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- Volume 16, Issue 1, 2004
South African Journal of Sports Medicine - Volume 16, Issue 1, 2004
Volumes & issues
Volume 16, Issue 1, 2004
Author Mike LambertSource: South African Journal of Sports Medicine 16 (2004)More Less
Extracted from text ... Welcome to the first issue of the Journal in 2004! This issue includes a range of articles covering the varied interests in exercise science and sports medicine. The first article is a review paper by Dr Edith Peters on upper respiratory infections in ultramarathoners. The author published one of the pioneering studies on upper respiratory tract infections in ultramarathoners 20 years ago (Peters and Bateman, S Afr Med J 1983; 64: 582-4). This topic has received much attention since then from laboratories around the world. Suffice to say there is still much that is not known about the syndrome. ..
Author R.J. DowdeswellSource: South African Journal of Sports Medicine 16, pp 2 –4 (2004)More Less
Much has been written in the medical literature of the presumed health consequences of intensive and prolonged leisure physical activities such as long distance running, cycling and skiing, and of occupations associated with high levels of physical activity such as longshoremen, bus conductors and lumberjacks. jogging has been widely recommended as a form of exercise for the rehabilitation of persons who have suffered heart attacks. However, before advocating running as the answer to CHD, the data supporting this notion should be critically reviewed.
Postrace upper respiratory tract 'infections' in ultramarathoners - infection, allergy or inflammation? : review articleAuthor E.M. PetersSource: South African Journal of Sports Medicine 16, pp 3 –9 (2004)More Less
Despite more than 20 years of research into mechanisms which could result in the increased predisposition of athletes to 'infection' incidence following excessive and prolonged exercise, definitive explanations are not yet available. A strong temporal relationship between the incidence of upper respiratory tract infection symptoms and immune system changes following excessive exercise load (EEL) have not been shown. T-helper cells are functionally polarised according to the cytokines which they produce. While exercise-induced upregulation of T-helper- 2 (T<sub>H</sub>2) cells and type 2 cytokines is indicative of enhanced activation of allergic responses, downregulation of T-helper-1 (T<sub>H</sub>1) cells and type 1 cytokines confirms suppression of cellular immune functions. The current knowledge regarding the exercise-induced kinetics of interleukin (IL)-4, a cytokine that is crucial in the activation of the T<sub>H</sub>2 cells, does, however, not appear to provide sufficient support for an upregulation of a type 2 response. Lowered or unchanged circulating concentrations of type 1 cytokines (IL12, IL-2 and interferon <SPAN lang=AF style="FONT-FAMILY: Symbol; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-char-type: symbol; mso-symbol-font-family: Symbol"><SPAN style="mso-char-type: symbol; mso-symbol-font: Symbol">g</SPAN></SPAN>) and short-term suppression of lymphocyte, natural killer cell and neutrophil function following EEL, reflect a transient, post-exercise suppression of cellular immunity. Despite a partial dampening thereof by the anti-inflammatory actions of IL-10, IL-1ra and IL-6, the evidence supporting a pro-inflammatory response to prolonged exercise and overtraining is unequivocal. At present, the data appear to support the theory that symptoms of 'infection' experienced by athletes are the manifestation of a significant pro-inflammatory response, combined with a modest, transient suppression of cellular immune functions which may be clinically insignificant.
Author I. CohenSource: South African Journal of Sports Medicine 16, pp 5 –8 (2004)More Less
Medical disorders in sportsmen are usually mild in nature and insidious in onset and consequently present to the doctor with less urgency than sports injuries. Nevertheless, medical disorders may ultimately be severely detrimental to sporting performance as well as to general health.
