 2.08 and

2.27 points/year. These indicators of female pupils of Kinh, Muong and San
Diu ethnic groups are 95.38, 92.53 and 91.27 at the age of 11 and at the age
of 17 years old, are 107.83, 103.19 and 102.29 points. There are increases of
2.08, 1.78 and 1.84 points per year on the average. In terms of gender, IQ of
male and female pupils are not different. IQ of Kinh pupils is higher than
those of Muong and San Diu pupils with p<0.05.

15
Table 3.23. IQ index of pupils by age, ethnics and gender

Ethnic
group

Age
IQ index (point)

21
- XX


p(1-2)
Male (1)
Female(2)
n
X
± SD
Increase
n
X
± SD

Increase
Kinh



11
120
95.23  14.94
-
121
95.38  14.94
-
-0.15
>0.05
12
120
97.19  14.14
1.96
121
98.09  14.94
2.71
-0.90
>0.05
13
121
100.31  15.01
3.12
120
101.06  14.32
2.97

-0.75
>0.05
14
122
102.41  14.99
2.10
120
102.92  16.25
1.86
-0.51
>0.05
15
121
104.85  15.01
2.44
119
104.34  14.87
1.42
0.51
>0.05
16
117
106.79  15.94
1.94
120
105.80  15.11
1.46
0.99
>0.05
17

118
108.69  15.06
1.90
120
107.83  14.94
2.03
0.86
>0.05
Average
102.18

15.89
2.24

102.19

16.54
2.08
-0.01
>0.05
Muong

11
84
91.91  14.91
-
81
92.53  14.87
-
-0.62

>0.05
12
83
93.87  15.09
1.96
84
94.78  15.00
2.25
-0.91
>0.05
13
82
95.16  15.00
1.29
86
95.67  14.87
0.89
-0.51
>0.05
14
84
97.97  15.09
2.81
84
98.17  14.88
2.50
-0.20
>0.05
15
81

101.11  14.82
3.14
85
100.45  14.82
2.28
0.66
>0.05
16
83
102.28  14.91
1.17
86
101.30  15.13
0.85
0.98
>0.05
17
85
104.76  15.09
2.48
83
103.19  14.88
1.89
1.57
>0.05
Average
98.17

15.57
2.14

98.04

15.64
1.78
0.13
>0.05
San Diu

11
60
90.00  14.88
-
61
91.27  14.91
-
-1.27
>0.05
12
62
92.02  15.13
2.02
58
92.38  14.91
1.11
-0.36
>0.05
13
59
94.83  14.88

2.81
60
95.41  15.00
3.03
-0.58
>0.05
14
61
97.43  15.13
2.60
57
97.80  14.91
2.39
-0.37
>0.05
15
62
100.26  15.13
2.83
60
100.06  14.94
2.26
0.20
>0.05
16
60
102.01  15.26
1.75
59
101.85  15.09

1.79
0.16
>0.05
17
60
103.62  15.12
1.61
61
102.29  14.94
0.44
1.33
>0.05
Average
97.16

15.45
2.27

97.44

15.68
1.84
-0.28
>0.05
3.4.1.2. Distributing pupils by intellectual levels
The distributing of pupils regarding intellectual levels in all three ethnic
groups Kinh, Muong and San Diu is a standard distribution and no pupils are
unintelligent. There is no difference in intellectual capacity by gender.
Percentage of pupils who have high intelligence level increases by age.
Especially, there is no high school pupil with level VI intelligence. Meanwhile,

the proportion of pupils with low IQ index decreases by age. Particularly, the
percentage of pupils who have average intelligence does not change. Kinh
pupils have higher intellectual capacity than that of Muong and San Diu pupils.
3.4.2. Short-term memory
3.4.2.1. Visual short-term memory
From the research results, level of visual memory of Kinh, Muong and
San Diu’s pupils gradually increases from 11 to 17 years old. Visual memory
growth is not uniform and the fastest increase period is from 11 to 13 years old.

