Liggaamsamestelling, groeivertraging en fisieke aktiwiteit van swart adolessente in 'n dorpsgemeenskap : PLAY studie
In South Africa a remarkable weight gain is found in black adolescent girls during mid-adolescence, which is not necessarily the case among boys (Kalk, 2001:577) . Anthropometry is one of the most basic methods for determining over-nutrition and malnutrition status. A considerable amount of research is indeed done on obesity, and quite an amount on growth stunting (OS), but few interventions exist for prevention and treatment of OS. The World Health Organization (WHO) has determined that approximately 230 million children world wide are growth stunted (OS) (WHO working group, 1986). Physical activity in children is affected by average or serious malnutrition and influences adolescents' body build and body composition (BC) because they are in a period of development. Hoffman et al. (2006), Mantsena et al. (2005) and Monyeki et al. (2005) have all found that OS children/adolescents are shorter in length and lighter in mass than adolescents that grow normally. But most OS adolescents have shown a higher skin fold-fat percentage as well as a higher body mass index (BMI). Intra-abdominal fat storage is also found in OS adolescents and children, which is a health risk. Cross sectional studies show that physical activity (p A) decrease with up to 50% during adolescence, which influences body composition. Research has indicated that a P A participation peak is reached between aged 13 and 14 years, when boys are more active than girls. What is less clear is how the pattern of adolescent obesity differs in terms of race, gender and age (Popkin & Udry, 1998). Firstly, the aim of this study was to determine what the nature of research is that has been undertaken regarding body composition (BC) of OS and malnourished adolescents in Africa and South America, by means of a literature study. The second aim was to determine which body composition variables best describe changes in BC in adolescents (13-18 years) after participation in a physical activity intervention. Thirdly, the aim was to determine which BC, relations and maturation differences are found between OS and non growth stunted (NOS) adolescents between ages 13 and 18 years. Finally, the aim was to establish whether the physical activity levels and physical activity patterns of adolescents (13 to 18 years) change congruent to age increase. The study was compiled by means of an availability sample by making use of two secondary black schools in Ikageng (Potchefstroom) in the North West Province. The availability sample comprised a control group and an experimental group of black learners each. The study was of a longitudinal study design nature which stretched from March 2004 to September 2006. Adolescents (N=309) in the North West Province (Potchefstroom, South Africa (158 boys, 211 girls) between ages 13 and 18 years were used in this study. All the learners were in grade 8 at the onset of the study 2004. The experimental group participated in a physical activity intervention programme for practically one hour, two days per week after school hours for twenty-three weeks in 2004 and in 2005 they practised three times per week for nineteen weeks (July school holiday excluded). Attendance percentage of the PA programme was noted according to attendance registers with the experimental group split into three categories, namely low (0%-30% attended), average (30%-60%) and high (60% and higher). The control group (N=87) attended no intervention program. BC, middle-to-hip ratio (MHR), body mass index (BMI), percentage body fat (% LV) and skin folds were measured for baseline and again after completion of the intervention programme. Maturation phase was determined by means of two gender specific questionnaires (Tanner Questionnaires). The Previous Physical Activity Recall (PDPAR), compiled by Trost et al. (1999), was used for the study to analyse the PA levels. Statistica (Statsoft Inc 9) and SAS (SAS Institute Inc, edition 8, Cary NC) computer processing packages were used to process the data collected. Descriptive statistics were used to represent BC components and participants. A Repeated measurements co-variance analysis (ANCOVA) (corrected for attendance percentage and gender) variance analysis (ANOVA) over time, with a Bonferroni post hoc analysis to establish how the different variables differ from each other over the various test period in months. The significance of differences found was set on p<0.05. Next the Mann-Whitney U test was applied to calculate the significant differences of certain variables between the GS and non-growth stunted (NGS) adolescents. The Chi-square test was also used to determine the categorical variables, namely differences in the distribution within the five Tanner phases, as well as the differences between the GS and NGS girls and boys separately, with regard to the distribution between the groups with a body fat percentage lower or higher than the median. The technique of multilevel modelling was used for analysing the change in PA data over time. The result gained from the literature clearly indicates that GS generally occurs in adolescents and children in developing countries. It was also found that physical activity is. beneficial to the adolescents in terms of body composition, especially for the boys. According to the body mass index (BM!) values, a small percentage of children are classified as overweight, whilst with methods such as the sum of skin folds calculation of skin fold fat percentage and %BF measured by means of air transfer pletismografie (ADP), a larger percentage of children was classified as "over fat". It has also been found that significant differences occurred between the mass, length, length-for-age-z-score (LOZ) , arm span, middle circumference, hip circumference and lean body mass of the GS (28 girls and 28 boys) and NGS (113 girls and 90 boys) groups. The results also indicated a difference in PA levels of boys in the experimental and control groups after participation in the P A programme. With increase in age and over time there was a decrease in weekend physical activity patterns in both groups (experimental and control) for both genders. The experimental group ended at higher PA level than that of the control group of boys over the 30.75 months period. Opposed to this the girls (152 and 59 subjects respectively) did indeed show significant differences during the week as well as during the weekend with the baseline measurements, whereas the experimental group initially showed higher PA levels. These differences were, however, not more significant during end measurements. Both groups of girls further showed a lower curve of PA than that of the boys. The experimental group of boys and girls, as well as the control groups displayed a decrease in PA over the 30.75 months period. With increase in age and over time, a decrease was observed in PA patterns in both groups for both genders, although the last two measurements showed a slight upward inclination, especially in the experimental group of boys. The results showed a difference in PA patterns in the boys in the experimental and control groups, which can be attributed to the PA intervention. From the literature overview the conclusion can be drawn that African countries and other developing countries, where food scarcity is more common, experience a larger extent of problems with GS. The occurrence of GS in South Africa is average. Hence it can be deduced that growth and development need to be taken into consideration when BC is determined in adolescents. Fat percentage is more sensitive measure of obesity than BMI following participation in a PA intervention programme in town community adolescents. Determining BF percentage by means of skin folds and air replacement pletismografie (ADP) is more accurate than BMI in this specific group of experimental subjects. From this study the conclusion can be drawn that differences occur between GS and NGS adolescents of both genders in certain BC and body proportion components, without a difference in sexual development. With regard to the girls in terms of PA levels, it had another effect as with the boys with the intervention. The experimental group of boys, after 3 years (of which they underwent a PA intervention for 2 years) showed a higher PA level than the control group of boys that did not participate in a PA intervention. From this it can be deduced that this intervention did indeed contribute to differences in PA of boys that participate in physical activity programmes in deprived environments, while strategies different from these will need to be developed for girls from these communities.
- ETD@PUK