The effects of an L-methionine combination supplement on symptoms of upper respiratory tract infections and performance in ultramarathon runners before, during and after ultra-endurance exercise : original research articleSource: South African Journal of Sports Medicine 16, pp 10 –16 (2004)More Less
<I>Objective.</I> To evaluate whether supplementation with an L-methionine combination would reduce the incidence of upper respiratory tract symptoms (URTS) and improve performance in ultramarathon runners. <br><I>Design.</I> A double-blind placebo-controlled study. <br><I>Setting.</I> Twenty-one ultramarathon runners (17 males, 4 females) preparing for participation in an 87.3 km ultramarathon. <br><I>Interventions.</I> L-methionine combination supplement (L-methionine, vitamin B<sub>6</sub>, vitamin B<sub>12</sub>, folic acid and magnesium) or placebo containing potato starch. <br><I>Main outcome measures.</I> Incidence of URTS was recorded during the runner's preparation for an ultramarathon race (75 days) and recovery from the same (75 days). CD4+, CD8+ cell counts and ratios were measured pre race, immediately post race and 75 days post race. VO<sub>2max</sub> and endurance fitness (percentage VO<sub>2max</sub> at 4 mmol<sup>-1</sup> lactate concentration) were measured during the preparation period for the race. <br><I>Results.</I> During the preparation period the incidence of URTS was 36% in the supplement group and 80% in the placebo group (<I>p</I> = 0.08). The incidence of URTS during the 3 weeks post race was 27% in the supplement group and 40% in the placebo group (<I>p</I> = 0.65). The CD4+/CD8+ cell ratios were not significantly different between groups. Endurance fitness prior to the race and race times were not significantly different. <br><I>Conclusions.</I> Although the findings of the current study show that an L-methionine combination supplement did not reduce the incidence of URTS or improve performance in ultramarathon runners, benefits may be found with a more detailed investigation using larger sample sizes and immunosuppressed athletes.
Author K. GordenSource: South African Journal of Sports Medicine 16, pp 15 –17 (2004)More Less
Mobilisation of satellite cells following ischaemia and reperfusion in primate skeletal muscle : original research articleSource: South African Journal of Sports Medicine 16, pp 17 –24 (2004)More Less
<I>Objective.</I> To describe the morphological and morphometric features of activated skeletal muscle satellite cells in primates, using an ischaemic reperfusion model. <br><I>Setting.</I> The study was undertaken at the Biomedical Resource Centre and the Electron Microscopy Unit of the University of KwaZulu-Natal. <br><I>Interventions.</I> Eight vervet monkeys were anaesthetised and subjected to 3 hours of tourniquet-induced lower limb ischaemia. Open muscle biopsies were taken from tibialis anterior muscle immediately after tourniquet release and 12, 24, 36 and 48 hours after tourniquet release. Control biopsies were taken from the opposite limb. <br><I>Main outcome measures.</I> Description of the morphological and morphometric changes in satellite cells after activation, as seen on transmission electron microscopy. <br><I>Results.</I> Two distinct patterns of satellite cell activation are described. In group 1, the cytoplasm of the satellite cell expands around the myocyte and the gap between the satellite cell and the myocyte appears to break down, or in group 2, the novel observation of the satellite cell breaking away from the myofibre and becoming a myocyte totally encased in its own basal lamina. The satellite cells of group 1 were significantly longer than the group 2 cells (<I>p</I> = 0.018) and this was associated with a significant reduction in the percentage of nuclear to cell area (<I>p</I> = 0.011). <br><I>Conclusions.</I> Tourniquet-induced ischaemic reperfusion injury is shown to result in two distinct patterns of satellite cell activation which may represent different functions or subsets of satellite cells.
Author T. NoakesSource: South African Journal of Sports Medicine 16, pp 18 –19 (2004)More Less
The author has received numerous requests to discuss the use of exercise in the rehabilitation of patients with coronary heart disease. The following article is a summary of the experience and philosophy gained in the Cardiac Rehabilitation Programme of the Cape Western Branch of the National Heart Foundation.
