Sports Science Institute of South Africa

Cape Town, South Africa

Sports Science Institute of South Africa

Cape Town, South Africa
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Durandt J.,University of Cape Town | Durandt J.,Sports Science Institute of South Africa | Lambert M.,University of Cape Town
Journal of Sports Sciences | Year: 2017

The purpose of this study was to determine whether there are differences between racial groups for body mass, stature and body mass index (BMI) in South African elite U18 rugby players and whether there were significant changes in these measurements between 2002 and 2012. Self-reported body mass and stature were obtained from U18 players (n = 4007) who attended the national tournament during this period. BMI was calculated for each player.White players were 9.8 kg heavier than black players, who were 2.3 kg heavier than coloured players (P < 0.0001). The body mass of all groups increased from 2002 to 2012 (P < 0.0001). White players were 7.0 cm taller than black players who were 0.5 cm taller than coloured players (P < 0.0001). Players’ stature measurements did not change significantly during the study period. The average BMI of white players was 0.9 kg·m−2 greater than black players who were on average 0.7 kg·m−2 greater than coloured players (P < 0.0001). The BMI of all groups changed similarly over the study period. The body mass, stature and BMI of elite under-18 rugby players in South Africa were significantly different between racial groups. This has implications for transforming the game to make it representative of the South African population. © 2017 Informa UK Limited, trading as Taylor & Francis Group


van Breda K.,University of Cape Town | van Breda K.,Sports Science Institute of South Africa | Collins M.,University of Cape Town | Stein D.J.,University of Cape Town | Rauch L.,University of Cape Town
Physiology and Behavior | Year: 2015

Chronic levels of physical activity have been associated with increased dopamine (D2) receptors resulting in increased sensitivity to dopamine release. The catechol-O-methyltransferase enzyme, responsible for dopamine degradation, contains a functional polymorphism, which plays an important role in dopamine regulation within the prefrontal cortex. This polymorphism has previously been shown to affect human cognition and personality. However, the effect of this polymorphism has not been shown in ultra-endurance athletes. Aim: To examine the association of the COMT val158met variant with personality traits (harm avoidance, novelty seeking, reward dependence, resilience) and psychological distress (K10) of habitual physically active Ironman athletes compared to recreationally active controls. Methods: 51 ultra-endurance Ironman athletes and 56 recreationally active controls were genotyped for the catechol-O-methyltransferase val158met polymorphism. Of the 107 participants, 55 ultra-endurance athletes and 32 recreationally active controls completed online personality questionnaires (harm avoidance, novelty seeking, reward dependence, resilience) and a psychological distress questionnaire (K10). Results: The personality trait, harm avoidance (p=0.001) and psychological distress (p=0.003) were significantly lower in Ironman athlete participants. Novelty seeking was significantly higher (p=0.02) in Ironman athlete participants with a significantly higher (p=0.04) score in Met158 homozygous allele carriers. Conclusion: Chronic levels of physical activity, as seen in ultra-endurance athletes, show increased novelty seeking scores in Met158 homozygous allele carriers. © 2015 Elsevier Inc.


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


PubMed | Sports Science Institute of South Africa, Stellenbosch University, University of Insubria and Tornier
Type: Journal Article | Journal: Computer methods in biomechanics and biomedical engineering | Year: 2016

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: 3027N vs. 1817N) needed to induce subluxation increase with a greater anterior jump distance (12mm vs. 7mm; refers to the vertical height of the anterior or posterior border of the tibial inserts articulating surface). The posterior jump distance for both tested TKA differed by 1.5mm and had minimal effect on the magnitude of the anterior drawer forces at dislocation in mid-flexion (unconstrained vs. constrained: 445N vs. 412N). 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.


