AMONG 4-20 YEAR-OLD MALE AND FEMALE STUDENTS
By
Hsu, Shuh- YIUIn
The purpo峙。f this study is to investigate the development of vertical jump among male and female students at different ages. To be more specific, the developmental and level-off stagesof vertical performance between 4 to 20 year-old subjects were examined. Four schoollevels of students were used as subjects. All students were selected from each of the following schools in rural area in Taiwan: kindergartens, primary schools, se∞ ndary
schools and junior colleges. The subjects ranged from 4 to 20 years of age. 1481 male students and 1448 female students were divided into 17 subgroups by age. Each subject jumped twice. BeUer trial was considered the subject's score. The resu1ts showed that: (a) male students from 4 to 17 years old improved in vertical jump as they grew older, whereas female students showed improvement from 4 to 15 years of age. Both male and female students' performances started to level off after these years'of age; (b) where the vertical jump performance in boys between age subgroups were compared, eight mean per-formances showed 1 % significant improvement and 3 mean perper-formances showed 5% significant improvement; and (c) in girls, however, 7 mean performances showed 1 % signi-ficant improvement, and 1 mean performance showed 1 % significant improvement as the age subgroups were compared.
Introduct蛤n
Vertical jump was respresentative item of explosive power (l). The best way to test explosive power is to find how much of
c.
G. can be raised in a standing jump. This can bc determined by meansuring the diffcrence between a person'sjumping reach and his standing reach, with his arms fully extend upward. This is sometimes called a Sargent jump. Dualey Sargent (2). one of the poineers of American physical education earlier in this century, found that it was a reliable test of physical ability.The work of Sargent marked the beginning of one 01' the most widely used tests il1
pur-師大學報 第卅一期
poses of: (a) classifying students, (b) predicting
“
athletic ability", (c) measuring physical fitness, and (d) validating new tests and training programs in physical education (3). Despite the wide use of the vertical jump as a testing device, there appears to have relatively little research devoted to the examination of the development of vertical jump performance with respect to àge and sex among the subjects. One such investigation was performed by A.S. Sohi (4), whc;> studied the development of explosive power among 6-14 year~ld boys and girls, and reported that the boys and girls improved in vertical jump as they grew older. During pubescence, the girls started levelling off while boys continued to improve in vertical jump. The boys outperformed girls in all age subgroups except during 6 and 7 years of age.The purpose of this stùdy is to examine the development of vertical jump with respect to age and sex among the subjects. Identification of development and levelling off perfor-mances in the verticaljump were also examined.
Review of Literature
L.W. Sargent (4) studied the cffects of size of dip, height, and weight, and reported that jumping performance was independent of these factors. Henry (5) investigatcd the effects of practice and fatigue on performance in the vertical jump. He reported that both variables influenced reliability and that practice influenced validity. Pacheco (6) studied the effectiveness of warm up exercises on subsequent performance and reported highlys屯nifi﹒ 臼nteffects.
Cratty (7) after having reviewed critically various studies observed that there was invariably a regular improvement in performances on various motor tasks during 6一 12
years old. Harre (8) has summarized performances of different age groups including fater childhood, adolescence and later adolescence by presenting the same in the form of growth curves. The common findings stressed the fact that there was a linear relationship between age and motor development. On the other hand, the periods of pubes臼nce and adolesce, which are maturing periods, may cause some setbackin performances in some motor tasks for boys and in others for girls. In fact, girls.suffer such a setback to a greater extent on account of biologica1 and attitudinal' changes during this period.
According to Keogh (9), girls reached levelling~f in the performances during their early pubescence period, aged 11-14, whereas ooys kept gaining in performance until 17 -18 years old.
恥的e曲時
Subjects. Four school levels of students were used as subjects. All students were selected from each of the following schools in rural areas in Taiwan: k.indergartens, prilnary schools, secondary schools and junior colleges. The subjects ranged in age from 4 to 20 years oId. 1481 rnales and 1448 females were divided into 17 subgroups by age.