16
3.4.2.2. Auditory short-term memory
From the research results (Table 3.26), level of auditory memory of
Kinh, Muong and San Diu’s pupils gradually increases from 11 to 17 years old.
Auditory memory growth is not uniform and the fastest increase at 11 to 13 years
old. The level of auditory memory of Kinh, Muong and San Diu male pupils
gradually increases from 4.17 to 4.43 points at 11 years old and from 6.18 to 6.78
points at 17 years old, an increase of 0.34-0.39 point/year on average. The level
of auditory memory of Kinh, Muong and San Diu female pupils increases from
4.09-4.25 points at the age of 11 to 6.16 - 6.58 points at the age of 17, increased
0.34 to 0.39 point/year on the average.
Short-term memory of Kinh pupils is better than those of Muong and
San Diu pupils. Visual memory is better than auditory memory of all three
ethnic groups Kinh, Muong and San Diu pupils with p<0.05.
3.4.3. Concentration
From results in Table 3.27, the concentration Kinh, Muong and San Diu
pupils increases from 11 to 17 years old with unsteady growth. There is no
difference in concentration between male and female pupils. Concentration of
Kinh pupils is higher than that of Muong and San Diu pupils with p<0.05.
3.5. RELATIONSHIP AMONG BIOLOGICAL INDEX OF PUPILS
3.5.1. The relationship between physical and functional indicators

The growth rate of weight, height and brust size of Kinh, Muong and San
Diu pupils are unbalanced. At the early stage, height increases faster than weight,
weight increases faster than height and brust at the next stage. This fact leads to
an increase in the pignet index of pupils at early stages and a decrease at later
stages in all three ethnic groups Kinh, Muong and San Diu.
In the studied indicators, VC, FVC, FEV1, systolic blood pressure and
diastolic blood pressure indicators increase by age, some other indicators,
such as breathing frequency and heart rate, decrease by age for pupils in all
three ethnic groups. VC, FVC and FEV1 coefficient increases greater than
arterial pressure. Thus, in the course of child development, the development
of the organs and organ systems are uneven in both structure and function.
The increasing time of VC, FVC, arterial blood pressure coindences with
the increasing time of height of pupils.
Results in Table 3.28 show that studied respiratory parameters
increase with height and age. For Kinh group, H coefficient is the highest,
followed by Muong group and the lowest one is that of San Diu group.
Correlating coefficies of the VC, FVC and FEV1 range from 0.874 to 0.985

17
indicating that the parameters are closely related to age and height, the
regression fomula: VC = aH + bA + c.
Table 3.28. Recurrent equation of lung function parameters of pupils
Ethnic
groups
Data
Units
Male
Female

Kinh
Recurrent equation
r
Recurrent equation
r
VC
liter
1.325H + 0.209A – 2.070
0.923
1.444H + 0.188A- 2.158
0.914
FVC
liter
1.125H + 0.221A – 2.048
0.930
1.470H + 0.190A- 2.343
0.915
FEV1
liter
1.106H + 0.194A – 1.991
0.945
1.063H + 0.169A- 1.759
0.911
FEV1/VC
%
0.615A + 75.521
0.148
0.41A + 79.719
0.159
FEV1/FVC

%
0.2A + 84.923
0.347
-0.238A + 92.955
0.309


Muong
VC
liter
0.778H + 0.2A - 1.893
0.943
1.058H + 0.214A- 1.979
0.874
FVC
liter
0.824H + 0.243A – 2.006
0.941
0.946H + 0.214A- 1.950
0.874
FEV1
liter
0.722H + 0.226A – 1.937
0.943
0.564H + 0.215A- 1.701
0.905
FEV1/VC
%
-0.4295A + 72.047
0.212

0.266A + 80.017
0.161
FEV1/FVC
%
-4.5325A + 75.949
0.213
-0.268A + 91.511
0.259


San Diu
VC
liter
0.917H + 0.238A – 2.079
0.912
0.891H + 0.223A- 2.041
0.923
FVC
liter
0.887H + 0.24A - 2.175
0.910
0.958H + 0.222A- 2.238
0.921
FEV1
liter
1.164H + 0.202A – 2.287
0.907
0.893H + 0.198A- 2.035
0.914
FEV1/VC

