1,721,000 research outputs found
Health-related physical fitness, physical activity and body composition status of adolescent learners residing within the Tlokwe Municipality : PAHL study
Full text linkPhD (Human Movement Science), North-West University, Potchefstroom Campus, 2014Obesity and physical inactivity (PI) are major health problems world-wide, and leading contributors to the high incidence of overweight, cardiovascular and metabolic diseases in children both globally and in South Africa in particular. Despite the importance of physical activity (PA), health-related physical fitness (HRPF) and body composition to health, very few studies have investigated the longitudinal relationship between these variables in children. Three articles based on this research were written in which a total of 283 adolescent learners (111 boys and 172 girls) with a mean age of 14.90±0.72 years from the Physical Activity and Health Longitudinal Study (PAHLS) participated. The students’ physical characteristics were measured using the protocol of the International Society for the Advancement of Kinanthropometry (ISAK); the EUROFIT test protocol and International Physical Activity Questionnaire (IPAQ) were used to assess the children’s HRPF and PA levels, respectively. In the first article, the results showed that girls had a slightly higher significant BMI (21.43±4.37 kg/m²) than the boys (20.01±3.71kg/m²) (p=0.002), and were substantially more overweight (32.4%) and fatter (%body fat=26.01±8.51) than the boys (17.1%)). A total of 85 (30%), 78 (27.5%) and 88 (31.1%) of the students had low, moderate and high PA involvement. It was concluded that girls were more overweight and less active than boys. The second article examined the relationships between body composition, health-related fitness and PA. Inverse relationships were found between BMI and the health-related fitness items of SBJ and BAH. Furthermore, BMI negatively associated with SAR and endurance performance, especially in girls. Percentage body fat was negatively related to SBJ, BAH, SAR and endurance performance. The aim of the third article was to evaluate the longitudinal development of HRPF, anthropometry and body composition status among the children. Regression coefficients showed that changes in BMI were inversely associated with those in health-related physical fitness. The changes in %BF were negatively associated with SBJ, BAH and aerobic capacity (VO2max) in the boys and girls. The results also yielded a low significantly positive association between changes in WHtR and SBJ in both genders, while low inverse associations were found between WHtR and BAH in girls, and VO2max in both genders. It is concluded that the incidence of overweight and PI was especially high in girls and excessive fatness negatively affected the girls’ fitness performances. Changes in BMI, % body fat and WHtR were negatively related with the children’s strength and running performances, especially among the girls in which the relative increase in overweight negatively affected their endurance running and static strength performances. In view of the health implications of the findings, it is necessary to create an enabling environment and opportunities to promote physically active lifestyles and develop life-long positive attitudes towards PA among students. Community-based strategies targeted at facilitating sustainable PA intervention programmes in schools are recommended.Doctora
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Health-related physical fitness and risk factors associated with obesity among primary school children in the Limpopo and Mpumalanga provinces of South Africa
Full text linkPhD (Human Movement Science), North-West University, Potchefstroom Campus, 2015It is well documented that behavioural and biological risk factors for Chronic Diseases of Lifestyle (CDL) such as overweight and high blood pressure persist from childhood into adulthood. CDL is considered to be a group of diseases that shares similar risk factors as a result of exposure over many decades to physical inactivity, unhealthy diets, smoking, lack of regular exercise, and possibly stress. This study assessed health-related physical fitness and risk factors associated with obesity among 1361 (boys: n=678; girls: n=683) primary school children aged 9-12 years in the Limpopo (LP) and Mpumalanga (MP) Provinces, South Africa. Anthropometric and physical fitness measurements were taken using the protocol of the International Society for the Advancement of Kinanthropometry (ISAK) (Marfell-Jones, et al., 2006) and EUROFIT (1988) test batteries. Body composition measures included body mass index (BMI) (weight/height2), percentage body fat (%BF) and waist-to-hip ratio, respectively. BMI for age and gender was used to classify the children as underweight, overweight or obese (Cole et al., 2007), whilst %BF calculated from the sum of two skinfolds (triceps and subscapular) using the equation of Slaughter et al. (1988) indicated adiposity. The International Physical Activity