Methods. Chalk, rulers and board were used, Prior to each testing session the subject faced the board, maintained his heels in contact with the floor, reached with right arm as high as possible, and attempted to mark the board with chalk. To start, the jumper bent his knees, dropped into a crouch, and swang his arms downward so that his hands were approxi-mately behind his things. From this position, he was ready to begin the upward acceleration of his body, pushing down forcefully on the floor, he straightened his body at the knees and hips. The subjects leaped into the air swinging his arm forcefully upward and marked the high point of hisjump with chalk.
Every subject tried twice. Better trial was taken for analysis.
R歸ults
The mean performances with standard deviations in vertical jump of boy and girl comprising different subgroups by age are presented in Table 1, and a graphical presentation appears in Figure 1. Table 1 also indicates the number of subjects in each subgroups.
The mean perfòrmances of boy students (4-17 years old) and girl students (4-15 years old) in vertical jump showed improvement year by year. After the best performance,
the mean performances of boys and girls gradual1y decreased yearly.
The improvements in mean performances over the span of 4一 17 years of age have been 305.6% for boy students, and 171.1 % for girl students over the span of 4-15 years of age. The setback in mean performances after the span of 17 - 20 years of age have becn 5.2% for boys, and 26.8% for girls after the span of 15-20' years of age. The setback in mean performances revealed slowly. The data shows that both male and female students improved in their vertical jump in certain span of ages, but males showed greater improve-ment and less setback as compared to females. Harre (8), Meniel and Schnabel (l0), Kω阱 。)and Sohi (11) have summarized the same results.
師大學報 第卅一期 (year) N.
4
24
5
24
6
109
7
96
8
78
9
84
10
125
11
85
12
98
13
179
14
114
15
120
16
99
17
93
18
105
19
33
20
40
Table 1Mean Performances in Vertical Jump of Male and Female Students by Their Age
Boy students Girl students
Ma (cm) S.D. (cm) N Ma (cm)
12.75
1.64
27
13.17
14.88
3.73
20
13.73
16.52
4.92
74
14.14
20.40
5
.47
78
19.94
22.03
3.89
67
20.97
24.16
3.65
78
23.15
27.40
5.17
100
24
.43
30.12
5.00
105
27.59
33.50
6.08
93
29.98
36.13
7.16
125
32.03
40.55
7.70
210
33.84
48.08
8.19
118
35.70
50.52
8
.42
107
34
.46
5
1.71
8.14
.84
33.91
50.07
6.62
111
3
1.88
49.13
6.64
44
30.27
49.02
5.35
27
26.14
一 336 一 S.D. (cm)2.91
3.52
4.69
4.96
3.98
3.83
5.51
5.16
6.13
6.00
6
.47
5.
-86
6.32
5.83
6.22
7.92
5.38
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師大學報 那卅一期
Discussion
The general trend in vertical jump by age has been indicated earli訂. To test whether there was a year by y組r significant development of the vertical jump among .boy and girl students, t-test for cornparing rnean perforrnances of age subgroups differing by one year has been used both for boy and girl students separately. The values of t-test are shown in Table 2. Under the ∞lurnn of age, the subgroups cornpared pair-wise for both the sexes are indicated. Boys showed a consistent, continuous and sjgnificant irnprovernents in vertical jurnp from 4-16 years of age and show the levelling-off perforrnances frorn 16-20 years of
ag~. T-values at 1 % significant level for the pairs of the subgroups ∞rnpared was observed to be of almost sarne magnitude in cases of rnost cornparable subgroups. The exceptions were 5-6 pair and 15-16 pair, but both of thern reached 5% significant Jevel. As boy students reached 17 years old, their rnean perforrnances in vertical jurnp raìsed to the peak, and started to level off afterwards.
Mean perforrnances in ve口 ical j ump for girl students, aged 4-15 years, were also char-acterized by continuous developrnent but with three exceptions. The three subgroups, 4 and 5 years, 5 and 6 ye缸s and 7 and 8 years did not show sjgnificant differences in the degree of vertical jump. As the girl students reached 15 years old, their rnean performances in vertical jump attained a peak and started to level off afterwards. The girl students showed 5% sjgnificant setback invertical jurnp as indicated by their mean perforrnances during 17 and 18 years old, whereas 1 % significant setback during 19 and 20 years 。腿，
The resuIts revealed that boys kept improving in performance during 4 and ..17 years of age whereas girls started to level off in their perforrnance after 15 years old. The results found in this study are sirni1ar to that found by Sohi (11). Sohì reported that boys and girls
(6一 14years old) irnproved in vertical jurnp as they grew older.