%
0.429A + 80.625
0.172
0.410A + 79.719
0.159
FEV1/FVC
%
0.02A + 90.018
0.208
-0.238A + 92.955
0.109
3.5.2. Relationship between IQ and short-term memory
The relationship between IQ and short-term memory of pupils in all three
ethnic groups is a positive linear relationship with r ranges from 0.602 to 0.815
and the regression fomula Y1 = a1IQ + b1 với a1>0.
3.5.3. Relationship between IQ index and concentration
Relationship between IQ and concentration of pupils in all three ethnic
groups is a positive linear relationship with r ranges from 0.682 to 0.785 and
the regression fomula Y2 = a2IQ + b2 với a2>0.
3.5.4. Relationship between IQ index and Sersor-motor reflection
Relationship between IQ index and visual - motor reflection and auditory -
motor reflection of pupils of pupils in all three ethnic groups is a negative linear
relationships with r ranges from -0.832 to -0.903, respectively.
CHAPTER 4. DISCUSSION
4.3. PUBERTY OF PUPILS
Changes in morphology, function closely associate to puberty period
of pupils. From the study, it can bee seen that puberty period of female
pupils in Phu Tho and Vinh Phuc provinces ranges from 12 years and 10
months to 13 years and 4 months. Age of first menstruation of Kinh pupils
is earlier than those of Muong and San Diu pupils. In our opinion, in

18
addition to genetic factors and gender, it is also because of diets of Kinh
people are better together with access to mass media such as books,
newspapers, TV, internet, community activities.
Puberty period of male pupils ranges from 14 years 2 months to 14
years 7 months. Signs of puberty of Muong pupils officially appear earlier
than those of Kinh and San Diu pupils. Signs of puberty of Kinh pupils
officially appear earlier than that of San Diu pupils. The explaination is
similar to the explaination of female pupils in the study.
The official puberty period of Kinh, Muong and San Diu pupils is earlier
than that of pupils in "Biological constant of Vietnamese people” in 1975 and
also earlier than those of pupils in Hanoi, Thai Binh, Ha Tay provinces in some
studies in the period of 1978-1990 and that of pupils in Hoa Binh province.
4.2. MORPHOLIGICAL - PHYSICAL STRENGTH INDICATORS
4.2.1. Standing height, weight and BMI
The research results show that the height of Kinh, Muong and San Diu’s
pupils is increasing by age with a significant speed. The average annual
increases for males are 4.93 cm, 4.78cm and 4.23cm, respectively, while thoes
for female are 3.26cm, 3.42cm, 3.24cm, respectively. In the period from 11 to
14 years old, height of female increases faster than male’s one. However, in the
period from 15 to 17 years old, height growth of male is faster than that of
female pupils. The fastest growth period of male’s height is from 13 to 15 years
old and that of female pupils is from 12 to 14 years old and it happens in
puberty period. Height of Kinh pupils higher than those of Muong and San Diu
pupils. This difference is probably influenced by different genetic factors and
living conditions of ethnic groups’ pupils.
Along with height, weight is also considered as a basic index to assess
physical strength of children. The research results showed that the weight of Kinh,
Muong and San Diu pupils gradually increases from the age 11 to 17. There is an

average annual increase of 2.89 to 3.12 kg for male and 2.58 to 2.67 kg for female.
Weight of pupils increases unevenly, rising fastest in puberty, from 14 to 16 years
old for male and from 13 to 15 years old for female. In general, weight of male
increases fasster than that of female. However, in the period from 11 to 14 years old,
the growth rate of this index of femal is faster than that of male and in the period from
14 to 17 years of age, weight of male increases faster and reaches higher values
compared with female’s. Weight of Kinh pupils is higher than those of Muong and
San Diu pupils. This happens because of economic conditions of Kinh ethnic group
is better than those of Muong and San Diu Ethnic groups.

