Journal of Sport Science, Vol. 4/2013

Published Journal Article - Kolimechkov et al. Sport and Science 2013

Journal of Sport Science

Journal of Sport Science

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National Sports Academy

Ministry of Physical Education and Sport

Bulgarian Union for Physical Education & Sport

Bulgarian Olympic Committee

 

Assessment of the physical development of pre-school and primary school children practising artistic gymnastics

Published Journal Article

Journal of Sport Science
Journal of Sport Science | Sport & Science Magazine

Vol. 4 / 2013, pp. 106-115, ISSN 1310-3393, Bulgaria
Section: Physical Education, page 106-115

ASSESSMENT OF THE PHYSICAL DEVELOPMENT
OF PRE-SCHOOL AND PRIMARY SCHOOL CHILDREN
PRACTISING ARTISTIC GYMNASTICS


Stefan Kolimechkov, Lubomir Petrov, PhD,  Bogdana Ilinova, PhD, Ass. Prof.  Albena Aleksandrova, PhD, Ass. Prof. Luba Andreeva, PhD, Prof. Petar Atanasov, DSc
National Sports Academy “Vassil Levski” - Sofia, Bulgaria

Assessment of the physical development of pre-school and primary school-age children practising artistic gymnastics

 

ABSTRACT

initial school-age children - gymnastics

Background

Artistic gymnastics is one of the few sports that pre-school children can practise. It develops basic physical skills and body symmetry. However, for the achievement of these characteristics, an individual approach to the training process appears to be a crucial factor, especially for children. The adequate assessment of physical development is essential for individualising sports training. Thus, the aim of our study was to assess, using accessible methods, the physical development in pre-school and primary school children practising artistic gymnastics.

skinfold measurement test - children

Methods

The survey included 40 children (22 boys and 18 girls) between the ages of 4 and 12, engaged in gymnastics. Certain anthropometric (height, weight, body mass index (BMI)) and dynamometric (grip strength of the left and right hands) indicators were measured. The age dependent percentile- and Z- scores for each anthropometric indicator were calculated using specialized software of the World Health Organization (WHO).

Results

According to BMI Z-scores, seven of the children, who were included in the study, were assessed as overweight. However, this group included gymnasts, with over two years of experience in sports and a low body fat percentage, who could not be defined as overweight children; greater sports experience led to equalization of grip strength in both hands and an increase in the arm muscle area.

Assessment of BMI Z-scores for children

Conclusion

BMI does not provide an adequate assessment of the weight and physical development in child athletes with greater muscle mass. In these cases, additional indicators (% fat, muscle hypertrophy and dynamometry) for proper assessment of a child’s growth and development for the purpose of training practice should be included.

Keywords:Anthropometry, Artistic gymnastics, Children, Dynamometry, Physical development

 

INTRODUCTION

The data analysis of anthropometric measurements and medical examinations over recent years have shown a positive change in terms of the height of children from 7 to 18 years of age. However, physical fitness decreases because PE and sports in schools does not provide enough of the physical activities which are crucial during the growth and development of young children (Petrova et al., 2009). Therefore, children and adolescents need extra physical activities, where they are engaged in appropriate sports.

Artistic gymnastics is one of the few sports which children from pre-school and primary school can practise. It develops those main qualities which define physical fitness: strength, speed, endurance and flexibility. The floor exercises and the apparatuses provide a huge diversity in terms of movements, which lead to positive outcomes for the pupil’s physical development (Pajek et al., 2010). Many studies highlight the benefits of this sport. Gymnastics classes integrated with physical education courses (independent from growth) promote positive changes in motor performance variables in seven-year–old girls. Precisely, ten weeks (twice-a-week) of gymnastics training improved flexibility, explosive/static strength, muscular endurance, speed and balance parameters in kids (Alpakaya, 2013). It is well-known that the amount, intensity and duration of training do not have the same effect on all of the participants. Therefore, individualisation of the training is needed in order to achieve proper and harmonious development. What is of essential importance regarding individualisation in sports training is the provision of an adequate assessment of the individual’s physical development with the employment of all accessible methods.

In order to track growth and development, as well as to reflect the overall status of children's health, the main criteria which are used are anthropometric data (height, body weight, skinfolds, etc.) (NHNES, 2007). Body mass index (BMI) is used to assess body weight by dividing weight in kilograms (kg) by height in metres (m), and the result is divided by height (m) again (Petrova et al., 2008). The WHO recommends that percentile and Z-scores should be used in order to assess height, weight and BMI results for children (5-18 years of age) (Kuczmarski, 2000). Measurement of skinfolds and body circumferences allows us to determine the percentage of body fat (%BF) (NHNES, 2007). Few equations in the literature are based on only 2 skinfold thicknesses (triceps and subscapular) and these were developed specifically for children and adolescents. One such set of equations, the quadratic equations of Slaughter et al (Boye et al., 2002), is frequently used in the United States and European countries (Slaughter et al., 1988). Another significant indicator is upper arm muscle area, which appears to be a useful index of muscle mass in healthy children. Upper arm circumference and triceps skinfold are needed for its calculation (Boye et al., 2002).