Questionnaire (IPAQ) was used to categorise the children’s physical activity (PA) level as follows: Low (METs scores of less than 500); Moderate (METs scores from 500 to 1499) or High (METs >1500). In general, 75% of the children were underweight/stunted and 1.6% overweight. Frequencies of underweight, normal weight and overweight were 77%, 22.4% and 0.2% in MP and 72%, 24% and 3% in LP province. Boys were generally taller and heavier than girls. At age 10 the MP boys performed significantly (p=0.05) better in sit-ups (SUP: 20.5 ±5.4) than the LP boys (18.6±6.56). However, the LP boys performed significantly better than the MP boys in sit-and-reach (SAR) at ages 10 and 11. The MP boys performed significantly (p=0.00) better in SBJ (121.6±9.1cm) compared to the Limpopo (118.4±11.00cm) boys at age 9. Generally, LP boys were significantly (p=0.00) better than the MP boys across all ages. The PA results showed that 27.7% (377), 58.5% (796) and 13.8% (188) of the children participate in low, moderate and high PA, respectively. Children in the MP province had higher PA (28.6%) in comparison to the low PA participation in LP children (26.7%). Furthermore, 59.7% of MP children compared to the LP children (57.3%) participate in moderate PA. A higher PA participation rate (15.8%) was found among the LP than MP children (11.6%). The girls had non-significantly higher BP values (systolic: 112.94±11.28mmHg; diastolic:
(79.40±12.80mmHg) than boys (systolic: 110.71±14.95mmHg; diastolic: (75.53±12.53mmHg) who had higher PA levels (METs =1286.72±317.47) than girls (METs =397.28±30.14) (p<0.01). A total of 81% (n=1089) and 19% (n=253) of the combined samples had normal BP and
prehypertension, respectively. When controlled for provinces, gender and age, results indicated that BMI was negatively associated with systolic BP (SBP) (-0.54) (p<0.01), but positively correlated with %BF (0.133) (p<0.01), whilst SBP related positively with %BF (0.125) (p<0.01). The children’s PA level correlated positively with BMI (0.86) (p<0.01) but negatively with %BF (-0.67); weight circumference (WC) (-0.41); SUP (sit-up) (-0.22); and predicted 2max •VO (-0.17) (p<0.05). The high percentage of underweight and pre-hypertensive children in the study warrants an urgent need to periodically evaluate PA levels among South African children and design appropriate intervention programmes to alleviate concerns over body weight disorders and
low PA levels in children, thus optimising health outcomes.Doctora
Exposure to, perceptions and levels of mental skills among tertiary institution field hockey players
No full textThesis (M.Sc. (Sport Science))--North-West University, Potchefstroom Campus, 2011.The importance of mental skills training (MST) is emphasized by previous/available research findings which show that by combining MST with physical training it enhances players’ ability to cope with the demands of the sport and subsequently results in better sport performance. The
main aims of the present study (presented in two articles which can be read independently) were twofold. The first was to determine field hockey players’ perceived need for MST, and their perception regarding their ability to prepare psychologically for matches, as well as compile a general profile of their psychological skill for the total group and by gender. The second aim of the study was to determine the possible positional differences in mental skill levels among 91
South African tertiary institutions’ male field hockey. A total of one hundred and ninety seven (91 males and 106 females) South African field hockey players who competed in the 2008 University Sport of South Africa tournament participated in the study. The participants completed the Psychological Skills Inventory (PSI) and the Ottawa Mental Skills Assessment Tool–3 (OMSAT–3) questionnaires. The results from Article 1 showed significant gender differences from the Psychological Skills Inventory (PSI) according to which the males outperformed the females in the skills of concentration, activation and activation control. In addition, significant gender differences were observed for mental skills training (MST) measures
for goal–setting and commitment in which the females outperformed the males, whilst the males fared better than the females in stress reaction. The hockey players perceived MST as important to enhance performance in field hockey. The players furthermore perceived their ability to
prepare psychologically for matches as good, which contradicts the results from the
questionnaires as the players showed poor mean scores for five of the six sub-scales of the PSI questionnaire. The results from article 2 showed that the goalkeepers had the lowest scores for seven of the 12 tested skills, whereas midfielders outperformed the other positions in six of the 12 sub-scales. It is clear from these results that MST is important for field hockey and therefore
warrants the attention of all role players in field hockey.Master