19
Weight of the pupils in the study is higher than that of pupils in the studies
of “Biological constant of Vietnamese people”, by Tran Van Dan and coworkers,
Tran Dinh Long and his coworkers and Dao Huy Khue and equivalent to that in
studies of Tran Thi Loan and Do Hong Cuong. In our opinion, this is partly due to
genetic factors and partly because ethnic pupils are living and studying at Ethnic
boarding schools.
Weight and height changes leading to changes in BMI. BMI of Kinh, Muong
and San Diu pupils gradually increases from 11 to 17 years old. This result is
consistent with the results in the “Biological value of ordinary Vietnamese in the
90s - the twentieth century” and in studies of Tran Dinh Long, Tran Thi Loan, Do
Hong Cuong. Based on Classification standard, BMI of children from 2 to 20 years
old by WHO in 2006, the majority of pupils have nomal physical strength (84.55%
for male and 84.85% for female), followed by pupils who are malnourished
(14.80% for male and 14.94% for female). Pupils at risk of obesity account for a
very low rate and there is no puffy pupils. This shows that nutrition level of Kinh,
Muong and San Diu pupils is still low and the diet does not ensure balanced
development for the body. However, compared to pupils about two decades ago,
physical strength of pupils in our study is better.
4.2.2. Average bust size and Pignet index

From results of this study, it can be seen that pupils’ average bust size of
Kinh, Muong and San Diu pupils gradually increases at from 11 to 17 years
old with an uneven growth rate. The average annual increase is from 2.23-
2.43cm for male pupils and from 1.97-2.43 cm for female pupils. In general,
growth rate of male pupils’ bust size is faster than that of female pupils.
Growth rates of male and fermale pupils’ bust size are not similar. The
increasing time for bust size of pupils is from 14-16 years old for male and
from 13 -15 years old for female.
Their pignet index gradually increases from 11-13 years old and decreases
from 14-17 years old. Pignet index of pupils changes by age due to the uneven
development of height, weight and bust size. Pignet index of pupils of three
ethnic groups from 11 -17 years old ranges from 42.50-33.89 for male and from
46.16-35.13 for female. Thus, physical strength of pupils of three ethnic groups
from 11 -17 years old is at average and weak levels.
Compared to other research data, physical strength index of pupils in our
study is lower than that of Hanoi pupils in Tran Thi Loan’s study and Hoa Binh
pupils in Do Hong Cuong’s study. Thus, in terms of overall development of our
country in recent years, for example the improved socio-economic conditions
especially with investments of the state, pupils learning and living at ethnic

20
boarding schools in Vinh Phuc and Phu Tho have better physical strength than
pupils in 1990s of the twentieth century and earlier.
4.3. CIRCULATORY, RESPIRATORY AND CATOPTRIC
FUNCTIONS OF PUPILS
4.3.1. Circulatory function indexes
From this study, heart rate of Kinh, Muong, San Diu pupils decreases by
age with an average annual reduction rate from 1.32 to 1.43 beats/year for male
and 1.37 to 1.57 beats/year for female. The period in which the heart rate of male
pupils quickly reduce appears later than that of females for about 1-2 years at the

time of puberty. This is probably influenced by changes in sympathetic and
parasympathetic nerve activities during puberty. Heart rate of female pupils is
always higher than that of male pupils at most age groups. This is consistent with
study results by DoanYen, Tran Thi Loan and Do Hong Cuong. There are
differences in heart rate among pupils of different ethnic groups.
The increasing influence of parasympathetic nervous activities on
circulatory system is also reflected by the change of blood pressure with
ages. From the study, it can be seen that arterial pressure increases by
pupil’s age and the certain levels depend on gender. The study results show
that blood pressure depends on the momentum of the heart, vascular
elasticity and activities of organs in the brust size.
4.3.2. Respiratory function indexes
Respiratory frequency gradually decreases by age. We think the change in
respiratory frequency intimately related to changes and regulation of nerves in
puberty period for operations of organs in the body. The phenomenon of
decreasing respiratory frequency by ages may be reported in earlier studies. The
phenomenon of decreased respiratory frequency is closely related to gas
exchange in one breath. The study shows that pupils' vital capacity increases
from 11 to 17 years old. Similar results can be seen in the previous studies. Vital
capacity of male pupils is higher than that of female pupils, Kinh pupils' vital
capacity is higher than those of Muong and San Diu pupils. However, changes in
living conditions lead to physical changes, so vital capacity of the pupils in our
study may slightly differ compared to that in previous studies. When being
compared with recent studies, there is no. We think this difference is because
vital capacity correlates closely and agreeably with height.
The change in FVC is similar to those in VC, FVC of Kinh pupils has
maximum value, followed by those of Muong and San Diu pupils. This
difference is probably infuenced by morphological characteristics and physical
strength of pupils which has a linear relationship with lung function index.