Conclusions
From the study we listed the fol1owing results:
1. Boys, from age 4 to 17, irnproved in vertical jump yearly; as to girls, however the improvement in vertical jurnp was from 4-15 years of age. Boys and girls started levelling off after these years of age.
. 2. The mean perforrnances of age subgroups compared in vertical jump for boys showed
Age subgroups Compared 4, 5 5, 6 6， 7 、 7, 8 8, 9 9,10 10,11 11,12 12,13 13,14 14,15 15,16 16,17 17,18 18,19 19,20 Table 2
T-test Comparisons of Mean Performances of Age Subgroups in Vertical Jump of Male and Female Students
Male stud ents Female students
(“t" values) df (“t" values) 2.561** 47 0.580 1.921* 132 0.428 5.311*.* 204 7.410** 2.292* 173 1.387 3.587** 161 3.346** 5.309** 208 1.825* 3.817** 209 4.234** 4.126** 182 2.947** 8.360** 276 2.452*. 4.922** 292 2.607** 7.249** 233 2.656** 2.161 * 218 1.522 0.996 191 0.624 1.543 197 2.339* 0.687 137 1.209 0.091 72 2.613** .p < 0.05, **p<O.Ol 一 339 一 df 46 93 151 144 144 177 204 197 217 334 327 224 190 194 154 70
師大學報 第卅一期
1 % significant improvement during 4 and 5 years, 6 and 7 y閱rs， 8 and 9 years, 9 and 10 years, 10 and 11 ye訂s， 11 and 12 ye訂s， 12 and 13 years and 14 and 15 years, and 5% significant improvement during 5 and 6 years and 15 and 16 years.
3. The mean performances of age subgroups ∞mpared in vertical jump for girls revealed 1 % significant improvement during 6 and 7 ye缸s，8 and 9 years, 10 and 11 years, 11 and 12 years. 12 and 13 years
,
13 and 14 ye訂sand 14 and 15 years,
and 5% significant level during 9 and 10 years.4. 甘le mean performance of 1 7 -year~ld girls is significantly higher than that of 18-year old girls. (p < 0.05)
5• The mean performance of 19-ye缸。ld girls is significantly higher than that of
20-year~ld girls. (p<O.Ol)
REFERENCE
1. Hsu, Shuh-Yuan. A study of selection in physical capacíty test items. R.O.C. Uníversity Sport Federatω n Presentation on Physical Education Research Finding. July 15-16,
1976. pp. 269-273.
2. Peter J. Brancazio (1984). Spοrt Science: Physical Laws and Optimum Performance.
Simon & Schuster, Inc. p. 261.
3. Sargent, D.A. The physical test of a rnan. American Physical Education Review 26:
188-94, 1921.
4. Sargent, L.W. Some observation on the Sargent test of neuromuscular efficiency.
American Physical Education Review 29: 4-7-56, 1924.
5. Henry, Franklin. The practice and fat.igue effects in the Sargent test. Research Quarter-ly 13: 16-29.1942.
6. Pacheco, Betty A. Improvement in jumpìng perforrnance due to prelirninary exercise.
Research Quarter1y 28: 55-63, 1957.
7. Cratty, 8.J. (1979). Perceptual and motor development in infants and children. New Jersey: Prentice-Hall Inc.
8. Harre, D. (Ed.) (1982). Principle且 ofSports Trainíng. Berlin: Sportsverlag.
9. Keoger, 1. (1973). Development in fundamental motor task in C.B. Corbin,A textbook
。Ifmotor devclopment, pp﹒ 56一、 74. Iowa: Wm C. Brown Publishers.
10. Meniel, K; Schnabel, G. (1976). Bewegungslhre. Berlin: Volkseigener Verlag.
11. So祉， A.S. Developrnent of Explosive Power Among 6-14 Years Boys and Gìrls,
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