Steyn N.P.,University of Cape Town | De Villiers A.,Non communicable Diseases Research Unit | Gwebushe N.,Biostatistics Unit | Draper C.E.,University of Cape Town | And 6 more authors.
BMC Public Health | Year: 2015

Background: Numerous studies in schools in the Western Cape Province, South Africa have shown that children have an unhealthy diet with poor diversity and which is high in sugar and fat. HealthKick (HK) was a three-year randomised controlled trial aimed at promoting healthy eating habits. Methods: Sixteen schools were selected from two low-income school districts and randomly allocated to intervention (n = 8) or control school (n = 8) status. The HK intervention comprised numerous activities to improve the school nutrition environment such as making healthier food choices available and providing nutrition education support. Dietary intake was measured by using a 24-h recall in 2009 in 500 grade 4 learners at intervention schools and 498 at control schools, and repeated in 2010 and 2011. A dietary diversity score (DDS) was calculated from nine food groups and frequency of snack food consumption was determined. A school level analysis was performed. Results: The mean baseline (2009) DDS was low in both arms 4.55 (SD = 1.29) and 4.54 (1.22) in the intervention and control arms respectively, and 49 % of learners in HK intervention schools had a DDS ≤4 (=low diversity). A small increase in DDS was observed in both arms by 2011: mean score 4.91 (1.17) and 4.83 (1.29) in the intervention and control arms respectively. The estimated DSS intervention effect over the two years was not significant [0.04 (95 % CI: -0.37 to 0.46)]. Food groups least consumed were eggs, fruit and vegetables. The most commonly eaten snacking items in 2009 were table sugar in beverages and/or cereals (80.5 %); followed by potato crisps (53.1 %); non-carbonated beverages (42.9 %); sweets (26.7 %) and sugar-sweetened carbonated beverages (16 %). Unhealthy snack consumption in terms of frequency of snack items consumed did not improve significantly in intervention or control schools. Discussion: The results of the HK intervention were disappointing in terms of improvement in DDS and a decrease in unhealthy snacking. We attribute this to the finding that the intervention model used by the researchers may not have been the ideal one to use in a setting where many children came from low-income homes and educators have to deal with daily problems associated with poverty. Conclusions: The HK intervention did not significantly improve quality of diet of children. © 2015 Steyn et al.


PubMed | Sports Science Institute of South Africa, Biostatistics Unit, BroadReach Healthcare, Non communicable Diseases Research Unit and University of Cape Town
Type: | Journal: BMC public health | Year: 2015

Numerous studies in schools in the Western Cape Province, South Africa have shown that children have an unhealthy diet with poor diversity and which is high in sugar and fat. HealthKick (HK) was a three-year randomised controlled trial aimed at promoting healthy eating habits.Sixteen schools were selected from two low-income school districts and randomly allocated to intervention (n=8) or control school (n=8) status. The HK intervention comprised numerous activities to improve the school nutrition environment such as making healthier food choices available and providing nutrition education support. Dietary intake was measured by using a 24-h recall in 2009 in 500 grade 4 learners at intervention schools and 498 at control schools, and repeated in 2010 and 2011. A dietary diversity score (DDS) was calculated from nine food groups and frequency of snack food consumption was determined. A school level analysis was performed.The mean baseline (2009) DDS was low in both arms 4.55 (SD=1.29) and 4.54 (1.22) in the intervention and control arms respectively, and 49% of learners in HK intervention schools had a DDS 4 (=low diversity). A small increase in DDS was observed in both arms by 2011: mean score 4.91 (1.17) and 4.83 (1.29) in the intervention and control arms respectively. The estimated DSS intervention effect over the two years was not significant [0 .04 (95% CI: -0.37 to 0.46)]. Food groups least consumed were eggs, fruit and vegetables. The most commonly eaten snacking items in 2009 were table sugar in beverages and/or cereals (80.5%); followed by potato crisps (53.1%); non-carbonated beverages (42.9%); sweets (26.7%) and sugar-sweetened carbonated beverages (16%). Unhealthy snack consumption in terms of frequency of snack items consumed did not improve significantly in intervention or control schools.The results of the HK intervention were disappointing in terms of improvement in DDS and a decrease in unhealthy snacking. We attribute this to the finding that the intervention model used by the researchers may not have been the ideal one to use in a setting where many children came from low-income homes and educators have to deal with daily problems associated with poverty.The HK intervention did not significantly improve quality of diet of children.


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.


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.


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.


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.

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