Shoulder injuries in provincial male fast bowlers - predisposing factors : original research articleSource: South African Journal of Sports Medicine 16, pp 25 –28 (2004)More Less
<I>Objectives.</I> To investigate the relationship between shoulder flexibility and isokinetic strength as possible factors that may predispose provincial fast bowlers to shoulder injuries. <br><I>Design.</I> Twenty-one players, 12 of whom had no history of shoulder injuries and 9 of whom had experienced a shoulder injury to the bowling arm, were assessed for shoulder strength using a Cybex Norm isokinetic dynamometer. Absolute and relative peak torque measures were obtained at isokinetic speeds of 90<sup>o</sup>/s and 180<sup>o</sup>/s, with both concentric and eccentric contractions performed. Shoulder flexibility was tested using a Leighton Flexometer in both internal and external shoulder rotation. The players were classified into a front-on (<I>N</I> = 7), semi front-on (<I>N</I> = 7) or side-on (<I>N</I> = 7) bowling action from video footage recorded after a bowling trial in the nets. <br><I>Results.</I> Shoulder injuries were more common in fast bowlers with a front-on action (<I>N</I> = 5) than the bowlers with a side-on (<I>N</I> = 2) or semi front-on (<I>N</I> = 2) action. Sixteen of the 21 fast bowlers showed low stability ratios compared with gravity corrected functional ratios, indicating an imbalance and the presence of possible dysfunction. The injured group of fast bowlers showed higher concentric weight-normalised torque values for internal rotation at the higher velocity (180<sup>o</sup>/s) (65.20 <u>+</u> 10.03 vs. 45.91 <u>+</u> 10.26 Nm.kg<sup>-1</sup> <I>p</I> < 0.009: injured vs. uninjured), which would suggest greater instability when compared with the uninjured players. This imbalance could indicate the presence of a predisposition to impingement syndrome in the injured subjects. There was an increase in the external rotation ranges of movement for both groups, indicating a degree of hypermobility in both groups. The results indicate that the presence of possible dysfunction in the shoulder rotators, combined with a front-on bowling action and external rotation hypermobility, are possible predisposing factors for chronic shoulder injuries in cricket fast bowlers.
Drugs in sport - testing results from the South African Laboratory 1995 - 2002 : original research articleAuthor P.J. Van der MerweSource: South African Journal of Sports Medicine 16, pp 29 –32 (2004)More Less
<I>Objective.</I> To summarise the results of the past 8 years obtained at the South African Doping Control Laboratory and to compare the results with international statistics. <br><I>Method.</I> Screening procedures were performed on 14 017 urine samples collected from competitors in 54 different sporting codes during the period 1995 - 2002. Samples were analysed using gas chromatography and gas chromatography/mass spectrometry for the presence of prohibited substances, which are listed by the International Olympic Committee (IOC). <br><I>Results.</I> The results obtained were compared with those of the IOC-accredited laboratories. Prohibited substances were detected in 300 samples (2.14%), of which 45.6% contained anabolic agents and 34.6% stimulants. The positive samples from the IOC laboratories contained 58.7% anabolic agents and 20.8% stimulants. Testosterone and nandrolone were the anabolic agents most frequently detected in positive samples, both in South Africa and internationally. The ephedrines as a group accounted for most stimulants detected in positive samples. <br><I>Conclusion.</I> It is of concern that the percentage of positive samples (2.14%) obtained in our laboratory is higher than the 1.70% in IOC laboratories. It is therefore necessary that doping control to curb the use of prohibited substances should continue and expand.
The effect of prophylactic knee bracing on proprioception performance in first division rugby union players : original research articleSource: South African Journal of Sports Medicine 16, pp 33 –36 (2004)More Less
<I>Objective.</I> To investigate the effects of prophylactic knee bracing on proprioceptive performance among first division rugby union players during a 2-minute Wilknox Quad Time Logger balancing task. <br><I>Design.</I> Each subject performed a 2-minute balancing task on the Wilknox Quad Time Logger. Test order, left or right leg, and the sequence of brace or non-brace, were randomised. Subjects were placed on the balancing board and instructed to balance for 2 minutes. Subjects performed 6 trials. Two days elapsed between testing. Each testing day involved 2 trials, 1 trial with and 1 without the prophylactic knee brace. <br><I>Settings.</I> Testing took place at the biokinetics laboratory of the University of Zululand. <br><I>Subjects.</I> Thirty playing (not injured) male rugby players, aged 22 - 30 years, participating in the KwaZulu-Natal club championships (2000). <br><I>Outcome measure.</I> Performance was measured in terms of time that balance was lost in a dynamic balance test. Peak proprioception was the best balancing performance recorded, and average proprioception the average balancing performance for all trials. <br><I>Results.</I> The findings showed an improvement of 17.9% in average proprioception times and 19.1% in peak proprioception times with the application of a prophylactic knee brace (<I>p</I> < 0.01). Conclusion. Prophylactic knee bracing improved proprioception performance of playing (uninjured) rugby players, and therefore may be responsible for the improvement in knee injury statistics reported in some studies on knee bracing.