21
Among studied ethnic groups, FEV
1
of Kinh pupils is higher than that of
Muong pupils, FEV
1
of Muong pupils is higher than that of San Diu pupils at
most studied for most studied age groups. Regarding gender, FEV
1
of male is
higher than that of female for most studied age groups. The gender differences
in these parameters are accordant with studies by Do Hong Cuong, Le Nam Tra
and Nguyen Van Tuong. In comparison with other studies, we found that FVC
and FEV
1
of Kinh pupils in this study are equivalent to results by Do Hong
Cuong’s study and “Biological value of ordinary Vietnamese in the 90s - the
twentieth century”, while FEV
1
of Muong and San Diu pupils is lower.
Regarding the correlation between FEV1 and height, we can see that FEV
1

closely correlates to height (coefficient r> 0.8).
Respiratory activity of pupils in the study is also evaluated with a
number of respiratory index (Tiffeneau, Gaensler and Demeny index).
The research results show that Tiffeneau index changes from 80.80 to
88.89% for male and from 80.32 to 88.20% for female. This index of male
is higher than that of female for most age groups. This is consistent with
studies by Nguyen Dinh Huong and Do Hong Cuong. Tiffeneau index has a

positive and untight correlation with age. In comparison with other studies,
it can be seen that Tiffeneau index of pupils in our study is equivalent to the
results of Do Hong Cuong and “Biological value of ordinary Vietnamese in the
90s - the twentieth century”.
Gaensler index of male pupils ranges from 85.57 to 91.46% for male
and from 84.89 to 93.47% for female. Gaensler index of Kinh, Muong and
San Diu changes a little by ethnic groups. Gaensler index has a negative and
untight correlation by age. In comparision with other studies, Gaensler index
of pupils in our study is lower than those in studies of Do Hong Cuong and
“Biological value of ordinary Vietnamese in the 90s - the twentieth century”.
To determine respiratory function in a comprehensive manner, we define
Demeny index (VC/weight). This index ranges from 63.33 to 76.52 for male and
54.74 to 75.09 for female depending on ethnic groups. In general, this index of
male is higher than that of women in most studied age groups. Compared to
other studies, it can be seen that Demeny index of pupils in our study is lower
than that of study of Do Hong Cuong and comparable to study results by Trinh
Binh Dy and his coworkers and Do Dinh Huong.
Compared to other studies, respiratory index of pupils in our study is higher
than the figures in "Biological constant of Vietnamese people”, study results by Doan
Yen and equivalent to study results of Tran Thi Loan, Do Hong Cuong, “Biological
value of ordinary Vietnamese in the 90s - the twentieth century”.

22
Based on respiration index, it can be said that currently, physical
strength of pupils tends to be better than that in two decades ago.
4.3.3. Sensor-motor reflection time
Reflection is the physiological norm allowing to evaluate mobilization of
pupils. The research results show that during the period from 11 to 14 years old,
sersor - motor reflection time of pupils gradually decreases and become more
stable between 14 to 17 years old. This happens since, from 14 to 15 years old,

