Physical education, school physical activity, school sports and academic performance

<p>Abstract</p> <p>Background</p> <p>The purpose of this paper is to review relationships of academic performance and some of its determinants to participation in school-based physical activities, including physical education (PE), free school physical activity (PA) and school sports.</p> <p>Methods</p> <p>Linkages between academic achievement and involvement in PE, school PA and sport programmes have been examined, based on a systematic review of currently available literature, including a comprehensive search of MEDLINE (1966 to 2007), PSYCHINFO (1974 to 2007), SCHOLAR.GOOGLE.COM, and ERIC databases.</p> <p>Results</p> <p>Quasi-experimental data indicate that allocating up to an additional hour per day of curricular time to PA programmes does not affect the academic performance of primary school students negatively, even though the time allocated to other subjects usually shows a corresponding reduction. An additional curricular emphasis on PE may result in small absolute gains in grade point average (GPA), and such findings strongly suggest a relative increase in performance per unit of academic teaching time. Further, the overwhelmingly majority of such programmes have demonstrated an improvement in some measures of physical fitness (PF). Cross-sectional observations show a positive association between academic performance and PA, but PF does not seem to show such an association. PA has positive influences on concentration, memory and classroom behaviour. Data from quasi-experimental studies find support in mechanistic experiments on cognitive function, pointing to a positive relationship between PA and intellectual performance.</p> <p>Conclusion</p> <p>Given competent providers, PA can be added to the school curriculum by taking time from other subjects without risk of hindering student academic achievement. On the other hand, adding time to "academic" or "curricular" subjects by taking time from physical education programmes does not enhance grades in these subjects and may be detrimental to health.</p

Effects of acute exercise on expressions of functional receptors on CD56dim and CD56bright natural killer cells

PURPOSE: Mobilization and cytotoxicity of natural killer (NK) cells are regulated by cell surface receptors such as adhesion molecules and activating/inhibitory receptors. In this study, we examined the effects of acute exercise on the expression of these cell surface molecules and receptors. METHODS: Six healthy male college students (22.8 ± 0.8 years olds) exercised on the cycle ergometer for 30 min at intensities corresponding to the individual onset of blood lactate accumulation level (70-85%VO2max). Venous blood samples were collected at rest (PRE); just before the end of exercise (END) and 30 (POST 30), 60 (POST 60), 120 (POST 120) and 180 (POST 180) min post exercise. The densities of cell surface molecules and receptors on CD56dim and CD56bright NK cells were determined by flow cytometry. One-way ANOVA and MANOVA were used for statistical analyses. RESULTS: At PRE, expressions of CD16, CD56, CD44, CD62L, CD314, CD335, CD159a and CX3CR1 differed between CD56dim and CD56bright NK cells. Expressions of adhesion molecules CD62L and CX3CR1 changed significantly in both subsets during and after exercise. The expressions of CD62L tended to decrease at END, and then they increased significantly at POST 30. These changes were mainly due to the proportional changes in CD62Lnegative cells. The opposite patterns of changes were seen in the expressions of CX3CR1. Additionally, the expressions of CX3CR1 decreased at POST 120 and 180 only in CD56dim NK cells. The changes in the expressions of CD44 were similar to those seen in the expressions of CD62L. Although changes in the expression of adhesion molecules were statistically significant, they were relatively unclear in histogram analyses. With regard to the expressions of NK cell activating/inhibitory receptors, most changes were observed in CD56dim NK cells. The expressions of CD16 decreased at END and returned at POST 30. The expressions of CD212 dropped from END to POST 30. In contrast, the expressions of CD335 increased from END to POST 30. Exceptionally, changes in the expressions of CD226 were found in both subsets. The expressions decreased at POST180. CONCLUSION: These results suggest that acute exercise influences the expressions of cell surface molecules and receptors. Changes were mainly observed at END and POST 30 in CD56dim NK cell. However, the delayed changes were also seen in some receptors. The changes in several receptors were related to cell mobilization. In contrast, the changes in other receptors were not directly related to mobilization and cytotoxicity