 

Purpose

The aim of this study was to assess, using accessible methods which will enjoy a wide application in practice, the physical development of pre-school and primary school children practising artistic gymnastics.

METHODS

The study included 40 children (22 boys and 18 girls) between the ages of 4 and 12 years, attending gymnastics classes at the ‘Sports Centre Levski’ in the capital of Bulgaria, Sofia. They were divided into two groups: pre-school and primary school. Moreover, another two subgroups were separated depending on the children’s sports experience: 13 boys (7-11 years old), who had less than two years (1-24 months) sports experience and had never taken part in gymnastics competitions, and 6 boys (7-11 years old), competitors with sports experience greater than two years (24-48 months), who had participated in national championships and tournaments.

The standing height of the children was measured to the nearest 0.1 cm with a stadiometer, and their weight using an electronic scale to the nearest 50g.

The body mass index (BMI) was calculated using the standard formula:

BMI (kg/m²) = Weight (kg) / Height (m)²

We used specialised software prepared by the World Health Organisation (WHO) – ‘WHO Anthro’ (for children under six years of age) and ‘WHO Anthro Plus’ (for children over six years of age), to assess height, weight and BMI in children (World Health Organization, 2007). For each variable we calculated the Z-score and percentile score for the relevant age. To distinguish the BMI scores, we used references provided by the WHO for children from 5 to 19 years of age (overweight > +1 SD, obese > +2 SD, underweight < -2 SD, mortality <-3 SD) (World Health Organization, 2007).

Body fat percentage (% fat) was determined by the sum (Sum) of the two skinfolds – triceps and scapula (Slaughter et al., 1988), using the equations of Slaughter, as they have been specifically recommended for male and female adolescents because of their accuracy and simplicity (Boye et al., 2002).

Boys under 10 years of age:
%Fat = 1.21 x Sum – 0.008 x Sum² – 1.7

Boys - 11 to 13 years of age:
%Fat = 1.21 x Sum – 0.008 x Sum² – 3.4

Girls – all ages:
%Fat = 1.33 x Sum – 0.013 x Sum² – 2.5

The upper arm muscle area – (UAMA) was calculated using the formulae (Boye et al., 2002).

UAMA = [(mid-) upper arm circumference - (π x triceps skinfold )]²/4π

Triceps and subscapular skinfolds were measured on the right side of the body to the nearest 1 mm, with a Lange skinfold caliper.

The maximal isometric grip force of both hands was determined by a threefold muscle effort using a dynamometer for children, which is accurate to within 0.5 kg.

All measurements were taken by following standard procedure (NHNES, 2007; Piwoz et al., 1985). In order to analyse the results we used the following methods: Analysis of variance (ANOVA) and Student’s t-test for statistical significance.

 

RESULTS AND DISCUSSION

The anthropometric data of the pre-school and primary school children, who were the subject of our study, are presented in Table 1. The calculated average BMI scores were in accordance with the literature data. In a study concerning elite gymnasts between 7-10 years of age and 11-14 years of age, the range of BMI was between 12.9-20.8 kg/m2 and 14.6-20 kg/m2 for the two groups respectively. The percentage of body fat for the same age groups was 5.1%-16.7% and 6%-15.1% respectively (Benardot et al., 1991).

Table 1. Anthropometric data of the pre-school (3-6 years) and primary school (7-11 years) children, who were the subject of our study (Average ± SD).

 

Males
3-6 years
(n=7)

Females
3-6 years
(n=5)

Males
7-11 years
(n=11)

Females
7-11 years
(n=10)

Age (y)

5.00 ± 0.58

5.6 ± 0.89

7.55 ± 0.52

8.7 ± 2.11

Sports experience (m)

7.4 ± 5.35

24.6 ± 12.28

26.8 ± 15.30

14.8 ± 14.0

Height (cm)

112.2 ± 6.25

116.7 ± 5.91

126.3 ± 3.87

131.8 ± 12.1

Z-score

-0.28 ± 0.65

0.10 ± 0.87

-0.28 ± 0.61

-0.27 ± 1.12

Percentile score

40.2 ± 22.5

50.4 ± 25.9

40.2 ± 21.1

44.6 ± 30.6

Weight (kg)

18.8 ± 2.83

21.6 ± 3.11

25.5 ± 2.79

30.9 ± 10.2

Z-score

-0.39 ± 0.77

0.25 ± 0.66

-0.10 ± 0.80

-0.02 ± 1.09

Percentile score

38.57 ± 22.8

58.6 ± 23.2

47.4 ± 26.9

52.5 ± 29.4

BMI (kg/cm²)