muscular and nervous systems of children complete in structure and function as
well as the conduction velocity of afferent and efferent nerves. After this time,
enhancing inhibitory influence of the cortex on subcortical structures makes
excitement and inhibition more balanced. This can be seen by study on the
changing EEG images of pupils by age. Sensor - motor reflection speed of Kinh
pupils is faster than those of Muong and San Diu pupils. The reason for this is
because Kinh pupils assess to computers earlier than Muong and San Diu pupils
do. Perhaps, because of this reason, at all studied age groups, sersor - motor
reflection time of male pupils is always shorter than that of female pupils. Visual
reaction time is always shorter than the auditory reaction time - movement. This
happens because structure of visual and auditory analysis organs and the different
transmission speed of light and sound.
4.4. INTELLECTUAL CAPACITY OF PUPILS
Intellectual capability is an integrated activity representing the
complete development of structure and function of the body. Research
results showed that IQ index of Kinh, Muong and San Diu pupils gradually
increases from 11 to 17 years old with irregular growth rate. The fastest
growth of IQ of pupils is from 12 to 15 years old. The results from EEG
studies show that this is the fully developed stage of the nervous system.
Among three ethnic groups, it can be seen that IQ of Kinh pupils is
higher than those of Muong and San Diu pupils. In addition to genetic
factors, the reason for this is because of environmental conditions, such as
nutrition, life habits, economic, cultural and educational conditions.
The research results show that the distribution graph of pupils by
intellectual level is a bell-shaped graph. In which, the number of pupils who
have average or higher intellectual level increases by age, while the
proportion of pupils who have normal or lower intellectual level decreases
by age. There is no stupid level for both genders. The total percentage of
outstanding and excellent male pupils is higher than that of female pupils
among three ethnic groups Kinh, Muong and San Diu. However, the

proportion of male and female pupils who have the same intellectual level is

23
not significantly different. This observation is consistent with the results
from Ngo Cong Hoan, Ta Thuy Lan and Vo Van Toan, Tran Thi Loan. This
proves that intellectual development of pupils depends on ability to
accumulate knowledge and operational methods of brain. Therefore, to
develop intellectual capacity, it is necessary to improve knowledge and
thinking. To implement these processes, we need to develop the ability to
remember. In fact, the ability to remember of pupils increases by age, rising
rapidly in the period from 11 to 14 years old. However, at the age of 15 to 17,
when the nervous system has developed relatively completed, the ability to
memorize trends to be stable. Visual memory of the pupils is always higher
than auditory memnory. This proves that ability to view for memorizing of
pupils is better than ability to hear for memorizing. This is a testament to the
saying "Observations is the best teacher". This is the basis for an innovative
teaching method which is the improvement from imparting knowledge to active
teaching at schools in particular and in education sector in general. The results
of our study also shows that there is no difference regarding memorize ability
between male and female pupils at the age from 11 to 17 in retention. This is
also a basis for the difference in intellectual activity by gender.
To remember well, it is necessary to concentrate. From our study, we
can see that pupils' attention changes by ethnic and age groups. The ability
to concentrate is an important indicator to determine complete development
of the nervous system in different stages of development. Like intellectual
capacity, ability to concentrate depends on living and studying conditions.
Therefore, ability to concentration of pupils in different ethnic groups is
different. Similar results can be seen in the previous studies.
4.5. RELATIONSHIP AMONG BIOLOGICAL INDEX OF PUPILS
4.5.1. The relationship between physical and functional indicators

Growth rate of weight, height and brust size of Kinh, Muong and San Diu
pupils are unbalanced. At the early stage, height increases faster than weight does.
At the next stage, weight increases faster than height and brust size do. This fact
leads to a increase in pignet index of pupils at early stages and a decrease at later
stages in all three ethnic groups Kinh, Muong and San Diu.
In which, VC, FVC and FEV1 coefficient increases greater than
arterial pressure. Thus, in the course of child development, the development
of the organs and organ systems are uneven in both structure and function.
Increasing time of VC, FVC, arterial blood pressure coindences with the
increasing time of height of pupils.

24
The results show that studied respiratory parameters increase with
height and age. There is a collative and tight relationship among indexes of
respiratory function to height and age. Particularly, linear correlation
between height and age and the regression fomula: VC = aH + bA + c. For
Kinh group, H coefficient is the highest, followed by Muong group and the
lowest one is that of San Diu group. Correlating coefficies of the VC, FVC
and FEV1 range from 0.874 to 0.985 indicating that these parameters are
closely related to age and height.
4.5.2. Relationship between IQ and short-term memory
The relationship between IQ and short-term memory of pupils in all three
ethnic groups is a positive linear relationship with r ranges from 0.602 to 0.815. It
means that pupils with high IQ own good memory and vise versa. However, there
remain some exceptions and some pupils with high IQ do not have good memory.
There is a collative and tight relationship among intellectual capability and short-
term memory and the regression fomula Y1 = a1IQ + b1 with a1>0. In which Y1 is
short-term memory of pupils, a1 is the coefficient of IQ and b1 is constant.
4.5.3. Relationship between IQ index and concentration
Relationship between IQ and concentration ability of pupils in all three