Effects of elastic band based plyometric exercise on explosive muscular performance and change of direction abilities of male team handball players

publishedVersio

Association between muscle strength and the cardiopulmonary status of individuals living with HIV/AIDS

OBJECTIVE: The purpose of this study was to compare aerobic function [anaerobic threshold (%VO2-AT), respiratory compensation point (%VO2-RCP) and peak oxygen uptake (VO2peak)] between physically active patients with HIV/AIDS and matched controls and to examine associations between disease status, poor muscle strength, depression (as estimated by the profile of mood states questionnaire) and the aerobic performance of patients. METHODS: Progressive treadmill test data for %VO2-AT (V-slope method), RCP and (VO2peak) were compared between 39 male patients with HIV/AIDS (age 40.6±1.4 years) and 28 male controls (age 44.4±2.1 years) drawn from the same community and matched for habitual physical activity. Within-patient data were also examined in relation to CD4+ counts (nadir and current data) and peak isokinetic knee torque. RESULTS: AT, RCP and (VO2peak) values were generally similar for patients and controls.Within the patient sample, binary classification suggested that AT, RCP and (VO2peak) values were not associated with either the nadir or current CD4+ count, but treadmill test variables were positively associated with peak isokinetic knee torque. CONCLUSION: The aerobic performance of physically active patients with HIV/AIDS is generally well conserved. Nevertheless, poor muscle strength is observed in some HIV/AIDS patients, which is associated with lower anaerobic power and (VO2peak), suggesting the possibility of enhancing the aerobic performance of patients with weak muscles through appropriate muscle-strengthening activities

Association between muscle strength and the\ud cardiopulmonary status of individuals living with\ud HIV/AIDS

OBJECTIVE: The purpose of this study was to compare aerobic function [anaerobic threshold (%_VVO2-AT),\ud respiratory compensation point (%_VVO2-RCP) and peak oxygen uptake (_VVO2peak)] between physically active patients\ud with HIV/AIDS and matched controls and to examine associations between disease status, poor muscle strength,\ud depression (as estimated by the profile of mood states questionnaire) and the aerobic performance of patients.\ud METHODS: Progressive treadmill test data for %_VVO2-AT (V-slope method), RCP and (_VVO2peak) were compared\ud between 39 male patients with HIV/AIDS (age 40.6¡1.4 years) and 28 male controls (age 44.4¡2.1 years) drawn\ud from the same community and matched for habitual physical activity. Within-patient data were also examined in\ud relation to CD4+ counts (nadir and current data) and peak isokinetic knee torque.\ud RESULTS: AT, RCP and (_VVO2peak) values were generally similar for patients and controls.Within the patient sample,\ud binary classification suggested that AT, RCP and (_VVO2peak) values were not associated with either the nadir or\ud current CD4+ count, but treadmill test variables were positively associated with peak isokinetic knee torque.\ud CONCLUSION: The aerobic performance of physically active patients with HIV/AIDS is generally well conserved.\ud Nevertheless, poor muscle strength is observed in some HIV/AIDS patients, which is associated with lower anaerobic\ud power and (_VVO2peak), suggesting the possibility of enhancing the aerobic performance of patients with weak\ud muscles through appropriate muscle-strengthening activities

Position statement part two: maintaining immune health

The physical training undertaken by athletes is one of a set of lifestyle or behavioural factors that can influence immune function, health and ultimately exercise performance. Others factors including potential exposure to pathogens, health status, lifestyle behaviours, sleep and recovery, nutrition and psychosocial issues, need to be considered alongside the physical demands of an athlete’s training programme. The general consensus on managing training to maintain immune health is to start with a programme of low to moderate volume and intensity; employ a gradual and periodised increase in training volumes and loads; add variety to limit training monotony and stress; avoid excessively heavy training loads that could lead to exhaustion, illness or injury; include non-specific cross-training to offset staleness; ensure sufficient rest and recovery; and instigate a testing programme for identifying signs of performance deterioration and manifestations of physical stress. Inter-individual variability in immunocompetence, recovery, exercise capacity, non-training stress factors, and stress tolerance likely explains the different vulnerability of athletes to illness. Most athletes should be able to train with high loads provided their programme includes strategies devised to control the overall strain and stress. Athletes, coaches and medical personnel should be alert to periods of increased risk of illness (e.g. intensive training weeks, the taper period prior to competition, and during competition) and pay particular attention to recovery and nutritional strategies. [...continues]