14.9 ± 1.30

15.8 ± 1.06

16.0 ± 1.59

17.3 ± 2.82

Z-score

-0.37± 1.03

0.24 ± 0.67

0.04 ± 1.03

0.30 ± 0.86

Percentile score

39.46 ± 32.2

59.5 ± 23.9

50.86 ± 33.2

58.5 ± 27.1

Body fat (%)

12.1 ± 2.21

14.7 ± 2.74

12.5 ± 2.80

17.4 ± 5.6

The average percentile and Z-scores of height in the children from our study showed slightly lower values. This data is normal for young gymnasts in comparison to other children (Jemni, 2011). All of the other scores from our study were in accordance with the norm. However, the results achieved by some authors point to a lower percentage of body fat and BMI score for children (especially girls) practising gymnastics, in comparison to school children (Jemni, 2011).

BMI Z-scores of the children under study are presented in Figure 1. Obesity (score > 2) or mortality (score < -2) was not registered.

BMI Z-scores for the children under study (gymnastics)

Figure 1. BMI Z-scores for the children under study.

The BMI Z-scores of 7 children were in the range of 1 to 2, which defines them as overweight. The anthropometric data of these children is presented in Table 2 according to their body fat percentage.

The data of the first two (N1 and N16) and the last two (N30 and N19) children stood out. The last two have little sport experience (5 months) and greater percentage of body fat (22.3% and 30.4%), which identifies them as overweight. Adjustments for these kids should be made in two directions. Firstly, the volume of the aerobic exercise in the preparatory part of the gymnastics session should be increased. Secondly, foods with high energy content (bakery products, chocolate, candy, etc.) should be minimized, and those of fruits and vegetables maximized. This change in diet can be achieved through conversation with the children’s parents, emphasizing the fact that normal weight helps to maintain good health and reduce the risk of many chronic diseases. Coaches and teachers can use their authority to encourage children to adopt a healthier diet.

Table 2. Anthropometric data of the overweight children (BMI Z-score between 1 and 2).

Age
(years)

Sex

Sports experience
(months)

Weight (kg)

BMI
(kg/cm²)

BMI
Z-score

Fat (%)

1

7

M

29

26.9

17.5

1.12

11.7

16

8

M

24

27.9

17.9

1.15

13.7

27

5

M

6

20.0

16.7

1.02

14.7

13

8

M

8

24.0

18.5

1.51

17.5

40

8

F

2

35.3

18.5

1.11

18.9

30

11

F

5

44.6

21.2

1.11

22.3

19

11

F

5

50.5

23.2

1.84

30.4

The first two children have great sports experience (about 2 years). Although their BMI Z-score exceeds 1, these children have a low % body fat (11.7% and 13.7%), which does not identify them as overweight. This example shows that BMI is not always a suitable indicator for assessing weight. Moreover, other authors express the same view in their studies concerning athletes with great sports experience in sports which require physical strength (Zaikova et al., 2011). Therefore, more anthropometric data (% fat, skinfolds) should be taken, as well as strength indicators (data for muscle hypertrophy and dynamometers) in order to accurately assess the weight of young athletes.

Anthropometric as well as dynamometric data (grip force) is presented in Table 3 according to age groups.

Table 3. Anthropometric and dynamometric data of the children under study (Average ± SD).

 

Males
3-6 years
(n=7)

Females
3-6 years
(n=5)

Males
7-11 years
(n=11)

Females
7-11 years
(n=10)

Upper arm circumference (сm)

16.80 ± 1.25

18.86 ± 1.61

18.96 ± 1.39

21.31 ± 3.44

Subscapular
skinfold (mm)

4.50 ± 0.58

5.72 ± 0.93

5.14 ± 0.81

7.99 ± 4.88

Triceps
skinfold (mm)

7.93 ± 1.67

9.52 ± 2.29

7.77 ± 2.16

11.25 ± 4.19

Upper arm muscle area UAMA (сm²)

16.35 ± 2.11

20.19 ± 3.84

21.80 ± 2.75

25.57 ± 7.23

Grip force
Left hand (N)

69.37 ± 12.48

79.26 ± 18.27

103.36 ± 28.46

93.29 ± 16.50

Grip force
Right hand (N)

83.39 ± 39.65

84.37 ± 17.48

111.92 ± 28.33

100.45 ± 26.22

The results showed no statistically significant differences in the values of grip strength indicators between the right and left hands. All respondents were right-hand dominant, but there was no more than a 10 N difference in the strength of their hands. We could not find data in the literature for pre-school children to compare their strength indicators. However, the results of primary school children (7-11 years old) were compared to the Dortmund Nutritional and Anthropometric Longitudinally Designed study, ‘DONALD’, concerning children between the ages of 6 to 18, in Germany (Boye et al., 2002). Their anthropometric data is measured on the right side of the body, as it is in our own study.