ethnic groups is a positive linear relationship with r ranges from 0.682 to 0.785.
There is a collative and tight relationship among intellectual capability and
concentration ability and the regression fomula Y2 = a2IQ + b2 with a2>0. In
which a2 is a ratio of IQ and b2 is a constant. The ratio of IQ in all correlations
are positve and different within ethnic groups.
4.5.4. Relationship between IQ index and Sersor-motor reflection
Relationship between IQ index and visual - motor reflection and auditory -
motor reflection of pupils of pupils in all three ethnic groups is a negative linear
relationships with r ranges from -0.832 to -0.903, respectively. The relationship
between intellectual capability and reaction time of senses - exercise is close and
inversely linear correlation and the regression fomula T = mIQ + n with m<0. In which
T is the reaction time of sensor - motor and m is the coefficient of IQ and n is constant.

CONCLUSION
1. Puberty period and morphological indexes-physical, physiological function
indexes
- Kinh, Muong and San Diu schoolgirls reach puberty time at 13 years
old and 12 months, 13 years old and 2 months and 13 years old and 4 months,

25
respectively. Kinh, Muong and San Diu schoolboys reach puberty time at 14
years old and 5 months, 14 years old and 2 months and 14 years old and 7
months, respectively.
- Schoolboys’ height gradually increases from 133.97 cm at the age of 11 to
164.45 cm at the age of 17. Especially when schoolboys are at the range from 13 to
15 years old, their height increases with the highest speed. Schoolgirls’ height
gradually increases from 135.03 cm at the age of 11 to 156.25 cm at the age of 17.
Especially when schoolgirls are at the age of 12-14, their height increases with the
highest speed. Girls’ height is greater than boys’ height at the age of 11 to 14, but
the height of schoolboys is greater than that of schoolgirls at the age of 15 to 17.

- Schoolboys’ weight increases from 29.63 kg at the age of 11 and
their weight reaches 48.86 kg when they are 17 years old. The weight
increases with the highest speed when they are at the age of 14-16.
Schoolgirls’ weight increases from 28.85 kg at the age of 11 and their
weight reaches 46.17 kg when they are 17 years old. The weight increases
with the highest speed when they are at the age of 13-15. Girls’ weight is
greater than boys’ weight at the age of 14-15, but the weight of schoolboys
is greater than schoolgirls at the age of 16-17. And the weight of both boys
and girls is the same when they are at the age of 11 to 13.
- The average breast size of schoolboys increases from 62.88 cm to 77.63 cm
at the age of 11 and 17, relatively, with the highest speed when they are at the age of
14-16. The average breast size of schoolgirls 60.62 cm and 74.95 cm at the age of
11 and 17, respectively, with the highest speed when they are at the age of 13-15.
- Girls archive the rapid increasing of the three morphological indexes
about one or two year earlier than boys do. Three indexes of height, weight and
bust size of Kinh pupils are greater than those of Muong and San Diu pupils.
- The BMI of pupils increases from the age of 11 to 17. The number of
normal physical pupils accounts for almost 84.55% in case of schoolboys and
84.83% in case of schoolgirls). The number of malnutrition pupils accounts for
a remarkable rate (14.80% in case of schoolboys and 14.95% in case of
schoolgirls). No pupil represents obesity since the rate of potential obesity is
very low (0.65% in the case of schoolboys and 0.22% in the case of schoolgirls).
- The Pignet index of pupil gradually increases from the age of 11 to
14 and gradually decreases at the age of 15 to 17. This index of pupils in
three kinds of ethnic groups is medium.
- The mean heart rate of schoolboys gradually decreases from the age of 11
to 17. It decreases quickly when schoolboys are at the range of 12-14 years old
and at the age of 11-13 for the schoolgirls. The systolic blood pressure and