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Physical activity, health-related fitness and social correlates among adolescents : the PAHL study
No full textPhD (Human Movement Science), North-West University, Potchefstroom Campus, 2015Research has shown that social correlates of physical activity play an important role in individual participation in physical activity or sport, hence their link with associated health benefits. However, in spite of the health benefits associated with physical activity, many children do not meet the daily guidelines of being active for at least 30 minutes a day. This study investigated
physical activity, health-related fitness and social correlates among 284 adolescents (111 boys and 173 girls) who are part of the on-going Physical Activity and Health Longitudinal Study (PAHLS). Height, weight, skinfold thickness (triceps, subscapular and calf skinfolds), waist and hip circumferences were measured through the standard procedures described by the International Standards of Advancement of Kinanthropometry (ISAK). Body mass index (BMI), waist-to-hip ratio (WHR) and percentage body fat (%BF) were used as measures of body composition. Health-related physical fitness (HRPF) was determined by measuring cardiorespiratory
endurance, muscle strength and endurance, and flexibility using standardised tests
according to the EUROFIT (1988) test protocol. The standardised International Physical Activity Questionnaire (IPAQ-Short form) and Social Support for Physical Activity
questionnaire were used to gather information on participation in physical activity and social correlates for physical activity respectively. The results show that 29.6% of the adolescents were underweight and 26.4% overweight. Girls were significantly (p<0.05) fatter (%BF and BMI) and shorter than the boys. A significant
gender difference (p<0.05) was also observed in WHR. Thirty four percent (34%) participated in low PA with 35% in high PA. Boys were significantly (z-4.52; p=0.000) more highly active compared to the girls. Boys measured significantly higher than girls (p<0.05) in SBJ, BAH, SUP, predicted 2max
• V O . Adolescents’ participation in physical activity was affected by ‘lack of support
by friends’, ‘encouragement by friends or family members’ and ‘lack of support during
engagement in physical activity’. A significant difference (p<0.05) was found between boys and girls regarding ‘friends’ encouragement to do physical activity or sports’, ‘participation in physical activity or sports with friends’ and ‘friends’ confirmation that the participant is doing a good job at physical activity’. Positive correlations were found between Total Physical Activity (TPA) and all social correlates of PA, with a significant relationship between total physical activity (TPA) and ‘how often do your friends tell you that you are doing a good job at physical
activity?’, and ‘has someone told you that you are doing well in physical activity?’ percentage body fat was negatively associated with social correlates of physical activity with a significant relationship in contrast with ‘friends’ encouragement that one is doing a good job at physical activity’. A significant positive correlation was observed between WC, WHR, SBJ, SUP, predicted 2max
• V O and ‘friends’ encouragement in a typical week to do physical activity or sports’. Further significant positive correlations were found with WC for ‘encouragement by someone in a typical week to do physical activity or sports’; WHR, SBJ, BAH, SUP, predicted 2max • V O for ‘participation in physical activity or sports with friends’; SBJ, SUP, predicted 2max • V O for ‘friends’
encouragement that one is doing a good job at physical activity’; SBJ, SUP, predicted 2max
• V O for ‘someone’s encouragement that one is doing a good job at physical activity’; BAH, SUP, predicted 2max • VO for ‘someone’s participation in sport with one’; SUP, predicted 2max • VO for ‘one’s
encouragement to friends to participate in physical activity or sport’; SUP for ‘provision of transportation to physical activity or sport’; and predicted 2max • V O for ‘someone watching one participate in physical activity or sport’. SAR, on the other hand, was negatively associated with all social correlates for physical activity. It can be concluded that the adolescent boys in the study were underweight and significantly
more active when compared to the relatively overweight and inactive girls. Boys also have
higher health-related fitness and higher social correlates compared to the girls. Social correlates for physical activity were positively associated with participation in physical activity and health related physical fitness variables. Thirty six percent (36%) of the participants indicated lack of transport as a negative factor for their participation in physical activity and sport. Based on these
findings, urgent strategic public health intervention by all stakeholders dealing with adolescents, as well as more research studies in the area, is required.Doctora
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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