Grip force and upper arm muscle area show higher average values in the German group (boys with an average age of 8.7 years, n = 59) in comparison to boys from our study (131.4 N against 111.9 N and 22.6 cm² against 21.8 cm², respectively). However, there is no statistical significance which can be placed upon these results. Average values of skinfold triceps and subscapular are 10 mm and 6.3 mm in German and 7.7 mm and 5.1 mm in Bulgarian boys. It should be observed, however, that the boys from Dortmund have a higher average age (by 1.2 years).

Age as well as skinfold thickness have approximately the same average values in German (n=50) and Bulgarian primary school girls (8.7 years against 8.4 years). However, the value of skinfold triceps is slightly higher in the German group (11.9 mm), in comparison to the Bulgarian girls (11.2 mm), and there is not enough data to check the statistical significance of the difference. The primary school girls from our study have a higher average value of their upper arm muscle area (25.5 сm² against 20.7 сm², p < 0.01). Probably, this difference is due to the fact that the Bulgarian girls practise gymnastics. The girls from Dortmund show a slightly higher average value of right hand grip force in comparison to our group (108 N against 100 N), but once again there is no statistical significance in these figures.

Figure 2 presents a comparison of the anthropometric and dynamometric data in primary school boys with less than two years’ sports experience in gymnastics (7.3 months average), and boys with sports experience greater than two years in gymnastics (36.8 months average), and who participate in national competitions.

Anthropometric and dynamometric data of primary school boys who practise artistic gymnastics

Figure 2. Anthropometric and dynamometric data of primary school boys with less than 2 years sports experience in gymnastics (n=13), and boys who are competitors with sports experience greater than 2 years (n=6). (* p < 0.05)

Although the competitors have a lower average age, the upper arm muscle area (UAMA) shows, statistically speaking, significantly (p < 0.05) higher values in those children with sports experience in comparison to those with less sports experience - 23.7 cm² against 20.5 cm² respectively. We have also noticed slightly higher values of grip force in both hands, weight and BMI in favour of the group of competitors. We assume that this is because of the greater muscle mass which is accumulated by the boys with greater sports experience, as a result of the gymnastics process. The equalization of their force grip in both hands is also well illustrated. That is once again a direct result of practising gymnastics, a sport which develops the body symmetrically.

 

CONCLUSIONS AND RECOMMENDATIONS

After assessing the physical development of the children of pre-school and primary school age under study, who practise artistic gymnastics, we can state the following conclusions and recommendations:

  1. BMI is not an adequate indicator of weight and physical composition for child athletes with greater muscle mass. In these cases, more anthropometric data (% fat, skinfolds) should be taken, as well as strength indicators (data for muscle hypertrophy and dynamometers);
  2. The proper assessment of physical development of children practising gymnastics is one of the factors for individualising and improving their training process;
  3. The amount of aerobic exercise in training sessions should be increased for overweight children, and adjustments in their diet should be made.

 

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Boye, K. at al. Anthropometric assessment of muscularity during growth: estimating fat-free mass with 2 skinfold-thickness measurements is superior to measuring midupper arm muscle area in healthy prepubertal children, Am J Clin Nutr, 2002, 76(3), 628-632

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Pajek, M.B., Cuk, I., Kovac, M., Jakse, B. Implementation of the gymnastics curriculum in the third cycle of basic school in Slovenia, Sci. Gym. J., 2010, 2(3), 15-27

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Zaikova, D., Zaekov, N., Petrov, L., Ilinova, B., Groshev, О., Jordanov, P., Atanasov, P. Control of nutrition and evaluation of the effect of dietary supplements for non-professional bodybuilders., Journal of Sport Science, 2011, 1, 122-133 (in Bulg.)

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Author details

Stefan Kolimechkov – NSA Sofia;
*Lubomir Petrov, PhD - Physiology and Biochemistry Department at the NSA;
Bogdana Ilinova, PhD - Sports Medicine Department at the NSA;
Assoc. Prof. Albena Alexandrova, PhD - Bulgarian Academy of Sciences;
Assoc. Prof. Luba Andreeva, PhD - NSA;
Full Prof. Petar Atanasov, D.Sc. - Physiology and Biochemistry Department, NSA

National Sports Academy (NSA) ‘Vassil Levski’ – Sofia, Bulgaria
* Correspondence: dr.lubomir.petov@gmail.com

Reviewer: Prof. Maria Toteva, D.Sc.

 

ISSN 1310-3393

Cite this article as:
Kolimechkov S., L. Petrov, B. Ilinova, A. Alexandrova, L. Andreeva, P. Atanasov (2013). Assessment of the physical development of pre-school and primary school children practising artistic gymnastics. Journal of Sport Science 2013, 4, 106-115