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Marraccini T.,University of Cape Town | Meltzer S.,Sports Science Institute of South Africa | Bourne L.,South African Medical Research Council | Elizabeth Draper C.,University of Cape Town
Childhood Obesity | Year: 2012

Background: Both under- and over-nutrition pose a public health concern, especially for children in South Africa. Several initiatives exist in South Africa directed at promoting healthy eating and nutrition at schools. One of them is the Woolworths Making the Difference (MTD) Programme aimed at eliminating barriers to promoting healthy lifestyles that exist at schools, such as the availability of low-cost, unhealthy foods either from tuck shops (small food shops) or street vendors. The Healthy Tuck Shop Guide is a recent addition to the MTD Programme. The aim of this evaluation was to assess awareness, potential uptake, and perceptions of the Woolworths Healthy Tuck Shop Guide among parents and staff in a sample of schools that were exposed to the guide. Methods: A qualitative study consisting of focus groups, interviews, and tuck shop observation was used to gather information on 13 schools and their exposure, comprehension, and use of the guide. A mix of schools was examined in terms of economic status and level of control over their tuck shop. Thematic analysis was used to extract findings. Results: Findings show that despite overall positive attitudes about the guide several barriers to its implementation exist, including children's preferences for unhealthy foods, the higher cost of healthy foods, and other issues related to a lack of facilities, time and manpower. Conclusion: Findings suggest that the Woolworths Healthy Tuck Shop Guide would contribute more meaningfully to the creation of healthier food environments if executed within a larger support network to address barriers to implementation. © 2012 Mary Ann Liebert, Inc. Source

Asplund C.A.,U.S. Army | O'Connor F.G.,Uniformed Services University of the Health Sciences | Noakes T.D.,University of Cape Town | Noakes T.D.,Sports Science Institute of South Africa
British Journal of Sports Medicine | Year: 2011

Exercise-associated collapse (EAC) commonly occurs after the completion of endurance running events. EAC is a collapse in conscious athletes who are unable to stand or walk unaided as a result of light headedness, faintness and dizziness or syncope causing a collapse that occurs after completion of an exertional event. Although EAC is perhaps the most common aetiology confronted by the medical provider attending to collapsed athletes in a fi nish-line tent, providers must fi rst maintain vigilance for other potential life-threatening aetiologies that cause collapse, such as cardiac arrest, exertional heat stroke or exercise-associated hyponatraemia. Previously, it has been believed that dehydration and hyperthermia were primary causes of EAC. On review of the evidence, EAC is now believed to be principally the result of transient postural hypotension caused by lower extremity pooling of blood once the athlete stops running and the resultant impairment of cardiac barorefl exes. Once life-threatening aetiologies are ruled out, treatment of EAC is symptomatic and involves oral hydration and a Trendelenburg position - total body cooling, intravenous hydration or advanced therapies is generally not needed. Source

Muller J.H.,Stellenbosch University | Zakaria T.,Tornier | van der Merwe W.,Sports Science Institute of South Africa | D'Angelo F.,University of Insubria
Computer Methods in Biomechanics and Biomedical Engineering | Year: 2015

Anterior–posterior stability in an unconstrained mobile-bearing total knee arthroplasty (TKA) and one with rotational constraints is compared in a computational model based on an ASTM test. Both TKA designs dislocate at loads greater than reported maximum in vivo forces. The posterior drawer forces (mean: 3027 N vs. 1817 N) needed to induce subluxation increase with a greater anterior jump distance (12 mm vs. 7 mm; refers to the vertical height of the anterior or posterior border of the tibial insert's articulating surface). The posterior jump distance for both tested TKA differed by 1.5 mm and had minimal effect on the magnitude of the anterior drawer forces at dislocation in mid-flexion (unconstrained vs. constrained: 445 N vs. 412 N). The unconstrained insert dislocated by means of spin-out whereas in the constrained TKA the femur dislocated from the bearing during posterior drawer and the bearing from the baseplate during anterior drawer. MCL function is an important consideration during ligament balancing since a ± 10% variation in MCL tension affects dislocation forces by ± 20%. The simulation platform provided the means to investigate TKA designs in terms of anterior–posterior stability as a function of knee flexion, collateral ligament function and mechanical morphology. © 2015 Taylor & Francis Source

Testa M.,University of Paris Descartes | Testa M.,Study Group for European Culture and Solidarity | Noakes T.D.,Sports Science Institute of South Africa | Desgorces F.-D.,University of Paris Descartes | Desgorces F.-D.,Institute of Sport Biomedical and Epidemiology Research
Journal of Strength and Conditioning Research | Year: 2012

Training state improves the relationship between rating of perceived exertion and relative exercise volume during resistance exercises. J Strength Cond Res 26(11): 2990-2996, 2012-The aim of this study was to investigate how the rating of perceived exertion (RPE) during resistance exercises was influenced by the exercise volume and athletes' training state. Eighty physical education students (well trained, less well trained, and novices) rated their perceived exertion of multilift sets using the category-ratio scale. These sets were performed with moderate (60-80% of 1-repetition maximum [1RM]) and heavy loads (80-100% of 1RM) involving low volume of exercise (5.5 6 1.1 reps for moderate and 1.3 6 0.4 reps for the heavy load) and high volume of exercise (moderate load: 17.562.1 reps; high load: 2.960.6 reps). The exercise volume of the sets was expressed relatively to individual maximal capacities using the maximum number of repetition (MNR) for the load lifted. General linear model describes that RPE was related to MNR % with a training state effect (p , 0.01) observed only for sets involving a low MNR % and without effect of absolute volume and exercise intensity (high MNR sets: adjusted R2 = 0.65 and 0.78 and low MNR sets adjusted R2 = 0.37 and 0.34 in lowMNR tests). High standard errors of estimated relative volume appeared when using the RPE from low exercise volume sets (12.8 and 14.4% of actual relative volume). Coaches should consider the RPE resulting from high exercise-induced physical strain to estimate the actual relative volume and to estimate the individual MNR at a given load. © 2012 National Strength and Conditioning Association. Source

In 1991, we provided definitive evidence that exercise-associated hyponatraemia (EAH) is caused by abnormal fluid retention in those who overdrink during prolonged exercise, but this finding was ignored. Instead, in 1996, influential guidelines of the American College of Sports Medicine (ACSM) promoted the concept that athletes should drink 'as much as tolerable' during exercise. What followed was an epidemic of cases of EAH and its associated encephalopathy (EAHE). A recent study funded by the sports drink industry confirms our 1991 finding by showing that 95% of the variance in the serum sodium concentration during exercise can be explained by changes in body mass alone. The possibility is that commercial influence delayed the acceptance of our findings for two decades. Source

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