Priming with recombinant auxotrophic BCG expressing HIV-1 Gag, RT and Gp120 and boosting with recombinant MVA induces a robust T cell response in mice

In previous studies we have shown that a pantothenate auxotroph of Myocbacterium bovis BCG (BCGΔ panCD ) expressing HIV-1 subtype C Gag induced Gag-specific immune responses in mice and Chacma baboons after prime-boost immunization in combination with matched rMVA and VLP vaccines respectively. In this study recombinant BCG (rBCG) expressing HIV-1 subtype C reverse transcriptase and a truncated envelope were constructed using both the wild type BCG Pasteur strain as a vector and the pantothenate auxotroph. Mice were primed with rBCG expressing Gag and RT and boosted with a recombinant MVA, expressing a polyprotein of Gag, RT, Tat and Nef (SAAVI MVA-C). Priming with rBCGΔ panCD expressing Gag or RT rather than the wild type rBCG expressing Gag or RT resulted in higher frequencies of total HIV-specific CD8 + T cells and increased numbers of T cells specific to the subdominant Gag and RT epitopes. Increasing the dose of rBCG from 10 5 cfu to 10 7 cfu also led to an increase in the frequency of responses to subdominant HIV epitopes. A mix of the individual rBCGΔ panCD vaccines expressing either Gag, RT or the truncated Env primed the immune system for a boost with SAAVI MVA-C and generated five-fold higher numbers of HIV-specific IFN-γ-spot forming cells than mice primed with rBCGΔ panCD containing an empty vector control. Priming with the individual rBCGΔ panCD vaccines or the mix and boosting with SAAVI MVA-C also resulted in the generation of HIV-specific CD4 + and CD8 + T cells producing IFN-γ and TNF-α and CD4 + cells producing IL-2. The rBCG vaccines tested in this study were able to prime the immune system for a boost with rMVA expressing matching antigens, inducing robust, HIV-specific T cell responses to both dominant and subdominant epitopes in the individual proteins when used as individual vaccines or in a mix

Laser textured surface gradients

This work demonstrates a novel technique for fabricating surfaces with roughness and wettability gradients and their subsequent applications for chemical sensors. Surface roughness gradients on brass sheets are obtained directly by nanosecond laser texturing. When these structured surfaces are exposed to air, their wettability decreases with time (up to 20 days) achieving both spatial and temporal wettability gradients. The surfaces are responsive to organic solvents. Contact angles of a series of dilute isopropanol solutions decay exponentially with concentration. In particular, a fall of 132° in contact angle is observed on a surface gradient, one order of magnitude higher than the 14° observed for the unprocessed surface, when the isopropanol concentration increased from 0 to 15.6 wt%. As the wettability changes gradually over the surface, contact angle also changes correspondingly. This effect offers multi-sensitivity at different zones on the surface and is useful for accurate measurement of chemical concentration

Exercise and functional foods

Appropriate nutrition is an essential prerequisite for effective improvement of athletic performance, conditioning, recovery from fatigue after exercise, and avoidance of injury. Nutritional supplements containing carbohydrates, proteins, vitamins, and minerals have been widely used in various sporting fields to provide a boost to the recommended daily allowance. In addition, several natural food components have been found to show physiological effects, and some of them are considered to be useful for promoting exercise performance or for prevention of injury. However, these foods should only be used when there is clear scientific evidence and with understanding of the physiological changes caused by exercise. This article describes various "functional foods" that have been reported to be effective for improving exercise performance or health promotion, along with the relevant physiological changes that occur during exercise